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Türk Börü Ü, Kadir Sarıtaş Z, Görücü Özbek F, Bölük C, Acar H, Koç Y, Zeytin Demiral G. Alterations in the spinal cord, trigeminal nerve ganglion, and infraorbital nerve through inducing compression of the dorsal horn region at the upper cervical cord in trigeminal neuralgia. Brain Res 2024; 1832:148842. [PMID: 38447599 DOI: 10.1016/j.brainres.2024.148842] [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: 01/08/2024] [Revised: 02/25/2024] [Accepted: 02/27/2024] [Indexed: 03/08/2024]
Abstract
BACKGROUND Idiopathic trigeminal neuralgia (TN) cases encountered frequently in daily practice indicate significant gaps that still need to be illuminated in the etiopathogenesis. In this study, a novel TN animal model was developed by compressing the dorsal horn (DH) of the upper cervical spinal cord. METHODS Eighteen rabbits were equally divided into three groups, namely control (CG), sham (SG), and spinal cord compression (SCC) groups. External pressure was applied to the left side at the C3 level in the SCC group. Dorsal hemilaminectomy was performed in the SG, and the operative side was closed without compression. No procedure was implemented in the control group. Samples from the SC, TG, and ION were taken after seven days. For the histochemical staining, damage and axons with myelin were scored using Hematoxylin and Eosin and Toluidine Blue, respectively. Immunohistochemistry, nuclei, apoptotic index, astrocyte activity, microglial labeling, and CD11b were evaluated. RESULTS Mechanical allodynia was observed on the ipsilateral side in the SCC group. In addition, both the TG and ION were partially damaged from SC compression, which resulted in significant histopathological changes and increased the expression of all markers in both the SG and SCC groups compared to that in the CG. There was a notable increase in tissue damage, an increase in the number of apoptotic nuclei, an increase in the apoptotic index, an indication of astrocytic gliosis, and an upsurge in microglial cells. Significant increases were noted in the SG group, whereas more pronounced significant increases were observed in the SCC group. Transmission electron microscopy revealed myelin damage, mitochondrial disruption, and increased anchoring particles. Similar changes were observed to a lesser extent in the contralateral spinal cord. CONCLUSION Ipsilateral trigeminal neuropathic pain was developed due to upper cervical SCC. The clinical finding is supported by immunohistochemical and ultrastructural changes. Thus, alterations in the DH due to compression of the upper cervical region should be considered as a potential cause of idiopathic TN.
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Affiliation(s)
- Ülkü Türk Börü
- Department of Neurology University of Afyonkarahisar Health Sciences, Afyonkarahisar, Turkey
| | - Zülfükar Kadir Sarıtaş
- Department of Surgery, Faculty of Veterinary Medicine, University of Afyon Kocatepe, Afyonkarahisar, Turkey
| | - Fatma Görücü Özbek
- Department of Surgery, Faculty of Veterinary Medicine, University of Afyon Kocatepe, Afyonkarahisar, Turkey
| | - Cem Bölük
- Department of Neurology and Clinical Neurophysiology, Sanliurfa Training and Research Hospital, Sanliurfa, Turkey.
| | - Hakan Acar
- Department of Neurology University of Afyonkarahisar Health Sciences, Afyonkarahisar, Turkey
| | - Yusuf Koç
- Department of Surgery, Faculty of Veterinary Medicine, University of Afyon Kocatepe, Afyonkarahisar, Turkey
| | - Gökçe Zeytin Demiral
- Department of Neurology University of Afyonkarahisar Health Sciences, Afyonkarahisar, Turkey
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Fang H, Rossano S, Wang X, Nabulsi N, Kelley B, Fowles K, Ropchan J, Strittmatter SM, Carson RE, Huang Y. Translational PET Imaging of Spinal Cord Injury with the Serotonin Transporter Tracer [ 11C]AFM. Mol Imaging Biol 2022; 24:560-569. [PMID: 35020138 PMCID: PMC9550197 DOI: 10.1007/s11307-021-01698-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 12/12/2021] [Accepted: 12/17/2021] [Indexed: 10/19/2022]
Abstract
PURPOSE The descending raphespinal serotonin (5-HT) system contributes to neural activities required for locomotion. The presynaptic serotonin transporter (SERT) is a marker of 5-HT innervation. In this study, we explored the use of PET imaging with the SERT radioligand [11C]AFM as a biomarker of 5-HT axon damage after spinal cord injury (SCI) in a rodent model and its translation to imaging SCI in humans. PROCEDURES PET imaging with [11C]AFM was performed in healthy rats under baseline and citalopram blocking conditions and a mid-thoracic transection rat model of SCI. The lumbar-to-cervical activity (L/C) ratio was calculated for the healthy and SCI animals to assess SERT binding decrease after SCI. Finally, translation of [11C]AFM PET was attempted to explore its potential to image SCI in humans. RESULTS Intense uptake in the brain and intact spinal cord was observed at 30-60 min post-injection of [11C]AFM in healthy rats. About 65% of [11C]AFM uptake in the spinal cord was blocked by citalopram. In the SCI rat model, the cervical uptake of [11C]AFM was similar to that in healthy rats, but the lumbar uptake was dramatically reduced, resulting in about half the L/C ratio in SCI rats compared to healthy rats. In contrast, [11C]AFM uptake in the human spinal cord showed no obvious decrease after treatment with citalopram. In the human subjects with SCI, decreases in [11C]AFM uptake were also not obvious in the section of spinal cord caudal to the injury point. CONCLUSION [11C]AFM PET imaging of SERT provides a useful preclinical method to non-invasively visualize the rodent spinal cord and detect SERT changes in SCI rodent models. However, there appears to be little detectable specific binding signal for [11C]AFM in the human spinal cord. An SERT tracer with higher affinity and lower non-specific binding signal is needed to image the spinal cord in humans and to assess the axonal status in SCI patients.
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Affiliation(s)
- Hanyi Fang
- PET Center, Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA.
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Samantha Rossano
- PET Center, Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Xingxing Wang
- Cellular Neuroscience, Neurodegeneration, and Repair Program, and Departments of Neurology and Neurobiology, Yale School of Medicine, New Haven, CT, USA
| | - Nabeel Nabulsi
- PET Center, Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Brian Kelley
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Krista Fowles
- PET Center, Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Jim Ropchan
- PET Center, Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Stephen M Strittmatter
- Cellular Neuroscience, Neurodegeneration, and Repair Program, and Departments of Neurology and Neurobiology, Yale School of Medicine, New Haven, CT, USA
| | - Richard E Carson
- PET Center, Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Yiyun Huang
- PET Center, Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA.
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Miranpuri GS, Bali P, Nguyen J, Kim JJ, Modgil S, Mehra P, Buttar S, Brown G, Yutuc N, Singh H, Wood A, Singh J, Anand A. Role of Microglia and Astrocytes in Spinal Cord Injury Induced Neuropathic Pain. Ann Neurosci 2022; 28:219-228. [PMID: 35341227 PMCID: PMC8948321 DOI: 10.1177/09727531211046367] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 08/03/2021] [Indexed: 12/30/2022] Open
Abstract
Background: Spinal cord injuries incite varying degrees of symptoms in patients, ranging
from weakness and incoordination to paralysis. Common amongst spinal cord
injury (SCI) patients, neuropathic pain (NP) is a debilitating medical
condition. Unfortunately, there remain many clinical impediments in treating
NP because there is a lack of understanding regarding the mechanisms behind
SCI-induced NP (SCINP). Given that more than 450,000 people in the United
States alone suffer from SCI, it is unsatisfactory that current treatments
yield poor results in alleviating and treating NP. Summary: In this review, we briefly discussed the models of SCINP along with the
mechanisms of NP progression. Further, current treatment modalities are
herein explored for SCINP involving pharmacological interventions targeting
glia cells and astrocytes. Key message: The studies presented in this review provide insight for new directions
regarding SCINP alleviation. Given the severity and incapacitating effects
of SCINP, it is imperative to study the pathways involved and find new
therapeutic targets in coordination with stem cell research, and to develop
a new gold-standard in SCINP treatment.
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Affiliation(s)
- Gurwattan S Miranpuri
- Department of Neurological Surgery, University of Wisconsin, School of Medicine and Public Health, Madison, Wisconsin, United States
| | - Parul Bali
- Department of Biological Sciences, Indian Institute of Science Education & Research Mohali, India
| | - Justyn Nguyen
- Department of Neurological Surgery, University of Wisconsin, School of Medicine and Public Health, Madison, Wisconsin, United States
| | - Jason J Kim
- Department of Neurological Surgery, University of Wisconsin, School of Medicine and Public Health, Madison, Wisconsin, United States
| | - Shweta Modgil
- Neuroscience research lab, Department of Neurology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Priya Mehra
- Neuroscience research lab, Department of Neurology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.,Department of Biotechnology, Panjab University, Chandigarh, India
| | - Seah Buttar
- Department of Neurological Surgery, University of Wisconsin, School of Medicine and Public Health, Madison, Wisconsin, United States
| | - Greta Brown
- Department of Neurological Surgery, University of Wisconsin, School of Medicine and Public Health, Madison, Wisconsin, United States
| | - Noemi Yutuc
- Department of Neurological Surgery, University of Wisconsin, School of Medicine and Public Health, Madison, Wisconsin, United States
| | - Harpreet Singh
- Department of Neurological Surgery, University of Wisconsin, School of Medicine and Public Health, Madison, Wisconsin, United States
| | - Aleksandar Wood
- Department of Neurological Surgery, University of Wisconsin, School of Medicine and Public Health, Madison, Wisconsin, United States
| | - Jagtar Singh
- Department of Biotechnology, Panjab University, Chandigarh, India
| | - Akshay Anand
- Neuroscience research lab, Department of Neurology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.,CCRYN- Collaborative Centre for Mind Body Intervention through Yoga.,Centre of Phenomenology and Cognitive Sciences, Panjab University, Chandigarh, India
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Fauss GNK, Hudson KE, Grau JW. Role of Descending Serotonergic Fibers in the Development of Pathophysiology after Spinal Cord Injury (SCI): Contribution to Chronic Pain, Spasticity, and Autonomic Dysreflexia. BIOLOGY 2022; 11:234. [PMID: 35205100 PMCID: PMC8869318 DOI: 10.3390/biology11020234] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/27/2022] [Accepted: 01/29/2022] [Indexed: 12/12/2022]
Abstract
As the nervous system develops, nerve fibers from the brain form descending tracts that regulate the execution of motor behavior within the spinal cord, incoming sensory signals, and capacity to change (plasticity). How these fibers affect function depends upon the transmitter released, the receptor system engaged, and the pattern of neural innervation. The current review focuses upon the neurotransmitter serotonin (5-HT) and its capacity to dampen (inhibit) neural excitation. A brief review of key anatomical details, receptor types, and pharmacology is provided. The paper then considers how damage to descending serotonergic fibers contributes to pathophysiology after spinal cord injury (SCI). The loss of serotonergic fibers removes an inhibitory brake that enables plasticity and neural excitation. In this state, noxious stimulation can induce a form of over-excitation that sensitizes pain (nociceptive) circuits, a modification that can contribute to the development of chronic pain. Over time, the loss of serotonergic fibers allows prolonged motor drive (spasticity) to develop and removes a regulatory brake on autonomic function, which enables bouts of unregulated sympathetic activity (autonomic dysreflexia). Recent research has shown that the loss of descending serotonergic activity is accompanied by a shift in how the neurotransmitter GABA affects neural activity, reducing its inhibitory effect. Treatments that target the loss of inhibition could have therapeutic benefit.
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Affiliation(s)
| | | | - James W. Grau
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, TX 77843, USA; (G.N.K.F.); (K.E.H.)
