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Marino AL, Rex TS, Harrison FE. Modulation of microglia activation by the ascorbic acid transporter SVCT2. Brain Behav Immun 2024; 120:557-570. [PMID: 38972487 DOI: 10.1016/j.bbi.2024.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 06/04/2024] [Accepted: 07/04/2024] [Indexed: 07/09/2024] Open
Abstract
Neuroinflammation is a major characteristic of pathology in several neurodegenerative diseases. Microglia, the brain's resident myeloid cells, shift between activation states under neuroinflammatory conditions, both responding to, but also driving damage in the brain. Vitamin C (ascorbate) is an essential antioxidant for central nervous system function that may have a specific role in the neuroinflammatory response. Uptake of ascorbate throughout the central nervous system is facilitated by the sodium-dependent vitamin C transporter 2 (SVCT2). SVCT2 transports the reduced form of ascorbate into neurons and microglia, however the contribution of altered SVCT2 expression to the neuroinflammatory response in microglia is not well understood. In this study we demonstrate that SVCT2 expression modifies microglial response, as shown through changes in cell morphology and mRNA expression, following a mild traumatic brain injury (mTBI) in mice with decreased or increased expression of SVCT2. Results were supported by in vitro studies in an immortalized microglial cell line and in primary microglial cultures derived from SVCT2-heterozygous and transgenic animals. Overall, this work demonstrates the importance of SVCT2 and ascorbate in modulating the microglial response to mTBI and suggests a potential role for both in response to neuroinflammatory challenges.
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Affiliation(s)
- Amanda L Marino
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States
| | - Tonia S Rex
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States; Division of Ophthalmology & Visual Sciences, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Fiona E Harrison
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States; Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States.
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Chen Z, Wang P, Cheng H, Wang N, Wu M, Wang Z, Wang Z, Dong W, Guan D, Wang L, Zhao R. Adolescent traumatic brain injury leads to incremental neural impairment in middle-aged mice: role of persistent oxidative stress and neuroinflammation. Front Neurosci 2023; 17:1292014. [PMID: 37965213 PMCID: PMC10642192 DOI: 10.3389/fnins.2023.1292014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Accepted: 10/13/2023] [Indexed: 11/16/2023] Open
Abstract
Background Traumatic brain injury (TBI) increases the risk of mental disorders and neurodegenerative diseases in the chronic phase. However, there is limited neuropathological or molecular data on the long-term neural dysfunction and its potential mechanism following adolescent TBI. Methods A total of 160 male mice aged 8 weeks were used to mimic moderate TBI by controlled cortical impact. At 1, 3, 6 and 12 months post-injury (mpi), different neurological functions were evaluated by elevated plus maze, forced swimming test, sucrose preference test and Morris water maze. The levels of oxidative stress, antioxidant response, reactive astrocytes and microglia, and expression of inflammatory cytokines were subsequently assessed in the ipsilateral hippocampus, followed by neuronal apoptosis detection. Additionally, the morphological complexity of hippocampal astrocytes was evaluated by Sholl analysis. Results The adolescent mice exhibited persistent and incremental deficits in memory and anxiety-like behavior after TBI, which were sharply exacerbated at 12 mpi. Depression-like behaviors were observed in TBI mice at 6 mpi and 12 mpi. Compared with the age-matched control mice, apoptotic neurons were observed in the ipsilateral hippocampus during the chronic phase of TBI, which were accompanied by enhanced oxidative stress, and expression of inflammatory cytokines (IL-1β and TNF-α). Moreover, the reactive astrogliosis and microgliosis in the ipsilateral hippocampus were observed in the late phase of TBI, especially at 12 mpi. Conclusion Adolescent TBI leads to incremental cognitive dysfunction, and depression- and anxiety-like behaviors in middle-aged mice. The chronic persistent neuroinflammation and oxidative stress account for the neuronal loss and neural dysfunction in the ipsilateral hippocampus. Our results provide evidence for the pathogenesis of chronic neural damage following TBI and shed new light on the treatment of TBI-induced late-phase neurological dysfunction.
