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McIlvried LA, Del Rosario JS, Pullen MY, Wangzhou A, Sheahan TD, Shepherd AJ, Slivicki RA, Lemen JA, Price TJ, Copits BA, Gereau RW. Intrinsic Homeostatic Plasticity in Mouse and Human Sensory Neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.13.544829. [PMID: 37398430 PMCID: PMC10312743 DOI: 10.1101/2023.06.13.544829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
In response to changes in activity induced by environmental cues, neurons in the central nervous system undergo homeostatic plasticity to sustain overall network function during abrupt changes in synaptic strengths. Homeostatic plasticity involves changes in synaptic scaling and regulation of intrinsic excitability. Increases in spontaneous firing and excitability of sensory neurons are evident in some forms of chronic pain in animal models and human patients. However, whether mechanisms of homeostatic plasticity are engaged in sensory neurons under normal conditions or altered after chronic pain is unknown. Here, we showed that sustained depolarization induced by 30mM KCl induces a compensatory decrease in the excitability in mouse and human sensory neurons. Moreover, voltage-gated sodium currents are robustly reduced in mouse sensory neurons contributing to the overall decrease in neuronal excitability. Decreased efficacy of these homeostatic mechanisms could potentially contribute to the development of the pathophysiology of chronic pain.
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Affiliation(s)
- Lisa A. McIlvried
- Washington University Pain Center and Department of Anesthesiology; Washington University School of Medicine; St. Louis, MO, 63110; USA
- These authors contributed equally
| | - John Smith Del Rosario
- Washington University Pain Center and Department of Anesthesiology; Washington University School of Medicine; St. Louis, MO, 63110; USA
- These authors contributed equally
| | - Melanie Y. Pullen
- Washington University Pain Center and Department of Anesthesiology; Washington University School of Medicine; St. Louis, MO, 63110; USA
| | - Andi Wangzhou
- Department of Neuroscience and Center for Advanced Pain Studies; The University of Texas at Dallas; Dallas, TX, 75080; USA
| | - Tayler D. Sheahan
- Washington University Pain Center and Department of Anesthesiology; Washington University School of Medicine; St. Louis, MO, 63110; USA
| | - Andrew J. Shepherd
- Washington University Pain Center and Department of Anesthesiology; Washington University School of Medicine; St. Louis, MO, 63110; USA
| | - Richard A. Slivicki
- Washington University Pain Center and Department of Anesthesiology; Washington University School of Medicine; St. Louis, MO, 63110; USA
| | | | - Theodore J. Price
- Department of Neuroscience and Center for Advanced Pain Studies; The University of Texas at Dallas; Dallas, TX, 75080; USA
| | - Bryan A. Copits
- Washington University Pain Center and Department of Anesthesiology; Washington University School of Medicine; St. Louis, MO, 63110; USA
| | - Robert W. Gereau
- Washington University Pain Center and Department of Anesthesiology; Washington University School of Medicine; St. Louis, MO, 63110; USA
- Department of Neuroscience and Department of Biomedical Engineering; Washington University School of Medicine; St. Louis, MO, 63110; USA
- Lead contact
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Xuelai L, Xueyan L, Wen X. Exploring the Use of the Current Perception Threshold in Pharyngeal Paresthesia Patients. Dysphagia 2022; 37:1431-1439. [PMID: 34978622 DOI: 10.1007/s00455-021-10401-5] [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: 05/17/2021] [Accepted: 12/13/2021] [Indexed: 12/16/2022]
Abstract
To explore pharyngeal sensory function by current perception threshold (CPT) measurement in paresthetic pharynx. In total, 58 healthy participants and 66 patients with pharyngeal paresthetic symptoms underwent CPT evaluation. Pharyngeal paresthesia (n = 66) was classified into three categories based on aetiologies: six cases with pain in pharynx; 34 neuropathic patients with glossopharyngeal nerve and/or vagus nerve or recurrent laryngeal nerve injury; and 26 patients with globus pharyngeus. CPT measurements were obtained from bilateral palatoglossal arch and tongue base at 2000, 250 and 5 Hz stimulation frequencies. Ranked from high to low, the CPT values for the bilateral palatoglossal arches and tongue bases were: lower cranial neuropathic patients, globus pharyngeus, healthy participants and patients with pain. The CPT values for neuropathic patients on the injured side were significantly higher than those on the healthy side (P < 0.05). The CPT values for patients with pain in pharynx were significantly lower than those of healthy participants (P < 0.05) when the bilateral tongue bases were stimulated. The CPT measurement is a reliable method for quantitatively assessing pharyngeal sensory function and able to differentiate pharyngeal paresthesia between lower cranial neuropathic and subjective discomfort. Pharyngeal sensory function is more sensitive in patients with pain in pharynx. Pharyngeal sensory function is significantly reduced in lower cranial neuropathic patients, especially on the injured side. Patients with globus pharyngeus have pharyngeal hyposensitivity.
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Affiliation(s)
- Liu Xuelai
- Department of Otorhinolaryngology-Head Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, 1 Dongjiaominxiang, Beijing, 100730, China
- Department of Otolaryngology Head and Neck Surgery, Chongqing General Hospital, Chongqing, China
| | - Li Xueyan
- Department of Otorhinolaryngology-Head Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, 1 Dongjiaominxiang, Beijing, 100730, China
| | - Xu Wen
- Department of Otorhinolaryngology-Head Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Key Laboratory of Otolaryngology Head and Neck Surgery, Ministry of Education, 1 Dongjiaominxiang, Beijing, 100730, China.
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Differential Activation of pERK1/2 and c-Fos Following Injury to Different Regions of Primary Sensory Neuron. Life (Basel) 2022; 12:life12050752. [PMID: 35629419 PMCID: PMC9147482 DOI: 10.3390/life12050752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/15/2022] [Accepted: 05/17/2022] [Indexed: 12/30/2022] Open
Abstract
Nerve injury causes hyperexcitability of the dorsal root ganglion (DRG) and spinal dorsal horn (DH) neurons, which results in neuropathic pain. We have previously demonstrated that partial dorsal rhizotomy (PDR) produced less severe pain-like behavior than chronic constriction injury (CCI) or chronic compression of DRG (CCD) and did not enhance DRG neuronal excitability. However, the mechanisms underlying such discrepancy remain unclear. This study was designed to compare the activation of phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2) in DRG and DH, and c-Fos in DH following treatments of CCI, CCD, and PDR. We confirmed that thermal hyperalgesia produced by PDR was less severe than that produced by CCI or CCD. We showed that pERK1/2 in DRG and DH was greatly activated by CCI or CCD, whereas PDR produced only transient and mild pERK1/2 activation. CCI, CCD, and PDR induced robust c-Fos expression in DH; nevertheless, c-Fos+ neurons following PDR were much fewer than that following CCI or CCD. Blocking retrograde axonal transport by colchicine proximal to the CCI injury site diminished thermal hyperalgesia and inhibited pERK1/2 and c-Fos activation. These findings demonstrate that less severe pain-like behavior produced by PDR than CCI or CCD attributes to less activation of pERK1/2 and c-Fos. Such neurochemical activation partially relies on retrograde axonal transport of certain “injury signals” from the peripheral injured site to DRG somata.
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Lin JH, Yu YW, Chuang YC, Lee CH, Chen CC. ATF3-Expressing Large-Diameter Sensory Afferents at Acute Stage as Bio-Signatures of Persistent Pain Associated with Lumbar Radiculopathy. Cells 2021; 10:cells10050992. [PMID: 33922541 PMCID: PMC8145235 DOI: 10.3390/cells10050992] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/09/2021] [Accepted: 04/21/2021] [Indexed: 11/16/2022] Open
Abstract
The mechanism of pain chronicity is largely unknown in lumbar radiculopathy (LR). The anatomical location of nerve injury is one of the important factors associated with pain chronicity of LR. Accumulating evidence has shown constriction distal to the dorsal root ganglion (DRG) caused more severe radiculopathy than constriction proximal to the DRG; thereby, the mechanism of pain chronicity in LR could be revealed by comparing the differences in pathological changes of DRGs between nerve constriction distal and proximal to the DRG. Here, we used 2 rat models of LR with nerve constriction distal or proximal to the DRG to probe how the different nerve injury sites could differentially affect pain chronicity and the pathological changes of DRG neuron subpopulations. As expected, rats with nerve constriction distal to the DRG showed more persistent pain behaviors than those with nerve constriction proximal to the DRG in 50% paw withdraw threshold, weight-bearing test, and acetone test. One day after the operation, distal and proximal nerve constriction showed differential pathological changes of DRG. The ratios of activating transcription factor3 (ATF3)-positive DRG neurons were significantly higher in rats with nerve constriction distal to DRG than those with nerve constriction proximal to DRG. In subpopulation analysis, the ratios of ATF3-immunoreactivity (IR) in neurofilament heavy chain (NFH)-positive DRG neurons significantly increased in distal nerve constriction compared to proximal nerve constriction; although, both distal and proximal nerve constriction presented increased ratios of ATF3-IR in calcitonin gene-related peptide (CGRP)-positive DRG neurons. Moreover, the nerve constriction proximal to DRG caused more hypoxia than did that distal to DRG. Together, ATF3 expression in NHF-positive DRG neurons at the acute stage is a potential bio-signature of persistent pain in rat models of LR.
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Affiliation(s)
- Jiann-Her Lin
- Department of Neurosurgery, Taipei Medical University Hospital, Taipei 110301, Taiwan;
- Department of Surgery, Division of Neurosurgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110301, Taiwan;
- Taipei Neuroscience Institute, Taipei Medical University, Taipei 110301, Taiwan
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115201, Taiwan; (Y.-C.C.); (C.-H.L.)
| | - Yu-Wen Yu
- Department of Surgery, Division of Neurosurgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110301, Taiwan;
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115201, Taiwan; (Y.-C.C.); (C.-H.L.)
| | - Yu-Chia Chuang
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115201, Taiwan; (Y.-C.C.); (C.-H.L.)
| | - Cheng-Han Lee
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115201, Taiwan; (Y.-C.C.); (C.-H.L.)
| | - Chih-Cheng Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115201, Taiwan; (Y.-C.C.); (C.-H.L.)
- Neuroscience Program of Academia Sinica, Academia Sinica, Taipei 115201, Taiwan
- Taiwan Mouse Clinic, Biomedical Translation Research Center, Academia Sinica, Taipei 115202, Taiwan
- Correspondence:
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The Wnt/ β-Catenin Pathway Regulated Cytokines for Pathological Neuropathic Pain in Chronic Compression of Dorsal Root Ganglion Model. Neural Plast 2021; 2021:6680192. [PMID: 33959159 PMCID: PMC8075704 DOI: 10.1155/2021/6680192] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 03/05/2021] [Accepted: 03/17/2021] [Indexed: 01/07/2023] Open
Abstract
Neuropathic pain is one of the important challenges in the clinic. Although a lot of research has been done on neuropathic pain (NP), the molecular mechanism is still elusive. We aimed to investigate whether the Wnt/β-catenin pathway was involved in NP caused by sustaining dorsal root ganglion (DRG) compression with the chronic compression of dorsal root ganglion model (CCD). Our RNA sequencing results showed that several genes related to the Wnt pathway have changed in DRG and spinal cord dorsal horn (SCDH) after CCD surgery. Therefore, we detected the activation of the Wnt/β-catenin pathway in DRG and SCDH and found active β-catenin significantly upregulated in DRG and SCDH 1 day after CCD surgery and peaked on days 7-14. Immunofluorescence results also confirmed nuclear translocalization of active β-catenin in DRG and SCDH. Additionally, rats had obvious mechanical induced pain after CCD surgery and the pain was significantly alleviated after the application of the Wnt/β-catenin pathway inhibitor XAV939. Furthermore, we found that the levels of proinflammatory factors tumor necrosis factor-α (TNF-α) and interleukin-18 (IL-18) were significantly elevated in CCD rat serum, while the levels of them were correspondingly decreased after the Wnt/β-catenin pathway being inhibited. The results of Spearman correlation coefficient analysis showed that the levels of TNF-α and IL-18 were negatively correlated with the mechanical withdrawal thresholds (MWT) after CCD surgery. Collectively, our findings suggest that the Wnt/β-catenin pathway plays a critical role in the pathogenesis of NP and may be an effective target for the treatment of NP.
