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Remigante A, Spinelli S, Zuccolini P, Gavazzo P, Marino A, Pusch M, Morabito R, Dossena S. Melatonin protects Kir2.1 function in an oxidative stress-related model of aging neuroglia. Biofactors 2024; 50:523-541. [PMID: 38095328 DOI: 10.1002/biof.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 11/01/2023] [Indexed: 06/15/2024]
Abstract
Melatonin is a pleiotropic biofactor and an effective antioxidant and free radical scavenger and, as such, can be protective in oxidative stress-related brain conditions including epilepsy and aging. To test the potential protective effect of melatonin on brain homeostasis and identify the corresponding molecular targets, we established a new model of oxidative stress-related aging neuroglia represented by U-87 MG cells exposed to D-galactose (D-Gal). This model was characterized by a substantial elevation of markers of oxidative stress, lipid peroxidation, and protein oxidation. The function of the inward rectifying K+ channel Kir2.1, which was identified as the main Kir channel endogenously expressed in these cells, was dramatically impaired. Kir2.1 was unlikely a direct target of oxidative stress, but the loss of function resulted from a reduction of protein abundance, with no alterations in transcript levels and trafficking to the cell surface. Importantly, melatonin reverted these changes. All findings, including the melatonin antioxidant effect, were reproduced in heterologous expression systems. We conclude that the glial Kir2.1 can be a target of oxidative stress and further suggest that inhibition of its function might alter the extracellular K+ buffering in the brain, therefore contributing to neuronal hyperexcitability and epileptogenesis during aging. Melatonin can play a protective role in this context.
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Affiliation(s)
- Alessia Remigante
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Sara Spinelli
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Paolo Zuccolini
- Institute of Biophysics, National Research Council, Genova, Italy
| | - Paola Gavazzo
- Institute of Biophysics, National Research Council, Genova, Italy
| | - Angela Marino
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Michael Pusch
- Institute of Biophysics, National Research Council, Genova, Italy
| | - Rossana Morabito
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy
| | - Silvia Dossena
- Institute of Pharmacology and Toxicology, Paracelsus Medical University, Salzburg, Austria
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2
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Wang X, Li X. Regulation of pain neurotransmitters and chondrocytes metabolism mediated by voltage-gated ion channels: A narrative review. Heliyon 2023; 9:e17989. [PMID: 37501995 PMCID: PMC10368852 DOI: 10.1016/j.heliyon.2023.e17989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 05/15/2023] [Accepted: 07/04/2023] [Indexed: 07/29/2023] Open
Abstract
Osteoarthritis (OA) is one of the leading causes of chronic pain and dysfunction. It is essential to comprehend the nature of pain and cartilage degeneration and its influencing factors on OA treatment. Voltage-gated ion channels (VGICs) are essential in chondrocytes and extracellular matrix (ECM) metabolism and regulate the pain neurotransmitters between the cartilage and the central nervous system. This narrative review focused primarily on the effects of VGICs regulating pain neurotransmitters and chondrocytes metabolism, and most studies have focused on voltage-sensitive calcium channels (VSCCs), voltage-gated sodium channels (VGSCs), acid-sensing ion channels (ASICs), voltage-gated potassium channels (VGKCs), voltage-gated chloride channels (VGCCs). Various ion channels coordinate to maintain the intracellular environment's homeostasis and jointly regulate metabolic and pain under normal circumstances. In the OA model, the ion channel transport of chondrocytes is abnormal, and calcium influx is increased, which leads to increased neuronal excitability. The changes in ion channels are strongly associated with the OA disease process and individual OA risk factors. Future studies should explore how VGICs affect the metabolism of chondrocytes and their surrounding tissues, which will help clinicians and pharmacists to develop more effective targeted drugs to alleviate the progression of OA disease.