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Affiliation(s)
- Ziyuan Chen
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning, China
| | - Pengfei Wang
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning, China
| | - Hao Cheng
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning, China
| | - Ning Wang
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning, China
| | - Mingzhe Wu
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning, China
| | - Ziwei Wang
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning, China
| | - Zhi Wang
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning, China
| | - Wenwen Dong
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning, China
| | - Dawei Guan
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning, China
| | - Linlin Wang
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning, China
| | - Rui Zhao
- Department of Forensic Pathology, School of Forensic Medicine, China Medical University, Shenyang, Liaoning, China
- Key Laboratory of Environmental Stress and Chronic Disease Control and Prevention, Ministry of Education, China Medical University, Shenyang, Liaoning, China
- Liaoning Province Key Laboratory of Forensic Bio-Evidence Sciences, Shenyang, China
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Spencer HF, Boese M, Berman RY, Radford KD, Choi KH. Effects of a Subanesthetic Ketamine Infusion on Inflammatory and Behavioral Outcomes after Closed Head Injury in Rats. Bioengineering (Basel) 2023; 10:941. [PMID: 37627826 PMCID: PMC10452037 DOI: 10.3390/bioengineering10080941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/28/2023] [Accepted: 08/03/2023] [Indexed: 08/27/2023] Open
Abstract
Traumatic brain injury (TBI) affects millions of people annually, and most cases are classified as mild TBI (mTBI). Ketamine is a potent trauma analgesic and anesthetic with anti-inflammatory properties. However, ketamine's effects on post-mTBI outcomes are not well characterized. For the current study, we used the Closed-Head Impact Model of Engineered Rotational Acceleration (CHIMERA), which replicates the biomechanics of a closed-head impact with resulting free head movement. Adult male Sprague-Dawley rats sustained a single-session, repeated-impacts CHIMERA injury. An hour after the injury, rats received an intravenous ketamine infusion (0, 10, or 20 mg/kg, 2 h period), during which locomotor activity was monitored. Catheter blood samples were collected at 1, 3, 5, and 24 h after the CHIMERA injury for plasma cytokine assays. Behavioral assays were conducted on post-injury days (PID) 1 to 4 and included rotarod, locomotor activity, acoustic startle reflex (ASR), and pre-pulse inhibition (PPI). Brain tissue samples were collected at PID 4 and processed for GFAP (astrocytes), Iba-1 (microglia), and silver staining (axonal injury). Ketamine dose-dependently altered locomotor activity during the infusion and reduced KC/GRO, TNF-α, and IL-1β levels after the infusion. CHIMERA produced a delayed deficit in rotarod performance (PID 3) and significant axonal damage in the optic tract (PID 4), without significant changes in other behavioral or histological measures. Notably, subanesthetic doses of intravenous ketamine infusion after mTBI did not produce adverse effects on behavioral outcomes in PID 1-4 or neuroinflammation on PID 4. A further study is warranted to thoroughly investigate beneficial effects of IV ketamine on mTBI given multi-modal properties of ketamine in traumatic injury and stress.
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Affiliation(s)
- Haley F. Spencer
- Program in Neuroscience, Uniformed Services University, 4301 Jones Bridge Rd, Bethesda, MD 20814, USA;
- Center for the Study of Traumatic Stress, Uniformed Services University, 4301 Jones Bridge Rd, Bethesda, MD 20814, USA;
| | - Martin Boese
- Daniel K. Inouye Graduate School of Nursing, Uniformed Services University, 4301 Jones Bridge Rd, Bethesda, MD 20814, USA; (M.B.); (K.D.R.)
| | - Rina Y. Berman
- Center for the Study of Traumatic Stress, Uniformed Services University, 4301 Jones Bridge Rd, Bethesda, MD 20814, USA;
| | - Kennett D. Radford
- Daniel K. Inouye Graduate School of Nursing, Uniformed Services University, 4301 Jones Bridge Rd, Bethesda, MD 20814, USA; (M.B.); (K.D.R.)
| | - Kwang H. Choi
- Program in Neuroscience, Uniformed Services University, 4301 Jones Bridge Rd, Bethesda, MD 20814, USA;
- Center for the Study of Traumatic Stress, Uniformed Services University, 4301 Jones Bridge Rd, Bethesda, MD 20814, USA;
- Daniel K. Inouye Graduate School of Nursing, Uniformed Services University, 4301 Jones Bridge Rd, Bethesda, MD 20814, USA; (M.B.); (K.D.R.)
