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Ca 2+-Permeable AMPA Receptors Contribute to Changed Dorsal Horn Neuronal Firing and Inflammatory Pain. Int J Mol Sci 2023; 24:ijms24032341. [PMID: 36768663 PMCID: PMC9916706 DOI: 10.3390/ijms24032341] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 01/26/2023] Open
Abstract
The dorsal horn (DH) neurons of the spinal cord play a critical role in nociceptive input integration and processing in the central nervous system. Engaged neuronal classes and cell-specific excitability shape nociceptive computation within the DH. The DH hyperexcitability (central sensitisation) has been considered a fundamental mechanism in mediating nociceptive hypersensitivity, with the proven role of Ca2+-permeable AMPA receptors (AMPARs). However, whether and how the DH hyperexcitability relates to changes in action potential (AP) parameters in DH neurons and if Ca2+-permeable AMPARs contribute to these changes remain unknown. We examined the cell-class heterogeneity of APs generated by DH neurons in inflammatory pain conditions to address these. Inflammatory-induced peripheral hypersensitivity increased DH neuronal excitability. We found changes in the AP threshold and amplitude but not kinetics (spike waveform) in DH neurons generating sustained or initial bursts of firing patterns. In contrast, there were no changes in AP parameters in the DH neurons displaying a single spike firing pattern. Genetic knockdown of the molecular mechanism responsible for the upregulation of Ca2+-permeable AMPARs allowed the recovery of cell-specific AP changes in peripheral inflammation. Selective inhibition of Ca2+-permeable AMPARs in the spinal cord alleviated nociceptive hypersensitivity, both thermal and mechanical modalities, in animals with peripheral inflammation. Thus, Ca2+-permeable AMPARs contribute to shaping APs in DH neurons and nociceptive hypersensitivity. This may represent a neuropathological mechanism in the DH circuits, leading to aberrant signal transfer to other nociceptive pathways.
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2
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Bella A, Diego AM, Finn DP, Roche M. Stress-induced changes in nociceptive responding post-surgery in preclinical rodent models. FRONTIERS IN PAIN RESEARCH (LAUSANNE, SWITZERLAND) 2023; 3:1106143. [PMID: 36703943 PMCID: PMC9871907 DOI: 10.3389/fpain.2022.1106143] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 12/19/2022] [Indexed: 01/12/2023]
Abstract
Chronic post-surgical pain affects up to 85% of individuals depending on the type of surgery, the extent of inflammation, tissue and/or nerve damage. Pre-surgical stress is associated with greater pain intensity, prolonged recovery and is one of the main risk factors for the development of chronic post-surgical pain. Clinically valid animal models provide an important means of examining the mechanisms underlying the effects of stress on post-surgical pain and identifying potential novel therapeutic targets. This review discusses the current data from preclinical animal studies examining the effect of stress on post-surgical pain, the potential underlying mechanisms and gaps in the knowledge that require further investigation.
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Affiliation(s)
- Ariadni Bella
- Physiology, School of Medicine, University of Galway, Galway, Ireland,Centre for Pain Research, University of Galway, Galway, Ireland,Galway Neuroscience Centre, University of Galway, Galway, Ireland
| | - Alba M. Diego
- Centre for Pain Research, University of Galway, Galway, Ireland,Galway Neuroscience Centre, University of Galway, Galway, Ireland,Pharmacology and Therapeutics, School of Medicine, University of Galway, Galway, Ireland
| | - David P. Finn
- Centre for Pain Research, University of Galway, Galway, Ireland,Galway Neuroscience Centre, University of Galway, Galway, Ireland,Pharmacology and Therapeutics, School of Medicine, University of Galway, Galway, Ireland
| | - Michelle Roche
- Physiology, School of Medicine, University of Galway, Galway, Ireland,Centre for Pain Research, University of Galway, Galway, Ireland,Galway Neuroscience Centre, University of Galway, Galway, Ireland,Correspondence: Michelle Roche
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3
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Rong Z, Yang L, Chen Y, Qin Y, Cheng CY, Zhao J, Li LF, Ma X, Wu YM, Liu SB, Liang YN, Zhao MG. Sophoridine alleviates hyperalgesia and anxiety-like behavior in an inflammatory pain mouse model induced by complete freund's adjuvant. Mol Pain 2023; 19:17448069231177634. [PMID: 37207346 DOI: 10.1177/17448069231177634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023] Open
Abstract
Chronic pain, along with comorbid psychiatric disorders, is a common problem worldwide. A growing number of studies have focused on non-opioid-based medicines, and billions of funds have been put into digging new analgesic mechanisms. Peripheral inflammation is one of the critical causes of chronic pain, and drugs with anti-inflammatory effects usually alleviate pain hypersensitivity. Sophoridine (SRI), one of the most abundant alkaloids in Chinese herbs, has been proved to exert antitumor, antivirus and anti-inflammation effects. Here, we evaluated the analgesic effect of SRI in an inflammatory pain mouse model induced by complete Freund's adjuvant (CFA) injection. SRI treatment significantly decreased pro-inflammatory factors release after LPS stimuli in microglia. Three days of SRI treatment relieved CFA-induced mechanical hypersensitivity and anxiety-like behavior, and recovered abnormal neuroplasticity in the anterior cingulate cortex of mice. Therefore, SRI may be a candidate compound for the treatment of chronic inflammatory pain and may serve as a structural basis for the development of new drugs.