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3
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Liu F, Zhang L, Su S, Fang Y, Yin X, Cui H, Sun J, Xie Y, Ma C. Neuronal C-Reactive Protein/FcγRI Positive Feedback Proinflammatory Signaling Contributes to Nerve Injury Induced Neuropathic Pain. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2205397. [PMID: 36727833 PMCID: PMC10074098 DOI: 10.1002/advs.202205397] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 12/23/2022] [Indexed: 06/18/2023]
Abstract
Neuropathic pain is difficult to treat in clinical practice, and the underlying mechanisms are insufficiently elucidated. Previous studies have demonstrated that the neuronal Fc-gamma-receptor type I (FcγRI) of the dorsal root ganglion (DRG) mediates antigen-specific pain. However, the mechanisms of neuronal FcγRI in neuropathic pain remain to be explored. Here, it is found that the activation of FcγRI-related signals in primary neurons induces neuropathic pain in a rat model. This work first reveals that sciatic nerve injury persistently activates neuronal FcγRI-related signaling in the DRG, and conditional knockout (CKO) of the FcγRI-encoding gene Fcgr1 in rat DRG neurons significantly alleviates neuropathic pain after nerve injury. C-reactive protein (CRP) is increased in the DRG after nerve injury, and CRP protein of the DRG evokes pain by activating neuronal FcγRI-related signals. Furthermore, microinjection of naive IgG into the DRG alleviates neuropathic pain by suppressing the activation of neuronal FcγRI. These results indicate that the activation of neuronal CRP/FcγRI-related signaling plays an important role in the development of neuropathic pain in chronic constriction injury (CCI) rats. The findings may provide novel insights into the neuroimmune responses after peripheral nerve injury and suggest potential therapeutic targets for neuropathic pain.
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Affiliation(s)
- Fan Liu
- National Human Brain Bank for Development and FunctionDepartment of Human AnatomyHistology and EmbryologyNeuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical SciencesSchool of Basic Medicine Peking Union Medical CollegeBeijing100005P. R. China
| | - Li Zhang
- Department of AnesthesiologyBeijing Friendship HospitalCapital Medical UniversityBeijing100050P. R. China
| | - Si Su
- National Human Brain Bank for Development and FunctionDepartment of Human AnatomyHistology and EmbryologyNeuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical SciencesSchool of Basic Medicine Peking Union Medical CollegeBeijing100005P. R. China
| | - Yehong Fang
- National Human Brain Bank for Development and FunctionDepartment of Human AnatomyHistology and EmbryologyNeuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical SciencesSchool of Basic Medicine Peking Union Medical CollegeBeijing100005P. R. China
| | - Xiang‐sha Yin
- National Human Brain Bank for Development and FunctionDepartment of Human AnatomyHistology and EmbryologyNeuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical SciencesSchool of Basic Medicine Peking Union Medical CollegeBeijing100005P. R. China
| | - Huan Cui
- National Human Brain Bank for Development and FunctionDepartment of Human AnatomyHistology and EmbryologyNeuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical SciencesSchool of Basic Medicine Peking Union Medical CollegeBeijing100005P. R. China
| | - Jianru Sun
- National Human Brain Bank for Development and FunctionDepartment of Human AnatomyHistology and EmbryologyNeuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical SciencesSchool of Basic Medicine Peking Union Medical CollegeBeijing100005P. R. China
| | - Yikuan Xie
- National Human Brain Bank for Development and FunctionDepartment of Human AnatomyHistology and EmbryologyNeuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical SciencesSchool of Basic Medicine Peking Union Medical CollegeBeijing100005P. R. China
| | - Chao Ma
- National Human Brain Bank for Development and FunctionDepartment of Human AnatomyHistology and EmbryologyNeuroscience CenterInstitute of Basic Medical Sciences Chinese Academy of Medical SciencesSchool of Basic Medicine Peking Union Medical CollegeBeijing100005P. R. China
- Chinese Institute for Brain ResearchBeijing102206P. R. China
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4
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Zhai M, Yang S, Lin S, Zhu H, Xu L, Liao H, Song XJ. Distinct Gene Expression Patterns of Ion Channels and Cytokines in Rat Primary Sensory Neurons During Development of Bone Cancer and Cancer Pain. Front Mol Neurosci 2021; 14:665085. [PMID: 34025351 PMCID: PMC8134751 DOI: 10.3389/fnmol.2021.665085] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 04/09/2021] [Indexed: 12/25/2022] Open
Abstract
Cancer and cancer pain processes a major clinical challenge and the underlined mechanisms of pathogenesis remain elusive. We examined the specific changes in the transcriptomic profiles in the dorsal root ganglion (DRG) neurons of rats with bone cancer and bone cancer pain (BCP) using RNA sequencing technology. The bone cancer and BCP was induced by tumor cells implantation (TCI) into the tibia bone cavity in adult female rats. One week after treatment, TCI caused up- and down-regulation of thousands of genes in DRG. These genes were mainly involved in the immune process, inflammatory response, and intracellular signaling transduction of carbohydrate and cytokine. The cAMP and calcium signaling pathways were the major processes in the initial responses. Differentially expressed gene (DEG) analysis further showed that the genes for ion channels increased during day 1-7, while the genes for cytokine signaling pathways sustainedly increased during day 7-14 after TCI. The time courses of gene expression for ion channels and cytokines support their distinct roles in the early induction and late maintenance of BCP development. In addition, among the top 500 up- and down-regulated genes, 80-90% were unique for bone cancer pain as well as neuropathic and inflammatory pain, while less than 2% were shared among the three different forms of pain. This study reveals the uniqueness of mechanisms underlying bone cancer with pain, which is, to a large extent, differently from pain after acute inflammatory and nerve injury and provides novel potential targets of DEGs for bone cancer with pain.
