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Erbacher C, Britz S, Dinkel P, Klein T, Sauer M, Stigloher C, Üçeyler N. Interaction of human keratinocytes and nerve fiber terminals at the neuro-cutaneous unit. eLife 2024; 13:e77761. [PMID: 38225894 PMCID: PMC10791129 DOI: 10.7554/elife.77761] [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: 02/09/2022] [Accepted: 12/19/2023] [Indexed: 01/17/2024] Open
Abstract
Traditionally, peripheral sensory neurons are assumed as the exclusive transducers of external stimuli. Current research moves epidermal keratinocytes into focus as sensors and transmitters of nociceptive and non-nociceptive sensations, tightly interacting with intraepidermal nerve fibers at the neuro-cutaneous unit. In animal models, epidermal cells establish close contacts and ensheath sensory neurites. However, ultrastructural morphological and mechanistic data examining the human keratinocyte-nerve fiber interface are sparse. We investigated this exact interface in human skin applying super-resolution array tomography, expansion microscopy, and structured illumination microscopy. We show keratinocyte ensheathment of afferents and adjacent connexin 43 contacts in native skin and have applied a pipeline based on expansion microscopy to quantify these parameter in skin sections of healthy participants versus patients with small fiber neuropathy. We further derived a fully human co-culture system, visualizing ensheathment and connexin 43 plaques in vitro. Unraveling human intraepidermal nerve fiber ensheathment and potential interaction sites advances research at the neuro-cutaneous unit. These findings are crucial on the way to decipher the mechanisms of cutaneous nociception.
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Affiliation(s)
| | - Sebastian Britz
- Imaging Core Facility, Biocenter, University of WürzburgWürzburgGermany
| | - Philine Dinkel
- Department of Neurology, University Hospital of WürzburgWürzburgGermany
| | - Thomas Klein
- Department of Neurology, University Hospital of WürzburgWürzburgGermany
| | - Markus Sauer
- Department of Biotechnology and Biophysics, University of WürzburgWürzburgGermany
| | | | - Nurcan Üçeyler
- Department of Neurology, University Hospital of WürzburgWürzburgGermany
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Chan KY, Tsai WC, Chiang CY, Sheu ML, Huang CY, Tsai YC, Tsai CY, Lu CJ, Ho ZP, Lai DW. Ameliorative Potential of Hot Compress on Sciatic Nerve Pain in Chronic Constriction Injury-Induced Rat Model. Front Synaptic Neurosci 2022; 14:859278. [PMID: 35685245 PMCID: PMC9171142 DOI: 10.3389/fnsyn.2022.859278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/25/2022] [Indexed: 11/24/2022] Open
Abstract
Hot compress modalities are used to ameliorate pain despite prevalent confusion about which modality should be used and when. Most recommendations for hot compresses are based on empirical experience, with limited evidence to support its efficacy. To obtain insight into the nerve transmission mechanism of hot compresses and to identify the nerve injury marker proteins specifically associated with sciatic nerve pain, we established a rat model of chronic constriction injury (CCI) and performed mechanical allodynia, electrophysiology, and histopathological analysis. All CCI rats exhibited geometric representation of the affected hind paw, which indicated a hyper-impact on both mechanical gait and asymmetry of gait on day 28. The CCI model after 28 days of surgery significantly reduced compound muscle action potential (CMAP) amplitude, but also significantly reduced latency. Administration of hot compress for 3 weeks (heated at 40–42°C, cycle of 40 min, and rest for 20 min, three cycles each time, three times per week) significantly increased the paw withdrawal thresholds in response to stimulation by Von Frey fibers and reversed the CCI-induced reduced sciatic functional index (SFI) scores. Hot compress treatment in the CCI model improved CMAP amplitude and latency. The S100 protein expression level in the CCI+Hot compression group was 1.5-fold higher than in the CCI group; it dramatically reduced inflammation, such as tumor necrosis factor alpha and CD68 expression in nerve injury sites. Synaptophysin (Syn) expression in the CCI+Hot compression group was less than threefold in the CCI group at both nerve injury sites and brain (somatosensory cortex and hippocampus). This finding indicates that local nerve damage and inflammation cause significant alterations in the sensorimotor strip, and hot compress treatment could significantly ameliorate sciatic nerve pain by attenuating Syn and inflammatory factors from local pathological nerves to the brain. This study determines the potential efficacy and safety of hot compress, and may have important implications for its widespread use in sciatic nerve pain treatment.