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Affiliation(s)
- Zheng Rong
- School of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, China
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Air Force Medical University, Xi'an, China
| | - Le Yang
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Air Force Medical University, Xi'an, China
| | - Yue Chen
- School of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, China
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Air Force Medical University, Xi'an, China
| | - Yan Qin
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Air Force Medical University, Xi'an, China
| | - Cai-Yan Cheng
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Air Force Medical University, Xi'an, China
- Institute of Medical Research, Northwestern Polytechnical University, Xi'an, Shaanxi, China
| | - Jun Zhao
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Air Force Medical University, Xi'an, China
| | - Long-Fei Li
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Air Force Medical University, Xi'an, China
| | - Xue Ma
- Department of Pharmacology, School of Pharmacy, Air Force Medical University, Xi'an, China
| | - Yu-Mei Wu
- Department of Pharmacology, School of Pharmacy, Air Force Medical University, Xi'an, China
| | - Shui-Bing Liu
- Department of Pharmacology, School of Pharmacy, Air Force Medical University, Xi'an, China
| | - Yan-Ni Liang
- School of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, China
| | - Ming-Gao Zhao
- School of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang, China
- Precision Pharmacy & Drug Development Center, Department of Pharmacy, Tangdu Hospital, Air Force Medical University, Xi'an, China
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Phenotypes of Motor Deficit and Pain after Experimental Spinal Cord Injury. BIOENGINEERING (BASEL, SWITZERLAND) 2022; 9:bioengineering9060262. [PMID: 35735505 PMCID: PMC9220047 DOI: 10.3390/bioengineering9060262] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/31/2022] [Accepted: 06/14/2022] [Indexed: 11/21/2022]
Abstract
Motor disability is a common outcome of spinal cord injury (SCI). The recovery of motor function after injury depends on the severity of neurotrauma; motor deficit can be reversible, at least partially, due to the innate tissue capability to recover, which, however, deteriorates with age. Pain is often a comorbidity of injury, although its prediction remains poor. It is largely unknown whether pain can attend motor dysfunction. Here, we implemented SCI for modelling severe and moderate neurotrauma and monitored SCI rats for up to 5 months post-injury to determine the profiles of both motor deficit and nociceptive sensitivity. Our data showed that motor dysfunction remained persistent after a moderate SCI in older animals (5-month-old); however, there were two populations among young SCI rats (1 month-old) whose motor deficit either declined or exacerbated even more over 4–5 weeks after identical injury. All young SCI rats displayed changed nociceptive sensitivity in thermal and mechanical modalities. The regression analysis of the changes revealed a population trend with respect to hyper- or hyposensitivity/motor deficit. Together, our data describe the phenotypes of motor deficit and pain, the two severe complications of neurotrauma. Our findings also suggest the predictability of motor dysfunction and pain syndromes following SCI that can be a hallmark for long-term rehabilitation and recovery after injury.