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Nava-Mesa MO, Aispuru Lanche GR. [Role of B vitamins, thiamine, pyridoxine, and cyanocobalamin in back pain and other musculoskeletal conditions: a narrative review]. Semergen 2021; 47:551-562. [PMID: 33865694 DOI: 10.1016/j.semerg.2021.01.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 01/12/2021] [Indexed: 12/25/2022]
Abstract
Low back pain, as well as other musculoskeletal disorders (neck pain, osteoarthritis, etc.), are a very frequent cause of consultation both in primary care and in other hospital specialties and are usually associated with high functional and work disability. Acute low back pain can present different nociceptive, neuropathic and nonciplastic components, which leads to consider it as a mixed type pain. The importance of the concept of mixed pain is due to the fact that the symptomatic relief of these pathologies requires a multimodal therapeutic approach to various pharmacological targets. The antinociceptive role of the B vitamin complex has been recognized for several decades, specifically the combination of Thiamine, Pyridoxine and Cyanocobalamin (TPC). Likewise, there is accumulated evidence that indicates an adjuvant analgesic action in low back pain. The aim of the present review is to present the existing evidence and the latest findings on the therapeutic effects of the TPC combination in low back pain. Likewise, some of the most relevant mechanisms of action involved that can explain these effects are analyzed. The reviewed evidence indicates that the combined use of PCT has an adjuvant analgesic effect in mixed pain, specifically in low back pain and other musculoskeletal disorders with nociceptive and neuropathic components. This effect can be explained by an anti-inflammatory, antinociceptive, neuroprotective and neuromodulatory action of the TPC combination on the descending pain system.
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Affiliation(s)
- M O Nava-Mesa
- Grupo de Investigación en Neurociencias (NEUROS), Escuela de Medicina y Ciencias de la Salud, Universidad del Rosario, Bogotá, Colombia
| | - G R Aispuru Lanche
- Grupo de Trabajo Aparato Locomotor Semergen. Gerencia de Atención Primaria de Burgos, Castilla y León, España.
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Pathophysiological roles and therapeutic potential of voltage-gated ion channels (VGICs) in pain associated with herpesvirus infection. Cell Biosci 2020; 10:70. [PMID: 32489585 PMCID: PMC7247163 DOI: 10.1186/s13578-020-00430-2] [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: 02/04/2020] [Accepted: 05/13/2020] [Indexed: 02/06/2023] Open
Abstract
Herpesvirus is ranked as one of the grand old members of all pathogens. Of all the viruses in the superfamily, Herpes simplex virus type 1 (HSV-1) is considered as a model virus for a variety of reasons. In a permissive non-neuronal cell culture, HSV-1 concludes the entire life cycle in approximately 18–20 h, encoding approximately 90 unique transcriptional units. In latency, the robust viral gene expression is suppressed in neurons by a group of noncoding RNA. Historically the lesions caused by the virus can date back to centuries ago. As a neurotropic pathogen, HSV-1 is associated with painful oral lesions, severe keratitis and lethal encephalitis. Transmission of pain signals is dependent on the generation and propagation of action potential in sensory neurons. T-type Ca2+ channels serve as a preamplifier of action potential generation. Voltage-gated Na+ channels are the main components for action potential production. This review summarizes not only the voltage-gated ion channels in neuropathic disorders but also provides the new insights into HSV-1 induced pain.
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Modulation of Voltage-Gated Sodium Channel Activity in Human Dorsal Root Ganglion Neurons by Herpesvirus Quiescent Infection. J Virol 2020; 94:JVI.01823-19. [PMID: 31694955 DOI: 10.1128/jvi.01823-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 10/25/2019] [Indexed: 12/15/2022] Open
Abstract
The molecular mechanisms of pain associated with alphaherpesvirus latency are not clear. We hypothesize that the voltage-gated sodium channels (VGSC) on the dorsal root ganglion (DRG) neurons controlling electrical impulses may have abnormal activity during latent viral infection and reactivation. We used herpes simplex virus 1 (HSV-1) to infect the human DRG-derived neuronal cell line HD10.6 in order to study the establishment and maintenance of viral latency, viral reactivation, and changes in the functional expression of VGSCs. Differentiated cells exhibited robust tetrodotoxin (TTX)-sensitive sodium currents, and acute infection significantly reduced the functional expression of VGSCs within 24 h and completely abolished VGSC activity within 3 days. A quiescent state of infection mimicking latency can be achieved in the presence of acyclovir (ACV) for 7 days followed by 5 days of ACV washout, and then the viruses can remain dormant for another 3 weeks. It was noted that during the establishment of HSV-1 latency, the loss of VGSC activity caused by HSV-1 infection could not be blocked by ACV treatment. However, neurons with continued ACV treatment for another 4 days showed a gradual recovery of VGSC functional expression. Furthermore, the latently infected neurons exhibited higher VGSC activity than controls. The overall regulation of VGSCs by HSV-1 during quiescent infection was proved by increased transcription and possible translation of Nav1.7. Together, these observations demonstrated a very complex pattern of electrophysiological changes during HSV infection of DRG neurons, which may have implications for understanding of the mechanisms of virus-mediated pain linked to latency and reactivation.IMPORTANCE The reactivation of herpesviruses, most commonly varicella-zoster virus (VZV) and pseudorabies virus (PRV), may cause cranial nerve disorder and unbearable pain. Clinical studies have also reported that HSV-1 causes postherpetic neuralgia and chronic occipital neuralgia in humans. The current work meticulously studies the functional expression profile changes of VGSCs during the processes of HSV-1 latency establishment and reactivation using human dorsal root ganglion-derived neuronal HD10.6 cells as an in vitro model. Our results indicated that VGSC activity was eliminated upon infection but steadily recovered during latency establishment and that latent neurons exhibited even higher VGSC activity. This finding advances our knowledge of how ganglion neurons generate uncharacteristic electrical impulses due to abnormal VGSC functional expression influenced by the latent virus.
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Li ZH, Cui D, Qiu CJ, Song XJ. Cyclic nucleotide signaling in sensory neuron hyperexcitability and chronic pain after nerve injury. NEUROBIOLOGY OF PAIN 2019; 6:100028. [PMID: 31223142 PMCID: PMC6565612 DOI: 10.1016/j.ynpai.2019.100028] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 03/06/2019] [Accepted: 03/07/2019] [Indexed: 11/08/2022]
Abstract
Activation of cAMP-PKA and cGMP-PKG pathways contributes to injury-induced sensory neuron hyperexcitability. Activation of cAMP and cGMP contributes to the development of bone cancer pain. PAR2 activation mediates injury-induced cAMP-dependent sensory neuron hyperexcitability.
The cyclic nucleotide signaling, including cAMP-PKA and cGMP-PKG pathways, has been well known to play critical roles in regulating cellular growth, metabolism and many other intracellular processes. In recent years, more and more studies have uncovered the roles of cAMP and cGMP in the nervous system. The cAMP and cGMP signaling mediates chronic pain induced by different forms of injury and stress. Here we summarize the roles of cAMP-PKA and cGMP-PKG signaling pathways in the pathogenesis of chronic pain after nerve injury. In addition, acute dissociation and chronic compression of the dorsal root ganglion (DRG) neurons, respectively, leads to neural hyperexcitability possibly through PAR2 activation-dependent activation of cAMP-PKA pathway. Clinically, radiotherapy can effectively alleviate bone cancer pain at least partly through inhibiting the cancer cell-induced activation of cAMP-PKA pathway. Roles of cyclic nucleotide signaling in neuropathic and inflammatory pain are also seen in many other animal models and are involved in many pro-nociceptive mechanisms including the activation of hyperpolarization-activated cyclic nucleotide (HCN)-modulated ion channels and the exchange proteins directly activated by cAMP (EPAC). Further understanding the roles of cAMP and cGMP signaling in the pathogenesis of chronic pain is theoretically significant and clinically valuable for treatment of chronic pain.
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Affiliation(s)
- Ze-Hua Li
- Department of Biology, SUSTech Center for Pain Medicine, and Medical School, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.,Department of Anesthesiology and Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education of China), Peking University School of Oncology, Beijing Cancer Hospital & Institute, Beijing 100142, China
| | - Dong Cui
- Department of Biology, SUSTech Center for Pain Medicine, and Medical School, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.,Department of Anesthesiology and Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education of China), Peking University School of Oncology, Beijing Cancer Hospital & Institute, Beijing 100142, China
| | - Cheng-Jie Qiu
- Department of Biology, SUSTech Center for Pain Medicine, and Medical School, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Xue-Jun Song
- Department of Biology, SUSTech Center for Pain Medicine, and Medical School, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.,Department of Anesthesiology and Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education of China), Peking University School of Oncology, Beijing Cancer Hospital & Institute, Beijing 100142, China
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Terashima Y, Takebayashi T, Jimbo S, Ogon I, Sato T, Ichise N, Tohse N, Yamashita T. Analgesic effects of calcitonin on radicular pain in male rats. J Pain Res 2019; 12:223-230. [PMID: 30655691 PMCID: PMC6322709 DOI: 10.2147/jpr.s185233] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Purpose Radicular pain is a frequently observed symptom of lumbar disk herniation or lumbar spinal canal stenosis. Achieving radicular pain relief is difficult. This type of pain may progress to chronic neuropathic pain. Calcitonin (elcatonin [eCT]) has been used mainly for hypercalcemia and pain associated with osteoporosis. The purpose of this study was to investigate analgesic effects of repeated eCT administration on radicular pain in male rats and changes in mRNA-expression levels of voltage-dependent sodium channels in the dorsal root ganglion (DRG). Methods Seventy male Sprague-Dawley rats were used. A right L5 hemilaminectomy and an L5-L6 partial facetectomy were performed to expose the right L5 nerve root. Under a microscope, the right L5 spinal nerve root was tightly ligated extradurally with 8-0 nylon suture proximally to the DRG to cause radicular pain in rats. Mechanical hyperalgesia, thermal hyperalgesia, and analgesic effects of eCT were compared among rats with radicular pain that received eCT, those that received the vehicle, and sham rats that received the vehicle. Real-time reverse-transcription PCR was performed to measure mRNA-expression levels of tetrodotoxin-sensitive (NaV1.3 and NaV1.6) and tetrodotoxin-resistant (NaV1.8 and NaV1.9) sodium channels in the DRG. Results Mechanical and thermal hyperalgesic reactions occurring in rats with radicular pain significantly improved on days 5 and 9 of eCT administration, respectively. In rats with radicular pain, mRNA-expression levels of NaV1.3, NaV1.8, and NaV1.9 increased. After repeated eCT administration, mRNA-expression levels of these sodium channels in rats with radicular pain improved to the same levels as in sham rats. Conclusion The present study demonstrated that repeated systemic eCT administration was effective for radicular pain. No serious side effects of eCT have been reported thus far. Therefore, calcitonin may be a preferred therapeutic option for patients with radicular pain or for those requiring long-term treatment.