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Affiliation(s)
- Kwan-Yu Chan
- Department of Rehabilitation, Chang Bing Show Chwan Memorial Hospital, Changhua, Taiwan
| | - Wen-Ching Tsai
- Department of Rehabilitation, Chang Bing Show Chwan Memorial Hospital, Changhua, Taiwan
| | - Chien-Yi Chiang
- Cardiovascular and Mitochondrial Related Disease Research Center, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan
| | - Meei-Ling Sheu
- Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan
- Rong Hsing Research Center for Translational Medicine, National Chung Hsing University, Taichung, Taiwan
- Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Chih-Yang Huang
- Cardiovascular and Mitochondrial Related Disease Research Center, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan
- Department of Medical Laboratory Science and Biotechnology, Asia University, Taichung, Taiwan
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
- Center of General Education, Buddhist Tzu Chi Medical Foundation, Tzu Chi University of Science and Technology, Hualien, Taiwan
- Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan
| | - Yi-Ching Tsai
- Immunomedicine Group, Department of Molecular Biology and Cell Research, Chang Bing Show Chwan Memorial Hospital, Changhua, Taiwan
| | - Chia-Yun Tsai
- Experimental Animal Center, Department of Molecular Biology and Cell Research, Chang Bing Show Chwan Memorial Hospital, Changhua, Taiwan
| | - Chia-Jung Lu
- Neurodiagnostic center, Chang Bing Show Chwan Memorial Hospital, Changhua, Taiwan
| | - Zih-Ping Ho
- Department of Medical Research, Chang Bing Show Chwan Memorial Hospital, Changhua, Taiwan
| | - De-Wei Lai
- Experimental Animal Center, Department of Molecular Biology and Cell Research, Chang Bing Show Chwan Memorial Hospital, Changhua, Taiwan
- *Correspondence: De-Wei Lai, ;
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Abstract
The chronification of pain can be attributed to changes in membrane receptors and channels underlying neuronal plasticity and signal transduction largely within nociceptive neurons that initiate and maintain pathological pain states. These proteins are subject to dynamic modification by posttranslational modifications, creating a code that controls protein function in time and space. Phosphorylation is an important posttranslational modification that affects ∼30% of proteins in vivo. Increased phosphorylation of various nociceptive ion channels and of their modulators underlies sensitization of different pain states. Cyclin-dependent kinases are proline-directed serine/threonine kinases that impact various biological and cellular systems. Cyclin-dependent kinase 5 (Cdk5), one member of this kinase family, and its activators p35 and p39 are expressed in spinal nerves, dorsal root ganglia, and the dorsal horn of the spinal cord. In neuropathic pain conditions, expression and/or activity of Cdk5 is increased, implicating Cdk5 in nociception. Experimental evidence suggests that Cdk5 is regulated through its own phosphorylation, through increasing p35's interaction with Cdk5, and through cleavage of p35 into p25. This narrative review discusses the molecular mechanisms of Cdk5-mediated regulation of target proteins involved in neuropathic pain. We focus on Cdk5 substrates that have been linked to nociceptive pathways, including channels (eg, transient receptor potential cation channel and voltage-gated calcium channel), proteins involved in neurotransmitter release (eg, synaptophysin and collapsin response mediator protein 2), and receptors (eg, glutamate, purinergic, and opioid). By altering the phosphoregulatory "set point" of proteins involved in pain signaling, Cdk5 thus appears to be an attractive target for treating neuropathic pain conditions.
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Spontaneous Neuronal Plasticity in the Contralateral Motor Cortex and Corticospinal Tract after Focal Cortical Infarction in Hypertensive Rats. J Stroke Cerebrovasc Dis 2020; 29:105235. [PMID: 32992200 DOI: 10.1016/j.jstrokecerebrovasdis.2020.105235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 07/02/2020] [Accepted: 08/02/2020] [Indexed: 01/14/2023] Open
Abstract
OBJECTIVES In this study, we investigated the spontaneous neural plasticity on the contralateral side in hypertensive rats, including the expression of nerve growth factors (synaptophysin [SYN] and growth-associated protein 43 [GAP-43]), and the association between nerve fiber sprouting and redistribution, and the recovery of motor functions following sensorimotor cortical infarction. METHODS Initially, Sprague-Dawley rats were induced with renal hypertension by the bilateral renal arteries clips method. Further, they were induced with cerebral ischemia by the middle cerebral artery electrocoagulation method; 70 male rats completed the study. We compared the changes in the corticospinal tract (CST) and the expressions of SYN and GAP-43 on the contralateral side in rats with cerebral infarction using immunohistochemical staining, western blot, and biotinylated dextran amine (BDA) tracing analyses. The recovery of motor function in rats after cortical infarction was evaluated by the foot-fault and beam-walk tests. RESULTS The motor behavior tests revealed that the motor function of rats could recover to various degrees after focal cortical infarction. Compared with the sham-operated group, the SYN and GAP-43 levels increased in the motor cortex of the opposite hemisphere within 28 days after middle cerebral artery occlusion (MCAO). The increase in SYN and GAP-43 expressions presented differently in layers Ⅱ, Ⅲ, and Ⅴ. The amount of BDA-positive fibers also increased significantly in the denervated cervical spinal gray matter on day 56 post-MCAO. CONCLUSIONS The increases in SYN and GAP-43 on the contralateral side of the motor cortex could promote CST sprouting and rewiring in the spinal cord gray matter and also spontaneous motor function recovery after cortical infarction.
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Wang XM, Gu P, Saligan L, Iadarola M, Wong SSC, Ti LK, Cheung CW. Dysregulation of EAAT2 and VGLUT2 Spinal Glutamate Transports via Histone Deacetylase 2 (HDAC2) Contributes to Paclitaxel-induced Painful Neuropathy. Mol Cancer Ther 2020; 19:2196-2209. [PMID: 32847971 DOI: 10.1158/1535-7163.mct-20-0006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 04/24/2020] [Accepted: 08/05/2020] [Indexed: 11/16/2022]
Abstract
Effective treatments for chemotherapy-induced peripheral neuropathy (CIPN) remain unavailable. Given the significance of spinal cord glutamate transporters in neuronal plasticity and central sensitization, this study investigated the role of excitatory amino acid transporter 2 (EAAT2) and vesicular-glutamate transporter 2 (VGLUT2) in the development of paclitaxel-induced painful neuropathy. Paclitaxel (2 mg/kg, i.p., cumulative dose 8 mg/kg) induced long-lasting mechanical allodynia (>28 days) with increased glutamate concentration and decreased EAAT2 expression with no changes in GABA/glycine or VGAT (vesicular GABA transporter) in rat spinal dorsal horn. VGLUT2 expression was upregulated and coexpressed with enhanced synaptophysin, characterizing nociceptive afferent sprouting and new synapse formation of glutamatergic neurons in the spinal cord dorsal horn. HDAC2 and transcription factor YY1 were also upregulated, and their interaction and colocalization were confirmed following paclitaxel treatment using co-immunoprecipitation. Inhibition or knockdown of HDAC2 expression by valproic acid, BRD6688, or HDAC2 siRNA not only attenuated paclitaxel-induced mechanical allodynia but also suppressed HDAC2 upregulation, glutamate accumulation, and the corresponding changes in EAAT2/VGLUT/synaptophysin expression and HDAC2/YY1 interaction. These findings indicate that loss of the balance between glutamate release and reuptake due to dysregulation EAAT2/VGLUT2/synaptophysin cascade in the spinal dorsal horn plays an important role in the development of paclitaxel-induced neuropathic pain. HDAC2/YY1 interaction as a complex appears essential in regulating this pathway, which can potentially be a therapeutic target to relieve CIPN by reversing central sensitization of spinal nociceptive neurons.