- Department of Psychiatry, Center for the Study of Traumatic Stress, Uniformed Services University, 4301 Jones Bridge Rd, Bethesda, MD 20814, USA
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Juan SMA, Daglas M, Truong PH, Mawal C, Adlard PA. Alterations in iron content, iron-regulatory proteins and behaviour without tau pathology at one year following repetitive mild traumatic brain injury. Acta Neuropathol Commun 2023; 11:118. [PMID: 37464280 PMCID: PMC10353227 DOI: 10.1186/s40478-023-01603-z] [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: 02/15/2023] [Accepted: 06/12/2023] [Indexed: 07/20/2023] Open
Abstract
Repetitive mild traumatic brain injury (r-mTBI) has increasingly become recognised as a risk factor for the development of neurodegenerative diseases, many of which are characterised by tau pathology, metal dyshomeostasis and behavioural impairments. We aimed to characterise the status of tau and the involvement of iron dyshomeostasis in repetitive controlled cortical impact injury (5 impacts, 48 h apart) in 3-month-old C57Bl6 mice at the chronic (12-month) time point. We performed a battery of behavioural tests, characterised the status of neurodegeneration-associated proteins (tau and tau-regulatory proteins, amyloid precursor protein and iron-regulatory proteins) via western blot; and metal levels using bulk inductively coupled plasma-mass spectrometry (ICP-MS). We report significant changes in various ipsilateral iron-regulatory proteins following five but not a single injury, and significant increases in contralateral iron, zinc and copper levels following five impacts. There was no evidence of tau pathology or changes in tau-regulatory proteins following five impacts, although some changes were observed following a single injury. Five impacts resulted in significant gait deficits, mild anhedonia and mild cognitive deficits at 9-12 months post-injury, effects not seen following a single injury. To the best of our knowledge, we are the first to describe chronic changes in metals and iron-regulatory proteins in a mouse model of r-mTBI, providing a strong indication towards an overall increase in brain iron levels (and other metals) in the chronic phase following r-mTBI. These results bring to question the relevance of tau and highlight the involvement of iron dysregulation in the development and/or progression of neurodegeneration following injury, which may lead to new therapeutic approaches in the future.
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Affiliation(s)
- Sydney M A Juan
- Synaptic Neurobiology Laboratory, The Florey Institute of Neuroscience and Mental Health, The Melbourne Dementia Research Centre, The University of Melbourne, Kenneth Myer Building, 30 Royal Parade, Parkville, Melbourne, VIC, 3052, Australia
| | - Maria Daglas
- Synaptic Neurobiology Laboratory, The Florey Institute of Neuroscience and Mental Health, The Melbourne Dementia Research Centre, The University of Melbourne, Kenneth Myer Building, 30 Royal Parade, Parkville, Melbourne, VIC, 3052, Australia
| | - Phan H Truong
- Synaptic Neurobiology Laboratory, The Florey Institute of Neuroscience and Mental Health, The Melbourne Dementia Research Centre, The University of Melbourne, Kenneth Myer Building, 30 Royal Parade, Parkville, Melbourne, VIC, 3052, Australia
| | - Celeste Mawal
- Synaptic Neurobiology Laboratory, The Florey Institute of Neuroscience and Mental Health, The Melbourne Dementia Research Centre, The University of Melbourne, Kenneth Myer Building, 30 Royal Parade, Parkville, Melbourne, VIC, 3052, Australia
| | - Paul A Adlard
- Synaptic Neurobiology Laboratory, The Florey Institute of Neuroscience and Mental Health, The Melbourne Dementia Research Centre, The University of Melbourne, Kenneth Myer Building, 30 Royal Parade, Parkville, Melbourne, VIC, 3052, Australia.
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Vasunilashorn SM, Lunardi N, Newman JC, Crosby G, Acker L, Abel T, Bhatnagar S, Cunningham C, de Cabo R, Dugan L, Hippensteel JA, Ishizawa Y, Lahiri S, Marcantonio ER, Xie Z, Inouye SK, Terrando N, Eckenhoff RG. Preclinical and translational models for delirium: Recommendations for future research from the NIDUS delirium network. Alzheimers Dement 2023; 19:2150-2174. [PMID: 36799408 PMCID: PMC10576242 DOI: 10.1002/alz.12941] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 02/18/2023]
Abstract
Delirium is a common, morbid, and costly syndrome that is closely linked to Alzheimer's disease (AD) and AD-related dementias (ADRD) as a risk factor and outcome. Human studies of delirium have advanced our knowledge of delirium incidence and prevalence, risk factors, biomarkers, outcomes, prevention, and management. However, understanding of delirium neurobiology remains limited. Preclinical and translational models for delirium, while challenging to develop, could advance our knowledge of delirium neurobiology and inform the development of new prevention and treatment approaches. We discuss the use of preclinical and translational animal models in delirium, focusing on (1) a review of current animal models, (2) challenges and strategies for replicating elements of human delirium in animals, and (3) the utility of biofluid, neurophysiology, and neuroimaging translational markers in animals. We conclude with recommendations for the development and validation of preclinical and translational models for delirium, with the goal of advancing awareness in this important field.