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5
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Search for Selective Glua1 Ampa Receptor Antagonists in a Series of Dicationic Compounds. Pharm Chem J 2022. [DOI: 10.1007/s11094-022-02635-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Phenylalanine-Based AMPA Receptor Antagonist as the Anticonvulsant Agent with Neuroprotective Activity-In Vitro and In Vivo Studies. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27030875. [PMID: 35164136 PMCID: PMC8840081 DOI: 10.3390/molecules27030875] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/15/2022] [Accepted: 01/25/2022] [Indexed: 11/28/2022]
Abstract
Trying to meet the multitarget-directed ligands strategy, a series of previously described aryl-substituted phenylalanine derivatives, reported as competitive antagonists of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, were screened in vitro for their free-radical scavenging and antioxidant capacity in two different assays: ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity fluorescent (ORAC-FL) assays. The most active antioxidants 1 and 8 were further examined to evaluate their neuroprotective properties in vitro. In this study, compound 1 showed a significant neuroprotective effect against the neurotoxin 6-hydroxydopamine in neuroblastoma SH-SY5Y and IMR-32 cell lines. Both compounds also showed prevention from high levels of reactive oxygen species (ROS) in SH-SY5Y cells. Furthermore, the desired monoamine oxidase B (MAO-B) inhibition effect (IC50 = 278 ± 29 nM) for 1 was determined. No toxic effects up to 100 µM of 1 and 8 against neuroblastoma cells were observed. Furthermore, in vivo studies showed that compound 1 demonstrated significant anticonvulsant potential in 6-Hz test, but in neuropathic pain models its antiallodynic and antihyperalgesic properties were not observed. Concluding, the compound 1 seems to be of higher importance as a new phenylalanine-based lead candidate due to its confirmed promise in in vitro and in vivo anticonvulsant activity.
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Kopach O, Voitenko N. Spinal AMPA receptors: Amenable players in central sensitization for chronic pain therapy? Channels (Austin) 2021; 15:284-297. [PMID: 33565904 PMCID: PMC7889122 DOI: 10.1080/19336950.2021.1885836] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 02/01/2021] [Accepted: 02/01/2021] [Indexed: 02/08/2023] Open
Abstract
The activity-dependent trafficking of AMPA receptors (AMPAR) mediates synaptic strength and plasticity, while the perturbed trafficking of the receptors of different subunit compositions has been linked to memory impairment and to causing neuropathology. In the spinal cord, nociceptive-induced changes in AMPAR trafficking determine the central sensitization of the dorsal horn (DH): changes in AMPAR subunit composition compromise the balance between synaptic excitation and inhibition, rendering interneurons hyperexcitable to afferent inputs, and promoting Ca2+ influx into the DH neurons, thereby amplifying neuronal hyperexcitability. The DH circuits become over-excitable and carry out aberrant sensory processing; this causes an increase in pain sensation in central sensory pathways, giving rise to chronic pain syndrome. Current knowledge of the contribution of spinal AMPAR to the cellular mechanisms relating to chronic pain provides opportunities for developing target-based therapies for chronic pain intervention.
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Affiliation(s)
- Olga Kopach
- Department of Sensory Signalling, Bogomoletz Institute of Physiology, Kyiv, Ukraine
- Present Address: Department of Clinical and Experimental Epilepsy, Queen Square Institute of Neurology, University College London, London, UK
| | - Nana Voitenko
- Department of Sensory Signalling, Bogomoletz Institute of Physiology, Kyiv, Ukraine
- Kyiv Academic University, Kyiv, Ukraine
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8
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Taylor BK, Sinha GP, Donahue RR, Grachen CM, Morón JA, Doolen S. Opioid receptors inhibit the spinal AMPA receptor Ca 2+ permeability that mediates latent pain sensitization. Exp Neurol 2019; 314:58-66. [PMID: 30660616 DOI: 10.1016/j.expneurol.2019.01.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 12/24/2018] [Accepted: 01/05/2019] [Indexed: 01/02/2023]
Abstract
Acute inflammation induces sensitization of nociceptive neurons and triggers the accumulation of calcium permeable (CP) α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs) in the dorsal horn of the spinal cord. This coincides with behavioral signs of acute inflammatory pain, but whether CP-AMPARs contribute to chronic pain remains unclear. To evaluate this question, we first constructed current-voltage (IV) curves of C-fiber stimulus-evoked, AMPAR-mediated EPSCs in lamina II to test for inward rectification, a key characteristic of CP-AMPARs. We found that the intraplantar injection of complete Freund's adjuvant (CFA) induced an inward rectification at 3 d that persisted to 21 d after injury. Furthermore, the CP- AMPAR antagonist IEM-1460 (50 μM) inhibited AMPAR-evoked Ca2+ transients 21d after injury but had no effect in uninflamed mice. We then used a model of long-lasting vulnerability for chronic pain that is determined by the balance between latent central sensitization (LCS) and mu opioid receptor constitutive activity (MORCA). When administered 21 d after the intraplantar injection of CFA, intrathecal administration of the MORCA inverse agonist naltrexone (NTX, 1 μg, i.t.) reinstated mechanical hypersensitivity, and superfusion of spinal cord slices with NTX (10 μM) increased the peak amplitude of AMPAR-evoked Ca2+ transients in lamina II neurons. The CP-AMPAR antagonist naspm (0-10 nmol, i.t.) inhibited these NTX-induced increases in mechanical hypersensitivity. NTX had no effect in uninflamed mice. Subsequent western blot analysis of the postsynaptic density membrane fraction from lumbar dorsal horn revealed that CFA increased GluA1 expression at 2 d and GluA4 expression at both 2 and 21 d post-injury, indicating that not just the GluA1 subunit, but also the GluA4 subunit, contributes to the expression of CP-AMPARs and synaptic strength during hyperalgesia. GluA2 expression increased at 21 d, an unexpected result that requires further study. We conclude that after tissue injury, dorsal horn AMPARs retain a Ca2+ permeability that underlies LCS. Because of their effectiveness in reducing naltrexone-induced reinstatement of hyperalgesia and potentiation of AMPAR-evoked Ca2+ signals, CP-AMPAR inhibitors are a promising class of agents for the treatment of chronic inflammatory pain.