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Affiliation(s)
- Xiao-Min Wang
- Laboratory and Clinical Research Institute for Pain, Department of Anaesthesiology, The University of Hong Kong, Hong Kong, SAR, China.
| | - Pan Gu
- Laboratory and Clinical Research Institute for Pain, Department of Anaesthesiology, The University of Hong Kong, Hong Kong, SAR, China
| | - Leorey Saligan
- National Institute of Nursing Research, Division of Intramural Research, NIH, Bethesda, Maryland
| | - Michael Iadarola
- Anesthesiology Research Laboratories, Department of Perioperative Medicine, Clinical Center, NIH, Bethesda, Maryland
| | - Stanley Sau Ching Wong
- Laboratory and Clinical Research Institute for Pain, Department of Anaesthesiology, The University of Hong Kong, Hong Kong, SAR, China.,Department of Anaesthesiology, The University of Hong Kong, Hong Kong, SAR, China
| | - Lian Kah Ti
- Department of Anaesthesia, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Chi Wai Cheung
- Laboratory and Clinical Research Institute for Pain, Department of Anaesthesiology, The University of Hong Kong, Hong Kong, SAR, China. .,Department of Anaesthesiology, The University of Hong Kong, Hong Kong, SAR, China
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Conditional Sox9 ablation improves locomotor recovery after spinal cord injury by increasing reactive sprouting. Exp Neurol 2016; 283:1-15. [DOI: 10.1016/j.expneurol.2016.05.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 05/18/2016] [Accepted: 05/21/2016] [Indexed: 12/23/2022]
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Chiang CY, Liu SA, Sheu ML, Chen FC, Chen CJ, Su HL, Pan HC. Feasibility of Human Amniotic Fluid Derived Stem Cells in Alleviation of Neuropathic Pain in Chronic Constrictive Injury Nerve Model. PLoS One 2016; 11:e0159482. [PMID: 27441756 PMCID: PMC4956194 DOI: 10.1371/journal.pone.0159482] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 07/05/2016] [Indexed: 01/01/2023] Open
Abstract
Purpose The neurobehavior of neuropathic pain by chronic constriction injury (CCI) of sciatic nerve is very similar to that in humans, and it is accompanied by a profound local inflammation response. In this study, we assess the potentiality of human amniotic fluid derived mesenchymal stem cells (hAFMSCs) for alleviating the neuropathic pain in a chronic constriction nerve injury model. Methods and Methods This neuropathic pain animal model was conducted by four 3–0 chromic gut ligatures loosely ligated around the left sciatic nerve in Sprague—Dawley rats. The intravenous administration of hAFMSCs with 5x105 cells was conducted for three consecutive days. Results The expression IL-1β, TNF-α and synaptophysin in dorsal root ganglion cell culture was remarkably attenuated when co-cultured with hAFMSCs. The significant decrease of PGP 9.5 in the skin after CCI was restored by administration of hAFMSCs. Remarkably increased expression of CD 68 and TNF-α and decreased S-100 and neurofilament expression in injured nerve were rescued by hAFMSCs administration. Increases in synaptophysin and TNF-α over the dorsal root ganglion were attenuated by hAFMSCs. Significant expression of TNF-α and OX-42 over the dorsal spinal cord was substantially attenuated by hAFMSCs. The increased amplitude of sensory evoked potential as well as expression of synaptophysin and TNF-α expression was alleviated by hAFMSCs. Human AFMSCs significantly improved the threshold of mechanical allodynia and thermal hyperalgesia as well as various parameters of CatWalk XT gait analysis. Conclusion Human AFMSCs administration could alleviate the neuropathic pain demonstrated in histomorphological alteration and neurobehavior possibly through the modulation of the inflammatory response.
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Affiliation(s)
- Chien-Yi Chiang
- Institute of Biomedical Sciences, National Chung-Hsing University, Taichung, Taiwan
| | - Shih-An Liu
- Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Meei-Ling Sheu
- Institute of Biomedical Sciences, National Chung-Hsing University, Taichung, Taiwan
| | - Fu-Chou Chen
- Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Chun-Jung Chen
- Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Hong-Lin Su
- Institute of Life Sciences, National Chung-Hsing University, Taichung, Taiwan
| | - Hung-Chuan Pan
- Department of Neurosurgery, Taichung Veterans General Hospital, Taichung, Taiwan
- Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- * E-mail:
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Moriarty O, Gorman CL, McGowan F, Ford GK, Roche M, Thompson K, Dockery P, McGuire BE, Finn DP. Impaired recognition memory and cognitive flexibility in the rat L5-L6 spinal nerve ligation model of neuropathic pain. Scand J Pain 2016; 10:61-73. [PMID: 28361775 DOI: 10.1016/j.sjpain.2015.09.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 09/29/2015] [Indexed: 11/17/2022]
Abstract
BACKGROUND AND AIMS Although neuropathic pain is known to negatively affect cognition, the neural mechanisms involved are poorly understood. Chronic pain is associated with changes in synaptic plasticity in the brain which may impact on cognitive functioning. The aim of this study was to model neuropathic pain in mid-aged rats using spinal nerve ligation (SNL). Following establishment of allodynia and hyperalgesia, behaviour was assessed in a battery of cognitive tests. Expression of the presynaptic protein, synaptophysin, and its colocalisation with the vesicular GABA and glutamate transporters (vGAT and vGLUT, respectively), was investigated in the medial prefrontal cortex (mPFC) and hippocampus. METHODS Nine month old male Sprague Dawley rats underwent L5-L6 spinal nerve ligation or a sham procedure. Mechanical and cold allodynia and thermal hyperalgesia were assessed using von Frey, acetone and Hargreaves tests, respectively. Cognition was assessed in the novel-object recognition, air-puff passive avoidance and Morris water maze behavioural tasks. Immunohistochemistry was used to examine the expression of synaptophysin in the mPFC and CA1 region of the hippocampus and double labelling of synaptophysin and the vesicular transporters vGAT and vGlut was used to investigate the distribution of synaptophysin on GABAergic and glutamatergic neurons. RESULTS SNL rats displayed impaired performance in the novel-object recognition task. Passive-avoidance responding, and spatial learning and memory in the Morris water maze, were unaffected by SNL surgery. However, in the water maze reversal task, pain-related impairments were evident during training and probe trials. SNL surgery was not associated with any differences in the expression of synaptophysin or its colocalisation with vGAT or vGLUT in the mPFC or the hippocampal CA1 region. CONCLUSIONS These results suggest that the SNL model of neuropathic pain is associated with deficits in recognition memory and cognitive flexibility, but these deficits are not associated with altered synaptophysin expression or distribution in the mPFC and CA1. IMPLICATIONS Cognitive complaints are common amongst chronic pain patients. Here we modelled cognitive impairment in a well-established animal model of neuropathic pain and investigated the neural mechanisms involved. A better understanding of this phenomenon is an important prerequisite for the development of improved treatment of patients affected.