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Affiliation(s)
- Mingzhu Zhai
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China.,Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education of China), Peking University Cancer Hospital and Institute, Beijing, China.,SUSTech Center for Pain Medicine, School of Medicine, Southern University of Science and Technology, Shenzhen, China.,Department of Perioperative Medicine, SUSTech Hospital, Southern University of Science and Technology, Shenzhen, China
| | - Shaomin Yang
- Department of Pain Medicine, Shenzhen Nanshan Hospital, Huazhong University of Science and Technology, Shenzhen, China
| | - Simin Lin
- Department of Laboratory Animal Center, Southern University of Science and Technology, Shenzhen, China
| | - Hanxu Zhu
- SUSTech Center for Pain Medicine, School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Lihong Xu
- SUSTech Center for Pain Medicine, School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Huabao Liao
- SUSTech Center for Pain Medicine, School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Xue-Jun Song
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education of China), Peking University Cancer Hospital and Institute, Beijing, China.,SUSTech Center for Pain Medicine, School of Medicine, Southern University of Science and Technology, Shenzhen, China.,Department of Perioperative Medicine, SUSTech Hospital, Southern University of Science and Technology, Shenzhen, China
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5
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Abstract
Spinal projection neurons convey nociceptive signals to multiple brain regions including the parabrachial (PB) nucleus, which contributes to the emotional valence of pain perception. Despite the clear importance of projection neurons to pain processing, our understanding of the factors that shape their intrinsic membrane excitability remains limited. Here, we investigate a potential role for the Na leak channel NALCN in regulating the activity of spino-PB neurons in the developing rodent. Pharmacological reduction of NALCN current (INALCN), or the genetic deletion of NALCN channels, significantly reduced the intrinsic excitability of lamina I spino-PB neurons. In addition, substance P (SP) activated INALCN in ascending projection neurons through downstream Src kinase signaling, and the knockout of NALCN prevented SP-evoked action potential discharge in this neuronal population. These results identify, for the first time, NALCN as a strong regulator of neuronal activity within central pain circuits and also elucidate an additional ionic mechanism by which SP can modulate spinal nociceptive processing. Collectively, these findings indicate that the level of NALCN conductance within spino-PB neurons tightly governs ascending nociceptive transmission to the brain and thereby potentially influences pain perception.
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6
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Shi Y, Chen Y, Wang Y. Kir2.1 Channel Regulation of Glycinergic Transmission Selectively Contributes to Dynamic Mechanical Allodynia in a Mouse Model of Spared Nerve Injury. Neurosci Bull 2018; 35:301-314. [PMID: 30203408 DOI: 10.1007/s12264-018-0285-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 07/20/2018] [Indexed: 11/25/2022] Open
Abstract
Neuropathic pain is a chronic debilitating symptom characterized by spontaneous pain and mechanical allodynia. It occurs in distinct forms, including brush-evoked dynamic and filament-evoked punctate mechanical allodynia. Potassium channel 2.1 (Kir2.1), which exhibits strong inward rectification, is and regulates the activity of lamina I projection neurons. However, the relationship between Kir2.1 channels and mechanical allodynia is still unclear. In this study, we first found that pretreatment with ML133, a selective Kir2.1 inhibitor, by intrathecal administration, preferentially inhibited dynamic, but not punctate, allodynia in mice with spared nerve injury (SNI). Intrathecal injection of low doses of strychnine, a glycine receptor inhibitor, selectively induced dynamic, but not punctate allodynia, not only in naïve but also in ML133-pretreated mice. In contrast, bicuculline, a GABAA receptor antagonist, induced only punctate, but not dynamic, allodynia. These results indicated the involvement of glycinergic transmission in the development of dynamic allodynia. We further found that SNI significantly suppressed the frequency, but not the amplitude, of the glycinergic spontaneous inhibitory postsynaptic currents (gly-sIPSCs) in neurons on the lamina II-III border of the spinal dorsal horn, and pretreatment with ML133 prevented the SNI-induced gly-sIPSC reduction. Furthermore, 5 days after SNI, ML133, either by intrathecal administration or acute bath perfusion, and strychnine sensitively reversed the SNI-induced dynamic, but not punctate, allodynia and the gly-sIPSC reduction in lamina IIi neurons, respectively. In conclusion, our results suggest that blockade of Kir2.1 channels in the spinal dorsal horn selectively inhibits dynamic, but not punctate, mechanical allodynia by enhancing glycinergic inhibitory transmission.