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Affiliation(s)
- Yoshinori Terashima
- Department of Orthopaedic Surgery, School of Medicine, Sapporo Medical University, Sapporo 060-0061, Japan, .,Department of Cellular Physiology and Signal Transduction, School of Medicine, Sapporo Medical University, Sapporo 060-0061, Japan
| | | | - Shunsuke Jimbo
- Department of Orthopaedic Surgery, School of Medicine, Sapporo Medical University, Sapporo 060-0061, Japan,
| | - Izaya Ogon
- Department of Orthopaedic Surgery, School of Medicine, Sapporo Medical University, Sapporo 060-0061, Japan,
| | - Tatsuya Sato
- Department of Cellular Physiology and Signal Transduction, School of Medicine, Sapporo Medical University, Sapporo 060-0061, Japan
| | - Nobutoshi Ichise
- Department of Cellular Physiology and Signal Transduction, School of Medicine, Sapporo Medical University, Sapporo 060-0061, Japan
| | - Noritsugu Tohse
- Department of Cellular Physiology and Signal Transduction, School of Medicine, Sapporo Medical University, Sapporo 060-0061, Japan
| | - Toshihiko Yamashita
- Department of Orthopaedic Surgery, School of Medicine, Sapporo Medical University, Sapporo 060-0061, Japan,
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Tampin B, Vollert J, Schmid AB. Sensory profiles are comparable in patients with distal and proximal entrapment neuropathies, while the pain experience differs. Curr Med Res Opin 2018. [PMID: 29526115 DOI: 10.1080/03007995.2018.1451313] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVE Distal and proximal entrapment neuropathies such as carpal tunnel syndrome (CTS) and cervical radiculopathy (CR) share similar etiologies. Experimental models suggest that, despite comparable etiology, pathomechanisms associated with injuries of the peripheral and central axon branches are distinct. This study therefore compared self-reported and elicited sensory profiles in patients with distal and proximal entrapment neuropathies. METHODS Patients with electrodiagnostically confirmed CTS (n = 103) and patients with CR (n = 23) were included in this study. A group of healthy participants served as controls (n = 39). Symptoms and sensory profiles were evaluated using quantitative sensory testing (QST) and a self-reported neuropathic pain questionnaire (painDETECT). RESULTS Both patient groups were characterized by a loss of function in thermal and mechanical detection in the main pain area and dermatome compared to healthy reference data (p < .001). There was no significant difference between patients with CTS and CR in pain and detection thresholds except for reduced vibration sense in the main pain area (p < .001) and reduced pressure pain sensitivity in the dermatome in patients with CR (p < .001). However, patients with CR reported higher pain intensities (p = .008), more severe pain attacks (p = .009) and evoked pain by light pressure (p = .002) compared to patients with CTS. CONCLUSION While QST profiles were similar between patients with CTS and CR, self-reported pain profiles differed and may suggest distinct underlying mechanisms in these patient cohorts.
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Affiliation(s)
- Brigitte Tampin
- a Department of Physiotherapy , Sir Charles Gairdner Hospital , Perth , Western Australia
- b Department of Neurosurgery , Sir Charles Gairdner Hospital , Perth , Western Australia
- c School of Physiotherapy and Exercise Science, Faculty of Health Sciences , Curtin University , Western Australia
- d Faculty of Business Management and Social Sciences , Hochschule Osnabrück, University of Applied Sciences , Osnabrück , Germany
| | - Jan Vollert
- e Department of Pain Medicine , BG University Hospital Bergmannsheil GmbH, Ruhr-University Bochum , Germany
- f Pain Research, Faculty of Medicine, Department of Surgery and Cancer , Imperial College London , UK
- g Center of Biomedicine and Medical Technology Mannheim CBTM, Medical Faculty Mannheim , Heidelberg University , Germany
| | - Annina B Schmid
- h Nuffield Department of Clinical Neurosciences , Oxford University, Oxford , United Kingdom
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Babola TA, Li S, Gribizis A, Lee BJ, Issa JB, Wang HC, Crair MC, Bergles DE. Homeostatic Control of Spontaneous Activity in the Developing Auditory System. Neuron 2018; 99:511-524.e5. [PMID: 30077356 DOI: 10.1016/j.neuron.2018.07.004] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 06/01/2018] [Accepted: 06/29/2018] [Indexed: 11/29/2022]
Abstract
Neurons in the developing auditory system exhibit spontaneous bursts of activity before hearing onset. How this intrinsically generated activity influences development remains uncertain, because few mechanistic studies have been performed in vivo. We show using macroscopic calcium imaging in unanesthetized mice that neurons responsible for processing similar frequencies of sound exhibit highly synchronized activity throughout the auditory system during this critical phase of development. Spontaneous activity normally requires synaptic excitation of spiral ganglion neurons (SGNs). Unexpectedly, tonotopic spontaneous activity was preserved in a mouse model of deafness in which glutamate release from hair cells is abolished. SGNs in these mice exhibited enhanced excitability, enabling direct neuronal excitation by supporting cell-induced potassium transients. These results indicate that homeostatic mechanisms maintain spontaneous activity in the pre-hearing period, with significant implications for both circuit development and therapeutic approaches aimed at treating congenital forms of deafness arising through mutations in key sensory transduction components.
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Affiliation(s)
- Travis A Babola
- The Solomon Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Sally Li
- The Solomon Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Alexandra Gribizis
- Department of Neurobiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Brian J Lee
- The Solomon Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, USA
| | - John B Issa
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Han Chin Wang
- The Solomon Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Michael C Crair
- Department of Neurobiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Dwight E Bergles
- The Solomon Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University, Baltimore, MD 21287, USA; Johns Hopkins University Kavli Neuroscience Discovery Institute, Baltimore, MD 21205, USA.
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13
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Lin JH, Hsieh YC, Chen YC, Wang Y, Chen CC, Chiang YH. Diagnostic accuracy of standardised qualitative sensory test in the detection of lumbar lateral stenosis involving the L5 nerve root. Sci Rep 2017; 7:10598. [PMID: 28878316 PMCID: PMC5587645 DOI: 10.1038/s41598-017-10641-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 08/14/2017] [Indexed: 12/31/2022] Open
Abstract
Misdiagnosis of symptomatic lumbar lateral stenosis (LS) may result in an unfavourable prognosis after surgical treatment. This study investigated the diagnostic accuracy of a standardised qualitative sensory test (SQST) in the detection of symptomatic LS in patients who had degenerative spinal disorders involving the L5 spinal nerve. We prospectively identified 75 patients, of which 60 met the inclusion criteria. Lateral recess stenosis at the L5 level or foraminal stenosis at the L5/S1 level on MRI was identified and graded by a neurosurgeon blinded to any clinical information. The reference criteria for the diagnosis of symptomatic LS were grade III LS on MRI and relevant clinical symptoms. Cutaneous sensory functions of the L5 dermatome on the symptomatic side were evaluated using the SQST. Each item of the SQST showed a satisfactory performance in the diagnosis of LS (sensitivity = 0.455-0.727, specificity = 0.868-1.0). A stepwise selection model identified low-strength von-Frey, high-strength von-Frey, and vibration as the most accurate predictors of symptomatic LS with an area under the receiver operating characteristic curve of 0.9563 (95% confidence interval = 0.9003-1.0). In combination with MRI, the SQST is a promising diagnostic tool for detecting symptomatic LS involving L5 nerve roots.
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Affiliation(s)
- Jiann-Her Lin
- PhD Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes, Taipei, Taiwan
- Department of Neurosurgery, Taipei Medical University Hospital, Taipei, Taiwan
- Division of Neurosurgery, Department of Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yi-Chen Hsieh
- PhD Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes, Taipei, Taiwan
| | - Yi-Chen Chen
- Department of Neurosurgery, Taipei Medical University Hospital, Taipei, Taiwan
| | - Yun Wang
- PhD Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes, Taipei, Taiwan
| | - Chih-Cheng Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yung-Hsiao Chiang
- PhD Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes, Taipei, Taiwan.
- Department of Neurosurgery, Taipei Medical University Hospital, Taipei, Taiwan.
- Division of Neurosurgery, Department of Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
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14
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Lu L, Pan C, Chen L, Hu L, Wang C, Han Y, Yang Y, Cheng Z, Liu WT. AMPK activation by peri-sciatic nerve administration of ozone attenuates CCI-induced neuropathic pain in rats. J Mol Cell Biol 2017; 9:132-143. [PMID: 27744376 DOI: 10.1093/jmcb/mjw043] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 05/26/2016] [Indexed: 12/11/2022] Open
Abstract
Neuropathic pain is a debilitating clinical condition with few efficacious treatments, warranting development of novel therapeutics. Ozone is widely used as an alternative therapy for many different pain conditions, with exact mechanisms still elusive. In this study, we found that a single peri-sciatic nerve injection of ozone decreased mechanical allodynia and thermal hyperalgesia, and normalized the phosphorylation of protein kinase C γ, N-methyl-D-aspartate receptor, and extracellular signal-regulated kinase in a chronic constriction injury (CCI) model in rat sciatic nerve. Meanwhile, ozone significantly suppressed CCI-induced activation of spinal microglia. More importantly, the anti-nociceptive effect of ozone depended on the activation of 5'-adenosine monophosphate (AMP)-activated protein kinase (AMPK), which was proved by the fact that the phosphorylated AMPK level increased during the ozone therapy and AMPK antagonist abolished the effect of ozone in vivo and in vitro. In addition, direct injection of AMPK agonist could replicate the anti-nociceptive effect of ozone in CCI rats. In conclusion, our observations indicate that peri-sciatic nerve injection of ozone activates AMPK to attenuate CCI-induced neuropathic pain.
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Affiliation(s)
- Lijuan Lu
- Department of Pain, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing 210008, China.,Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing 210029, China
| | - Cailong Pan
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing 210029, China
| | - Lu Chen
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China
| | - Liang Hu
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing 210029, China
| | - Chaoyu Wang
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing 210029, China
| | - Yuan Han
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing 210029, China
| | - Yanjing Yang
- Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing 210029, China
| | - Zhixiang Cheng
- Department of Pain Management & Cancer Biotherapy Center, The Second Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Wen-Tao Liu
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing 210029, China
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Zhang A, Wang K, Ding L, Bao X, Wang X, Qiu X, Liu J. Bay11-7082 attenuates neuropathic pain via inhibition of nuclear factor-kappa B and nucleotide-binding domain-like receptor protein 3 inflammasome activation in dorsal root ganglions in a rat model of lumbar disc herniation. J Pain Res 2017; 10:375-382. [PMID: 28243141 PMCID: PMC5315342 DOI: 10.2147/jpr.s119820] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Lumbar disc herniation (LDH) is an important cause of radiculopathy, but the underlying mechanisms are incompletely understood. Many studies suggested that local inflammation, rather than mechanical compression, results in radiculopathy induced by LDH. On the molecular and cellular level, nuclear factor-kappa B (NF-κB) and nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome have been implicated in the regulation of neuroinflammation formation and progression. In this study, the autologous nucleus pulposus (NP) was implanted in the left L5 dorsal root ganglion (DRG) to mimic LDH in rats. We investigated the expression of NF-κB and the components of NLRP3 inflammasome in the DRG neurons in rats. Western blotting and immunofluorescence for the related molecules, including NLRP3, apoptosis-associated speck-like protein containing caspase-1 activator domain (ASC), caspase-1, interleukin (IL)-1β, IL-18, IκBα, p-IκBα, p65, p-p65, and calcitonin gene-related peptide (CGRP) were examined. In the NP-treated group, the activations of NLRP3, ASC, caspase-1, IL-1β, IL-18, p-IκBα, and p-p65 in DRG neurons in rats were elevated at 1 day after surgery, and the peak occurred at 7 days. Treatment with Bay11-7082, an inhibitor of the actions of IKK-β, was able to inhibit expression and activation of the molecules (NLRP3, ASC, caspase-1, IL-1β, IL-18, p-IκBα, and p-p65) and relieve the pain in rats. Our study shows that NF-κB and NLRP3 inflammasome are involved in the maintenance of NP-induced pain, and that Bay11-7082 could alleviate mechanical allodynia and thermal hyperalgesia by inhibiting NF-κB and NLRP3 inflammasome activation.