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Kulesskaya N, Molotkov D, Sliepen S, Mugantseva E, Garcia Horsman A, Paveliev M, Rauvala H. Heparin-Binding Growth-Associated Molecule (Pleiotrophin) Affects Sensory Signaling and Selected Motor Functions in Mouse Model of Anatomically Incomplete Cervical Spinal Cord Injury. Front Neurol 2021; 12:738800. [PMID: 34938257 PMCID: PMC8685413 DOI: 10.3389/fneur.2021.738800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 11/02/2021] [Indexed: 11/23/2022] Open
Abstract
Heparin-binding growth-associated molecule (pleiotrophin) is a neurite outgrowth-promoting secretory protein that lines developing fiber tracts in juvenile CNS (central nervous system). Previously, we have shown that heparin-binding growth-associated molecule (HB-GAM) reverses the CSPG (chondroitin sulfate proteoglycan) inhibition on neurite outgrowth in the culture medium of primary CNS neurons and enhances axon growth through the injured spinal cord in mice demonstrated by two-photon imaging. In this study, we have started studies on the possible role of HB-GAM in enhancing functional recovery after incomplete spinal cord injury (SCI) using cervical lateral hemisection and hemicontusion mouse models. In vivo imaging of blood-oxygen-level-dependent (BOLD) signals associated with functional activity in the somatosensory cortex was used to assess the sensory functions during vibrotactile hind paw stimulation. The signal displays an exaggerated response in animals with lateral hemisection that recovers to the level seen in the sham-operated mice by injection of HB-GAM to the trauma site. The effect of HB-GAM treatment on sensory-motor functions was assessed by performance in demanding behavioral tests requiring integration of afferent and efferent signaling with central coordination. Administration of HB-GAM either by direct injection into the trauma site or by intrathecal injection improves the climbing abilities in animals with cervical hemisection and in addition enhances the grip strength in animals with lateral hemicontusion without affecting the spontaneous locomotor activity. Recovery of sensory signaling in the sensorimotor cortex by HB-GAM to the level of sham-operated mice may contribute to the improvement of skilled locomotion requiring integration of spatiotemporal signals in the somatosensory cortex.
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Affiliation(s)
- Natalia Kulesskaya
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Dmitry Molotkov
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Sonny Sliepen
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Ekaterina Mugantseva
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Arturo Garcia Horsman
- Real-time Imaging Laboratory, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
| | - Mikhail Paveliev
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Heikki Rauvala
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
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6
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Ma KH, Cheng CY, Chan WH, Chen SY, Kao LT, Sung CS, Hueng DY, Yeh CC. Pulsed Radiofrequency Upregulates Serotonin Transporters and Alleviates Neuropathic Pain-Induced Depression in a Spared Nerve Injury Rat Model. Biomedicines 2021; 9:biomedicines9101489. [PMID: 34680606 PMCID: PMC8533300 DOI: 10.3390/biomedicines9101489] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/10/2021] [Accepted: 10/14/2021] [Indexed: 02/06/2023] Open
Abstract
Neuropathic pain (NP) is difficult to treat due to complex pathophysiological mechanisms. Pulsed radiofrequency (RRF) has been used widely with neuromodulation effect in refractory chronic pain treatment. A recent study found that PRF treatment may decrease chronic pain-related anxiety-depressant symptoms in patients, even though the mechanisms are unclear. Additionally, accumulated evidence has shown serotonin uptake is correlated with various neuropsychiatric diseases. Therefore, we investigated the effects and underlying mechanisms of PRF on depression-like behaviors, resulting from spared nerve injury (SNI)-induced NP. We examined the indexes of mechanical allodynia, cold allodynia, depression-like behavior, and blood cytokines by dynamic plantar aesthesiometry, acetone spray test, forced swimming test, and ProcartaPlex multiplex immunoassays in male Wistar rats, respectively. Serotonin transporters (SERTs) in rat brains were examined by using 4-[18F]-ADAM/PET imaging. We found that specific uptake ratios (SURs) of SERTs were significantly decreased in the brain regions of the thalamus and striatum in rats with SNI-induced NP and depression-like behaviors. Additionally, the decrease in SERT density was correlated with the development of a depression-like behavior indicated by the forced swimming test results and pronounced IL-6 cytokines. Moreover, we demonstrated that PRF application could modulate the descending serotoninergic pathway to relieve pain and depression behaviors.
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Affiliation(s)
- Kuo-Hsing Ma
- Department of Biology and Anatomy, National Defense Medical Center, Taipei 115, Taiwan;
| | - Cheng-Yi Cheng
- Department of Nuclear Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei 115, Taiwan;
| | - Wei-Hung Chan
- Department of Anesthesiology, Tri-Service General Hospital, National Defense Medical Center, Taipei 115, Taiwan; (W.-H.C.); (S.-Y.C.)
| | - Shih-Yu Chen
- Department of Anesthesiology, Tri-Service General Hospital, National Defense Medical Center, Taipei 115, Taiwan; (W.-H.C.); (S.-Y.C.)
| | - Li-Ting Kao
- Department of Pharmacy Practice, Tri-Service General Hospital, National Defense Medical Center, Taipei 115, Taiwan;
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 115, Taiwan
| | - Chun-Sung Sung
- Department of Anesthesiology, Taipei Veterans General Hospital, Taipei 112, Taiwan;
- School of Medicine, National Yang-Ming Chiao-Tung University, Taipei 112, Taiwan
| | - Dueng-Yuan Hueng
- Department of Neurological Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei 115, Taiwan;
| | - Chun-Chang Yeh
- Department of Anesthesiology, Tri-Service General Hospital, National Defense Medical Center, Taipei 115, Taiwan; (W.-H.C.); (S.-Y.C.)
- Integrated Pain Management Center, Tri-Service General Hospital, National Defense Medical Center, Taipei 115, Taiwan
- Correspondence:
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Hsu YC, Ma KH, Guo SL, Lin BF, Tsai CS, Yeh CC. The Occurrence of Pain-Induced Depression Is Different between Rat Models of Inflammatory and Neuropathic Pain. J Clin Med 2021; 10:jcm10174016. [PMID: 34501464 PMCID: PMC8432452 DOI: 10.3390/jcm10174016] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/18/2021] [Accepted: 09/02/2021] [Indexed: 12/15/2022] Open
Abstract
Various pain conditions may be associated with depressed mood. However, the effect of inflammatory or neuropathic pain on depression-like behavior and its associated time frame has not been well established in rat models. This frontward study investigated the differences in pain behavior, depression-like behavior, and serotonin transporter (SERT) distribution in the brain between rats subjected to spared nerve injury (SNI)-induced neuropathic pain or complete Freund’s adjuvant (CFA)-induced inflammatory pain. A dynamic plantar aesthesiometer and an acetone spray test were used to evaluate mechanical and cold allodynia responses, and depression-like behavior was examined using a forced swimming test and sucrose preference test. We also investigated SERT expression by using positron emission tomography. We found that the inflammation-induced pain was less severe than neuropathic pain from days 3 to 28 after induced pain; however, the CFA-injected rats exhibited more noticeable depression-like behavior and had significantly reduced SERT expression in the brain regions (thalamus and striatum) at an early stage (on days 14, 21, and 28 in two groups of CFA-injected rats versus day 28 in SNI rats). We speculated that not only the pain response after initial injury but also the subsequent neuroinflammation may have been the crucial factors influencing depression-like behavior in rats.
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Affiliation(s)
- Yung-Chi Hsu
- Department of Anesthesiology, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan; (Y.-C.H.); (S.-L.G.); (B.-F.L.)
- Integrated Pain Management Center, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan
| | - Kuo-Hsing Ma
- Department of Biology and Anatomy, National Defense Medical Center, Taipei 114, Taiwan;
| | - Shu-Lin Guo
- Department of Anesthesiology, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan; (Y.-C.H.); (S.-L.G.); (B.-F.L.)
- Department of Anesthesiology, Cathay General Hospital, Taipei 106, Taiwan
- School of Medicine, Fu Jen Catholic University, New Taipei City 242, Taiwan
| | - Bo-Feng Lin
- Department of Anesthesiology, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan; (Y.-C.H.); (S.-L.G.); (B.-F.L.)
- Integrated Pain Management Center, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan
| | - Chien-Sung Tsai
- Division of Cardiovascular Surgery, Department of Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan;
- Department and Graduate Institute of Pharmacology, National Defense Medical Center, Taipei 114, Taiwan
| | - Chun-Chang Yeh
- Department of Anesthesiology, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan; (Y.-C.H.); (S.-L.G.); (B.-F.L.)
- Integrated Pain Management Center, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan
- Correspondence: ; Tel.: +886-2-8792-3311 (ext. 17051); Fax: +886-2-8792-7127
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Bannerman CA, Douchant K, Sheth PM, Ghasemlou N. The gut-brain axis and beyond: Microbiome control of spinal cord injury pain in humans and rodents. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2021; 9:100059. [PMID: 33426367 PMCID: PMC7779861 DOI: 10.1016/j.ynpai.2020.100059] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/26/2020] [Accepted: 12/10/2020] [Indexed: 12/17/2022]
Abstract
Spinal cord injury (SCI) is a devastating injury to the central nervous system in which 60 to 80% of patients experience chronic pain. Unfortunately, this pain is notoriously difficult to treat, with few effective options currently available. Patients are also commonly faced with various compounding injuries and medical challenges, often requiring frequent hospitalization and antibiotic treatment. Change in the gut microbiome from the "normal" state to one of imbalance, referred to as gut dysbiosis, has been found in both patients and rodent models following SCI. Similarities exist in the bacterial changes observed after SCI and other diseases with chronic pain as an outcome. These changes cause a shift in the regulation of inflammation, causing immune cell activation and secretion of inflammatory mediators that likely contribute to the generation/maintenance of SCI pain. Therefore, correcting gut dysbiosis may be used as a tool towards providing patients with effective pain management and improved quality of life.
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Affiliation(s)
- Courtney A. Bannerman
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - Katya Douchant
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
- Gastrointestinal Disease Research Unit, Kingston Health Sciences Center, Kingston, Ontario, Canada
| | - Prameet M. Sheth
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
- Department of Pathology and Molecular Medicine, Queen’s University, Kingston, Ontario, Canada
- Division of Microbiology, Kingston Health Sciences Centre, Kingston, Ontario, Canada
- Gastrointestinal Disease Research Unit, Kingston Health Sciences Center, Kingston, Ontario, Canada
| | - Nader Ghasemlou
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
- Department of Anesthesiology and Perioperative Medicine, Kingston Health Sciences Centre, Kingston, Ontario, Canada
- Centre for Neuroscience Studies, Queen’s University, Kingston, Ontario, Canada
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Farrell K, Houle JD. Systemic Inhibition of Soluble Tumor Necrosis Factor with XPro1595 Exacerbates a Post-Spinal Cord Injury Depressive Phenotype in Female Rats. J Neurotrauma 2019; 36:2964-2976. [PMID: 31064292 PMCID: PMC6791477 DOI: 10.1089/neu.2019.6438] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Spinal cord injury (SCI) is associated with a three-fold risk of major depressive disorder compared with the general population. Current antidepressant therapy is often not as effective in this patient population, suggesting the need for a more efficacious therapeutic target. The goal of this study was to elucidate the role of inflammatory cytokine tumor necrosis factor (TNF) in the dorsal raphe nucleus (DRN, the principle source of serotonin to the brain) in the development and possible treatment of depression after SCI. A depressive phenotype following moderate T9 contusion was identified in adult female rats using a battery of behavioral tests (forced swim test, sucrose preference test, novel object recognition test, open field locomotion, and social exploration). Data revealed two clusters of injured rats (58%) that exhibit increased immobility in the forced swim test, indicating depressive phenotype or a melancholic-depressive phenotype with concomitant decrease in sucrose preference. ElevatedTNF levels in the DRN of these two clusters correlated with increased immobility in the forced swim test. We then tested the efficacy of soluble TNF inhibition with XPro1595 treatment to prevent the depressive phenotype after SCI. Subcutaneous (s.c.) delivery of XPro1595 caused an exacerbation of depressive phenotype, with all treated clusters exhibiting increased forced swim immobility compared with saline-treated non-depressed rats. Intracerebroventricular (i.c.v.) administration of the drug did not prevent or enhance the development of depression after injury. These results suggest a complex role for TNF-based neuroinflammation in SCI-induced depression that needs to be further explored, perhaps in conjunction with a broader targeting of additional post-SCI inflammatory cytokines.