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Affiliation(s)
- Yiqian Shi
- Department of Neurology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China
| | - Yangyang Chen
- Department of Neurology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China
| | - Yun Wang
- Department of Neurology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China.
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7
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Zemel BM, Ritter DM, Covarrubias M, Muqeem T. A-Type K V Channels in Dorsal Root Ganglion Neurons: Diversity, Function, and Dysfunction. Front Mol Neurosci 2018; 11:253. [PMID: 30127716 PMCID: PMC6088260 DOI: 10.3389/fnmol.2018.00253] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/04/2018] [Indexed: 12/13/2022] Open
Abstract
A-type voltage-gated potassium (Kv) channels are major regulators of neuronal excitability that have been mainly characterized in the central nervous system. By contrast, there is a paucity of knowledge about the molecular physiology of these Kv channels in the peripheral nervous system, including highly specialized and heterogenous dorsal root ganglion (DRG) neurons. Although all A-type Kv channels display pore-forming subunits with similar structural properties and fast inactivation, their voltage-, and time-dependent properties and modulation are significantly different. These differences ultimately determine distinct physiological roles of diverse A-type Kv channels, and how their dysfunction might contribute to neurological disorders. The importance of A-type Kv channels in DRG neurons is highlighted by recent studies that have linked their dysfunction to persistent pain sensitization. Here, we review the molecular neurophysiology of A-type Kv channels with an emphasis on those that have been identified and investigated in DRG nociceptors (Kv1.4, Kv3.4, and Kv4s). Also, we discuss evidence implicating these Kv channels in neuropathic pain resulting from injury, and present a perspective of outstanding challenges that must be tackled in order to discover novel treatments for intractable pain disorders.
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Affiliation(s)
- Benjamin M. Zemel
- Vollum Institute, Oregon Health and Science University, Portland, OR, United States
| | - David M. Ritter
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Manuel Covarrubias
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College and Jefferson College of Life Sciences at Thomas Jefferson University, Philadelphia, PA, United States
| | - Tanziyah Muqeem
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College and Jefferson College of Life Sciences at Thomas Jefferson University, Philadelphia, PA, United States
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8
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Wang T, Hurwitz O, Shimada SG, Tian D, Dai F, Zhou J, Ma C, LaMotte RH. Anti-nociceptive effects of bupivacaine-encapsulated PLGA nanoparticles applied to the compressed dorsal root ganglion in mice. Neurosci Lett 2018; 668:154-158. [PMID: 29355697 DOI: 10.1016/j.neulet.2018.01.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 01/05/2018] [Accepted: 01/16/2018] [Indexed: 11/24/2022]
Abstract
Bupivacaine is a commonly used local anesthetic in postoperative pain management. We evaluated the effects of a prolonged, local delivery of bupivacaine on pain behavior accompanying a chronic compression of the dorsal root ganglion (CCD) - an animal model of radicular pain. Poly(lactide-coglycolide) (PLGA) nanoparticles encapsulating bupivacaine were injected unilaterally into the L3 and L4 DRGs of mice just before producing CCD by implanting a stainless-steel rod in the intervertebral foramen of each ganglion. Behavioral sensitivity to punctate mechanical stimuli (Von Frey filaments) of different forces of indentation, delivered to each hind paw, was measured before and on subsequent days of testing after the CCD. Nanoparticles were spherical in morphology and 150 ± 10 nm in diameter. Bupivacaine was steadily released as measured in vitro over 35 days. A dye that was encapsulated in the nanoparticles was found in the intact DRG after 2 weeks. CCD alone or with injection of blank (control) nanoparticles produced a behavioral hypersensitivity to the punctate stimuli on the ipsilateral paw without affecting sensitivity on the contralateral, over a period of 7-14 days. The hypersensitivity was manifested as an increased incidence of paw-withdrawal to indentation forces normally below threshold (allodynia) and an increased shaking to a filament force that always elicited withdrawal prior to CCD (hyperalgesia). In contrast, nanoparticles with bupivacaine prevented any manifestation of allodynia or hyperalgesia on the ipsilateral hind paw while leaving normal nociceptive responses largely intact on both hind paws. CCD induced behavioral hypersensitivity to nociceptive stimuli is known to be associated with a hyperexcitability of sensory neurons originating in the compressed ganglion. We hypothesize that bupivacaine-loaded PLGA nanoparticles may prevent the occurrence of this neuronal hyperexcitability without reducing the nociceptive information normally conducted from the periphery to the central nervous system. The slow, sustained delivery of bupivacaine by nanoparticles may provide a means of preventing the occurrence of postoperative neuronal hyperexcitability that could develop into chronic neuropathic pain.