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Affiliation(s)
- Ailiang Zhang
- Spine Surgery, Third Affiliated Hospital of Soochow University, Changzhou, People's Republic of China
| | - Kun Wang
- Spine Surgery, Third Affiliated Hospital of Soochow University, Changzhou, People's Republic of China
| | - Lianghua Ding
- Spine Surgery, Third Affiliated Hospital of Soochow University, Changzhou, People's Republic of China
| | - Xinnan Bao
- Spine Surgery, Third Affiliated Hospital of Soochow University, Changzhou, People's Republic of China
| | - Xuan Wang
- Spine Surgery, Third Affiliated Hospital of Soochow University, Changzhou, People's Republic of China
| | - Xubin Qiu
- Spine Surgery, Third Affiliated Hospital of Soochow University, Changzhou, People's Republic of China
| | - Jinbo Liu
- Spine Surgery, Third Affiliated Hospital of Soochow University, Changzhou, People's Republic of China
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Song XJ, Huang ZJ, Song WB, Song XS, Fuhr AF, Rosner AL, Ndtan H, Rupert RL. Attenuation Effect of Spinal Manipulation on Neuropathic and Postoperative Pain Through Activating Endogenous Anti-Inflammatory Cytokine Interleukin 10 in Rat Spinal Cord. J Manipulative Physiol Ther 2016; 39:42-53. [PMID: 26837229 DOI: 10.1016/j.jmpt.2015.12.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 12/09/2015] [Accepted: 12/10/2015] [Indexed: 10/22/2022]
Abstract
OBJECTIVES The purpose of this study was to investigate roles of the anti-inflammatory cytokine interleukin (IL) 10 and the proinflammatory cytokines IL-1β and tumor necrosis factor α (TNF-α) in spinal manipulation-induced analgesic effects of neuropathic and postoperative pain. METHODS Neuropathic and postoperative pain were mimicked by chronic compression of dorsal root ganglion (DRG) (CCD) and decompression (de-CCD) in adult, male, Sprague-Dawley rats. Behavioral pain after CCD and de-CCD was determined by the increased thermal and mechanical hypersensitivity of the affected hindpaw. Hematoxylin and eosin staining, whole-cell patch clamp electrophysiological recordings, immunohistochemistry, and enzyme-linked immunosorbent assay were used to examine the neural inflammation, neural excitability, and expression of c-Fos and PKC as well as levels of IL-1β, TNF-α, and IL-10 in blood plasma, DRG, or the spinal cord. We used the activator adjusting instrument, a chiropractic spinal manipulative therapy tool, to deliver force to the spinous processes of L5 and L6. RESULTS After CCD and de-CCD treatments, the animals exhibited behavioral and neurochemical signs of neuropathic pain manifested as mechanical allodynia and thermal hyperalgesia, DRG inflammation, DRG neuron hyperexcitability, induction of c-Fos, and the increased expression of PKCγ in the spinal cord as well as increased level of IL-1β and TNF-α in DRG and the spinal cord. Repetitive Activator-assisted spinal manipulative therapy significantly reduced simulated neuropathic and postoperative pain, inhibited or reversed the neurochemical alterations, and increased the anti-inflammatory IL-10 in the spinal cord. CONCLUSION These findings show that spinal manipulation may activate the endogenous anti-inflammatory cytokine IL-10 in the spinal cord and thus has the potential to alleviate neuropathic and postoperative pain.
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Affiliation(s)
- Xue-Jun Song
- Professor, Parker University, Parker Research Institute, Dallas, TX.
| | - Zhi-Jiang Huang
- Research Scientist, Parker University, Parker Research Institute, Dallas, TX
| | - William B Song
- (Volunteer) Research Assistant, Parker University, Parker Research Institute, Dallas, TX
| | - Xue-Song Song
- Research Scientist, Parker University, Parker Research Institute, Dallas, TX
| | - Arlan F Fuhr
- Professor, Parker University, Parker Research Institute, Dallas, TX
| | - Anthony L Rosner
- Research Consultant, Parker University, Parker Research Institute, Dallas, TX
| | - Harrison Ndtan
- Associate Professor, Parker University, Parker Research Institute, Dallas, TX
| | - Ronald L Rupert
- Research Consultant, Parker University, Parker Research Institute, Dallas, TX
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17
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Trainor D, Moeschler S, Pingree M, Hoelzer B, Wang Z, Mauck W, Qu W. Landmark-based versus ultrasound-guided ilioinguinal/iliohypogastric nerve blocks in the treatment of chronic postherniorrhaphy groin pain: a retrospective study. J Pain Res 2015; 8:767-70. [PMID: 26604817 PMCID: PMC4631426 DOI: 10.2147/jpr.s86777] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Background Chronic postherniorrhaphy groin pain (CPGP) is a debilitating condition, which is often refractory to conservative medical management. To our knowledge, there have been no studies directly comparing landmarked-based and ultrasound-guided approaches in this population. Objective To compare the effectiveness of landmark-based and ultrasound-guided ilioinguinal/iliohypogastric nerve blocks in the treatment of CPGP. Study design This is a retrospective chart review of patients who presented to our tertiary care pain medicine clinic with a diagnosis of CPGP. Inclusion criteria were the following: age >18 years, diagnosis of groin pain, and prior history of herniorrhaphy. Exclusion criteria included those who were seen for initial consultation but were lost to follow-up. Primary outcomes were 50% or greater reduction in pain on visual analog scale (VAS). Secondary outcomes were 30% or greater reduction in VAS pain score, changes in VAS pain scores, and reported complications. Results A total of 36 patients were included in the study. Of them, 20 patients underwent the landmark-based and 16 underwent the ultrasound-guided techniques. There was no significant difference in baseline demographics. The average VAS score preinjection was 7.08 in the landmark-based and 7.0 in the ultrasound-guided groups (P=0.65). A total of 14 patients (70%) in the landmark-based and eleven patients (79%) in the ultrasound-guided groups experienced at least a 50% reduction in VAS scores. There was no statistically significant difference between the two groups (P=1.0), and no complications were noted. We also did not find a significant difference in terms of number of patients with 30% or greater reduction (P=0.71) and changes in VAS pain scores (P=0.64). No complications were reported in either group. Conclusion In our study, there was no statistically significant difference between the landmark-based and ultrasound-guided groups in terms of a reduction in VAS pain scores, and no complications were noted in either group.
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Affiliation(s)
- Drew Trainor
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN, USA
| | - Susan Moeschler
- Department of Anesthesiology, Division of Pain Medicine, Mayo Clinic, Rochester, MN, USA
| | - Matthew Pingree
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN, USA ; Department of Anesthesiology, Division of Pain Medicine, Mayo Clinic, Rochester, MN, USA
| | - Brian Hoelzer
- Department of Anesthesiology, Division of Pain Medicine, Mayo Clinic, Rochester, MN, USA
| | - Zhen Wang
- Department of Anesthesiology, Division of Pain Medicine, Mayo Clinic, Rochester, MN, USA
| | - William Mauck
- Department of Anesthesiology, Division of Pain Medicine, Mayo Clinic, Rochester, MN, USA
| | - Wenchun Qu
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN, USA ; Department of Anesthesiology, Division of Pain Medicine, Mayo Clinic, Rochester, MN, USA
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18
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Hwang HY, Zhang E, Park S, Chung W, Lee S, Kim DW, Ko Y, Lee W. TWIK-Related Spinal Cord K⁺ Channel Expression Is Increased in the Spinal Dorsal Horn after Spinal Nerve Ligation. Yonsei Med J 2015; 56:1307-15. [PMID: 26256973 PMCID: PMC4541660 DOI: 10.3349/ymj.2015.56.5.1307] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 11/19/2014] [Accepted: 12/17/2014] [Indexed: 11/27/2022] Open
Abstract
PURPOSE The TWIK-related spinal cord K⁺ channel (TRESK) has recently been discovered and plays an important role in nociceptor excitability in the pain pathway. Because there have been no reports on the TRESK expression or its function in the dorsal horn of the spinal cord in neuropathic pain, we analyzed TRESK expression in the spinal dorsal horn in a spinal nerve ligation (SNL) model. MATERIALS AND METHODS We established a SNL mouse model by using the L5-6 spinal nerves ligation. We used real-time polymerase chain reaction and immunohistochemistry to investigate TRESK expression in the dorsal horn and L5 dorsal rot ganglion (DRG). RESULTS The SNL group showed significantly higher expression of TRESK in the ipsilateral dorsal horn under pain, but low expression in L5 DRG. Double immunofluorescence staining revealed that immunoreactivity of TRESK was mostly restricted in neuronal cells, and that synapse markers GAD67 and VGlut2 appeared to be associated with TRESK expression. We were unable to find a significant association between TRESK and calcineurin by double immunofluorescence. CONCLUSION TRESK in spinal cord neurons may contribute to the development of neuropathic pain following injury.
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Affiliation(s)
- Hee Youn Hwang
- Department of Anesthesia and Pain Medicine, Chungnam National University Medical School, Daejeon, Korea
| | - Enji Zhang
- Department of Anesthesia and Pain Medicine, Chungnam National University Hospital, Daejeon, Korea
| | - Sangil Park
- Department of Anesthesia and Pain Medicine, Chungnam National University Hospital, Daejeon, Korea
| | - Woosuk Chung
- Department of Anesthesia and Pain Medicine, Chungnam National University Hospital, Daejeon, Korea
| | - Sunyeul Lee
- Department of Anesthesia and Pain Medicine, Chungnam National University Hospital, Daejeon, Korea
| | - Dong Woon Kim
- Department of Anatomy, Chungnam National University Medical School, Daejeon, Korea
| | - Youngkwon Ko
- Department of Anesthesia and Pain Medicine, Chungnam National University Hospital, Daejeon, Korea.
| | - Wonhyung Lee
- Department of Anesthesia and Pain Medicine, Chungnam National University Hospital, Daejeon, Korea.
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Gong K, Zou X, Fuchs PN, Lin Q. Minocycline inhibits neurogenic inflammation by blocking the effects of tumor necrosis factor-α. Clin Exp Pharmacol Physiol 2015; 42:940-949. [DOI: 10.1111/1440-1681.12444] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Revised: 06/19/2015] [Accepted: 06/27/2015] [Indexed: 01/25/2023]
Affiliation(s)
- Kerui Gong
- Department of Psychology; College of Science; University of Texas at Arlington; Arlington TX USA
- Department of Neurobiology; Tai Shan Medical University; Tai'an Shan Dong Province China
| | - Xiaoju Zou
- Department of Psychology; College of Science; University of Texas at Arlington; Arlington TX USA
| | - Perry N Fuchs
- Department of Psychology; College of Science; University of Texas at Arlington; Arlington TX USA
| | - Qing Lin
- Department of Psychology; College of Science; University of Texas at Arlington; Arlington TX USA
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20
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cGMP and cGMP-dependent protein kinase I pathway in dorsal root ganglia contributes to bone cancer pain in rats. Spine (Phila Pa 1976) 2014; 39:1533-41. [PMID: 24921837 DOI: 10.1097/brs.0000000000000456] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A prospective, randomized experimental research. OBJECTIVE To demonstrate the role of cGMP (cyclic guanosine monophosphate)-cGKI (cGMP-dependent protein kinase I) pathway in dorsal root ganglia (DRG) in bone cancer pain. SUMMARY OF BACKGROUND DATA Treating bone cancer pain continues to possess a major clinical challenge because the specific cellular and molecular mechanisms underlying bone cancer pain remain elusive. cGMP and cGMP-dependent protein kinases pathway in DRG plays important role in nerve injury-induced hyperexcitability of DRG neurons, as well as neuropathic pain, however, whether this pathway participates in bone cancer pain is unknown. METHODS The rat model of bone cancer pain was produced by intramedullary injection of rat breast cancer cells (Walker 256) into right tibia. Thermal hyperalgesia and mechanical allodynia were measured before and after administration of inhibitor of cGMP-cGKs pathway (Rp-8-pCPT-cGMPS). Immunofluorescence and reverse transcription-polymerase chain reaction were used to reflect expression of cGKI in DRG neurons, whereas the concentration of cGMP in DRG was tested using enzyme-linked immunosorbent assay method. Whole-cell patch clamp was used to record the hyperexcitability of small neurons in DRG with or without cGKs inhibitor after tumor cell implantation (TCI). RESULTS TCI treatment significantly increased the concentration of cGMP in DRG and activity of cGKs in DRG and the spinal cord. TCI treatment also induced upregulation of cGKI messenger ribonucleic acid and protein in DRG, as well as enhanced hyperexcitability in DRG neurons. Spinal administration of Rp-8-pCPT-cGMPS, cGMP-cGKs inhibitor, significantly suppressed TCI-induced activation of cGMP-cGKI signaling, and hyperexcitability of DRG neurons. Meanwhile, in vivo intrathecal delivery of the Rp-8-pCPT-cGMPS significantly prevented and suppressed TCI-induced hyperalgesia and allodynia. CONCLUSION From these results, we confirm that TCI treatment activates cGMP-cGKI signaling pathway and continuing activation of this pathway in DRG is required for hyperalgesia and/or hyperalgesia and allodynia after TCI treatment. LEVEL OF EVIDENCE N/A.