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Affiliation(s)
- Orla Moriarty
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland, Galway, Ireland
- NCBES Neuroscience Centre, National University of Ireland, Galway, Ireland
- Centre for Pain Research, National University of Ireland, Galway, Ireland
| | - Claire L Gorman
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland, Galway, Ireland
| | - Fiona McGowan
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland, Galway, Ireland
- NCBES Neuroscience Centre, National University of Ireland, Galway, Ireland
- Centre for Pain Research, National University of Ireland, Galway, Ireland
| | - Gemma K Ford
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland, Galway, Ireland
- NCBES Neuroscience Centre, National University of Ireland, Galway, Ireland
- Centre for Pain Research, National University of Ireland, Galway, Ireland
| | - Michelle Roche
- Physiology, School of Medicine, National University of Ireland, Galway, Ireland
- NCBES Neuroscience Centre, National University of Ireland, Galway, Ireland
- Centre for Pain Research, National University of Ireland, Galway, Ireland
| | - Kerry Thompson
- Anatomy, School of Medicine, National University of Ireland, Galway, Ireland
- Centre for Microscopy and Imaging, National University of Ireland, Galway, Ireland
| | - Peter Dockery
- Anatomy, School of Medicine, National University of Ireland, Galway, Ireland
- NCBES Neuroscience Centre, National University of Ireland, Galway, Ireland
- Centre for Microscopy and Imaging, National University of Ireland, Galway, Ireland
| | - Brian E McGuire
- School of Psychology, National University of Ireland, Galway, Ireland
- NCBES Neuroscience Centre, National University of Ireland, Galway, Ireland
- Centre for Pain Research, National University of Ireland, Galway, Ireland
| | - David P Finn
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland, Galway, Ireland
- NCBES Neuroscience Centre, National University of Ireland, Galway, Ireland
- Centre for Pain Research, National University of Ireland, Galway, Ireland
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Bonetti LV, Ilha J, Schneider APK, Barbosa S, Faccioni-Heuser MC. Balance and coordination training, but not endurance training, enhances synaptophysin and neurotrophin-3 immunoreactivity in the lumbar spinal cord after sciatic nerve crush. Muscle Nerve 2015; 53:617-25. [PMID: 26316168 DOI: 10.1002/mus.24889] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 08/19/2015] [Accepted: 08/25/2015] [Indexed: 11/08/2022]
Abstract
INTRODUCTION Numerous rehabilitation treatments have been shown to be useful for peripheral and central restoration after (PNI). METHODS After sciatic nerve crush, we investigated 4 weeks of endurance training (ET) and balance and coordination training (BCT) with sciatic function index, hind-paw stride length, and spinal cord dorsal horn synaptophysin and neurotrophin-3 immunoreactivity. RESULTS Our results demonstrated no significant differences between the non-trained (NT), ET, and BCT groups in sciatic functional index, and in stride-length analysis, but the ET showed higher values compared with the NT group. Synaptophysin immunoreactivity was higher in the BCT group compared with the NT group, and neurotrophin-3 immunoreactivity in the BCT group was greater compared with the other groups. CONCLUSION BCT can positively affect spinal cord plasticity after a (PNI), and these modifications are important in the rehabilitation process.
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Affiliation(s)
- Leandro Viçosa Bonetti
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.,Laboratório de Histofisiologia Comparada, Departamento de Ciências Morfológicas, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Sarmento Leite 500, CEP 90050-170, Porto Alegre, Rio Grande do Sul, Brazil
| | - Jocemar Ilha
- Laboratório de Pesquisa Experimental, Departamento de Fisioterapia, Universidade do Estado de Santa Catarina, Santa Catarina, Brazil
| | - Ana Paula Krauthein Schneider
- Laboratório de Histofisiologia Comparada, Departamento de Ciências Morfológicas, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Sarmento Leite 500, CEP 90050-170, Porto Alegre, Rio Grande do Sul, Brazil
| | - Silvia Barbosa
- Laboratório de Histofisiologia Comparada, Departamento de Ciências Morfológicas, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Sarmento Leite 500, CEP 90050-170, Porto Alegre, Rio Grande do Sul, Brazil
| | - Maria Cristina Faccioni-Heuser
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.,Laboratório de Histofisiologia Comparada, Departamento de Ciências Morfológicas, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Sarmento Leite 500, CEP 90050-170, Porto Alegre, Rio Grande do Sul, Brazil
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Park J, Trinh VN, Sears-Kraxberger I, Li KW, Steward O, Luo ZD. Synaptic ultrastructure changes in trigeminocervical complex posttrigeminal nerve injury. J Comp Neurol 2015; 524:309-22. [PMID: 26132987 DOI: 10.1002/cne.23844] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 06/23/2015] [Accepted: 06/25/2015] [Indexed: 12/20/2022]
Abstract
Trigeminal nerves collecting sensory information from the orofacial area synapse on second-order neurons in the dorsal horn of subnucleus caudalis and cervical C1/C2 spinal cord (Vc/C2, or trigeminocervical complex), which is critical for sensory information processing. Injury to the trigeminal nerves may cause maladaptive changes in synaptic connectivity that plays an important role in chronic pain development. Here we examined whether injury to the infraorbital nerve, a branch of the trigeminal nerves, led to synaptic ultrastructural changes when the injured animals have developed neuropathic pain states. Transmission electron microscopy was used to examine synaptic profiles in Vc/C2 at 3 weeks postinjury, corresponding to the time of peak behavioral hypersensitivity following chronic constriction injury to the infraorbital nerve (CCI-ION). Using established criteria, synaptic profiles were classified as associated with excitatory (R-), inhibitory (F-), and primary afferent (C-) terminals. Each type was counted within the superficial dorsal horn of the Vc/C2 and the means from each rat were compared between sham and injured animals; synaptic contact length was also measured. The overall analysis indicates that rats with orofacial pain states had increased numbers and decreased mean synaptic length of R-profiles within the Vc/C2 superficial dorsal horn (lamina I) 3 weeks post-CCI-ION. Increases in the number of excitatory synapses in the superficial dorsal horn of Vc/C2 could lead to enhanced activation of nociceptive pathways, contributing to the development of orofacial pain states.