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Affiliation(s)
- Tao Wang
- Department of Anatomy, Histology and Embryology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China; Department of Anesthesiology, Yale University School of Medicine, New Haven, CT, 06520-8051, USA
| | - Olivia Hurwitz
- Department of Anesthesiology, Yale University School of Medicine, New Haven, CT, 06520-8051, USA
| | - Steven G Shimada
- Department of Anesthesiology, Yale University School of Medicine, New Haven, CT, 06520-8051, USA
| | - Daofeng Tian
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT, USA
| | - Feng Dai
- Department of Anesthesiology, Yale University School of Medicine, New Haven, CT, 06520-8051, USA
| | - Jiangbing Zhou
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT, USA
| | - Chao Ma
- Department of Anatomy, Histology and Embryology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China; Department of Anesthesiology, Yale University School of Medicine, New Haven, CT, 06520-8051, USA.
| | - Robert H LaMotte
- Department of Anesthesiology, Yale University School of Medicine, New Haven, CT, 06520-8051, USA.
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9
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Ford NC, Baccei ML. Inward-rectifying K + (K ir2) leak conductance dampens the excitability of lamina I projection neurons in the neonatal rat. Neuroscience 2016; 339:502-510. [PMID: 27751963 DOI: 10.1016/j.neuroscience.2016.10.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 09/20/2016] [Accepted: 10/07/2016] [Indexed: 01/03/2023]
Abstract
Spinal lamina I projection neurons serve as a major conduit by which noxious stimuli detected in the periphery are transmitted to nociceptive circuits in the brain, including the parabrachial nucleus (PB) and the periaqueductal gray (PAG). While neonatal spino-PB neurons are more than twice as likely to exhibit spontaneous activity compared to spino-PAG neurons, the underlying mechanisms remain unclear since nothing is known about the voltage-independent (i.e. 'leak') ion channels expressed by these distinct populations during early life. To begin identifying these key leak conductances, the present study investigated the role of classical inward-rectifying K+ (Kir2) channels in the regulation of intrinsic excitability in neonatal rat spino-PB and spino-PAG neurons. The data demonstrate that a reduction in Kir2-mediated conductance by external BaCl2 significantly enhanced intrinsic membrane excitability in both groups. Similar results were observed in spino-PB neurons following Kir2 channel block with the selective antagonist ML133. In addition, voltage-clamp experiments showed that spino-PB and spino-PAG neurons express similar amounts of Kir2 current during the early postnatal period, suggesting that the differences in the prevalence of spontaneous activity between the two populations are not explained by differential expression of Kir2 channels. Overall, the results indicate that Kir2-mediated conductance tonically dampens the firing of multiple subpopulations of lamina I projection neurons during early life. Therefore, Kir2 channels are positioned to tightly shape the output of the immature spinal nociceptive circuit and thus regulate the ascending flow of nociceptive information to the developing brain, which has important functional implications for pediatric pain.
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Affiliation(s)
- Neil C Ford
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267, USA; Pain Research Center, Department of Anesthesiology, University of Cincinnati Medical Center, 231 Albert Sabin Way, Cincinnati, OH 45267, USA
| | - Mark L Baccei
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267, USA; Pain Research Center, Department of Anesthesiology, University of Cincinnati Medical Center, 231 Albert Sabin Way, Cincinnati, OH 45267, USA.