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21
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Gu N, Niu JY, Liu WT, Sun YY, Liu S, Lv Y, Dong HL, Song XJ, Xiong LZ. Hyperbaric oxygen therapy attenuates neuropathic hyperalgesia in rats and idiopathic trigeminal neuralgia in patients. Eur J Pain 2013; 16:1094-105. [PMID: 22354664 DOI: 10.1002/j.1532-2149.2012.00113.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Neuropathic pain after nerve injury is severe and intractable, and current drug and non-drug therapies offer very limited pain relief. Hyperbaric oxygen (HBO 2) has been clinically used for protection of the nervous system after acute injury. We investigated whether HBO 2 treatment could prevent and/or attenuate neuropathic pain in animals and in patients. METHODS Mechanical allodynia and thermal hyperalgesia and neurochemical alterations of neuropathic pain were analysed in male, adult, Sprague-Dawley rats with sciatic nerve injury. Clinical trials were conducted in patients with idiopathic trigeminal neuralgia. RESULTS Repetitive HBO 2 treatment [a combination of pressure at 3 atmosphere absolute (ATA) and pure oxygen] greatly inhibited behavioural signs of neuropathic pain manifested as thermal hyperalgesia and mechanical allodynia. Such an HBO 2 treatment also inhibited nerve injury-induced induction of c-Fos and activation of astrocytes and increased phosphorylation of NR2B receptor and the subsequent Ca 2+-dependent signals in rats. Neither high pressure (up to 3 ATA) nor pure oxygen alone resulted in analgesic effect. In clinical trials, one course of HBO 2 therapy (10 consecutive days) produced a rapid-onset, dose-dependent and long-lasting analgesic effects evidenced by the decreased doses of carbamazepine required for keeping patient pain at a minimum and decreased scores of visual analogue scales, which was used for patient's self-evaluation. CONCLUSIONS These findings support that HBO 2 therapy is an effective approach for treating neuropathic pain in both animals and human beings and suggest that neural protection, anti-inflammation and inhibition of nerve injury-induced altered neural activity may contribute to the analgesic effect of HBO 2 therapy.
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Affiliation(s)
- N Gu
- Department of Anesthesiology, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
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Dorsal root ganglion compression as an animal model of sciatica and low back pain. Neurosci Bull 2012; 28:618-30. [PMID: 23054639 DOI: 10.1007/s12264-012-1276-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Accepted: 06/08/2012] [Indexed: 01/17/2023] Open
Abstract
As sciatica and low back pain are among the most common medical complaints, many studies have duplicated these conditions in animals. Chronic compression of the dorsal root ganglion (CCD) is one of these models. The surgery is simple: after exposing the L4/L5 intervertebral foramina, stainless steel rods are implanted unilaterally, one rod for each vertebra, to chronically compress the lumbar dorsal root ganglion (DRG). Then, CCD can be used to simulate the clinical conditions caused by stenosis, such as a laterally herniated disc or foraminal stenosis. As the intraforaminal implantation of a rod results in neuronal somal hyperexcitability and spontaneous action potentials associated with hyperalgesia, spontaneous pain, and mechanical allodynia, CCD provides an animal model that mimics radicular pain in humans. This review concerns the mechanisms of neuronal hyperexcitability, focusing on various patterns of spontaneous discharge including one possible pain signal for mechanical allodynia - evoked bursting. Also, new data regarding its significant property of maintaining peripheral input are also discussed. Investigations using this animal model will enhance our understanding of the neural mechanisms for low back pain and sciatica. Furthermore, the peripheral location of the DRG facilitates its use as a locus for controlling pain with minimal central effects, in the hope of ultimately uncovering analgesics that block neuropathic pain without influencing physiological pain.
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Walters ET. Nociceptors as chronic drivers of pain and hyperreflexia after spinal cord injury: an adaptive-maladaptive hyperfunctional state hypothesis. Front Physiol 2012; 3:309. [PMID: 22934060 PMCID: PMC3429080 DOI: 10.3389/fphys.2012.00309] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2012] [Accepted: 07/13/2012] [Indexed: 11/13/2022] Open
Abstract
Spinal cord injury (SCI) causes chronic peripheral sensitization of nociceptors and persistent generation of spontaneous action potentials (SA) in peripheral branches and the somata of hyperexcitable nociceptors within dorsal root ganglia (DRG). Here it is proposed that SCI triggers in numerous nociceptors a persistent hyperfunctional state (peripheral, synaptic, and somal) that originally evolved as an adaptive response to compensate for loss of sensory terminals after severe but survivable peripheral injury. In this hypothesis, nociceptor somata monitor the status of their own receptive field and the rest of the body by integrating signals received by their peripheral and central branches and the soma itself. A nociceptor switches into a potentially permanent hyperfunctional state when central neural, glial, and inflammatory signal combinations are detected that indicate extensive peripheral injury. Similar signal combinations are produced by SCI and disseminated widely to uninjured as well as injured nociceptors. This paper focuses on the uninjured nociceptors that are altered by SCI. Enhanced activity generated in below-level nociceptors promotes below-level central sensitization, somatic and autonomic hyperreflexia, and visceral dysfunction. If sufficient ascending fibers survive, enhanced activity in below-level nociceptors contributes to below-level pain. Nociceptor activity generated above the injury level contributes to at- and above-level sensitization and pain (evoked and spontaneous). Thus, SCI triggers a potent nociceptor state that may have been adaptive (from an evolutionary perspective) after severe peripheral injury but is maladaptive after SCI. Evidence that hyperfunctional nociceptors make large contributions to behavioral hypersensitivity after SCI suggests that nociceptor-specific ion channels required for nociceptor SA and hypersensitivity offer promising targets for treating chronic pain and hyperreflexia after SCI.
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Affiliation(s)
- Edgar T Walters
- Department of Integrative Biology and Pharmacology, University of Texas Medical School at Houston Houston, TX, USA
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Zhu YF, Wu Q, Henry JL. Changes in functional properties of A-type but not C-type sensory neurons in vivo in a rat model of peripheral neuropathy. J Pain Res 2012; 5:175-92. [PMID: 22792004 PMCID: PMC3392709 DOI: 10.2147/jpr.s26367] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Background The aim of this study was to compare primary sensory neurons in controls and in an animal neuropathic pain model in order to understand which types of neurons undergo changes associated with peripheral neuropathy. On the basis of intracellular recordings in vivo from somata, L4 sensory dorsal root ganglion neurons were categorized according to action potential configuration, conduction velocity, and receptive field properties to mechanical stimuli. Methods Intracellular recordings were made from functionally identified dorsal root ganglion neurons in vivo in the Mosconi and Kruger animal model of peripheral neuropathic pain. Results In this peripheral neuropathy model, a specific population of Aβ-fiber low threshold mechanoreceptor neurons, which respond normally to innocuous mechanical stimuli, exhibited differences in action potential configuration and conduction velocity when compared with control animals. No abnormal conduction velocity, action potential shapes, or tactile sensitivity of C-fiber neurons were encountered. Conclusion This study provides evidence for defining a potential role of Aβ-fiber low threshold mechanoreceptor neurons that might contribute to peripheral neuropathic pain.
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Affiliation(s)
- Yong Fang Zhu
- Michael G DeGroote Institute for Pain Research and Care, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada
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LipoxinA(4) induced antinociception and decreased expression of NF-κB and pro-inflammatory cytokines after chronic dorsal root ganglia compression in rats. Eur J Pain 2012; 16:18-27. [PMID: 21658981 DOI: 10.1016/j.ejpain.2011.05.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Inflammatory and immune responses following nerve injury have been shown to play an important role in neuropathic pain. Lipoxins are endogenous lipoxygenase-derived eicosanoids performing protective roles in a range of pathophysiologic processes. Here, we examined the effects of intrathecal lipoxinA4 (LXA4) on NF-κB activation and pro-inflammatory cytokine (TNF-α, IL-1β and IL-6) expression in dorsal root ganglia (DRG) following chronic compression of DRG (CCD), a model of neuropathic pain. Daily intrathecal injection of vehicle or LXA4 (10 ng or 100 ng) was performed for three successive days post-CCD. CCD induced both mechanical allodynia and thermal hyperalgesia, and increased the expression of TNF-α, IL-1β, IL-6 and NF-κB. Intrathecal injection of LXA4 prevented the development of neuropathic pain and inhibited NF-κB activation and pro-inflammatory cytokine upregulation in a dose-dependent manner. In this study, we have shown the strong protective effect of intrathecal LXA4 on the development of nociceptive behaviors induced by CCD and that these effects might be associated with its anti-inflammatory and pro-resolution properties.
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Huang ZJ, Li HC, Cowan AA, Liu S, Zhang YK, Song XJ. Chronic compression or acute dissociation of dorsal root ganglion induces cAMP-dependent neuronal hyperexcitability through activation of PAR2. Pain 2012; 153:1426-1437. [PMID: 22541444 DOI: 10.1016/j.pain.2012.03.025] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 03/04/2012] [Accepted: 03/23/2012] [Indexed: 02/07/2023]
Abstract
Chronic compression (CCD) or dissociation of dorsal root ganglion (DRG) can induce cyclic adenosine monophosphate (cAMP)-dependent DRG neuronal hyperexcitability and behaviorally expressed hyperalgesia. Here, we report that protease-activated receptor 2 (PAR2) activation after CCD or dissociation mediates the increase of cAMP activity and protein kinase A (PKA) and cAMP-dependent hyperexcitability and hyperalgesia in rats. CCD and dissociation, as well as trypsin (a PAR2 activator) treatment, increased level of cAMP concentration, mRNA, and protein expression for PKA subunits PKA-RII and PKA-c and protein expression of PAR2, in addition to producing neuronal hyperexcitability and, in CCD rats, thermal hyperalgesia. The increased expression of PAR2 was colocalized with PKA-c subunit. A PAR2 antagonistic peptide applied before and/or during the treatment, prevented or largely diminished the increased activity of cAMP and PKA, neuronal hyperexcitability, and thermal hyperalgesia. However, posttreatment with the PAR2 antagonistic peptide failed to alter either hyperexcitability or hyperalgesia. In contrast, an adenylyl cyclase inhibitor, SQ22536, administrated after dissociation or CCD, successfully suppressed hyperexcitability and hyperalgesia, in vitro and/or in vivo. Trypsin-induced increase of the intracellular calcium [Ca(2+)](i) was prevented in CCD or dissociation DRG neurons. These alterations were further confirmed by knockdown of PAR2 with siRNA. In addition, trypsin and PAR2 agonistic peptide-induced increase of cAMP was prevented by inhibition of PKC, but not Gαs. These findings suggest that PAR2 activation is critical to induction of nerve injury-induced neuronal hyperexcitability and cAMP-PKA activation. Inhibiting PAR2 activation may be a potential target for preventing/suppressing development of neuropathic pain.