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Affiliation(s)
- Bradley K Taylor
- Department of Anesthesiology, Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, 200 Lothrop St. Pittsburgh, PA 15213, USA; Department of Physiology, University of Kentucky School of Medicine, 800 Rose, St. Lexington, KY 40536-0298, USA.
| | - Ghanshyam P Sinha
- Department of Anesthesiology, Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, 200 Lothrop St. Pittsburgh, PA 15213, USA; Department of Physiology, University of Kentucky School of Medicine, 800 Rose, St. Lexington, KY 40536-0298, USA.
| | - Renee R Donahue
- Department of Physiology, University of Kentucky School of Medicine, 800 Rose, St. Lexington, KY 40536-0298, USA.
| | - Carolyn M Grachen
- Department of Anesthesiology, Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, 200 Lothrop St. Pittsburgh, PA 15213, USA; Department of Physiology, University of Kentucky School of Medicine, 800 Rose, St. Lexington, KY 40536-0298, USA.
| | - Jose A Morón
- Department of Anesthesiology, Washington University Pain Center, Washington University School of Medicine, 600 South Euclid, St Louis, MO 63110, USA.
| | - Suzanne Doolen
- Department of Anesthesiology, Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, 200 Lothrop St. Pittsburgh, PA 15213, USA; Department of Physiology, University of Kentucky School of Medicine, 800 Rose, St. Lexington, KY 40536-0298, USA.
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Kopach O, Zheng K, Dong L, Sapelkin A, Voitenko N, Sukhorukov GB, Rusakov DA. Nano-engineered microcapsules boost the treatment of persistent pain. Drug Deliv 2018; 25:435-447. [PMID: 29383961 PMCID: PMC5796488 DOI: 10.1080/10717544.2018.1431981] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/16/2018] [Accepted: 01/21/2018] [Indexed: 11/17/2022] Open
Abstract
Persistent pain remains a major health issue: common treatments relying on either repeated local injections or systemic drug administration are prone to concomitant side-effects. It is thought that an alternative could be a multifunctional cargo system to deliver medicine to the target site and release it over a prolonged time window. We nano-engineered microcapsules equipped with adjustable cargo release properties and encapsulated the sodium-channel blocker QX-314 using the layer-by-layer (LbL) technology. First, we employed single-cell electrophysiology to establish in vitro that microcapsule application can dampen neuronal excitability in a controlled fashion. Secondly, we used two-photon excitation imaging to monitor and adjust long-lasting release of encapsulated cargo in target tissue in situ. Finally, we explored an established peripheral inflammation model in rodents to find that a single local injection of QX-314-containing microcapsules could provide robust pain relief lasting for over a week. This was accompanied by a recovery of the locomotive deficit and the amelioration of anxiety in animals with persistent inflammation. Post hoc immunohistology confirmed biodegradation of microcapsules over a period of several weeks. The overall remedial effect lasted 10-20 times longer than that of a single focal drug injection. It depended on the QX-314 encapsulation levels, involved TRPV1-channel-dependent cell permeability of QX-314, and showed no detectable side-effects. Our data suggest that nano-engineered encapsulation provides local drug delivery suitable for prolonged pain relief, which could be highly advantageous compared to existing treatments.