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Affiliation(s)
- Kaitlin Farrell
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - John D. Houle
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, Pennsylvania
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Perrin FE, Noristani HN. Serotonergic mechanisms in spinal cord injury. Exp Neurol 2019; 318:174-191. [PMID: 31085200 DOI: 10.1016/j.expneurol.2019.05.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 05/07/2019] [Accepted: 05/08/2019] [Indexed: 12/12/2022]
Abstract
Spinal cord injury (SCI) is a tragic event causing irreversible losses of sensory, motor, and autonomic functions, that may also be associated with chronic neuropathic pain. Serotonin (5-HT) neurotransmission in the spinal cord is critical for modulating sensory, motor, and autonomic functions. Following SCI, 5-HT axons caudal to the lesion site degenerate, and the degree of axonal degeneration positively correlates with lesion severity. Rostral to the lesion, 5-HT axons sprout, irrespective of the severity of the injury. Unlike callosal fibers and cholinergic projections, 5-HT axons are more resistant to an inhibitory milieu and undergo active sprouting and regeneration after central nervous system (CNS) traumatism. Numerous studies suggest that a chronic increase in serotonergic neurotransmission promotes 5-HT axon sprouting in the intact CNS. Moreover, recent studies in invertebrates suggest that 5-HT has a pro-regenerative role in injured axons. Here we present a brief description of 5-HT discovery, 5-HT innervation of the CNS, and physiological functions of 5-HT in the spinal cord, including its role in controlling bladder function. We then present a comprehensive overview of changes in serotonergic axons after CNS damage, and discuss their plasticity upon altered 5-HT neurotransmitter levels. Subsequently, we provide an in-depth review of therapeutic approaches targeting 5-HT neurotransmission, as well as other pre-clinical strategies to promote an increase in re-growth of 5-HT axons, and their functional consequences in SCI animal models. Finally, we highlight recent findings signifying the direct role of 5-HT in axon regeneration and suggest strategies to further promote robust long-distance re-growth of 5-HT axons across the lesion site and eventually achieve functional recovery following SCI.
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Affiliation(s)
- Florence Evelyne Perrin
- University of Montpellier, Montpellier, F-34095 France; INSERM, U1198, Montpellier, F-34095 France; EPHE, Paris, F-75014 France
| | - Harun Najib Noristani
- Shriners Hospitals Pediatric Research Center, Center for Neural Repair, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA; Department of Anatomy and Cell Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA.
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11
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Bravo L, Llorca-Torralba M, Berrocoso E, Micó JA. Monoamines as Drug Targets in Chronic Pain: Focusing on Neuropathic Pain. Front Neurosci 2019; 13:1268. [PMID: 31942167 PMCID: PMC6951279 DOI: 10.3389/fnins.2019.01268] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 11/08/2019] [Indexed: 12/11/2022] Open
Abstract
Monoamines are involved in regulating the endogenous pain system and indeed, peripheral and central monoaminergic dysfunction has been demonstrated in certain types of pain, particularly in neuropathic pain. Accordingly, drugs that modulate the monaminergic system and that were originally designed to treat depression are now considered to be first line treatments for certain types of neuropathic pain (e.g., serotonin and noradrenaline (and also dopamine) reuptake inhibitors). The analgesia induced by these drugs seems to be mediated by inhibiting the reuptake of these monoamines, thereby reinforcing the descending inhibitory pain pathways. Hence, it is of particular interest to study the monoaminergic mechanisms involved in the development and maintenance of chronic pain. Other analgesic drugs may also be used in combination with monoamines to facilitate descending pain inhibition (e.g., gabapentinoids and opioids) and such combinations are often also used to alleviate certain types of chronic pain. By contrast, while NSAIDs are thought to influence the monoaminergic system, they just produce consistent analgesia in inflammatory pain. Thus, in this review we will provide preclinical and clinical evidence of the role of monoamines in the modulation of chronic pain, reviewing how this system is implicated in the analgesic mechanism of action of antidepressants, gabapentinoids, atypical opioids, NSAIDs and histaminergic drugs.
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Affiliation(s)
- Lidia Bravo
- Neuropsychopharmacology and Psychobiology Research Group, Department of Neuroscience, University of Cádiz, Cádiz, Spain
- Instituto de Investigación e Innovación Biomédica de Cádiz, INiBICA, Hospital Universitario Puerta del Mar, Cádiz, Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Instituto de Salud Carlos III, Madrid, Spain
| | - Meritxell Llorca-Torralba
- Neuropsychopharmacology and Psychobiology Research Group, Department of Neuroscience, University of Cádiz, Cádiz, Spain
- Instituto de Investigación e Innovación Biomédica de Cádiz, INiBICA, Hospital Universitario Puerta del Mar, Cádiz, Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Instituto de Salud Carlos III, Madrid, Spain
| | - Esther Berrocoso
- Instituto de Investigación e Innovación Biomédica de Cádiz, INiBICA, Hospital Universitario Puerta del Mar, Cádiz, Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Instituto de Salud Carlos III, Madrid, Spain
- Neuropsychopharmacology and Psychobiology Research Group, Department of Psychology, University of Cádiz, Cádiz, Spain
| | - Juan Antonio Micó
- Neuropsychopharmacology and Psychobiology Research Group, Department of Neuroscience, University of Cádiz, Cádiz, Spain
- Instituto de Investigación e Innovación Biomédica de Cádiz, INiBICA, Hospital Universitario Puerta del Mar, Cádiz, Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Instituto de Salud Carlos III, Madrid, Spain
- *Correspondence: Juan Antonio Micó,
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12
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Jeffrey-Gauthier R, Josset N, Bretzner F, Leblond H. Facilitation of Locomotor Spinal Networks Activity by Buspirone after a Complete Spinal Cord Lesion in Mice. J Neurotrauma 2018; 35:2208-2221. [DOI: 10.1089/neu.2017.5476] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- Renaud Jeffrey-Gauthier
- Department of Anatomy, Université du Québec à Trois-Rivières (UQTR), Québec, Canada
- CogNAC Research Group, Université du Québec à Trois-Rivières (UQTR), Québec, Canada
| | | | - Frédéric Bretzner
- CHU de Québec-Université Laval, Québec, Canada
- Faculty of Medicine, Department of Psychiatry and Neurosciences, Université Laval, Québec, Canada
| | - Hugues Leblond
- Department of Anatomy, Université du Québec à Trois-Rivières (UQTR), Québec, Canada
- CogNAC Research Group, Université du Québec à Trois-Rivières (UQTR), Québec, Canada
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13
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Wang Y, Wu W, Wu X, Sun Y, Zhang YP, Deng LX, Walker MJ, Qu W, Chen C, Liu NK, Han Q, Dai H, Shields LB, Shields CB, Sengelaub DR, Jones KJ, Smith GM, Xu XM. Remodeling of lumbar motor circuitry remote to a thoracic spinal cord injury promotes locomotor recovery. eLife 2018; 7:39016. [PMID: 30207538 PMCID: PMC6170189 DOI: 10.7554/elife.39016] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 09/09/2018] [Indexed: 12/18/2022] Open
Abstract
Retrogradely-transported neurotrophin signaling plays an important role in regulating neural circuit specificity. Here we investigated whether targeted delivery of neurotrophin-3 (NT-3) to lumbar motoneurons (MNs) caudal to a thoracic (T10) contusive spinal cord injury (SCI) could modulate dendritic patterning and synapse formation of the lumbar MNs. In vitro, Adeno-associated virus serotype two overexpressing NT-3 (AAV-NT-3) induced NT-3 expression and neurite outgrowth in cultured spinal cord neurons. In vivo, targeted delivery of AAV-NT-3 into transiently demyelinated adult mouse sciatic nerves led to the retrograde transportation of NT-3 to the lumbar MNs, significantly attenuating SCI-induced lumbar MN dendritic atrophy. NT-3 enhanced sprouting and synaptic formation of descending serotonergic, dopaminergic, and propriospinal axons on lumbar MNs, parallel to improved behavioral recovery. Thus, retrogradely transported NT-3 stimulated remodeling of lumbar neural circuitry and synaptic connectivity remote to a thoracic SCI, supporting a role for retrograde transport of NT-3 as a potential therapeutic strategy for SCI.
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Affiliation(s)
- Ying Wang
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, United States.,Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, United States.,Neural Tissue Engineering Research Institute, Mudanjiang College of Medicine, Mudanjiang, China
| | - Wei Wu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, United States.,Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, United States
| | - Xiangbing Wu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, United States.,Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, United States
| | - Yan Sun
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, United States.,Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, United States.,Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Yi P Zhang
- Norton Neuroscience Institute, Norton Healthcare, Louisville, United States
| | - Ling-Xiao Deng
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, United States.,Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, United States
| | - Melissa Jane Walker
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, United States.,Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, United States
| | - Wenrui Qu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, United States.,Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, United States
| | - Chen Chen
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, United States.,Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, United States.,Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indiana, United States
| | - Nai-Kui Liu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, United States.,Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, United States
| | - Qi Han
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, United States.,Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, United States
| | - Heqiao Dai
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, United States.,Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, United States
| | - Lisa Be Shields
- Norton Neuroscience Institute, Norton Healthcare, Louisville, United States
| | | | - Dale R Sengelaub
- Program in Neuroscience, Department of Psychological and Brain Sciences, Indiana University, Bloomington, United States
| | - Kathryn J Jones
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, United States
| | - George M Smith
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, United States
| | - Xiao-Ming Xu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, United States.,Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, United States.,Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, United States
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14
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Huang YJ, Grau JW. Ionic plasticity and pain: The loss of descending serotonergic fibers after spinal cord injury transforms how GABA affects pain. Exp Neurol 2018; 306:105-116. [PMID: 29729247 PMCID: PMC5994379 DOI: 10.1016/j.expneurol.2018.05.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 04/24/2018] [Accepted: 05/01/2018] [Indexed: 12/14/2022]
Abstract
Activation of pain (nociceptive) fibers can sensitize neural circuits within the spinal cord, inducing an increase in excitability (central sensitization) that can foster chronic pain. The development of spinally-mediated central sensitization is regulated by descending fibers and GABAergic interneurons. In adult animals, the co-transporter KCC2 maintains a low intracellular concentration of the anion Cl-. As a result, when the GABA-A receptor is engaged, Cl- flows in the neuron which has a hyperpolarizing (inhibitory) effect. Spinal cord injury (SCI) can down-regulate KCC2 and reverse the flow of Cl-. Under these conditions, engaging the GABA-A receptor can have a depolarizing (excitatory) effect that fosters the development of nociceptive sensitization. The present paper explores how SCI alters GABA function and provides evidence that the loss of descending fibers alters pain transmission to the brain. Prior work has shown that, after SCI, administration of a GABA-A antagonist blocks the development of capsaicin-induced nociceptive sensitization, implying that GABA release plays an essential role. This excitatory effect is linked to serotonergic (5HT) fibers that descend through the dorsolateral funiculus (DLF) and impact spinal function via the 5HT-1A receptor. Supporting this, blocking the 5HT-1A receptor, or lesioning the DLF, emulated the effect of SCI. Conversely, spinal application of a 5HT-1A agonist up-regulated KCC2 and reversed the effect of bicuculline treatment. Finally, lesioning the DLF reversed how a GABA-A antagonist affects a capsaicin-induced aversion in a place conditioning task; in sham operated animals, bicuculline enhanced aversion whereas in DLF-lesioned rats biciculline had an antinociceptive effect.
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Affiliation(s)
- Yung-Jen Huang
- Behavioral and Cellular Neuroscience, Department of Psychology, Texas A&M University, College Station, TX 77843, USA.
| | - James W Grau
- Behavioral and Cellular Neuroscience, Department of Psychology, Texas A&M University, College Station, TX 77843, USA
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15
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Shiao R, Lee-Kubli CA. Neuropathic Pain After Spinal Cord Injury: Challenges and Research Perspectives. Neurotherapeutics 2018; 15:635-653. [PMID: 29736857 PMCID: PMC6095789 DOI: 10.1007/s13311-018-0633-4] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Neuropathic pain is a debilitating consequence of spinal cord injury (SCI) that remains difficult to treat because underlying mechanisms are not yet fully understood. In part, this is due to limitations of evaluating neuropathic pain in animal models in general, and SCI rodents in particular. Though pain in patients is primarily spontaneous, with relatively few patients experiencing evoked pains, animal models of SCI pain have primarily relied upon evoked withdrawals. Greater use of operant tasks for evaluation of the affective dimension of pain in rodents is needed, but these tests have their own limitations such that additional studies of the relationship between evoked withdrawals and operant outcomes are recommended. In preclinical SCI models, enhanced reflex withdrawal or pain responses can arise from pathological changes that occur at any point along the sensory neuraxis. Use of quantitative sensory testing for identification of optimal treatment approach may yield improved identification of treatment options and clinical trial design. Additionally, a better understanding of the differences between mechanisms contributing to at- versus below-level neuropathic pain and neuropathic pain versus spasticity may shed insights into novel treatment options. Finally, the role of patient characteristics such as age and sex in pathogenesis of neuropathic SCI pain remains to be addressed.