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Affiliation(s)
- Sarinnapha M. Vasunilashorn
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
- Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Nadia Lunardi
- Department of Anesthesiology, University of Virginia, Charlottesville, Virginia, USA
| | - John C. Newman
- Department of Medicine, University of California, San Francisco, California, USA
- Buck Institute for Research on Aging, Novato, California, USA
| | - Gregory Crosby
- Harvard Medical School, Boston, Massachusetts, USA
- Department of Anesthesiology, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Leah Acker
- Department of Anesthesiology, Duke University, Durham, Massachusetts, USA
| | - Ted Abel
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Seema Bhatnagar
- Department of Anesthesiology and Critical Care, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Colm Cunningham
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Dublin, Ireland
- Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland
| | - Rafael de Cabo
- Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, Baltimore, Maryland, USA
| | - Laura Dugan
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee, USA
- Division of Geriatric Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- VA Tennessee Valley Geriatric Research, Education, and Clinical Center (GRECC), Nashville, Tennessee, USA
| | - Joseph A. Hippensteel
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Yumiko Ishizawa
- Harvard Medical School, Boston, Massachusetts, USA
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Shouri Lahiri
- Department of Neurology, Neurosurgery, and Biomedical Sciences, Cedar-Sinai Medical Center, Los Angeles, California, USA
| | - Edward R. Marcantonio
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
- Marcus Institute for Aging Research, Hebrew SeniorLife, Boston, Massachusetts, USA
| | - Zhongcong Xie
- Harvard Medical School, Boston, Massachusetts, USA
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Sharon K. Inouye
- Harvard Medical School, Boston, Massachusetts, USA
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
- Marcus Institute for Aging Research, Hebrew SeniorLife, Boston, Massachusetts, USA
| | - Niccolò Terrando
- Department of Anesthesiology, Duke University, Durham, North Carolina, USA
- Department of Cell Biology, Duke University, Durham, North Carolina, USA
- Department of Immunology, Duke University, Durham, North Carolina, USA
- Duke Center for the Study of Aging and Human Development, Duke University School of Medicine, Durham, USA
| | - Roderic G. Eckenhoff
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, USA
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Lipov E, Sethi Z, Nandra G, Frueh C. Efficacy of combined subanesthetic ketamine infusion and cervical sympathetic blockade as a symptomatic treatment of PTSD/TBI in a special forces patient with a 1-year follow-up: A case report. Heliyon 2023; 9:e14891. [PMID: 37089345 PMCID: PMC10119561 DOI: 10.1016/j.heliyon.2023.e14891] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 03/13/2023] [Accepted: 03/21/2023] [Indexed: 03/29/2023] Open
Abstract
Co-occurrence of posttraumatic stress disorder (PTSD) and traumatic brain injury (TBI) symptoms are particularly prevalent in the special operations forces' community, along with other related conditions (e.g., endocrine dysregulation, sleep disorders, chronic pain). Ketamine infusion (KI) has been shown to increase neuroplasticity as well as memory improvement and cervical sympathetic block (CSB) has been shown to improve cognitive function, reduce sympathetic overactivity, and improve other symptoms of PTSD. We want to report the efficacious use of a single intervention consisting of bilateral CSB technique with subanesthetic KI X5 in a Special Operations Forces patient, diagnosed with PTSD with comorbid TBI, evaluated during treatment and at 1-year follow-up. We postulated KI and CSB would have a synergistic effect. Our patient received KI starting at 0.5 mg/kg, which was escalated daily. KI was combined with right-sided ultrasound-guided CSB (C6 and C4 levels). This was followed the next day by left-sided CSB and KI. Patient's PTSD symptoms were evaluated using the Posttraumatic Stress Disorder Checklist (PCL-5), Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), suicidal ideation and other related factors by Concise Health Risk Tracking Self Report (CHRTSR). All measures were assessed prior to treatment, during treatment, and 394 days after. KI combined with CSB showed immediate and prolonged benefits 394 days later regarding the symptoms of PTSD, anxiety, depression, suicidal ideation, and cognitive deterioration (patient report). KI combined with CSB can markedly reduce symptoms of PTSD, psychiatric comorbidities, and cognitive dysfunction.