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Affiliation(s)
- Olga Kopach
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK
| | - Kayiu Zheng
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK
| | - Luo Dong
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
| | - Andrei Sapelkin
- Centre for Condensed Matter and Materials Physics, Queen Mary University of London, London, UK
| | - Nana Voitenko
- Department of Sensory Signaling, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Gleb B. Sukhorukov
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
| | - Dmitri A. Rusakov
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK
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Twomey EC, Yelshanskaya MV, Vassilevski AA, Sobolevsky AI. Mechanisms of Channel Block in Calcium-Permeable AMPA Receptors. Neuron 2018; 99:956-968.e4. [PMID: 30122377 PMCID: PMC6181147 DOI: 10.1016/j.neuron.2018.07.027] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 06/20/2018] [Accepted: 07/17/2018] [Indexed: 01/14/2023]
Abstract
AMPA receptors mediate fast excitatory neurotransmission and are critical for CNS development and function. Calcium-permeable subsets of AMPA receptors are strongly implicated in acute and chronic neurological disorders. However, despite the clinical importance, the therapeutic landscape for specifically targeting them, and not the calcium-impermeable AMPA receptors, remains largely undeveloped. To address this problem, we used cryo-electron microscopy and electrophysiology to investigate the mechanisms by which small-molecule blockers selectively inhibit ion channel conductance in calcium-permeable AMPA receptors. We determined the structures of calcium-permeable GluA2 AMPA receptor complexes with the auxiliary subunit stargazin bound to channel blockers, including the orb weaver spider toxin AgTx-636, the spider toxin analog NASPM, and the adamantane derivative IEM-1460. Our structures provide insights into the architecture of the blocker binding site and the mechanism of trapping, which are critical for development of small molecules that specifically target calcium-permeable AMPA receptors.
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Affiliation(s)
- Edward C Twomey
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Integrated Program in Cellular, Molecular and Biomedical Studies, Columbia University, New York, NY 10032, USA
| | - Maria V Yelshanskaya
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Alexander A Vassilevski
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow 117997, Russia; Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow Oblast 141700, Russia
| | - Alexander I Sobolevsky
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
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Kopach O, Krotov V, Shysh A, Sotnic A, Viatchenko-Karpinski V, Dosenko V, Voitenko N. Spinal PKCα inhibition and gene-silencing for pain relief: AMPAR trafficking at the synapses between primary afferents and sensory interneurons. Sci Rep 2018; 8:10285. [PMID: 29980697 PMCID: PMC6035211 DOI: 10.1038/s41598-018-28512-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 06/22/2018] [Indexed: 01/21/2023] Open
Abstract
Upregulation of Ca2+-permeable AMPA receptors (CP-AMPARs) in dorsal horn (DH) neurons has been causally linked to persistent inflammatory pain. This upregulation, demonstrated for both synaptic and extrasynaptic AMPARs, depends on the protein kinase C alpha (PKCα) activation; hence, spinal PKC inhibition has alleviated peripheral nociceptive hypersensitivity. However, whether targeting the spinal PKCα would alleviate both pain development and maintenance has not been explored yet (essential to pharmacological translation). Similarly, if it could balance the upregulated postsynaptic CP-AMPARs also remains unknown. Here, we utilized pharmacological and genetic inhibition of spinal PKCα in various schemes of pain treatment in an animal model of long-lasting peripheral inflammation. Pharmacological inhibition (pre- or post-treatment) reduced the peripheral nociceptive hypersensitivity and accompanying locomotive deficit and anxiety in rats with induced inflammation. These effects were dose-dependent and observed for both pain development and maintenance. Gene-therapy (knockdown of PKCα) was also found to relieve inflammatory pain when applied as pre- or post-treatment. Moreover, the revealed therapeutic effects were accompanied with the declined upregulation of CP-AMPARs at the DH synapses between primary afferents and sensory interneurons. Our results provide a new focus on the mechanism-based pain treatment through interference with molecular mechanisms of AMPAR trafficking in central pain pathways.
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Affiliation(s)
- Olga Kopach
- Department of Sensory Signalling, Bogomoletz Institute of Physiology, Kyiv, Ukraine. .,Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK.
| | - Volodymyr Krotov
- Department of Sensory Signalling, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Angela Shysh
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Andrij Sotnic
- Department of Sensory Signalling, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Viacheslav Viatchenko-Karpinski
- Department of Sensory Signalling, Bogomoletz Institute of Physiology, Kyiv, Ukraine.,The University of Alabama at Birmingham, Birmingham, United States
| | - Victor Dosenko
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, Kyiv, Ukraine.,Kyiv Academic University, Kyiv, Ukraine
| | - Nana Voitenko
- Department of Sensory Signalling, Bogomoletz Institute of Physiology, Kyiv, Ukraine. .,Kyiv Academic University, Kyiv, Ukraine.