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Affiliation(s)
- Rani Shiao
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 N. Torrey Pines, La Jolla, California, 92073, USA
| | - Corinne A Lee-Kubli
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 N. Torrey Pines, La Jolla, California, 92073, USA.
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16
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Walters ET. How is chronic pain related to sympathetic dysfunction and autonomic dysreflexia following spinal cord injury? Auton Neurosci 2017; 209:79-89. [PMID: 28161248 DOI: 10.1016/j.autneu.2017.01.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 01/24/2017] [Accepted: 01/25/2017] [Indexed: 12/29/2022]
Abstract
Autonomic dysreflexia (AD) and neuropathic pain occur after severe injury to higher levels of the spinal cord. Mechanisms underlying these problems have rarely been integrated in proposed models of spinal cord injury (SCI). Several parallels suggest significant overlap of these mechanisms, although the relationships between sympathetic function (dysregulated in AD) and nociceptive function (dysregulated in neuropathic pain) are complex. One general mechanism likely to be shared is central sensitization - enhanced responsiveness and synaptic reorganization of spinal circuits that mediate sympathetic reflexes or that process and relay pain-related information to the brain. Another is enhanced sensory input to spinal circuits caused by extensive alterations in primary sensory neurons. Both AD and SCI-induced neuropathic pain are associated with spinal sprouting of peptidergic nociceptors that might increase synaptic input to the circuits involved in AD and SCI pain. In addition, numerous nociceptors become hyperexcitable, hypersensitive to chemicals associated with injury and inflammation, and spontaneously active, greatly amplifying sensory input to sensitized spinal circuits. As discussed with the aid of a preliminary functional model, these effects are likely to have mutually reinforcing relationships with each other, and with consequences of SCI-induced interruption of descending excitatory and inhibitory influences on spinal circuits, with SCI-induced inflammation in the spinal cord and in DRGs, and with activity in sympathetic fibers within DRGs that promotes local inflammation and spontaneous activity in sensory neurons. This model suggests that interventions selectively targeting hyperactivity in C-nociceptors might be useful for treating chronic pain and AD after high SCI.
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Affiliation(s)
- Edgar T Walters
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, TX 77030, USA.
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17
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Liu ZH, Yip PK, Priestley JV, Michael-Titus AT. A Single Dose of Docosahexaenoic Acid Increases the Functional Recovery Promoted by Rehabilitation after Cervical Spinal Cord Injury in the Rat. J Neurotrauma 2017; 34:1766-1777. [PMID: 27881040 DOI: 10.1089/neu.2016.4556] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Task-specific rehabilitation has been shown to promote functional recovery after acute spinal cord injury (SCI). Recently, the omega-3 polyunsaturated fatty acid, docosahexaenoic acid (DHA), has been shown to promote neuroplasticity after SCI. Here, we investigated whether the combination of a single bolus of DHA with rehabilitation can enhance the effect of DHA or rehabilitation therapy in adult injured spinal cord. We found enhanced functional improvement with DHA in combination with rehabilitation compared with either treatment alone in a rat cervical lateral hemisection SCI model. This behavioral improvement correlated with a significant sprouting of uninjured corticospinal and serotonergic fibers. We also observed that the greatest increase in the synaptic vesicle protein, synaptophysin, and the synaptic active zone protein, Bassoon, occurred in animals that received both DHA and rehabilitation. In summary, the functional, anatomical, and synaptic plasticity induced by task-specific rehabilitation can be further enhanced by DHA treatment. This study shows the potential beneficial effects of DHA combined with rehabilitation for the treatment of patients with SCI.
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Affiliation(s)
- Zhou-Hao Liu
- 1 Queen Mary University of London , Barts and The London School of Medicine and Dentistry, Blizard Institute, London, United Kingdom .,2 Chang Gung Medical College and University , Chang Gung Memorial Hospital, Department of Neurosurgery, Linkou, Taiwan
| | - Ping K Yip
- 1 Queen Mary University of London , Barts and The London School of Medicine and Dentistry, Blizard Institute, London, United Kingdom
| | - John V Priestley
- 1 Queen Mary University of London , Barts and The London School of Medicine and Dentistry, Blizard Institute, London, United Kingdom
| | - Adina T Michael-Titus
- 1 Queen Mary University of London , Barts and The London School of Medicine and Dentistry, Blizard Institute, London, United Kingdom
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18
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Abstract
The cervical spine is the most common site of traumatic vertebral column injuries. Respiratory insufficiency constitutes a significant proportion of the morbidity burden and is the most common cause of mortality in these patients. In seeking to enhance our capacity to treat specifically the respiratory dysfunction following spinal cord injury, investigators have studied the "crossed phrenic phenomenon", wherein contraction of a hemidiaphragm paralyzed by a complete hemisection of the ipsilateral cervical spinal cord above the phrenic nucleus can be induced by respiratory stressors and recovers spontaneously over time. Strengthening of latent contralateral projections to the phrenic nucleus and sprouting of new descending axons have been proposed as mechanisms contributing to the observed recovery. We have recently demonstrated recovery of spontaneous crossed phrenic activity occurring over minutes to hours in C1-hemisected unanesthetized decerebrate rats. The specific neurochemical and molecular pathways underlying crossed phrenic activity following injury require further clarification. A thorough understanding of these is necessary in order to develop targeted therapies for respiratory neurorehabilitation following spinal trauma. Animal studies provide preliminary evidence for the utility of neuropharmacological manipulation of serotonergic and adenosinergic pathways, nerve grafts, olfactory ensheathing cells, intraspinal microstimulation and a possible role for dorsal rhizotomy in recovering phrenic activity following spinal cord injury.
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Combination of grafted Schwann cells and lentiviral-mediated prevention of glial scar formation improve recovery of spinal cord injured rats. J Chem Neuroanat 2016; 76:48-60. [DOI: 10.1016/j.jchemneu.2015.12.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 11/26/2015] [Accepted: 12/25/2015] [Indexed: 01/03/2023]
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Zeinali H, Manaheji H, Zaringhalam J, Bahari Z, Nazemi S, Sadeghi M. Age-Related Differences in Neuropathic Pain Behavior and Spinal Microglial Activity after L5 Spinal Nerve Ligation in Male Rats. Basic Clin Neurosci 2016; 7:203-12. [PMID: 27563413 PMCID: PMC4981832 DOI: 10.15412/j.bcn.03070305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Introduction: Several studies have reported the involvement of age-related changes in the development of neuropathic pain behaviors. However, limited data are available on the role of age in establishing and maintaining chronic neuropathic pain after peripheral nerve injury. Methods: In the present study, we examined age-related neuropathic behavior among rats in 4 age groups: pups (4 weeks old; weight, 60–80 g), juvenile rats (6 weeks old; weight, 120–140 g), and mature rats (10–12 weeks old; weight, 200–250 g). Because the exact contribution of spinal microglia and its association with the development of neuropathic pain remains unknown, we also evaluated the expression of spinal Iba1, a microglial marker, by using western blotting before and 5 days after spinal nerve ligation (SNL) as well as after the daily IP administration of minocycline (30 mg/kg). Results: Our results showed that SNL-induced mechanical allodynia but not thermal hyperalgesia in mature rats but not in pups (P<0.05 and P<0.01, respectively). The expression of spinal Iba1 in the juvenile rats was significantly lower than that in pups and mature rats (P<0.01). Moreover, administration of minocycline decreased the expression of spinal Iba1 in the pup rats more than in juvenile rats (P<0.001) and in the juvenile rats more than in the mature rats (P<0.05). Conclusion: These data suggest that the development of neuropathic behaviors and microglial activation after SNL could be age dependent.
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Affiliation(s)
- Hossein Zeinali
- Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Homa Manaheji
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Jalal Zaringhalam
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Zahra Bahari
- Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Samad Nazemi
- Department of Physiology, School of Medicine, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | - Mehdi Sadeghi
- Department of Physiology, Faculty of Medicine, Boushehr University of Medical Sciences, Boushehr, Iran
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Kami K, Tajima F, Senba E. Exercise-induced hypoalgesia: potential mechanisms in animal models of neuropathic pain. Anat Sci Int 2016; 92:79-90. [DOI: 10.1007/s12565-016-0360-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 07/21/2016] [Indexed: 02/02/2023]
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22
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Mifflin KA, Benson C, Thorburn KC, Baker GB, Kerr BJ. Manipulation of Neurotransmitter Levels Has Differential Effects on Formalin-Evoked Nociceptive Behavior in Male and Female Mice. THE JOURNAL OF PAIN 2016; 17:483-98. [DOI: 10.1016/j.jpain.2015.12.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 11/30/2015] [Accepted: 12/14/2015] [Indexed: 01/06/2023]
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23
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A Single Bolus of Docosahexaenoic Acid Promotes Neuroplastic Changes in the Innervation of Spinal Cord Interneurons and Motor Neurons and Improves Functional Recovery after Spinal Cord Injury. J Neurosci 2016; 35:12733-52. [PMID: 26377463 DOI: 10.1523/jneurosci.0605-15.2015] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
UNLABELLED Docosahexaenoic acid (DHA) is an ω-3 polyunsaturated fatty acid that is essential in brain development and has structural and signaling roles. Acute DHA administration is neuroprotective and promotes functional recovery in animal models of adult spinal cord injury (SCI). However, the mechanisms underlying this recovery have not been fully characterized. Here we investigated the effects of an acute intravenous bolus of DHA delivered after SCI and characterized DHA-induced neuroplasticity within the adult injured spinal cord. We found robust sprouting of uninjured corticospinal and serotonergic fibers in a rat cervical hemisection SCI model. A mouse pyramidotomy model was used to confirm that this robust sprouting was not species or injury model specific. Furthermore, we demonstrated that corticospinal fibers sprouting to the denervated side of the cord following pyramidotomy contact V2a interneurons. We also demonstrated increased serotonin fibers and synaptophysin in direct contact with motor neurons. DHA also increased synaptophysin in rat cortical cell cultures. A reduction in phosphatase and tensin homolog (PTEN) has been shown to be involved in axonal regeneration and synaptic plasticity. We showed that DHA significantly upregulates miR-21 and downregulates PTEN in corticospinal neurons. Downregulation of PTEN and upregulation of phosphorylated AKT by DHA were also seen in primary cortical neuron cultures and were accompanied by increased neurite outgrowth. In summary, acute DHA induces anatomical and synaptic plasticity in adult injured spinal cord. This study shows that DHA has therapeutic potential in cervical SCI and provides evidence that DHA could exert its beneficial effects in SCI via enhancement of neuroplasticity. SIGNIFICANCE STATEMENT In this study, we show that an acute intravenous injection of docosahexaenoic acid (DHA) 30 min after spinal cord injury induces neuroplasticity. We found robust sprouting of uninjured corticospinal and serotonergic fibers in a rat hemisection spinal cord injury model. A mouse pyramidotomy model was used to confirm that the robust sprouting involved V2a interneurons. We show that DHA significantly upregulates miR-21 and phosphorylated AKT, and downregulates phosphatase and tensin homolog (PTEN), which is involved in suppressing anatomical plasticity, in corticospinal neurons and in primary cortical neuron cultures. We conclude that acute DHA can induce anatomical and synaptic plasticity. This provides direct evidence that DHA could exert its beneficial effects in spinal cord injury via neuroplasticity enhancement.