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Affiliation(s)
- John Park
- Department of Pharmacology, University of California Irvine, School of Medicine, Irvine, California, 92697
| | - Van Nancy Trinh
- Department of Anesthesiology & Perioperative Care, University of California Irvine, School of Medicine, Irvine, California, 92697
| | - Ilse Sears-Kraxberger
- Reeve-Irvine Research Center, University of California Irvine, School of Medicine, Irvine, California, 92697
| | - Kang-Wu Li
- Department of Anesthesiology & Perioperative Care, University of California Irvine, School of Medicine, Irvine, California, 92697
| | - Oswald Steward
- Reeve-Irvine Research Center, University of California Irvine, School of Medicine, Irvine, California, 92697
| | - Z David Luo
- Department of Pharmacology, University of California Irvine, School of Medicine, Irvine, California, 92697.,Department of Anesthesiology & Perioperative Care, University of California Irvine, School of Medicine, Irvine, California, 92697.,Reeve-Irvine Research Center, University of California Irvine, School of Medicine, Irvine, California, 92697
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Marques MR, Stigger F, Segabinazi E, Augustin OA, Barbosa S, Piazza FV, Achaval M, Marcuzzo S. Beneficial effects of early environmental enrichment on motor development and spinal cord plasticity in a rat model of cerebral palsy. Behav Brain Res 2014; 263:149-57. [DOI: 10.1016/j.bbr.2014.01.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 01/09/2014] [Accepted: 01/11/2014] [Indexed: 11/25/2022]
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Hung KL, Wang SJ, Wang YC, Chiang TR, Wang CC. Upregulation of presynaptic proteins and protein kinases associated with enhanced glutamate release from axonal terminals (synaptosomes) of the medial prefrontal cortex in rats with neuropathic pain. Pain 2014; 155:377-387. [DOI: 10.1016/j.pain.2013.10.026] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 10/04/2013] [Accepted: 10/29/2013] [Indexed: 11/25/2022]
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Chiang CY, Sheu ML, Cheng FC, Chen CJ, Su HL, Sheehan J, Pan HC. Comprehensive analysis of neurobehavior associated with histomorphological alterations in a chronic constrictive nerve injury model through use of the CatWalk XT system. J Neurosurg 2014; 120:250-62. [DOI: 10.3171/2013.9.jns13353] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Neuropathic pain is debilitating, and when chronic, it significantly affects the patient physically, psychologically, and socially. The neurobehavior of animals used as a model for chronic constriction injury seems analogous to the neurobehavior of humans with neuropathic pain. However, no data depicting the severity of histomorphological alterations of the nervous system associated with graded changes in neurobehavior are available. To determine the severity of histomorphological alteration related to neurobehavior, the authors created a model of chronic constrictive injury of varying intensity in rats and used the CatWalk XT system to evaluate neurobehavior.
Methods
A total of 60 Sprague-Dawley rats, weighing 250–300 g each, were randomly assigned to 1 of 5 groups that would receive sham surgery or 1, 2, 3, or 4 ligatures of 3-0 chromic gut loosely ligated around the left sciatic nerve. Neurobehavior was assessed by CatWalk XT, thermal hyperalgesia, and mechanic allodynia before injury and periodically after injury. The nerve tissue from skin to dorsal spinal cord was obtained for histomorphological analysis 1 week after injury, and brain evoked potentials were analyzed 4 weeks after injury.
Results.
Significant differences in expression of nerve growth factor existed in skin, and the differences were associated with the intensity of nerve injury. After injury, expression of cluster of differentiation 68 and tumor necrosis factor–α was increased, and expression of S100 protein in the middle of the injured nerve was decreased. Increased expression of synaptophysin in the dorsal root ganglion and dorsal spinal cord correlated with the intensity of injury. The amplitude of sensory evoked potential increased with greater severity of nerve damage. Mechanical allodynia and thermal hyperalgesia did not differ significantly among treatment groups at various time points. CatWalk XT gait analysis indicated significant differences for print areas, maximum contact maximum intensity, stand phase, swing phase, single stance, and regular index, with sham and/or intragroup comparisons.
Conclusions.
Histomorphological and electrophysiological alterations were associated with severity of nerve damage. Subtle neurobehavioral differences were detected by the CatWalk XT system but not by mechanical allodynia or thermal hyperalgesia. Thus, the CatWalk XT system should be a useful tool for monitoring changes in neuropathic pain, especially subtle alterations.