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Affiliation(s)
- Zhi-Jiang Huang
- Department of Neurobiology, Parker University Research Institute, Dallas, TX, USA Neuroscience Research Institute, Peking University, Beijing 100191, China
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Evoked bursting in injured Aβ dorsal root ganglion neurons: A mechanism underlying tactile allodynia. Pain 2012; 153:657-665. [DOI: 10.1016/j.pain.2011.11.030] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 11/28/2011] [Accepted: 11/29/2011] [Indexed: 11/17/2022]
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Excitability of Aβ sensory neurons is altered in an animal model of peripheral neuropathy. BMC Neurosci 2012; 13:15. [PMID: 22289651 PMCID: PMC3292996 DOI: 10.1186/1471-2202-13-15] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Accepted: 01/30/2012] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Causes of neuropathic pain following nerve injury remain unclear, limiting the development of mechanism-based therapeutic approaches. Animal models have provided some directions, but little is known about the specific sensory neurons that undergo changes in such a way as to induce and maintain activation of sensory pain pathways. Our previous studies implicated changes in the Aβ, normally non-nociceptive neurons in activating spinal nociceptive neurons in a cuff-induced animal model of neuropathic pain and the present study was directed specifically at determining any change in excitability of these neurons. Thus, the present study aimed at recording intracellularly from Aβ-fiber dorsal root ganglion (DRG) neurons and determining excitability of the peripheral receptive field, of the cell body and of the dorsal roots. METHODS A peripheral neuropathy was induced in Sprague Dawley rats by inserting two thin polyethylene cuffs around the right sciatic nerve. All animals were confirmed to exhibit tactile hypersensitivity to von Frey filaments three weeks later, before the acute electrophysiological experiments. Under stable intracellular recording conditions neurons were classified functionally on the basis of their response to natural activation of their peripheral receptive field. In addition, conduction velocity of the dorsal roots, configuration of the action potential and rate of adaptation to stimulation were also criteria for classification. Excitability was measured as the threshold to activation of the peripheral receptive field, the response to intracellular injection of depolarizing current into the soma and the response to electrical stimulation of the dorsal roots. RESULTS In control animals mechanical thresholds of all neurons were within normal ranges. Aβ DRG neurons in neuropathic rats demonstrated a mean mechanical threshold to receptive field stimulation that were significantly lower than in control rats, a prolonged discharge following this stimulation, a decreased activation threshold and a greater response to depolarizing current injection into the soma, as well as a longer refractory interval and delayed response to paired pulse electrical stimulation of the dorsal roots. CONCLUSIONS The present study has demonstrated changes in functionally classified Aβ low threshold and high threshold DRG neurons in a nerve intact animal model of peripheral neuropathy that demonstrates nociceptive responses to normally innocuous cutaneous stimuli, much the same as is observed in humans with neuropathic pain. We demonstrate further that the peripheral receptive fields of these neurons are more excitable, as are the somata. However, the dorsal roots exhibit a decrease in excitability. Thus, if these neurons participate in neuropathic pain this differential change in excitability may have implications in the peripheral drive that induces central sensitization, at least in animal models of peripheral neuropathic pain, and Aβ sensory neurons may thus contribute to allodynia and spontaneous pain following peripheral nerve injury in humans.
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Wu XF, Liu WT, Liu YP, Huang ZJ, Zhang YK, Song XJ. Reopening of ATP-sensitive potassium channels reduces neuropathic pain and regulates astroglial gap junctions in the rat spinal cord. Pain 2011; 152:2605-2615. [PMID: 21907492 DOI: 10.1016/j.pain.2011.08.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 07/26/2011] [Accepted: 08/02/2011] [Indexed: 01/27/2023]
Abstract
Adenosine triphosphate-sensitive potassium (K(ATP)) channels are suggested to be involved in pathogenesis of neuropathic pain, but remain underinvestigated in primary afferents and in the spinal cord. We examined alterations of K(ATP) channels in rat spinal cord and tested whether and how they could contribute to neuropathic pain. The results showed that protein expression for K(ATP) channel subunits SUR1, SUR2, and Kir6.1, but not Kir6.2, were significantly downregulated and associated with thermal hyperalgesia and mechanical allodynia after sciatic nerve injury. Spinal administration of a K(ATP) channel opener cromakalim (CRO, 5, 10, and 20 μg, respectively) prevented or suppressed, in a dose-dependent manner, the hyperalgesia and allodynia. Nerve injury also significantly increased expression and phosphorylation of connexin 43, an astroglial gap junction protein. Such an increase of phosphorylation of connexin 43 was inhibited by CRO treatment. Furthermore, preadministration of an astroglial gap junction decoupler carbenoxolone (10 μg) completely reversed the inhibitory effects of CRO treatment on the hyperalgesia and allodynia and phosphorylation of NR1 and NR2B receptors and the subsequent activation of Ca(2+)-dependent signals Ca(2+)/calmodulin-dependent kinase II and cyclic adenosine monophosphate (cAMP) response element binding protein. These findings suggest that nerve injury-induced downregulation of the K(ATP) channels in the spinal cord may interrupt the astroglial gap junctional function and contribute to neuropathic pain, thus the K(ATP) channels opener can reduce neuropathic pain probably partly via regulating the astroglial gap junctions. This study may provide a new strategy for treating neuropathic pain using K(ATP) channel openers in the clinic.
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Affiliation(s)
- Xue-Feng Wu
- Department of Neurobiology, Parker University Research Institute, Dallas, TX, USA State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, Jiangsu, China
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Chew DJ, Carlstedt T, Shortland PJ. A comparative histological analysis of two models of nerve root avulsion injury in the adult rat. Neuropathol Appl Neurobiol 2011; 37:613-32. [DOI: 10.1111/j.1365-2990.2011.01176.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Fan N, Sikand P, Donnelly DF, Ma C, Lamotte RH. Increased Na+ and K+ currents in small mouse dorsal root ganglion neurons after ganglion compression. J Neurophysiol 2011; 106:211-8. [PMID: 21525373 DOI: 10.1152/jn.00065.2011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
We investigated the effects of chronic compression (CCD) of the L3 and L4 dorsal root ganglion (DRG) on pain behavior in the mouse and on the electrophysiological properties of the small-diameter neuronal cell bodies in the intact ganglion. CCD is a model of human radicular pain produced by intraforaminal stenosis and other disorders affecting the DRG, spinal nerve, or root. On days 1, 3, 5, and 7 after the onset of compression, there was a significant decrease from preoperative values in the threshold mechanical force required to elicit a withdrawal of the foot ipsilateral to the CCD (tactile allodynia). Whole cell patch-clamp recordings were obtained, in vitro, from small-sized somata and, for the first time, in the intact DRG. Under current clamp, CCD neurons exhibited a significantly lower rheobase compared with controls. A few CCD but no control neurons exhibited spontaneous action potentials. CCD neurons showed an increase in the density of TTX-resistant and TTX-sensitive Na(+) current. CCD neurons also exhibited an enhanced density of voltage-dependent K(+) current, due to an increase in delayed rectifier K(+) current, without a change in the transient or "A" current. We conclude that CCD in the mouse produces a model of radicular pain, as we have previously demonstrated in the rat. While the role of enhanced K(+) current remains to be elucidated, we speculate that it represents a compensatory neuronal response to reduce ectopic or aberrant levels of neuronal activity produced by the injury.
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Affiliation(s)
- Ni Fan
- Department of Anesthesiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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Ma C, Rosenzweig J, Zhang P, Johns DC, LaMotte RH. Expression of inwardly rectifying potassium channels by an inducible adenoviral vector reduced the neuronal hyperexcitability and hyperalgesia produced by chronic compression of the spinal ganglion. Mol Pain 2010; 6:65. [PMID: 20923570 PMCID: PMC2959023 DOI: 10.1186/1744-8069-6-65] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 10/06/2010] [Indexed: 11/20/2022] Open
Abstract
Background A chronic compressed dorsal root ganglion (CCD) in rat produces pain behavior and an enhanced excitability of neurons within the compressed ganglion. Kir2.1 is an inwardly rectifying potassium channel that acts to stabilize the resting potential of certain cell types. We hypothesized that an inducible expression of Kir2.1 channels in CCD neurons might suppress neuronal excitability in the dorsal root ganglion (DRG) and reduce the associated pain behavior. Results We delivered, by microinjection into the fourth lumbar (L4) DRG, an adenoviral vector containing a reporter gene encoding the enhanced green fluorescent protein (GFP) and a Kir2.1 channel (AdKir). At the same time the ganglion was compressed by implantation of a rod through the intervertebral foramen (CCD). The in vivo expression of the transferred gene was controlled by an ecdysone analog via an ecdysone-inducible promoter in the viral vector. In comparison with the effects of vehicle or a control vector containing only the GFP gene, AdKir significantly reduced the neuronal hyperexcitability after CCD. Electrophysiological recordings, in vivo, from nociceptive and non-nociceptive DRG neurons expressing the virally produced Kir2.1 channels revealed a hyperpolarized resting membrane potential, an increased rheobase, and lack of spontaneous activity. Inducing the Kir2.1 gene at the beginning of CCD surgery partially prevented the development of mechanical hyperalgesia. However, a delayed induction of the Kir2.1 gene (3 days after CCD surgery) produced no significant effect on the pain behavior. Conclusions We found that an inducible expression of Kir2.1 channels in chronically compressed DRG neurons can effectively suppress the neuronal excitability and, if induced at the beginning of CCD injury, prevent the development of hyperalgesia. We hypothesize that a higher level of neuronal hyperexcitability in the DRG is required to initiate than to maintain the hyperalgesia and that the hyperexcitability contributing to neuropathic pain is best inhibited as soon as possible after injury.
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Affiliation(s)
- Chao Ma
- Dept, Anesthesiology, Yale University School of Medicine, New Haven, CT, USA
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Gallaher ZR, Larios RM, Ryu V, Sprunger LK, Czaja K. Recovery of viscerosensory innervation from the dorsal root ganglia of the adult rat following capsaicin-induced injury. J Comp Neurol 2010; 518:3529-40. [DOI: 10.1002/cne.22412] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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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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Yakovlev AE, Al Tamimi M, Barolat G, Karasev SA, Merkulov YA, Resch BE, Yakovleva VE. Spinal Cord Stimulation as Alternative Treatment for Chronic Post-Herniorrhaphy Pain. Neuromodulation 2010; 13:288-90; discussion 291. [DOI: 10.1111/j.1525-1403.2010.00276.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Hoschouer EL, Basso MD, Jakeman LB. Aberrant sensory responses are dependent on lesion severity after spinal cord contusion injury in mice. Pain 2009; 148:328-342. [PMID: 20022699 DOI: 10.1016/j.pain.2009.11.023] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Revised: 10/07/2009] [Accepted: 11/23/2009] [Indexed: 11/28/2022]
Abstract
Following spinal cord injury (SCI), individuals lose normal sensation and often develop debilitating neuropathic pain. Basic research has helped to elucidate many of the underlying mechanisms, but unanswered questions remain concerning how sensation changes after SCI and potential negative consequences of regenerative therapies. Mouse models provide an opportunity to explore these questions using genetic markers and manipulations. However, despite the increasing use of mice in pain and sensory research, the responses to sensory stimuli after SCI are poorly characterized in this species. This study evaluated behavioral responses to mechanical and nociceptive stimuli applied to the hindlimbs and the dorsal trunk in C57BL/6 mice after mid-thoracic SCI. Adult mice were subjected to laminectomy, contusion injuries of different severities, or complete transections to test the hypothesis that the patterns of sensory pathology depend on the extent of tissue damage at the injury site. In the hind paws, hyper-responsiveness to a heat stimulus developed independent of injury severity, while mechanical sensitivity decreased, except after the most severe contusion injuries sparing less than 2% of the white matter at the injury site, when enhanced sensitivity was observed. On the trunk, mechanical and pin prick testing revealed diminished sensitivity at and below the injury level, while responses above the level of the injury were unchanged. The contrast in injury severity threshold for thermal and mechanical hypersensitivity in the hind paws suggests that these responses have different underlying mechanisms. These results establish essential baseline information for murine studies of pain and changes in sensation after SCI.