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Linnstaedt SD, Walker MG, Parker JS, Yeh E, Sons RL, Zimny E, Lewandowski C, Hendry PL, Damiron K, Pearson C, Velilla MA, O'Neil BJ, Jones J, Swor R, Domeier R, Hammond S, McLean SA. MicroRNA circulating in the early aftermath of motor vehicle collision predict persistent pain development and suggest a role for microRNA in sex-specific pain differences. Mol Pain 2015; 11:66. [PMID: 26498117 PMCID: PMC4619556 DOI: 10.1186/s12990-015-0069-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 10/13/2015] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Molecular mediators influencing the transition from acute to persistent musculoskeletal pain following common stress exposures such as motor vehicle collision (MVC) remain poorly understood. In this exploratory, proof of concept study, we compared circulating microRNA (miRNA) expression profiles in the early aftermath of MVC among individuals who did and did not subsequently develop persistent pain. Blood RNA samples were obtained from African American individuals (n = 53) who presented to the emergency department after MVC and were discharged to home after evaluation. The presence or absence of severe pain in the axial region, the most common and morbid region in which post-MVC pain occurs, was assessed 6 weeks following MVC via standardized questionnaire. miRNA expression was determined using miRNA-sequencing; nonparametric analyses were used to compare miRNA expression levels among individuals with and without persistent pain. RESULTS Thirty-two mature miRNA were differentially expressed (p < 0.05) in those with and without severe axial pain at 6 weeks. miR-135a-5p, a regulator of the serotonin receptor that is known to be stress-responsive, differed most significantly between groups (p = 3 × 10(-4)). This miRNA, and miR-3613-3p (p = 0.001) survived correction for multiple testing (FDR = 0.15) in this small sample. Interestingly, differentially expressed miRNA were enriched for X chromosome location. In secondary analyses, the eight X chromosome miRNA were (a) more significantly associated with axial pain in women than men, (b) expressed more highly in the peripheral blood of women than men, and (c) predicted in pathway analyses (DIANA miRPath v 2.0) to regulate neuronal and neuroendocrine pathways previously implicated in various pain pathologies. CONCLUSIONS These results show that circulating miRNA predict persistent severe axial pain after MVC and suggest that they may be involved in the pathogenesis of post-traumatic musculoskeletal pain. However, further studies are needed to determine if these miRNA play a direct causal role.
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Affiliation(s)
- Sarah D Linnstaedt
- TRYUMPH Research Program, Chapel Hill, NC, USA.
- Department of Anesthesiology, University of North Carolina, Medical School Wing C CB#7010, Chapel Hill, NC, 27599-7010, USA.
| | - Margaret G Walker
- TRYUMPH Research Program, Chapel Hill, NC, USA.
- Department of Anesthesiology, University of North Carolina, Medical School Wing C CB#7010, Chapel Hill, NC, 27599-7010, USA.
| | - Joel S Parker
- Department of Genetics, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA.
| | - Eunice Yeh
- TRYUMPH Research Program, Chapel Hill, NC, USA.
- Department of Anesthesiology, University of North Carolina, Medical School Wing C CB#7010, Chapel Hill, NC, 27599-7010, USA.
| | - Robert L Sons
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, USA.
| | - Erin Zimny
- Department of Emergency Medicine, Henry Ford Hospital, Detroit, MI, USA.
| | | | - Phyllis L Hendry
- Department of Emergency Medicine, University of Florida College of Medicine-Jacksonville, Gainesville, FL, USA.
| | - Kathia Damiron
- Department of Emergency Medicine, Albert Einstein Medical Center, Philadelphia, PA, USA.
| | - Claire Pearson
- Department of Emergency Medicine, Detroit Receiving, Detroit, MI, USA.
| | | | - Brian J O'Neil
- Department of Emergency Medicine, Wayne State University, Detroit, MI, USA.
- The Cardiovascular Research Institute, School of Medicine, Wayne State University, Detroit, MI, USA.
| | - Jeffrey Jones
- Department of Emergency Medicine, Spectrum Health Butterworth Campus, Grand Rapids, MI, USA.
| | - Robert Swor
- Department of Emergency Medicine, William Beaumont Hospital, Troy, MI, USA.
| | - Robert Domeier
- Department of Emergency Medicine, St Joseph Mercy Health System, Ypsilanti, MI, USA.
| | - Scott Hammond
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, USA.
| | - Samuel A McLean
- TRYUMPH Research Program, Chapel Hill, NC, USA.
- Department of Anesthesiology, University of North Carolina, Medical School Wing C CB#7010, Chapel Hill, NC, 27599-7010, USA.
- Department of Emergency Medicine, University of North Carolina, Chapel Hill, NC, USA.
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Spinal Cord Hemisection Facilitates Aromatic L-Amino Acid Decarboxylase Cells to Produce Serotonin in the Subchronic but Not the Chronic Phase. Neural Plast 2015; 2015:549671. [PMID: 26504602 PMCID: PMC4609486 DOI: 10.1155/2015/549671] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 05/12/2015] [Accepted: 05/19/2015] [Indexed: 11/18/2022] Open
Abstract
Neuromodulators, such as serotonin (5-hydroxytryptamine, 5-HT) and noradrenalin, play an essential role in regulating the motor and sensory functions in the spinal cord. We have previously shown that in the rat spinal cord the activity of aromatic L-amino acid decarboxylase (AADC) cells to produce 5-HT from its precursor (5-hydroxytryptophan, 5-HTP) is dramatically increased following complete spinal cord transection. In this study, we investigated whether a partial loss of 5-HT innervation could similarly increase AADC activity. Adult rats with spinal cord hemisected at thoracic level (T11/T12) were used with a postoperation interval at 5 days or 60 days. Using immunohistochemistry, first, we observed a significant reduction in the density of 5-HT-immunoreactive fibers in the spinal cord below the lesion on the injured side for both groups. Second, we found that the AADC cells were similarly expressed on both injured and uninjured sides in both groups. Third, increased production of 5-HT in AADC cells following 5-HTP was seen in 5-day but not in 60-day postinjury group. These results suggest that plastic changes of the 5-HT system might happen primarily in the subchronic phase and for longer period its function could be compensated by plastic changes of other intrinsic and/or supraspinal modulation systems.
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Walters ET. Neuroinflammatory contributions to pain after SCI: roles for central glial mechanisms and nociceptor-mediated host defense. Exp Neurol 2014; 258:48-61. [PMID: 25017887 DOI: 10.1016/j.expneurol.2014.02.001] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 01/23/2014] [Accepted: 02/02/2014] [Indexed: 12/30/2022]
Abstract
Neuropathic pain after spinal cord injury (SCI) is common, often intractable, and can be severely debilitating. A number of mechanisms have been proposed for this pain, which are discussed briefly, along with methods for revealing SCI pain in animal models, such as the recently applied conditioned place preference test. During the last decade, studies of animal models have shown that both central neuroinflammation and behavioral hypersensitivity (indirect reflex measures of pain) persist chronically after SCI. Interventions that reduce neuroinflammation have been found to ameliorate pain-related behavior, such as treatment with agents that inhibit the activation states of microglia and/or astroglia (including IL-10, minocycline, etanercept, propentofylline, ibudilast, licofelone, SP600125, carbenoxolone). Reversal of pain-related behavior has also been shown with disruption by an inhibitor (CR8) and/or genetic deletion of cell cycle-related proteins, deletion of a truncated receptor (trkB.T1) for brain-derived neurotrophic factor (BDNF), or reduction by antisense knockdown or an inhibitor (AMG9810) of the activity of channels (TRPV1 or Nav1.8) important for electrical activity in primary nociceptors. Nociceptor activity is known to drive central neuroinflammation in peripheral injury models, and nociceptors appear to be an integral component of host defense. Thus, emerging results suggest that spinal and systemic effects of SCI can activate nociceptor-mediated host defense responses that interact via neuroinflammatory signaling with complex central consequences of SCI to drive chronic pain. This broader view of SCI-induced neuroinflammation suggests new targets, and additional complications, for efforts to develop effective treatments for neuropathic SCI pain.
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Affiliation(s)
- Edgar T Walters
- Department of Integrative Biology and Pharmacology, University of Texas Medical School at Houston, TX, USA.
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Moxon KA, Oliviero A, Aguilar J, Foffani G. Cortical reorganization after spinal cord injury: always for good? Neuroscience 2014; 283:78-94. [PMID: 24997269 DOI: 10.1016/j.neuroscience.2014.06.056] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 06/09/2014] [Accepted: 06/25/2014] [Indexed: 12/29/2022]
Abstract
Plasticity constitutes the basis of behavioral changes as a result of experience. It refers to neural network shaping and re-shaping at the global level and to synaptic contacts remodeling at the local level, either during learning or memory encoding, or as a result of acute or chronic pathological conditions. 'Plastic' brain reorganization after central nervous system lesions has a pivotal role in the recovery and rehabilitation of sensory and motor dysfunction, but can also be "maladaptive". Moreover, it is clear that brain reorganization is not a "static" phenomenon but rather a very dynamic process. Spinal cord injury immediately initiates a change in brain state and starts cortical reorganization. In the long term, the impact of injury - with or without accompanying therapy - on the brain is a complex balance between supraspinal reorganization and spinal recovery. The degree of cortical reorganization after spinal cord injury is highly variable, and can range from no reorganization (i.e. "silencing") to massive cortical remapping. This variability critically depends on the species, the age of the animal when the injury occurs, the time after the injury has occurred, and the behavioral activity and possible therapy regimes after the injury. We will briefly discuss these dependencies, trying to highlight their translational value. Overall, it is not only necessary to better understand how the brain can reorganize after injury with or without therapy, it is also necessary to clarify when and why brain reorganization can be either "good" or "bad" in terms of its clinical consequences. This information is critical in order to develop and optimize cost-effective therapies to maximize functional recovery while minimizing maladaptive states after spinal cord injury.
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Affiliation(s)
- K A Moxon
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA.
| | - A Oliviero
- Hospital Nacional de Parapléjicos, SESCAM, Finca la Peraleda s/n, 45071 Toledo, Spain
| | - J Aguilar
- Hospital Nacional de Parapléjicos, SESCAM, Finca la Peraleda s/n, 45071 Toledo, Spain
| | - G Foffani
- Hospital Nacional de Parapléjicos, SESCAM, Finca la Peraleda s/n, 45071 Toledo, Spain.
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Ward PJ, Herrity AN, Smith RR, Willhite A, Harrison BJ, Petruska JC, Harkema SJ, Hubscher CH. Novel multi-system functional gains via task specific training in spinal cord injured male rats. J Neurotrauma 2014; 31:819-33. [PMID: 24294909 DOI: 10.1089/neu.2013.3082] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Locomotor training (LT) after spinal cord injury (SCI) is a rehabilitative therapy used to enhance locomotor recovery. There is evidence, primarily anecdotal, also associating LT with improvements in bladder function and reduction in some types of SCI-related pain. In the present study, we determined if a step training paradigm could improve outcome measures of locomotion, bladder function, and pain/allodynia. After a T10 contusive SCI trained animals (adult male Wistar rats), trained animals began quadrupedal step training beginning 2 weeks post-SCI for 1 h/day. End of study experiments (3 months of training) revealed significant changes in limb kinematics, gait, and hindlimb flexor-extensor bursting patterns relative to non-trained controls. Importantly, micturition function, evaluated with terminal transvesical cystometry, was significantly improved in the step trained group (increased voiding efficiency, intercontraction interval, and contraction amplitude). Because both SCI and LT affect neurotrophin signaling, and neurotrophins are involved with post-SCI plasticity in micturition pathways, we measured bladder neurotrophin mRNA. Training regulated the expression of nerve growth factor (NGF) but not BDNF or NT3. Bladder NGF mRNA levels were inversely related to bladder function in the trained group. Monitoring of overground locomotion and neuropathic pain throughout the study revealed significant improvements, beginning after 3 weeks of training, which in both cases remained consistent for the study duration. These novel findings, improving non-locomotor in addition to locomotor functions, demonstrate that step training post-SCI could contribute to multiple quality of life gains, targeting patient-centered high priority deficits.
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Affiliation(s)
- Patricia J Ward
- 1 Department of Anatomical Sciences and Neurobiology, University of Louisville , Louisville, Kentucky
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Tomoyose O, Kodama D, Ono H, Tanabe M. Presynaptic Inhibitory Effects of Fluvoxamine, a Selective Serotonin Reuptake Inhibitor, on Nociceptive Excitatory Synaptic Transmission in Spinal Superficial Dorsal Horn Neurons of Adult Mice. J Pharmacol Sci 2014; 126:136-45. [DOI: 10.1254/jphs.14127fp] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Hu JG, Wang XF, Deng LX, Liu NK, Gao X, Chen J, Zhou FC, Xu XM. Cotransplantation of Glial Restricted Precursor Cells and Schwann Cells Promotes Functional Recovery after Spinal Cord Injury. Cell Transplant 2013; 22:2219-36. [DOI: 10.3727/096368912x661373] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Oligodendrocyte (OL) replacement can be a promising strategy for spinal cord injury (SCI) repair. However, the poor posttransplantation survival and inhibitory properties to axonal regeneration are two major challenges that limit their use as donor cells for repair of CNS injuries. Therefore, strategies aimed at enhancing the survival of grafted oligodendrocytes as well as reducing their inhibitory properties, such as the use of more permissive oligodendrocyte progenitor cells (OPCs), also called glial restricted precursor cells (GRPs), should be highly prioritized. Schwann cell (SC) transplantation is a promising translational strategy to promote axonal regeneration after CNS injuries, partly due to their expression and secretion of multiple growth-promoting factors. Whether grafted SCs have any effect on the biological properties of grafted GRPs remains unclear. Here we report that either SCs or SC-conditioned medium (SCM) promoted the survival, proliferation, and migration of GRPs in vitro. When GRPs and SCs were cografted into the normal or injured spinal cord, robust survival, proliferation, and migration of grafted GRPs were observed. Importantly, grafted GRPs differentiated into mature oligodendrocytes and formed new myelin on axons caudal to the injury. Finally, cografts of GRPs and SCs promoted recovery of function following SCI. We conclude that cotransplantation of GRPs and SCs, the only two kinds of myelin-forming cells in the nervous system, act complementarily and synergistically to promote greater anatomical and functional recovery after SCI than when either cell type is used alone.