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Affiliation(s)
| | | | - Fu-Chou Cheng
- 4Education and Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Chun-Jung Chen
- 4Education and Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Hong-Lin Su
- 2Institute of Life Sciences, National Chung-Hsing University
| | - Jason Sheehan
- 5Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia; and
| | - Hung-Chuan Pan
- 1Institute of Biomedical Sciences and
- 3Departments of Neurosurgery and
- 6Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan
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14
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Zhang HH, Zhang XQ, Wang WY, Xue QS, Lu H, Huang JL, Gui T, Yu BW. Increased synaptophysin is involved in inflammation-induced heat hyperalgesia mediated by cyclin-dependent kinase 5 in rats. PLoS One 2012; 7:e46666. [PMID: 23056393 PMCID: PMC3462774 DOI: 10.1371/journal.pone.0046666] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2012] [Accepted: 09/02/2012] [Indexed: 01/05/2023] Open
Abstract
Mechanisms associated with cyclin-dependent kinase 5 (Cdk5)-mediated heat hyperalgesia induced by inflammation remain undefined. This study was designed to examine whether Cdk5 mediates heat hyperalgesia resulting from peripheral injection of complete Freund's adjuvant (CFA) in the spinal dorsal horns of rats by interacting with synaptophysin, a well known membrane protein mediating the endocytosis-exocytosis cycle of synaptic vesicles as a molecular marker associated with presynaptic vesicle membranes. The role of Cdk5 in mediating synaptophysin was examined through the combined use of behavioral approaches, imaging studies, and immunoprecipitation following CFA-induced inflammatory pain. Results showed that Cdk5 colocalized with both synaptophysin and soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptors (SNAREs) consisting of VAMP-2, SNAP-25, and syntaxin 1A in spinal dorsal horn of rats. Increased synaptophysin expression of spinal cord horn neurons post intraplantar injection of CFA coincided with increased duration of heat hyperalgesia lasting from 6 h to 3 d. Intrathecal administration of roscovitine, a Cdk5 specific inhibitor, significantly depressed synaptophysin expression during peak heat hyperalgesia and heat hyperalgesia induced by peripheral injection of CFA. Data presented in this report indicated that calpain activity was transiently upregulated 6 h post CFA-treatment despite previous reports suggesting that calpain was capable of cleaving p35 into p25. Results from previous studies obtained by other laboratories demonstrated that significant changes in p35 expression levels within spinal cord horn neurons were not observed in the CFA-treated inflammatory pain model although significant upregulation of Cdk5 kinase was observed between 2 h to 7 d. Therefore, generation of p25 occurred in a calpain-independent fashion in a CFA-treated inflammatory pain model. Our results demonstrated that increased synaptophysin levels were involved in heat hyperalgesia mediated by Cdk5 in spinal cord dorsal horns of CFA-treated rats, suggesting that inhibiting abnormal activation of Cdk5-synaptophysin may present a novel target for diminishing inflammatory pain.
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Affiliation(s)
- Hong-Hai Zhang
- Department of Anesthesiology Ruijin Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, P.R. China
| | - Xiao-Qin Zhang
- Department of Anesthesiology Ruijin Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, P.R. China
| | - Wen-Yuan Wang
- Department of Anesthesiology Ruijin Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, P.R. China
| | - Qing-Sheng Xue
- Department of Anesthesiology Ruijin Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, P.R. China
| | - Han Lu
- Department of Anesthesiology Ruijin Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, P.R. China
| | - Jin-Lu Huang
- Department of Pharmacy, the Sixth Affiliated Hospital of Shanghai JiaoTong University School of Medicine, Shanghai, P.R. China
| | - Ting Gui
- Department of Anatomy, Institutes of Medical Sciences, Shanghai JiaoTong University School of Medicine, Shanghai, P.R. China
| | - Bu-Wei Yu
- Department of Anesthesiology Ruijin Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, P.R. China
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15
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Fukushima T, Takasusuki T, Tomitori H, Hori Y. Possible involvement of syntaxin 1A downregulation in the late phase of allodynia induced by peripheral nerve injury. Neuroscience 2011; 175:344-57. [DOI: 10.1016/j.neuroscience.2010.11.049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Revised: 11/11/2010] [Accepted: 11/22/2010] [Indexed: 11/16/2022]
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16
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Peng B, Lin JY, Shang Y, Yang ZW, Wang YP. Plasticity in the synaptic number associated with neuropathic pain in the rat spinal dorsal horn: A stereological study. Neurosci Lett 2010; 486:24-8. [DOI: 10.1016/j.neulet.2010.09.037] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Revised: 08/24/2010] [Accepted: 09/13/2010] [Indexed: 11/17/2022]
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17
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Early Changes of β-Catenins and Menins in Spinal Cord Dorsal Horn after Peripheral Nerve Injury. Cell Mol Neurobiol 2010; 30:885-90. [DOI: 10.1007/s10571-010-9517-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Accepted: 03/18/2010] [Indexed: 12/13/2022]
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18
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Jaken RJ, Joosten EA, Knüwer M, Miller R, van der Meulen I, Marcus MA, Deumens R. Synaptic plasticity in the substantia gelatinosa in a model of chronic neuropathic pain. Neurosci Lett 2010; 469:30-3. [DOI: 10.1016/j.neulet.2009.11.038] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Revised: 10/11/2009] [Accepted: 11/12/2009] [Indexed: 10/20/2022]
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19
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Abstract
Hyperalgesia and allodynia are frequent symptoms of disease and may be useful adaptations to protect vulnerable tissues. Both may, however, also emerge as diseases in their own right. Considerable progress has been made in developing clinically relevant animal models for identifying the most significant underlying mechanisms. This review deals with experimental models that are currently used to measure (sect. II) or to induce (sect. III) hyperalgesia and allodynia in animals. Induction and expression of hyperalgesia and allodynia are context sensitive. This is discussed in section IV. Neuronal and nonneuronal cell populations have been identified that are indispensable for the induction and/or the expression of hyperalgesia and allodynia as summarized in section V. This review focuses on highly topical spinal mechanisms of hyperalgesia and allodynia including intrinsic and synaptic plasticity, the modulation of inhibitory control (sect. VI), and neuroimmune interactions (sect. VII). The scientific use of language improves also in the field of pain research. Refined definitions of some technical terms including the new definitions of hyperalgesia and allodynia by the International Association for the Study of Pain are illustrated and annotated in section I.