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Affiliation(s)
- Emily L Hoschouer
- Dept of Physiology and Cell Biology, The Ohio State University College of Medicine, 1645 Neil Ave., Columbus, OH 43210, USA Dept of Neuroscience, The Ohio State University College of Medicine, 333 W. 10th Ave., Columbus, OH 43210, USA Division of Physical Therapy, The Ohio State University School of Allied Medical Professions, 453 W. 10th Ave., Columbus, OH 43210, USA Neuroscience Graduate Studies Program, The Ohio State University, Columbus, OH 43210, USA Center for Brain and Spinal Cord Repair, The Ohio State University College of Medicine, 460 W. 12th Ave., Columbus, OH 43210, USA
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Ding XL, Wang YH, Ning LP, Zhang Y, Ge HY, Jiang H, Wang R, Yue SW. Involvement of TRPV4-NO-cGMP-PKG pathways in the development of thermal hyperalgesia following chronic compression of the dorsal root ganglion in rats. Behav Brain Res 2009; 208:194-201. [PMID: 19948193 DOI: 10.1016/j.bbr.2009.11.034] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2009] [Revised: 11/18/2009] [Accepted: 11/20/2009] [Indexed: 12/18/2022]
Abstract
The aim of the present study was to test the hypothesis that the TRPV4-NO-cGMP-PKG cascade is involved in the maintenance of thermal hyperalgesia following chronic compression of the dorsal root ganglion (DRG) (the procedure hereafter termed CCD) in rats. CCD rats showed thermal hyperalgesia and increased nitrite production. Intrathecal administration of ruthenium red (TRPV4 antagonist, 0.1-1 nmol), TRPV4 antisense ODN (TRPV4 AS, 40 microg, daily for 7 days), N(G)-L-nitro-arginine methyl ester (l-NAME, inhibitor of NO synthase, 30-300 nmol), 1H-[1,2,4]-oxadiazolo [4,3-a] quinoxalin-1-one (ODQ, a soluble guanylate cyclase inhibitor, 50-100 nmol) or 8-(4-Chlorophenylthio) guanosine 3',5'-cyclic Monophosphothioate, Rp-Isomer sodium salt (Rp-8-pCPT-cGMPS, a PKG inhibitor, 25-50 nmol) induced a significant (P<0.001) and dose-dependent increase in the paw withdrawal latency (PWL) compared with control rats, respectively. Ruthenium red (1 nmol), TRPV4 AS (40 microg, daily for 7 days) or L-NAME (300 nmol) decreased nitrite (an index of nitric oxide formation) in the DRG of CCD rats. In addition, the phorbol ester 4alpha-phorbol 12,13-didecanoate (4alpha-PDD, TRPV4 synthetic activator, 1 nmol), co-administered with L-NAME (300 nmol), attenuated the suppressive effect of L-NAME on CCD-induced thermal hyperalgesia and nitrite production. Our data suggested that the TRPV4-NO-cGMP-PKG pathway could be involved in CCD-induced thermal hyperalgesia.
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Affiliation(s)
- Xin-Li Ding
- Department of Physical Medicine & Rehabilitation, Qilu Hospital, Medical School of Shandong University, Jinan 250012, China
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Sorkin LS, Yaksh TL. Behavioral models of pain states evoked by physical injury to the peripheral nerve. Neurotherapeutics 2009; 6:609-19. [PMID: 19789066 PMCID: PMC5084283 DOI: 10.1016/j.nurt.2009.07.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Accepted: 07/09/2009] [Indexed: 11/30/2022] Open
Abstract
Physical injury or compression of the root, dorsal root ganglion, or peripheral sensory axon leads to well-defined changes in biology and function. Behaviorally, humans report ongoing painful dysesthesias and aberrations in function, such that an otherwise innocuous stimulus will yield a pain report. These behavioral reports are believed to reflect the underlying changes in nerve function after injury, wherein increased spontaneous activity arises from the neuroma and dorsal root ganglion and spinal changes increase the response of spinal projection neurons. These pain states are distinct from those associated with tissue injury and pose particular problems in management. To provide for developing an understanding of the underlying mechanisms of these pain states and to promote development of therapeutic agents, preclinical models involving section, compression, and constriction of the peripheral nerve or compression of the dorsal root ganglion have been developed. These models give rise to behaviors, which parallel those observed in the human after nerve injury. The present review considers these models and their application.
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Affiliation(s)
- Linda S. Sorkin
- grid.266100.30000000121074242Department of Anesthesiology, University of California, San Diego, 9500 Gilman Dr., Mail Code 0818, 92093-0818 La Jolla, CA
| | - Tony L. Yaksh
- grid.266100.30000000121074242Department of Anesthesiology, University of California, San Diego, 9500 Gilman Dr., Mail Code 0818, 92093-0818 La Jolla, CA
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Zhang XJ, Chen HL, Li Z, Zhang HQ, Xu HX, Sung JJY, Bian ZX. Analgesic effect of paeoniflorin in rats with neonatal maternal separation-induced visceral hyperalgesia is mediated through adenosine A(1) receptor by inhibiting the extracellular signal-regulated protein kinase (ERK) pathway. Pharmacol Biochem Behav 2009; 94:88-97. [PMID: 19664651 DOI: 10.1016/j.pbb.2009.07.013] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2008] [Revised: 07/04/2009] [Accepted: 07/27/2009] [Indexed: 12/19/2022]
Abstract
UNLABELLED Paeoniflorin (PF), a chief active ingredient in the root of Paeonia lactiflora Pall (family Ranunculaceae), is effective in relieving colorectal distention (CRD)-induced visceral pain in rats with visceral hyperalgesia induced by neonatal maternal separation (NMS). This study aimed at exploring the underlying mechanisms of PF's analgesic effect on CRD-evoked nociceptive signaling in the central nervous system (CNS) and investigating whether the adenosine A(1) receptor is involved in PF's anti-nociception. RESULTS CRD-induced visceral pain as well as phosphorylated-extracellular signal-regulated protein kinase (p-ERK) and phospho-cAMP response element-binding protein (p-CREB) expression in the CNS structures of NMS rats were suppressed by NMDA receptor antagonist dizocilpine (MK-801) and ERK phosphorylation inhibitor U0126. PF could similarly inhibit CRD-evoked p-ERK and c-Fos expression in laminae I-II of the lumbosacral dorsal horn and anterior cingulate cortex (ACC). PF could also reverse the CRD-evoked increased glutamate concentration by CRD as shown by dynamic microdialysis monitoring in ACC, whereas, DPCPX, an antagonist of adenosine A(1) receptor, significantly blocked the analgesic effect of PF and PF's inhibition on CRD-induced p-ERK and p-CREB expression. These results suggest that PF's analgesic effect is possibly mediated by adenosine A(1) receptor by inhibiting CRD-evoked glutamate release and the NMDA receptor dependent ERK signaling.
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Affiliation(s)
- Xiao-Jun Zhang
- School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China
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Sekiguchi M, Sekiguchi Y, Konno SI, Kobayashi H, Homma Y, Kikuchi SI. Comparison of neuropathic pain and neuronal apoptosis following nerve root or spinal nerve compression. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2009; 18:1978-85. [PMID: 19543754 PMCID: PMC2899442 DOI: 10.1007/s00586-009-1064-z] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Revised: 04/15/2009] [Accepted: 06/01/2009] [Indexed: 02/07/2023]
Abstract
Altered dorsal root ganglion (DRG) function is associated with neuropathic pain following spinal nerve injury. However, compression of the cauda equina and dorsal rhizotomy proximal to the DRG do not induce significant pain, whereas in the spinal nerve and peripheral nerve, injury distal to the DRG does induce neuropathic pain. Caspase signaling induces apoptosis, and caspase inhibitors prevent pain-related behavior. The degree of DRG neuronal apoptosis is thought to play a role in pain behavior. We suggest that differences in pain behavior according to the injury sites within the DRG may be related to imbalances in apoptotic injuries. The aim of this study was to determine which compression injury was more painful and to compare behavior with expression of tumor necrosis factor (TNF)-alpha in DRG and apoptosis in the DRG following crush injury to the L5 nerve root or L5 spinal nerve. Sprague–Dawley rats received a crush injury to the L5 spinal nerve (distal to the DRG), crush injury to the L5 nerve root (proximal to the DRG), or no crush injury (sham). Mechanical allodynia was determined by the von Frey test. Expression of TNF-alpha was compared among three groups using immunoblot findings. Furthermore, we compared the percentage of neurons injured in the DRG using immunostaining for apoptotic cells and localization of activated caspase 3. Mechanical allodynia was observed in both crush injury groups. The duration of mechanical allodynia in the distal crush group was significantly longer than in the proximal crush group (P < 0.05). TNF-alpha expression was increased in DRG neurons following injury. DRG apoptosis in the distal crush group was significantly higher than in the proximal group at each time point (P < 0.05). This study suggests that spinal nerve crush injuries produce a greater degree of DRG apoptosis than do corresponding nerve root crush injuries, and that the former injuries are associated with longer lasting mechanical allodynia. Thus, differences in the time course of mechanical allodynia might be associated with an imbalance in DRG apoptosis.
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Affiliation(s)
- Miho Sekiguchi
- Department of Orthopaedic Surgery, Fukushima Medical University School of Medicine, 1-Hikarigaoka, Fukushima City, Fukushima, 960-1295, Japan.
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Han Y, Song XS, Liu WT, Henkemeyer M, Song XJ. Targeted mutation of EphB1 receptor prevents development of neuropathic hyperalgesia and physical dependence on morphine in mice. Mol Pain 2008; 4:60. [PMID: 19025592 PMCID: PMC2605438 DOI: 10.1186/1744-8069-4-60] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Accepted: 11/21/2008] [Indexed: 01/03/2023] Open
Abstract
EphB receptor tyrosine kinases, which play important roles in synaptic connection and plasticity during development and in matured nervous system, have recently been implicated in processing of pain after nerve injury and morphine dependence. Subtypes of the EphB receptors that may contribute to the neuropathic pain and morphine dependence have not been identified. Here we demonstrate that the subtype EphB1 receptor is necessary for development of neuropathic pain and physical dependence on morphine. The results showed that peripheral nerve injury produced thermal hyperalgesia in wild-type (EphB1+/+) control littermate mice, but not in EphB1 receptor homozygous knockout (EphB1-/-) and heterozygous knockdown (EphB1+/-) mice. Hyperalgesia in the wild-type mice was inhibited by intrathecal administration of an EphB receptor blocking reagent EphB2-Fc (2 microg). Intrathecal administration of an EphB receptor activator ephrinB1-Fc (1 microg) evoked thermal hyperalgesia in EphB1+/+, but not EphB1-/- and EphB1+/- mice. Cellularly, nerve injury-induced hyperexcitability of the medium-sized dorsal root ganglion neurons was prevented in EphB1-/- and EphB1+/- mice. In chronically morphine-treated mice, most of the behavioral signs and the overall score of naloxone-precipitated withdrawal were largely diminished in EphB1-/- mice compared to those in the wild-type. These findings indicate that the EphB1 receptor is necessary for development of neuropathic pain and physical dependence on morphine and suggest that the EphB1 receptor is a potential target for preventing, minimizing, or reversing the development of neuropathic pain and opiate dependence.
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Affiliation(s)
- Yuan Han
- Jiangsu Province Key Laboratory of Anesthesiology and Center for Pain Research and Treatment, Xuzhou Medical College, Xuzhou, Jiangsu, PR China.
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Abstract
STUDY DESIGN DNA array analysis of dorsal root ganglion (DRG) using a rat model with nerve root constriction. OBJECTIVE To determine the molecular changes in the DRG adjacent to the injured nerve root in a lumbar radiculopathy model. SUMMARY OF BACKGROUND DATA DNA array analysis in lumbar radiculopathy model has so far focused on the spinal dorsal horn. The molecular changes in the DRG adjacent to the injured nerve root in lumbar radiculopathy remain to be determined. METHODS Bilateral L5 DRGs were removed from 12 Sprague-Dawley rats on days 2, 7, 14, and 21 after nerve root ligation and on day 7 from 3 rats with sham operation. The aRNAs from the DRGs with nerve root ligation were labeled with Cy5 dye and those from the opposite side DRG (control) were labeled with Cy3 dye, and then hybridized to a 7793-spot Panorama Micro Array. It was considered to be significantly upregulated, when an average expression ratio of Cy5 to Cy3 was 2 or more. Genes upregulated were classified into early phase group (upregulated on day 2), midphase group (upregulated on days 7 and 14), and continuous group (upregulated from day 2 to 21). Seventeen genes were subjected to validation analysis with real-time quantitative PCR. RESULTS There were 16 upregulated genes in the early phase group, 56 genes in the midphase group, and 17 genes in the continuous group. Functional categorization revealed dominantly upregulated gene categories in each group; transcription/translation in the early phase group, enzyme/metabolism in the midphase group, and structure in the continuous group. Validation analysis of 17 genes demonstrated mean relative expression of 2.0 or more in all but 1 gene in the DRGs with nerve root ligation and none of them in the DRGs with sham operation. CONCLUSION The genes identified in this study, especially those involved in pain signaling and inflammation, serve as potential targets for molecular-based therapy for lumbar radiculopathy.