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Affiliation(s)
- Jian-Guo Hu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
- Anhui Key Laboratory of Tissue Transplantation, The First Affiliated Hospital, Bengbu Medical College, Bengbu, P.R. China
| | - Xiao-Fei Wang
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Ling-Xiao Deng
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Nai-Kui Liu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Xiang Gao
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Jinhui Chen
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Feng C. Zhou
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Xiao-Ming Xu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA
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Hooten WM, Hartman WR, Black JL, Laures HJ, Walker DL. Associations between serotonin transporter gene polymorphisms and heat pain perception in adults with chronic pain. BMC MEDICAL GENETICS 2013; 14:78. [PMID: 23895108 PMCID: PMC3737051 DOI: 10.1186/1471-2350-14-78] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 07/23/2013] [Indexed: 11/10/2022]
Abstract
BACKGROUND The triallelic serotonin transporter gene linked polymorphic region (5-HTTLPR) has been associated with alterations in thermal pain perception. The primary aim of this study was to investigate the associations between heat pain (HP) perception and the triallelic 5-HTTLPR in a large cohort of adults with chronic pain. METHODS The cohort included 277 adults with chronic pain who met inclusion criteria, and were consecutively admitted to an outpatient pain rehabilitation program from March 2009 through March 2010. Individuals were genotyped for the triallelic 5-HTTLPR (including rs25531) and categorized as high, intermediate, or low expressors of the serotonin transporter. Standardized measures of HP perception were obtained using a validated quantitative sensory test method of levels. RESULTS The distribution of the high, intermediate, and low expressing genotypes was 61 (22%), 149 (54%) and 67 (24%), respectively. The Hardy-Weinberg P-value was 0.204 which indicated no departure from equilibrium. A significant effect of genotype was observed for values of HP threshold (P = 0.029). Individual group comparisons showed that values of HP threshold were significantly greater in the intermediate compared to the high expressing group (P = 0.009) but not the low expressing group (P > 0.1). In a multiple variable linear regression model, the intermediate group (P = 0.034) and male sex (P = 0.021) were associated with significantly greater values of HP 0.5, but no significant genotype-by-sex interaction effect was observed. CONCLUSIONS In this study that involved adults with chronic pain, the intermediate triallelic 5-HTTLPR expressing group, but not the low expressing group, was associated with greater HP thresholds compared to the high expressing group.
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Affiliation(s)
- W Michael Hooten
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
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The antinociceptive effect of reversible monoamine oxidase-A inhibitors in a mouse neuropathic pain model. Prog Neuropsychopharmacol Biol Psychiatry 2013; 44:136-42. [PMID: 23419243 DOI: 10.1016/j.pnpbp.2013.02.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 01/23/2013] [Accepted: 02/08/2013] [Indexed: 01/04/2023]
Abstract
Neuropathic pain is a debilitating condition that is often resistant to common analgesics, such as opioids, but is sensitive to some antidepressants, an effect that seems to be mediated by spinal cord 5-HT3 receptors. Because the analgesic potential of monoamine oxidase-A (MAO-A) inhibitors is understudied, we evaluated the potential antinociceptive effect of the reversible MAO-A inhibitors moclobemide and 2-(3,4-dimethoxy-phenyl)-4,5-dihydro-1H-imidazole (2-DMPI) in a mouse neuropathic pain model induced by chronic constriction injury (CCI) of the sciatic nerve. Neuropathic mice showed a decreased mechanical paw withdrawal threshold (PWT) 7 days after lesion compared with the baseline PWT, characterizing the development of hyperalgesia. Moclobemide (100-300 μmol/kg, s.c.) and 2-DMPI (30-300 μmol/kg, s.c.) treatments were able to reverse the CCI-induced hyperalgesia, with 50% inhibitory dose (ID50) values of 39 (18-84) and 11 (4-33) μmol/kg, and maximum inhibition (Imax) values of 88±14 and 98±15%, respectively, at the 300 μmol/kg dose. In addition, we observed a significant increase in the MAO-A activity in the lumbar spinal cord of CCI-submitted mice compared with sham-operated animals. Furthermore, the antihyperalgesic effects of both 2-DMPI and moclobemide were largely reversed by intrathecal injection of the 5-HT3 receptor antagonist ondansetron (10 μg/site). These results suggest a possible involvement of MAO-A in the mechanisms of neuropathic pain and a potential utility of the reversible inhibitors of MAO-A in the development of new therapeutic approaches to treat it.
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Das S, Kumar S, Jain S, Avelev VD, Mathur R. Exposure to ELF- magnetic field promotes restoration of sensori-motor functions in adult rats with hemisection of thoracic spinal cord. Electromagn Biol Med 2013; 31:180-94. [PMID: 22897399 DOI: 10.3109/15368378.2012.695706] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Clinically effective modalities of treatment for spinal cord injury (SCI) still remain unsatisfactory and are largely invasive in nature. There are reports of accelerated regeneration in injured peripheral nerves by extremely low-frequency pulsed electromagnetic field (ELF-EMF) in the rat. In the present study, the effect of (50 Hz), low-intensity (17.96 μT) magnetic field (MF) exposure of rats after-hemisection of T13 spinal cord (hSCI) was investigated on sensori-motor and locomotor functions. Rats were divided into hSCI (sham-exposed) and hSCI+MF (MF: 2 h/d X 6 weeks) groups. Besides their general conditions, locomotor function by Basso, Beattie, and Brenahan (BBB) score; motor responses to noxious stimuli by threshold of tail flick (TTF), simple vocalization (TSV), tail flick latency (TFL), and neuronal excitability by H-reflex were noted. It is found that, in the hSCI+MF group, a statistically significant improvement over the hSCI control group was noted in BBB score from post-SCI wk2 and TFL and TTF by post-hSCI wk1 and wk3, respectively. Correspondingly, TSV gradually restored by post-hSCI wk5.The threshold of H-reflex was reduced on ipsilateral side vs. contralateral side in hSCI and hSCI+MF group. A complete bladder control was dramatically restored on post-hSCI day4 (vs. day7 of hSCI group) and the survival rate was 100% in the hSCI+MF group (vs. 90% of hSCI group). The results of our study suggest that extremely low-frequency (50 Hz), low-intensity (17.96 μT) MF exposure for 2 h/d x 6wks promotes recovery of sensori-motor behavior including locomotion and bladder control both in terms of temporal pattern and magnitude in hemisection injury of (T13) spinal cord rats.
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Affiliation(s)
- Suman Das
- Department of Physiology, All India Institute of Medical Sciences, New Delhi, India
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Viguier F, Michot B, Hamon M, Bourgoin S. Multiple roles of serotonin in pain control mechanisms--implications of 5-HT₇ and other 5-HT receptor types. Eur J Pharmacol 2013; 716:8-16. [PMID: 23500207 DOI: 10.1016/j.ejphar.2013.01.074] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 11/30/2012] [Accepted: 01/29/2013] [Indexed: 11/25/2022]
Abstract
Among monoamine neurotransmitters, serotonin (5-HT) is known to play complex modulatory roles in pain signaling mechanisms since the first reports, about forty years ago, on its essentially pro-nociceptive effects at the periphery and anti-nociceptive effects when injected directly at the spinal cord level. The discovery of multiple 5-HT receptor subtypes allowed possible explanations to this dual action at the periphery versus the central nervous system (CNS) since both excitatory and inhibitory effects can be exerted through 5-HT activation of different 5-HT receptors. However, it also appeared that activation of the same receptor subtype at CNS level might induce variable effects depending on the physiological or pathophysiological status of the animal administered with agonists. In particular, the marked neuroplastic changes induced by nerve lesion, which account for sensitization of pain signaling mechanisms, can contribute to dramatic changes in the effects of a given 5-HT receptor agonist in neuropathic rats versus intact healthy rats. This has notably been observed with 5-HT₇ receptor agonists which exert a pronociceptive action in healthy rats but alleviate hyperalgesia consecutive to nerve lesion in neuropathic animals. Analysis of cellular mechanisms underlying such dual 5-HT actions mediated by a single receptor subtype indicates that the neuronal phenotype which expresses this receptor also plays a key role in determining which modulatory action 5-HT would finally exert on pain signaling mechanisms.
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Affiliation(s)
- Florent Viguier
- INSERM U894, CPN, Neuropsychopharmacology, Faculty of Medicine Pierre & Marie Curie, UPMC, Site Pitié-Salpêtrière, 75013 Paris, France; University Pierre et Marie Curie (UPMC), Neuropsychopharmacology, Faculty of Medicine Pierre & Marie Curie, UPMC, Site Pitié-Salpêtrière, 75013 Paris, France.
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Xifró X, Puig T, Boadas-Vaello P. Diagnóstico y tratamiento farmacológico del dolor neuropático del lesionado medular: del laboratorio a la clínica. Med Clin (Barc) 2013. [DOI: 10.1016/j.medcli.2012.09.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Ohnami S, Kato A, Ogawa K, Shinohara S, Ono H, Tanabe M. Effects of milnacipran, a 5-HT and noradrenaline reuptake inhibitor, on C-fibre-evoked field potentials in spinal long-term potentiation and neuropathic pain. Br J Pharmacol 2013; 167:537-47. [PMID: 22537101 DOI: 10.1111/j.1476-5381.2012.02007.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND AND PURPOSE The analgesic action of 5-HT and noradrenaline reuptake inhibitors (SNRIs) on nociceptive synaptic transmission in the spinal cord is poorly understood. We investigated the effects of milnacipran, an SNRI, on C-fibre-evoked field potentials (FPs) in spinal long-term potentiation (LTP), a proposed synaptic mechanism of hypersensitivity, and on the FPs in a neuropathic pain model. EXPERIMENTAL APPROACH C-fibre-evoked FPs by electrical stimulation of the sciatic nerve fibres were recorded in the spinal dorsal horn of anaesthetized adult rats, and LTP was induced by high-frequency stimulation of the sciatic nerve fibres. A rat model of neuropathic pain was produced by L5 spinal nerve ligation and transection. KEY RESULTS Milnacipran produced prolonged inhibition of C-fibre-evoked FPs when applied spinally after the establishment of LTP of C-fibre-evoked FPs in naïve animals. In the neuropathic pain model, spinal administration of milnacipran clearly reduced the basal C-fibre-evoked FPs. These inhibitory effects of milnacipran were blocked by spinal administration of methysergide, a 5-HT½ receptor antagonist, and yohimbine or idazoxan, α₂-adrenoceptor antagonists. However, spinal administration of milnacipran in naïve animals did not affect the basal C-fibre-evoked FPs and the induction of spinal LTP. CONCLUSION AND IMPLICATIONS Milnacipran inhibited C-fibre-mediated nociceptive synaptic transmission in the spinal dorsal horn after the establishment of spinal LTP and in the neuropathic pain model, by activating both spinal 5-hydroxytryptaminergic and noradrenergic systems. The condition-dependent inhibition of the C-fibre-mediated transmission by milnacipran could provide novel evidence regarding the analgesic mechanisms of SNRIs in chronic pain.