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Affiliation(s)
- Jürgen Sandkühler
- Department of Neurophysiology, Center for Brain Research, Medical University of Vienna, Vienna, Austria
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20
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Gilerovich EG, Moshonkina TR, Fedorova EA, Shishko TT, Pavlova NV, Gerasimenko YP, Otellin VA. Morphofunctional characteristics of the lumbar enlargement of the spinal cord in rats. ACTA ACUST UNITED AC 2008; 38:855-60. [PMID: 18802763 DOI: 10.1007/s11055-008-9056-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 03/12/2007] [Indexed: 11/25/2022]
Abstract
The topography of the lumbar enlargement of the spinal cord in rats was studied; an immunohistochemical method was used to determine the distribution of synaptophysin--a membrane protein of synaptic vesicles. Synaptophysin-immunoreactive structures were detected in the gray matter of all Rexed laminae, around most neurons and in the neuropil. Previously undescribed subpial synaptic contacts were detected immunohistochemically in the white matter and confirmed by electron microscopy. A non-myelinated component of the corticospinal tract, including axonal varicosities and synaptic contacts, was observed in the dorsal part of the white matter of the lumbar enlargement of the spinal cord.
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Affiliation(s)
- E G Gilerovich
- Department of Morphology, Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia
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21
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Ossipov MH, Bazov I, Gardell LR, Kowal J, Yakovleva T, Usynin I, Ekström TJ, Porreca F, Bakalkin G. Control of chronic pain by the ubiquitin proteasome system in the spinal cord. J Neurosci 2007; 27:8226-37. [PMID: 17670969 PMCID: PMC6673055 DOI: 10.1523/jneurosci.5126-06.2007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Chronic pain is maintained in part by long-lasting neuroplastic changes in synapses and several proteins critical for synaptic plasticity are degraded by the ubiquitin-proteasome system (UPS). Here, we show that proteasome inhibitors administered intrathecally or subcutaneously prevented the development and reversed nerve injury-induced pain behavior. They also blocked pathological pain induced by sustained administration of morphine or spinal injection of dynorphin A, an endogenous mediator of chronic pain. Proteasome inhibitors blocked mechanical allodynia and thermal hyperalgesia in all three pain models although they did not modify responses to mechanical stimuli, but partially inhibited responses to thermal stimuli in control rats. In the spinal cord, these compounds abolished the enhanced capsaicin-evoked calcitonin gene-related peptide (CGRP) release and dynorphin A upregulation, both elicited by nerve injury. Model experiments demonstrated that the inhibitors may act directly on dynorphin-producing cells, blocking dynorphin secretion. Thus, the effects of proteasome inhibitors on chronic pain were apparently mediated through several cellular mechanisms indispensable for chronic pain, including those of dynorphin A release and postsynaptic actions, and of CGRP secretion. Levels of several UPS proteins were reduced in animals with neuropathic pain, suggesting that UPS downregulation, like effects of proteasome inhibitors, counteracts the development of chronic pain. The inhibitors did not produce marked or disabling motor disturbances at doses that were used to modify chronic pain. These results suggest that the UPS is a critical intracellular regulator of pathological pain, and that UPS-mediated protein degradation is required for maintenance of chronic pain and nociceptive, but not non-nociceptive responses in normal animals.
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Affiliation(s)
- Michael H. Ossipov
- Department of Pharmacology, University of Arizona Health Sciences Center, Tucson, Arizona 85724, and
| | - Igor Bazov
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm S-17176, Sweden
| | - Luis R. Gardell
- Department of Pharmacology, University of Arizona Health Sciences Center, Tucson, Arizona 85724, and
| | - Justin Kowal
- Department of Pharmacology, University of Arizona Health Sciences Center, Tucson, Arizona 85724, and
| | - Tatiana Yakovleva
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm S-17176, Sweden
| | - Ivan Usynin
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm S-17176, Sweden
| | - Tomas J. Ekström
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm S-17176, Sweden
| | - Frank Porreca
- Department of Pharmacology, University of Arizona Health Sciences Center, Tucson, Arizona 85724, and
| | - Georgy Bakalkin
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm S-17176, Sweden
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22
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Niederberger E, Schmidtko A, Coste O, Marian C, Ehnert C, Geisslinger G. The glutamate transporter GLAST is involved in spinal nociceptive processing. Biochem Biophys Res Commun 2006; 346:393-9. [PMID: 16765320 DOI: 10.1016/j.bbrc.2006.05.163] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Accepted: 05/13/2006] [Indexed: 12/19/2022]
Abstract
GLAST and GLT-1 are the most abundant glutamate transporters in the CNS and protect neurons from glutamate neurotoxicity. Here, we investigated the role of GLAST in spinal nociceptive processing. GLAST protein expression was not altered after treatment of rats with either formalin or zymosan. Surprisingly, knock-down of GLAST in the spinal cord using antisense-oligonucleotides decreased glutamate concentrations in cerebrospinal fluid (CSF) and reduced the nociceptive behaviour in the rat formalin assay. However, it did not influence thermal hyperalgesia in the zymosan-induced paw inflammation model indicating that GLAST is associated with spontaneous rather than inflammatory nociception. Mechanisms that might explain the decreased response in the formalin assay may include compensatory activation of other glutamate transporters, inhibition of glutamate release or disturbance of glutamate recycling. In conclusion, these data suggest that inhibition of GLAST expression in the spinal cord reduces excitatory synaptic activity and thereby spontaneous responses after nociceptive stimulation of the paw.
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Affiliation(s)
- Ellen Niederberger
- pharmazentrum frankfurt/ZAFES, Klinikum der Johann Wolfgang Goethe-Universität Frankfurt, Theodor Stern Kai 7, Frankfurt am Main, Germany.