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Kopach O, Krotov V, Voitenko N. Atlanto-occipital catheterization of young rats for long-term drug delivery into the lumbar subarachnoid space combined with in vivo testing and electrophysiology in situ. J Neurosci Methods 2017; 290:125-132. [PMID: 28780368 DOI: 10.1016/j.jneumeth.2017.08.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 07/30/2017] [Accepted: 08/01/2017] [Indexed: 12/12/2022]
Abstract
BACKGROUND Catheterization has been widely used in neuroscience and pain research for local drug delivery. Though different modifications were developed, the use of young animals for spinal catheterization remains limited because of a little success rate. A reliable technique is needed to catheterize young animals aimed for in vivo testing combined with spinal cord electrophysiology, often limited by animal age, to facilitate pain research. NEW METHODS We describe intrathecal catheterization of young rats (3-week-old) through atlanto-occipical approach for long-lasting drug delivery into the lumbar subarachnoid space. The technique represents a surgical approach of minimized invasiveness that requires PE-10 catheter and few equipment of standard laboratory use. RESULTS Behavioral assessments revealed that spinal catheterization does not change peripheral sensitivity of different modalities (thermal and mechanical) and gives no rise to locomotive deficit or anxiety-like behavior in young rats. The long-term administration of genetic material (oligodeoxynucleotides given up to 4days), examined both in vivo and in situ, produced no adverse effects on basal peripheral sensitivity, but changed the AMPA receptor-mediated currents in sensory interneurons of the spinal cord. COMPARISON WITH EXISTING METHODS Dissimilar to already described methods, the method is designed for the use of young rats for behavioral testing in vivo and/or spinal cord electrophysiology in situ. CONCLUSIONS A practical method for spinal catheterization of young animals designed for studies in vivo and in situ is proposed. The method is rapid and effective and should facilitate investigation of therapeutic effects on both systemic and subcellular levels, as an advantage over the existing methods.
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Affiliation(s)
- Olga Kopach
- Bogomoletz Institute of Physiology, Bogomoletz str. 4, Kyiv 01024, Ukraine; Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK.
| | - Volodymyr Krotov
- Bogomoletz Institute of Physiology, Bogomoletz str. 4, Kyiv 01024, Ukraine
| | - Nana Voitenko
- Bogomoletz Institute of Physiology, Bogomoletz str. 4, Kyiv 01024, Ukraine
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Opposite, bidirectional shifts in excitation and inhibition in specific types of dorsal horn interneurons are associated with spasticity and pain post-SCI. Sci Rep 2017; 7:5884. [PMID: 28724992 PMCID: PMC5517549 DOI: 10.1038/s41598-017-06049-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 06/01/2017] [Indexed: 11/23/2022] Open
Abstract
Spasticity, a common complication after spinal cord injury (SCI), is frequently accompanied by chronic pain. The physiological origin of this pain (critical to its treatment) remains unknown, although spastic motor dysfunction has been related to the hyperexcitability of motoneurons and to changes in spinal sensory processing. Here we show that the pain mechanism involves changes in sensory circuits of the dorsal horn (DH) where nociceptive inputs integrate for pain processing. Spasticity is associated with the DH hyperexcitability resulting from an increase in excitation and disinhibition occurring in two respective types of sensory interneurons. In the tonic-firing inhibitory lamina II interneurons, glutamatergic drive was reduced while glycinergic inhibition was potentiated. In contrast, excitatory drive was boosted to the adapting-firing excitatory lamina II interneurons while GABAergic and glycinergic inhibition were reduced. Thus, increased activity of excitatory DH interneurons coupled with the reduced excitability of inhibitory DH interneurons post-SCI could provide a neurophysiological mechanism of central sensitization and chronic pain associated with spasticity.
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14
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Inhibition of calcium-permeable and calcium-impermeable AMPA receptors by perampanel in rat brain neurons. Neurosci Lett 2016; 633:146-151. [DOI: 10.1016/j.neulet.2016.09.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 09/12/2016] [Accepted: 09/19/2016] [Indexed: 11/22/2022]
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