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Affiliation(s)
- S Ohnami
- Laboratory of CNS Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Japan
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Ferguson AR, Huie JR, Crown ED, Baumbauer KM, Hook MA, Garraway SM, Lee KH, Hoy KC, Grau JW. Maladaptive spinal plasticity opposes spinal learning and recovery in spinal cord injury. Front Physiol 2012; 3:399. [PMID: 23087647 PMCID: PMC3468083 DOI: 10.3389/fphys.2012.00399] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Accepted: 09/20/2012] [Indexed: 01/23/2023] Open
Abstract
Synaptic plasticity within the spinal cord has great potential to facilitate recovery of function after spinal cord injury (SCI). Spinal plasticity can be induced in an activity-dependent manner even without input from the brain after complete SCI. A mechanistic basis for these effects is provided by research demonstrating that spinal synapses have many of the same plasticity mechanisms that are known to underlie learning and memory in the brain. In addition, the lumbar spinal cord can sustain several forms of learning and memory, including limb-position training. However, not all spinal plasticity promotes recovery of function. Central sensitization of nociceptive (pain) pathways in the spinal cord may emerge in response to various noxious inputs, demonstrating that plasticity within the spinal cord may contribute to maladaptive pain states. In this review we discuss interactions between adaptive and maladaptive forms of activity-dependent plasticity in the spinal cord below the level of SCI. The literature demonstrates that activity-dependent plasticity within the spinal cord must be carefully tuned to promote adaptive spinal training. Prior work from our group has shown that stimulation that is delivered in a limb position-dependent manner or on a fixed interval can induce adaptive plasticity that promotes future spinal cord learning and reduces nociceptive hyper-reactivity. On the other hand, stimulation that is delivered in an unsynchronized fashion, such as randomized electrical stimulation or peripheral skin injuries, can generate maladaptive spinal plasticity that undermines future spinal cord learning, reduces recovery of locomotor function, and promotes nociceptive hyper-reactivity after SCI. We review these basic phenomena, how these findings relate to the broader spinal plasticity literature, discuss the cellular and molecular mechanisms, and finally discuss implications of these and other findings for improved rehabilitative therapies after SCI.
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Affiliation(s)
- Adam R Ferguson
- Department of Neurological Surgery, Brain and Spinal Injury Center, University of California San Francisco San Francisco, CA, USA
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Grau JW, Huie JR, Garraway SM, Hook MA, Crown ED, Baumbauer KM, Lee KH, Hoy KC, Ferguson AR. Impact of behavioral control on the processing of nociceptive stimulation. Front Physiol 2012; 3:262. [PMID: 22934018 PMCID: PMC3429038 DOI: 10.3389/fphys.2012.00262] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 06/23/2012] [Indexed: 12/24/2022] Open
Abstract
How nociceptive signals are processed within the spinal cord, and whether these signals lead to behavioral signs of neuropathic pain, depends upon their relation to other events and behavior. Our work shows that these relations can have a lasting effect on spinal plasticity, inducing a form of learning that alters the effect of subsequent nociceptive stimuli. The capacity of lower spinal systems to adapt, in the absence of brain input, is examined in spinally transected rats that receive a nociceptive shock to the tibialis anterior muscle of one hind leg. If shock is delivered whenever the leg is extended (controllable stimulation), it induces an increase in flexion duration that minimizes net shock exposure. This learning is not observed in subjects that receive the same amount of shock independent of leg position (uncontrollable stimulation). These two forms of stimulation have a lasting, and divergent, effect on subsequent learning: controllable stimulation enables learning whereas uncontrollable stimulation disables it (learning deficit). Uncontrollable stimulation also enhances mechanical reactivity. We review evidence that training with controllable stimulation engages a brain-derived neurotrophic factor (BDNF)-dependent process that can both prevent and reverse the consequences of uncontrollable shock. We relate these effects to changes in BDNF protein and TrkB signaling. Controllable stimulation is also shown to counter the effects of peripheral inflammation (from intradermal capsaicin). A model is proposed that assumes nociceptive input is gated at an early sensory stage. This gate is sensitive to current environmental relations (between proprioceptive and nociceptive input), allowing stimulation to be classified as controllable or uncontrollable. We further propose that the status of this gate is affected by past experience and that a history of uncontrollable stimulation will promote the development of neuropathic pain.
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Affiliation(s)
- James W Grau
- Cellular and Behavioral Neuroscience, Department of Psychology, Texas A&M University College Station, TX, USA
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Eaton MJ, Berrocal Y, Wolfe SQ, Widerström-Noga E. Review of the history and current status of cell-transplant approaches for the management of neuropathic pain. PAIN RESEARCH AND TREATMENT 2012; 2012:263972. [PMID: 22745903 PMCID: PMC3382629 DOI: 10.1155/2012/263972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 04/09/2012] [Indexed: 11/18/2022]
Abstract
Treatment of sensory neuropathies, whether inherited or caused by trauma, the progress of diabetes, or other disease states, are among the most difficult problems in modern clinical practice. Cell therapy to release antinociceptive agents near the injured spinal cord would be the logical next step in the development of treatment modalities. But few clinical trials, especially for chronic pain, have tested the transplant of cells or a cell line to treat human disease. The history of the research and development of useful cell-transplant-based approaches offers an understanding of the advantages and problems associated with these technologies, but as an adjuvant or replacement for current pharmacological treatments, cell therapy is a likely near future clinical tool for improved health care.
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Affiliation(s)
- Mary J. Eaton
- Miami VA Health System Center, D806C, 1201 NW 16th Street, Miami, FL 33125, USA
| | - Yerko Berrocal
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA
| | - Stacey Q. Wolfe
- Department of Neurosurgery, Tripler Army Medical Center, 1 Jarrett White Road, Honolulu, HI 96859, USA
| | - Eva Widerström-Noga
- Miami VA Health System Center, D806C, 1201 NW 16th Street, Miami, FL 33125, USA
- The Miami Project to Cure Paralysis, Miller School of Medicine at the University of Miami, Miami, FL 33136, USA
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Eaton MJ, Berrocal Y, Wolfe SQ. Potential for Cell-Transplant Therapy with Human Neuronal Precursors to Treat Neuropathic Pain in Models of PNS and CNS Injury: Comparison of hNT2.17 and hNT2.19 Cell Lines. PAIN RESEARCH AND TREATMENT 2012; 2012:356412. [PMID: 22619713 PMCID: PMC3348681 DOI: 10.1155/2012/356412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Accepted: 01/15/2012] [Indexed: 01/07/2023]
Abstract
Effective treatment of sensory neuropathies in peripheral neuropathies and spinal cord injury (SCI) is one of the most difficult problems in modern clinical practice. Cell therapy to release antinociceptive agents near the injured spinal cord is a logical next step in the development of treatment modalities. But few clinical trials, especially for chronic pain, have tested the potential of transplant of cells to treat chronic pain. Cell lines derived from the human neuronal NT2 cell line parentage, the hNT2.17 and hNT2.19 lines, which synthesize and release the neurotransmitters gamma-aminobutyric acid (GABA) and serotonin (5HT), respectively, have been used to evaluate the potential of cell-based release of antinociceptive agents near the lumbar dorsal (horn) spinal sensory cell centers to relieve neuropathic pain after PNS (partial nerve and diabetes-related injury) and CNS (spinal cord injury) damage in rat models. Both cell lines transplants potently and permanently reverse behavioral hypersensitivity without inducing tumors or other complications after grafting. Functioning as cellular minipumps for antinociception, human neuronal precursors, like these NT2-derived cell lines, would likely provide a useful adjuvant or replacement for current pharmacological treatments for neuropathic pain.
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Affiliation(s)
- Mary J. Eaton
- Miami VA Health System Center, D806C, 1201 NW 16th Street, Miami, FL 33199, USA
| | - Yerko Berrocal
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Stacey Q. Wolfe
- Department of Neurosurgery, Tripler Army Medical Center, 1 Jarrett White Road, Honolulu, HI 96859-5000, USA
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Kim KY, Sim KC, Kim HS, Choi WS, Kim GD. Analgesic Effects of Transcranial Direct Current Stimulation on Central Neuropathic Pain in Spinal Cord Contusive Rat Model. INTERNATIONAL JOURNAL OF CONTENTS 2012. [DOI: 10.5392/ijoc.2012.8.1.074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Effect of NMDA NR2B antagonist on neuropathic pain in two spinal cord injury models. Pain 2012; 153:1022-1029. [PMID: 22424878 DOI: 10.1016/j.pain.2012.02.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2011] [Revised: 12/06/2011] [Accepted: 02/02/2012] [Indexed: 10/28/2022]
Abstract
N-Methyl-d-aspartate (NMDA) receptors are thought to play an important role in the processes of central sensitization and pathogenesis of neuropathic pain, particularly after spinal cord injury (SCI). NMDA antagonists effectively reduce neuropathic pain, but serious side effects prevent their use as therapeutic drugs. NMDA NR2B antagonists have been reported to effectively reduce inflammatory and neuropathic pain. In this study, we investigated the effects of NR2B antagonists on neuropathic pain and the expression of NR2B in the spinal cord in 2 SCI models. SCI was induced at T12 by a New York University impactor (contusion) or by sectioning of the lateral half of the spinal cord (hemisection). Ifenprodil (100, 200, 500, 1000nmol) and Ro25-6981 (20, 50, 100, 200nmol) were intrathecally injected and behavioral tests were conducted. Ifenprodil increased the paw withdrawal threshold in both models but also produced mild motor depression at higher doses. Ro25-6981 increased the mechanical nociceptive threshold in a dose-dependent manner without motor depression. NR2B expression was significantly increased on both sides at the spinal segments of L1-2 and L4-5 in the hemisection model but did not change in the contusion model. Increased expression of NR2B in the hemisection model was reduced by intrathecal ifenprodil. These results suggest that intrathecal NMDA NR2B antagonist increased the mechanical nociceptive threshold after SCI without motor depression. A selective subtype of NMDA receptor, such as NR2B, may be a more selective target for pain control because NMDA receptors play a crucial role in the development and maintenance of chronic pain.
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Brown A, Weaver LC. The dark side of neuroplasticity. Exp Neurol 2011; 235:133-41. [PMID: 22116043 DOI: 10.1016/j.expneurol.2011.11.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 10/04/2011] [Accepted: 11/07/2011] [Indexed: 12/19/2022]
Abstract
Whether dramatic or modest, recovery of neurological function after spinal cord injury (SCI) is greatly due to neuroplasticity--the process by which the nervous system responds to injury by establishing new synaptic connections or by altering the strength of existing synapses. However, the same neuroplasticity that allows locomotor function to recover also produces negative consequences such as pain and dysfunction of organs controlled by the autonomic nervous system. In this review we focus specifically on structural neuroplasticity (the growth of new synaptic connections) after SCI and on the consequent development of pain and autonomic dysreflexia, a condition of episodic hypertension. Neuroplasticity after SCI is stimulated by the deafferentation of spinal neurons below the lesion and by the expression of growth-promoting neurotrophins such as nerve growth factor (NGF). A broad range of therapeutic strategies that affect neuroplasticity is being developed for the treatment of SCI. At one end of the spectrum are therapeutic strategies that directly or indirectly increase NGF in the injured spinal cord, and have the most robust effects on neuroplasticity. At the other end of the spectrum are neuroprotective strategies focused on supporting and rescuing uninjured, or partially injured, axons; these might limit the deafferentation stimulus for neuroplasticity. In the middle of this spectrum are strategies that block axon growth inhibitors without necessarily providing a growth stimulus. The literature supports the view that the negative consequences of neuroplasticity develop more commonly with therapies that directly stimulate nerve growth than they develop in the untreated injured cord. Compared to these conditions, neuroplasticity with negative outcomes is less prevalent after treatments that that neutralize axon growth inhibitors, and least apparent after strategies that promote neuroprotection.
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Affiliation(s)
- Arthur Brown
- Spinal Cord Injury Laboratory, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.