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23
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Balasubramanyan S, Stemkowski PL, Stebbing MJ, Smith PA. Sciatic chronic constriction injury produces cell-type-specific changes in the electrophysiological properties of rat substantia gelatinosa neurons. J Neurophysiol 2006; 96:579-90. [PMID: 16611846 DOI: 10.1152/jn.00087.2006] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Peripheral nerve injury increases spontaneous action potential discharge in spinal dorsal horn neurons and augments their response to peripheral stimulation. This "central hypersensitivity, " which relates to the onset and persistence of neuropathic pain, reflects spontaneous activity in primary afferent fibers as well as long-term changes in the intrinsic properties of the dorsal horn (centralization). To isolate and investigate cellular mechanisms underlying "centralization," sciatic nerves of 20-day-old rats were subjected to 13-25 days of chronic constriction injury (CCI; Mosconi-Kruger polyethylene cuff model). Spinal cord slices were then acutely prepared from sham-operated or CCI animals, and whole cell recording was used to compare the properties of five types of substantia gelatinosa neuron. These were defined as tonic, irregular, phasic, transient, or delay according to their discharge pattern in response to depolarizing current. CCI did not affect resting membrane potential, rheobase, or input resistance in any neuron type but increased the amplitude and frequency of spontaneous and miniature excitatory postsynaptic currents (EPSCs) in delay, transient, and irregular cells. These changes involved alterations in the action potential-independent neurotransmitter release machinery and possible increases in the postsynaptic effectiveness of glutamate. By contrast, in tonic cells, CCI reduced the amplitude and frequency of spontaneous and miniature EPSCs. Such changes may relate to the putative role of tonic cells as inhibitory GABAergic interneurons, whereas increased synaptic drive to delay cells may relate to their putative role as the excitatory output neurons of the substantia gelatinosa. Complementary changes in synaptic excitation of inhibitory and excitatory neurons may thus contribute to pain centralization.
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Affiliation(s)
- Sridhar Balasubramanyan
- Department of Pharmacology and Centre for Neuroscience, University of Alberta, Edmonton, Alberta, Canada
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24
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Shojo H, Kibayashi K. Changes in localization of synaptophysin following fluid percussion injury in the rat brain. Brain Res 2006; 1078:198-211. [PMID: 16497279 DOI: 10.1016/j.brainres.2006.01.063] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2005] [Revised: 01/05/2006] [Accepted: 01/09/2006] [Indexed: 11/24/2022]
Abstract
Traumatic brain injuries damage neurons and cause progressing dysfunctions of the brain. Synaptophysin (SYP), a major integral transmembrane protein of synaptic vesicles, provides a molecular marker for the synapse and serves as a functional marker of the brain. This study examined magnitude-dependent changes of SYP in the rat brain 2 days following low, moderate or high fluid percussion injuries and investigated time-dependent changes of SYP in the rat brain with moderate fluid percussion injury 2, 15 and 30 days after trauma using immunohistochemistry and Western blotting. SYP immunoreactivity increased in the lateral cortex and in the subcortical white matter, with increasing magnitude of injury and time after trauma. Increased SYP immunoreactivity was accompanied with degeneration of neuronal cell bodies, their processes and terminals as well as glial cell proliferations. Amounts of SYP measured by Western blotting remained unchanged in brains with moderate fluid percussion within 30 days after trauma. These findings indicate that trauma accumulates SYP at injured sites of neurons without changing SYP contents and that increased SYP immunoreactivity in the cerebral cortex following traumatic injury reflects an inhibition of synaptic vesicle transportation and dysfunction of synapses, thus providing a histological substrate for brain dysfunctions.
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Affiliation(s)
- Hideki Shojo
- Department of Forensic Medicine, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501, Japan.
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25
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Chou AK, Yang LC, Wu PC, Wong WT, Liu GS, Chen JT, Howng SL, Tai MH. Intrathecal gene delivery of glial cell line-derived neurotrophic factor ameliorated paraplegia in rats after spinal ischemia. ACTA ACUST UNITED AC 2005; 133:198-207. [PMID: 15710236 DOI: 10.1016/j.molbrainres.2004.10.036] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/17/2004] [Indexed: 11/28/2022]
Abstract
Paraplegia is a catastrophic complication of thoracic aortic surgery. At present, there is no effective mean to prevent the ischemia-induced spinal cord trauma. Gene delivery of neurotrophic factors may hold promises for prevention of spinal injury. In the present study, we evaluated the effect of glial cell line-derived neurotrophic factor (GDNF) gene delivery on prevention of the pathological changes due to spinal ischemia. Recombinant adenovirus vectors encoding GDNF (Ad-GDNF) and green fluorescent protein (Ad-GFP) were used for gene transfer studies. Treatment with cobalt chloride induced dose-dependent bcl-2 and synaptophysin downregulation in spinal neuronal cells, which could be effectively reversed by GDNF gene transfer. Intrathecal injection of Ad-GDNF led to maximal GDNF expression in spinal cord within 2-7 days. Thus, after intrathecal administration of adenovirus vectors for 3 days, Sprague-Dawley rats received transient aortic occlusion to induce spinal ischemia and were monitored for behavior deficits. The Ad-GDNF-treated rats showed significantly lower paraplegia rate (40%) than that of Ad-GFP- or saline-treated groups (75-85%; P<0.01). In addition, the Ad-GDNF-treated rats exhibited significantly improved locomotor function comparing with rats of control groups (P<0.001). Histological analysis revealed that GDNF gene delivery profoundly attenuated the infiltration of leukocytes in spinal cord after ischemic insults. Furthermore, GDNF gene delivery prominently attenuated the ischemia-induced neuronal loss in dorsal horn lamina VI-VIII and reduction in synaptophysin expression in spinal cords. In conclusion, GDNF gene transfer confers protection to the neuronal cells and synapses networks, thereby alleviated the paraplegia due to spinal ischemia.
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Affiliation(s)
- An Kuo Chou
- Department of Anesthesiology, Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan; Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
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