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Affiliation(s)
- Eugene Lipov
- Stella Center, Chicago, United States
- Corresponding author.
| | - Zubin Sethi
- Midwestern University Chicago College of Osteopathic Medicine, United States
| | | | - Christopher Frueh
- Department of Psychology, University of Hawaii, Hilo, HI, United States
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Yost JG, Wulf HA, Browne CA, Lucki I. Antinociceptive and Analgesic Effects of (2 R,6 R)-Hydroxynorketamine. J Pharmacol Exp Ther 2022; 382:256-265. [PMID: 35779947 PMCID: PMC9426759 DOI: 10.1124/jpet.122.001278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 06/01/2022] [Indexed: 11/22/2022] Open
Abstract
Commonly used pain therapeutics, such as opioid medications, exert dangerous side effects and lack effectiveness in treating some types of pain. Ketamine is also used to treat pain, but side effects limit its widespread use. (2R,6R)-hydroxynorketamine (HNK) is a ketamine metabolite that potentially shares some beneficial behavioral effects of its parent drug without causing significant side effects. This study compared the profile and potential mechanisms mediating the antinociception activity of ketamine and (2R,6R)-HNK in C57BL/6J mice. Additionally, this study compared the reversal of mechanical allodynia by (2R,6R)-HNK with gabapentin in a model of neuropathic pain. Unlike the near-immediate and short-lived antinociception caused by ketamine, (2R,6R)-HNK produced late-developing antinociception 24 hours following administration. Pharmacological blockade of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors with 2,3-dioxo-6-nitro-7-sulfamoyl-benzo[f]quinoxaline (NBQX) prevented the initiation and expressionof (2R,6R)-HNK antinociception, suggesting the involvement of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor-dependent glutamatergic mechanisms in the pain reduction-like responses. Blockade of opioid receptors with naltrexone partially prevented the antinociceptive effect of ketamine but was ineffective against (2R,6R)-HNK. Furthermore, (2R,6R)-HNK did not produce dystaxia, even when tested at doses five times greater than those needed to produce antinociception, indicating a superior safety profile for (2R,6R)-HNK over ketamine. Additionally, (2R,6R)-HNK reversed mechanical allodynia in a spared nerve injury model of neuropathic pain with similar short-term efficacy to gabapentin (within 4 hours) while outperforming gabapentin 24 hours after administration. These findings support the further study of (2R,6R)-HNK as a potentially valuable agent for treating different types of pain and establish certain advantages of (2R,6R)-HNK treatment over ketamine and gabapentin in corresponding assays for pain. SIGNIFICANCE STATEMENT: The ketamine metabolite (2R,6R)-HNK produced antinociception in male and female mice 24 hours after administration via activation of AMPA receptors. The effects of (2R,6R)-HNK differed in time course and mechanism and presented a better safety profile than ketamine. (2R,6R)-HNK also reversed allodynia in SNI-operated animals within 4 hours of treatment onset, with a duration of effect lasting longer than gabapentin. Taken together, (2R,6R)-HNK demonstrates the potential for development as a non-opioid analgesic drug.
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Affiliation(s)
- Jonathan G Yost
- Neuroscience Graduate Program (J.G.Y., C.A.B., I.L.), Department of Pharmacology and Molecular Therapeutics (H.A.W., C.A.B., I.L.), and Department of Psychiatry (I.L.), Uniformed Services University, Bethesda, Maryland
| | - Hildegard A Wulf
- Neuroscience Graduate Program (J.G.Y., C.A.B., I.L.), Department of Pharmacology and Molecular Therapeutics (H.A.W., C.A.B., I.L.), and Department of Psychiatry (I.L.), Uniformed Services University, Bethesda, Maryland
| | - Caroline A Browne
- Neuroscience Graduate Program (J.G.Y., C.A.B., I.L.), Department of Pharmacology and Molecular Therapeutics (H.A.W., C.A.B., I.L.), and Department of Psychiatry (I.L.), Uniformed Services University, Bethesda, Maryland
| | - Irwin Lucki
- Neuroscience Graduate Program (J.G.Y., C.A.B., I.L.), Department of Pharmacology and Molecular Therapeutics (H.A.W., C.A.B., I.L.), and Department of Psychiatry (I.L.), Uniformed Services University, Bethesda, Maryland
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