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Avila-Martin G, Galan-Arriero I, Gómez-Soriano J, Taylor J. Treatment of rat spinal cord injury with the neurotrophic factor albumin-oleic acid: translational application for paralysis, spasticity and pain. PLoS One 2011; 6:e26107. [PMID: 22046257 PMCID: PMC3202524 DOI: 10.1371/journal.pone.0026107] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 09/19/2011] [Indexed: 01/11/2023] Open
Abstract
Sensorimotor dysfunction following incomplete spinal cord injury (iSCI) is often characterized by the debilitating symptoms of paralysis, spasticity and pain, which require treatment with novel pleiotropic pharmacological agents. Previous in vitro studies suggest that Albumin (Alb) and Oleic Acid (OA) may play a role together as an endogenous neurotrophic factor. Although Alb can promote basic recovery of motor function after iSCI, the therapeutic effect of OA or Alb-OA on a known translational measure of SCI associated with symptoms of spasticity and change in nociception has not been studied. Following T9 spinal contusion injury in Wistar rats, intrathecal treatment with: i) Saline, ii) Alb (0.4 nanomoles), iii) OA (80 nanomoles), iv) Alb-Elaidic acid (0.4/80 nanomoles), or v) Alb-OA (0.4/80 nanomoles) were evaluated on basic motor function, temporal summation of noxious reflex activity, and with a new test of descending modulation of spinal activity below the SCI up to one month after injury. Albumin, OA and Alb-OA treatment inhibited nociceptive Tibialis Anterior (TA) reflex activity. Moreover Alb-OA synergistically promoted early recovery of locomotor activity to 50 ± 10% of control and promoted de novo phasic descending inhibition of TA noxious reflex activity to 47 ± 5% following non-invasive electrical conditioning stimulation applied above the iSCI. Spinal L4-L5 immunohistochemistry demonstrated a unique increase in serotonin fibre innervation up to 4.2 ± 1.1 and 2.3 ± 0.3 fold within the dorsal and ventral horn respectively with Alb-OA treatment when compared to uninjured tissue, in addition to a reduction in NR1 NMDA receptor phosphorylation and microglia reactivity. Early recovery of voluntary motor function accompanied with tonic and de novo phasic descending inhibition of nociceptive TA flexor reflex activity following Alb-OA treatment, mediated via known endogenous spinal mechanisms of action, suggests a clinical application of this novel neurotrophic factor for the treatment of paralysis, spasticity and pain.
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Affiliation(s)
- Gerardo Avila-Martin
- Neurología Experimental, Hospital Nacional de Parapléjicos, Servicio de Salud de Castilla-La Mancha, Toledo, Castilla La-Mancha, Spain
| | - Iriana Galan-Arriero
- Neurología Experimental, Hospital Nacional de Parapléjicos, Servicio de Salud de Castilla-La Mancha, Toledo, Castilla La-Mancha, Spain
| | - Julio Gómez-Soriano
- Neurología Experimental, Hospital Nacional de Parapléjicos, Servicio de Salud de Castilla-La Mancha, Toledo, Castilla La-Mancha, Spain
- Escuela de Enfermería y Fisioterapia de Toledo, Universidad de Castilla La-Mancha, Toledo, Castilla-La Mancha, Spain
| | - Julian Taylor
- Neurología Experimental, Hospital Nacional de Parapléjicos, Servicio de Salud de Castilla-La Mancha, Toledo, Castilla La-Mancha, Spain
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Eaton MJ, Widerström-Noga E, Wolfe SQ. Subarachnoid Transplant of the Human Neuronal hNT2.19 Serotonergic Cell Line Attenuates Behavioral Hypersensitivity without Affecting Motor Dysfunction after Severe Contusive Spinal Cord Injury. Neurol Res Int 2011; 2011:891605. [PMID: 21799949 PMCID: PMC3135871 DOI: 10.1155/2011/891605] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2011] [Accepted: 03/21/2011] [Indexed: 11/21/2022] Open
Abstract
Transplant of cells which make biologic agents that can modulate the sensory and motor responses after spinal cord injury (SCI) would be useful to treat pain and paralysis. To address this need for clinically useful human cells, a unique neuronal cell line that synthesizes and secretes/releases the neurotransmitter serotonin (5HT) was isolated. Hind paw tactile allodynia and thermal hyperalgesia induced by severe contusive SCI were potently reversed after lumbar subarachnoid transplant of differentiated cells, but had no effect on open field motor scores, stride length, foot rotation, base of support, or gridwalk footfall errors associated with the SCI. The sensory effects appeared 1 week after transplant and did not diminish during the 8-week course of the experiment when grafts were placed 2 weeks after SCI. Many grafted cells were still present and synthesizing 5HT at the end of the study. These data suggest that the human neuronal serotonergic hNT2.19 cells can be used as a biologic minipump for receiving SCI-related neuropathic pain, but likely requires intraspinal grafts for motor recovery.
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Affiliation(s)
- Mary J. Eaton
- Miami VA Health System Center, D806C, 1201 NW 16th Street, Miami, FL 33125, USA
| | - Eva Widerström-Noga
- Miami VA Health System Center, D806C, 1201 NW 16th Street, Miami, FL 33125, USA
- The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami, 1095 NW 14th Terrace, Miami, FL 33136, USA
| | - Stacey Quintero Wolfe
- Department of Neurosurgery, Tripler Army Medical Center, 1 Jarrett White Road, Honolulu, HI 96859-5000, USA
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Berger JV, Knaepen L, Janssen SPM, Jaken RJP, Marcus MAE, Joosten EAJ, Deumens R. Cellular and molecular insights into neuropathy-induced pain hypersensitivity for mechanism-based treatment approaches. ACTA ACUST UNITED AC 2011; 67:282-310. [PMID: 21440003 DOI: 10.1016/j.brainresrev.2011.03.003] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2010] [Revised: 02/16/2011] [Accepted: 03/18/2011] [Indexed: 12/15/2022]
Abstract
Neuropathic pain is currently being treated by a range of therapeutic interventions that above all act to lower neuronal activity in the somatosensory system (e.g. using local anesthetics, calcium channel blockers, and opioids). The present review highlights novel and often still largely experimental treatment approaches based on insights into pathological mechanisms, which impact on the spinal nociceptive network, thereby opening the 'gate' to higher brain centers involved in the perception of pain. Cellular and molecular mechanisms such as ectopia, sensitization of nociceptors, phenotypic switching, structural plasticity, disinhibition, and neuroinflammation are discussed in relation to their involvement in pain hypersensitivity following either peripheral neuropathies or spinal cord injury. A mechanism-based treatment approach may prove to be successful in effective treatment of neuropathic pain, but requires more detailed insights into the persistence of cellular and molecular pain mechanisms which renders neuropathic pain unremitting. Subsequently, identification of the therapeutic window-of-opportunities for each specific intervention in the particular peripheral and/or central neuropathy is essential for successful clinical trials. Most of the cellular and molecular pain mechanisms described in the present review suggest pharmacological interference for neuropathic pain management. However, also more invasive treatment approaches belong to current and/or future options such as neuromodulatory interventions (including spinal cord stimulation) and cell or gene therapies, respectively.
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Affiliation(s)
- Julie V Berger
- Department of Anesthesiology, Maastricht University Medical Centre, Maastricht, The Netherlands
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Kim DS, Jung SJ, Nam TS, Jeon YH, Lee DR, Lee JS, Leem JW, Kim DW. Transplantation of GABAergic neurons from ESCs attenuates tactile hypersensitivity following spinal cord injury. Stem Cells 2011; 28:2099-108. [PMID: 20848655 DOI: 10.1002/stem.526] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Dae-Sung Kim
- Department of Physiology,Yonsei University College of Medicine, Seoul, Korea
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The time course of serotonin 2A receptor expression after spinal transection of rats: an immunohistochemical study. Neuroscience 2011; 177:114-26. [PMID: 21211552 DOI: 10.1016/j.neuroscience.2010.12.062] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 12/28/2010] [Accepted: 12/30/2010] [Indexed: 11/22/2022]
Abstract
Hyperexcitability of motoneurons is one of the key mechanism that has been demonstrated to underlie the pathogenesis of spasticity after spinal injury. Serotonin (5-HT) denervation supersensitivity is one of the mechanisms underlying this increased motoneuron excitability. In this study, to examine whether the supersensitivity is caused by 5-HT receptor upregulation we investigated changes in levels of 5-HT2A receptor immunoreactivity (5-HT2AR-IR) following a spinal transection in the sacral spinal cord of rats at seven different time points post injury: 2, 8, 16 h, and 1, 2, 7 and 28 days, respectively. 5-HT2AR-IR density was analyzed in motoneurons (regions containing their somata and dendrites) in the spinal segments below the lesion. The results showed no significant changes in 5-HT2AR-IR in the motoneurons up to 16 h following the transection. After 1-day, however the levels of 5-HT2AR-IR increased in the motoneurons and their dendrites, with the density level being 3.4-fold higher in spinalized rats than in sham-operated rats. The upregulation increased progressively until a maximal level was reached at 28 days post-injury. We also investigated 5-HT and 5-HT transporter expressions at five different post injury time points: 1, 2, 7, 21 and 60 days and they showed concurrent down-regulation changes after 2 days. These results suggest that the upregulation of 5-HT2ARs may at least partly underlie the development of 5-HT denervation supersensitivity in spinal motoneurons following spinal injury and thereby implicates their involvement in the pathogenesis of the subsequent development of spasticity.
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Yague JG, Foffani G, Aguilar J. Cortical hyperexcitability in response to preserved spinothalamic inputs immediately after spinal cord hemisection. Exp Neurol 2010; 227:252-63. [PMID: 21093438 DOI: 10.1016/j.expneurol.2010.11.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Accepted: 11/09/2010] [Indexed: 01/27/2023]
Abstract
Chronic injury of the main somatosensory pathways ascending along the spinal cord - the dorsal columns and the spinothalamic tract - can produce both changes in the organization of cortical somatotopic maps and neuropathic pain. Little is known, however, about the early neurophysiological changes occurring immediately after injury. We bilaterally recorded the neural activity of the hindpaw representation of the primary somatosensory cortex evoked by stimuli delivered to the hindpaws before and immediately after a thoracic spinal cord hemisection in anesthetized rats. This unilateral spinal cord injury allowed us to separately investigate the cortical effects of deafferenting the dorsal column (stimuli ipsilateral to the hemisection) or the spinothalamic tract (stimuli contralateral to the hemisection). The hemisection produced immediate bilateral changes in the cortical responses evoked by stimuli delivered to the hindpaw ipsilateral to the hemisection (deafferented dorsal column): an expected loss of classical short-latency cortical responses, accompanied by an unexpected appearance of long-latency activations. At the population level, these activations reflected a progressive stimulus-induced transition of the hindpaw somatosensory cortex from up-and-down states to a sustained activated state. At the single-cell level, these cortical activations resembled the "wind-up" typically observed - with the same type of stimuli - in the dorsal horn cells originating the spinothalamic tract. Virtually no changes were observed in the responses evoked by stimuli delivered to the hindpaw contralateral to the hemisection (deafferented spinothalamic tract). These results suggest that spinal cord hemisection immediately produces an abnormal hyperexcitability of the primary somatosensory cortex in response to preserved spinothalamic inputs from the hindpaw. This immediate cortical hyperexcitability could be important to understand the long-term development of cortical reorganization and neuropathic pain after incomplete spinal cord lesions.
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Affiliation(s)
- J G Yague
- Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain
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50
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Wijnvoord N, Albuquerque B, Häussler A, Myrczek T, Popp L, Tegeder I. Inter-strain differences of serotonergic inhibitory pain control in inbred mice. Mol Pain 2010; 6:70. [PMID: 20977736 PMCID: PMC2987995 DOI: 10.1186/1744-8069-6-70] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Accepted: 10/26/2010] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Descending inhibitory pain control contributes to the endogenous defense against chronic pain and involves noradrenergic and serotonergic systems. The clinical efficacy of antidepressants suggests that serotonin may be particularly relevant for neuropathic pain conditions. Serotonergic signaling is regulated by synthesis, metabolisms, reuptake and receptors. RESULTS To address the complexity, we used inbred mouse strains, C57BL/6J, 129 Sv, DBA/2J and Balb/c, which differ in brain serotonin levels. Serotonin analysis after nerve injury revealed inter-strain differences in the adaptation of descending serotonergic fibers. Upregulation of spinal cord and midbrain serotonin was apparent only in 129 Sv mice and was associated with attenuated nerve injury evoked hyperalgesia and allodynia in this strain. The increase of dorsal horn serotonin was blocked by hemisectioning of descending fibers but not by rhizotomy of primary afferents indicating a midbrain source. Para-chlorophenylalanine-mediated serotonin depletion in spinal cord and midbrain intensified pain hypersensitivity in the nerve injury model. In contrast, chronic inflammation of the hindpaw did not evoke equivalent changes in serotonin levels in the spinal cord and midbrain and nociceptive thresholds dropped in a parallel manner in all strains. CONCLUSION The results suggest that chronic nerve injury evoked hypernociception may be contributed by genetic differences of descending serotonergic inhibitory control.
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Affiliation(s)
- Nina Wijnvoord
- Pharmazentrum frankfurt, ZAFES, Clinical Pharmacology, Goethe-University, Frankfurt, Germany
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