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EphrinB-EphB receptor signaling contributes to neuropathic pain by regulating neural excitability and spinal synaptic plasticity in rats. Pain 2008; 139:168-180. [DOI: 10.1016/j.pain.2008.03.019] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Revised: 03/17/2008] [Accepted: 03/18/2008] [Indexed: 11/20/2022]
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Roles of TRESK, a novel two-pore domain K+ channel, in pain pathway and general anesthesia. Neurosci Bull 2008; 24:166-72. [PMID: 18500390 DOI: 10.1007/s12264-008-0225-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
TRESK is the most recently reported two-pore domain K+ channel, and different from other two-pore domain channels in gene, molecular structure, electrophysiological and pharmacological properties. Although the current knowledge of this potassium channel is inadequate, researches have demonstrated that TRESK is remarkablely linked to acute and chronic pain by activation of calcineurin. The fact that TRESK is sensitive to volatile anesthetics and localization in central nerve system implies that TRESK may play a very important role in the mechanism mediating general anesthesia. The further research of TRESK may contribute to explore the underlying mechanism of some pathological conditions and yield novel treatments for some diseases.
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Hayar A, Gu C, Al-Chaer ED. An improved method for patch clamp recording and calcium imaging of neurons in the intact dorsal root ganglion in rats. J Neurosci Methods 2008; 173:74-82. [PMID: 18588915 DOI: 10.1016/j.jneumeth.2008.05.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Revised: 04/30/2008] [Accepted: 05/19/2008] [Indexed: 10/22/2022]
Abstract
The properties of dorsal root ganglion (DRG) neurons have been mostly investigated in culture of dissociated cells, and it is uncertain whether these cells maintain the electrophysiological properties of the intact DRG neurons. Few attempts have been made to record from DRG neurons in the intact ganglion using the patch clamp technique. In this study, rat DRGs were dissected and incubated for at least 1h at 37 degrees C in collagenase (10mg/ml). We used oblique epi-illumination to visualize DRG neurons and perform patch clamp recordings. All DRG neurons exhibited strong delayed rectifier potassium current and a high threshold for spike generation (-15 mV) that rendered the cells very weakly excitable, generating only one action potential upon strong current injection (>300 pA). It is therefore possible that cultured DRG neurons, commonly used in studies of pain processing, may be hyperexcitable because they acquired "neuropathic" properties due to the injury induced by their dissociation. Electrical stimulation of the attached root produced an antidromic spike in the soma that could be blocked by intracellular hyperpolarization or high frequency stimulation. Imaging intracellular calcium concentration with Oregon Green BAPTA-1 indicates that antidromic stimulation caused a long-lasting increase in intracellular calcium concentration mostly near the cell membrane. This study describes a simple approach to examine the electrophysiological and pharmacological properties and intracellular calcium signaling in DRG neurons in the intact ganglion where the effects of somatic spike invasion can be studied as well.
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Affiliation(s)
- Abdallah Hayar
- Center for Translational Neuroscience, Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, United States.
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Huang ZJ, Song XJ. Differing alterations of sodium currents in small dorsal root ganglion neurons after ganglion compression and peripheral nerve injury. Mol Pain 2008; 4:20. [PMID: 18513405 PMCID: PMC2427019 DOI: 10.1186/1744-8069-4-20] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2008] [Accepted: 05/30/2008] [Indexed: 12/17/2022] Open
Abstract
Voltage-gated sodium channels play important roles in modulating dorsal root ganglion (DRG) neuron hyperexcitability and hyperalgesia after peripheral nerve injury or inflammation. We report that chronic compression of DRG (CCD) produces profound effect on tetrodotoxin-resistant (TTX-R) and tetrodotoxin-sensitive (TTX-S) sodium currents, which are different from that by chronic constriction injury (CCI) of the sciatic nerve in small DRG neurons. Whole cell patch-clamp recordings were obtained in vitro from L4 and/or L5 dissociated, small DRG neurons following in vivo DRG compression or nerve injury. The small DRG neurons were classified into slow and fast subtype neurons based on expression of the slow-inactivating TTX-R and fast-inactivating TTX-S Na+ currents. CCD treatment significantly reduced TTX-R and TTX-S current densities in the slow and fast neurons, but CCI selectively reduced the TTX-R and TTX-S current densities in the slow neurons. Changes in half-maximal potential (V1/2) and curve slope (k) of steady-state inactivation of Na+ currents were different in the slow and fast neurons after CCD and CCI treatment. The window current of TTX-R and TTX-S currents in fast neurons were enlarged by CCD and CCI, while only that of TTX-S currents in slow neurons was increased by CCI. The decay rate of TTX-S and both TTX-R and TTX-S currents in fast neurons were reduced by CCD and CCI, respectively. These findings provide a possible sodium channel mechanism underlying CCD-induced DRG neuron hyperexcitability and hyperalgesia and demonstrate a differential effect in the Na+ currents of small DRG neurons after somata compression and peripheral nerve injury. This study also points to a complexity of hyperexcitability mechanisms contributing to CCD and CCI hyperexcitability in small DRG neurons.
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Affiliation(s)
- Zhi-Jiang Huang
- Department of Neurobiology, Parker University Research Institute, Dallas, TX 75229, USA.
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Saab CY, Waxman SG, Hains BC. Alarm or curse? The pain of neuroinflammation. ACTA ACUST UNITED AC 2008; 58:226-35. [PMID: 18486228 DOI: 10.1016/j.brainresrev.2008.04.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Revised: 04/03/2008] [Accepted: 04/04/2008] [Indexed: 02/07/2023]
Abstract
The nociceptive nervous system and the immune system serve to defend and alarm the host of imminent or actual damage. However, persistent or recurring exposure of neurons to activated immune cells is associated with an increase in painful behavior following experimental neuropathic injuries. Our understanding of the functional consequences of immune cell-neuron interaction is still incomplete. The purpose of this review is to focus on a seriously detrimental consequence of chronic activation of these two systems, by discussing the contributions of microglia and polymorphonuclear neutrophils to neuropathic pain following experimental spinal cord injury or peripheral nerve injury. Identification of molecules mediating pro-nociceptive signaling between immune cells and neurons, as well as the distinction between neuroprotective versus neuroexcitatory effects of activated immune cells, may be useful in the development of pharmacotherapy for the management of chronic pain and restoration of the beneficial alarm function of pain.
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Affiliation(s)
- Carl Y Saab
- Department of Surgery, Rhode Island Hospital, Brown Medical School and Department of Neuroscience, Brown University, 593 Eddy St, NAB 210, Providence, RI 02903, USA.
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Song XJ, Cao JL, Li HC, Zheng JH, Song XS, Xiong LZ. Upregulation and redistribution of ephrinB and EphB receptor in dorsal root ganglion and spinal dorsal horn neurons after peripheral nerve injury and dorsal rhizotomy. Eur J Pain 2008; 12:1031-9. [PMID: 18321739 DOI: 10.1016/j.ejpain.2008.01.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Revised: 01/16/2008] [Accepted: 01/25/2008] [Indexed: 11/15/2022]
Abstract
EphrinB-EphB receptor signaling plays diverse roles during development, but recently has been implicated in synaptic plasticity in the matured nervous system and in pain processes. The present study investigated the correlation between expression of ephrinB and EphB receptor proteins and chronic constriction injury (CCI) of the sciatic nerve and dorsal rhizotomy (DR) in dorsal root ganglion (DRG) and spinal cord (SC); and interaction of CCI and DR on expression of these signals. Adult, male Sprague-Dawley rats were employed and thermal sensitivity was determined in the sham operated CCI and DR rats. Western blot and immunobiochemistry analysis and immunofluorescence staining techniques were used to detect the expression and location of the ephrinB-EphB receptor proteins in DRG and SC. The results showed that expression of ephrinB1 and EphB1 receptor proteins was significantly upregulated in DRG and SC in a time-dependent manner corresponding to the development of thermal hyperalgesia after CCI. The increased expression is predominately located in the medium- and small-sized DRG neurons, the superficial layers of spinal dorsal horn (DH) neurons, and the IB4 positive nociceptive terminals. DR increases ephrinB1 in DRG, not SC and EphB receptor in SC, not DRG. DR suppressed CCI-induced upregulation of ephrinB1 in SC and EphB1 receptor in DRG and SC. These findings indicate that ephrinB-EphB receptor activation and redistribution in DRG and DH neurons after nerve injury could contribute to neuropathic pain. This study may also provide a new mechanism underlying DR-induced analgesia in clinic.
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Affiliation(s)
- Xue-Jun Song
- Department of Neurobiology, Parker University Research Institute, Dallas, TX 75229, USA.
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Multiple sites for generation of ectopic spontaneous activity in neurons of the chronically compressed dorsal root ganglion. J Neurosci 2008; 27:14059-68. [PMID: 18094245 DOI: 10.1523/jneurosci.3699-07.2007] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
In a chronically compressed dorsal root ganglion (CCD) in the rat, a model of foraminal stenosis and radicular pain in human, a subpopulation of neurons with functional axons exhibits spontaneous activity (SA) that originates within the ganglion. Intracellular electrophysiological recordings were obtained from the somata of neurons of the compressed ganglion both in vitro and in vivo. The SA was classified into two types according to the presence (type I) or absence (type II) of subthreshold membrane potential oscillation. Neurons with type I SA had significantly higher somal excitability than those with type II SA. In most cases, depolarization of the membrane potential by current injection increased the discharge rates of type I--but not type II SA. Both types occasionally coexisted in the same neuron. Several lines of evidence suggested that the origin of SA in the DRG was most likely the soma for type I SA and the axon for type II. Therefore CCD neurons have multiple sites for generation of action potentials other than the terminal endings. In vivo recordings revealed the same two types of SA in a subpopulation of neurons with functionally characterized peripheral receptive fields. Thus, SA might not only produce spurious sensory input to the afferent pathways but also add to or block impulse transmission generated by natural stimulation of peripheral receptors. SA originating in the compressed ganglion is likely to interfere with sensory transmission in nociceptive and non-nociceptive neurons, thereby contributing to radicular pain, paresthesias, hyperalgesia and allodynia.
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A transient receptor potential vanilloid 4 contributes to mechanical allodynia following chronic compression of dorsal root ganglion in rats. Neurosci Lett 2007; 432:222-7. [PMID: 18206306 DOI: 10.1016/j.neulet.2007.12.028] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 12/07/2007] [Accepted: 12/13/2007] [Indexed: 11/20/2022]
Abstract
The aim of the present study was to investigate the role of transient receptor potential vanilloid 4 (TRPV4) in mediating mechanical allodynia in rodent models of chronic compression of the dorsal root ganglion (CCD). First, the levels of TRPV4 mRNA and protein expression in the dorsal root ganglion (DRG) were assessed using real-time RT-PCR and Western blotting analysis respectively at 7, 14, and 28 days post-CCD. Then, the effects of spinal administration of TRPV4 antisense oligodeoxynucleotide (ODN) and mismatch ODN on CCD-induced mechanical allodynia were evaluated. Lastly, the calcium responses to hypotonic solution and 4alpha-phorbol 12,13-didecanoate (4alpha-PDD) were assessed following sham surgery, CCD, spinal application of TRPV4 antisense ODN and mismatch ODN. The results showed that the levels of TRPV4 mRNA and protein expression increased significantly at 7-28 days post-CCD when compared with the sham group, with the highest level at 7 days post-CCD. TRPV4 antisense ODN, but not mismatch ODN, partly reversed the CCD-induced mechanical allodynia. Additionally, TRPV4 antisense ODN had no effect on the baseline nociceptive response. The percentage of DRG neurons responsive to hypotonic solution and 4alpha-PDD and the fluorescence ratio of calcium response were also enhanced significantly in both the CCD group and the mismatch ODN group. These increased responses were significantly inhibited by TRPV4 antisense ODN. In conclusion, TRPV4 plays a crucial role in CCD-induced mechanical allodynia.
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