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10
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Pleticha J, Maus TP, Beutler AS. Future Directions in Pain Management: Integrating Anatomically Selective Delivery Techniques With Novel Molecularly Selective Agents. Mayo Clin Proc 2016; 91:522-33. [PMID: 27046525 DOI: 10.1016/j.mayocp.2016.02.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 02/19/2016] [Accepted: 02/22/2016] [Indexed: 01/12/2023]
Abstract
Treatment for chronic, locoregional pain ranks among the most prevalent unmet medical needs. The failure of systemic analgesic drugs, such as opioids, is often due to their off-target toxicity, development of tolerance, and abuse potential. Interventional pain procedures provide target specificity but lack pharmacologically selective agents with long-term efficacy. Gene therapy vectors are a new tool for the development of molecularly selective pain therapies, which have already been proved to provide durable analgesia in preclinical models. Taken together, advances in image-guided delivery and gene therapy may lead to a new class of dual selective analgesic treatments integrating the molecular selectivity of analgesic genes with the anatomic selectivity of interventional delivery techniques.
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Affiliation(s)
- Josef Pleticha
- Department of Anesthesiology and Oncology, Mayo Clinic, Rochester, MN
| | | | - Andreas S Beutler
- Department of Anesthesiology and Oncology, Mayo Clinic, Rochester, MN
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11
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Laumet G, Garriga J, Chen SR, Zhang Y, Li DP, Smith TM, Dong Y, Jelinek J, Cesaroni M, Issa JP, Pan HL. G9a is essential for epigenetic silencing of K(+) channel genes in acute-to-chronic pain transition. Nat Neurosci 2015; 18:1746-55. [PMID: 26551542 PMCID: PMC4661086 DOI: 10.1038/nn.4165] [Citation(s) in RCA: 139] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 10/07/2015] [Indexed: 02/07/2023]
Abstract
Neuropathic pain is a debilitating clinical problem and difficult to treat. Nerve injury causes a long-lasting reduction in K+ channel expression in the dorsal root ganglion (DRG), but little is known about the epigenetic mechanisms involved. Here we show that nerve injury increased H3K9me2 occupancy at Kcna4, Kcnd2, Kcnq2 and Kcnma1 promoters but did not affect DNA methylation levels of these genes in DRGs. Nerve injury increased activity of G9a, histone deacetylases and EZH2, but only G9a inhibition consistently restored K+ channel expression. Selective G9a knockout in DRG neurons completely blocked K+ channel silencing and chronic pain development after nerve injury. Remarkably, RNA sequencing analysis revealed that G9a inhibition not only reactivated 40 of 42 silenced K+ channel genes but also normalized 638 genes down- or up-regulated by nerve injury. Thus G9a plays a dominant role in transcriptional repression of K+ channels and in acute-to-chronic pain transition after nerve injury.
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Affiliation(s)
- Geoffroy Laumet
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Judit Garriga
- Fels Institute for Cancer Research and Molecular Biology, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania, USA
| | - Shao-Rui Chen
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Yuhao Zhang
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - De-Pei Li
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Trevor M Smith
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Yingchun Dong
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.,Department of Anesthesiology, Institute and Hospital of Stomatology, Nanjing University Medical School, Nanjing, China
| | - Jaroslav Jelinek
- Fels Institute for Cancer Research and Molecular Biology, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania, USA
| | - Matteo Cesaroni
- Fels Institute for Cancer Research and Molecular Biology, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania, USA
| | - Jean-Pierre Issa
- Fels Institute for Cancer Research and Molecular Biology, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania, USA
| | - Hui-Lin Pan
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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12
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Snowball A, Schorge S. Changing channels in pain and epilepsy: Exploiting ion channel gene therapy for disorders of neuronal hyperexcitability. FEBS Lett 2015; 589:1620-34. [PMID: 25979170 DOI: 10.1016/j.febslet.2015.05.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 04/29/2015] [Accepted: 05/02/2015] [Indexed: 11/25/2022]
Abstract
Chronic pain and epilepsy together affect hundreds of millions of people worldwide. While traditional pharmacotherapy provides essential relief to the majority of patients, a large proportion remains resistant, and surgical intervention is only possible for a select few. As both disorders are characterised by neuronal hyperexcitability, manipulating the expression of the most direct modulators of excitability - ion channels - represents an attractive common treatment strategy. A number of viral gene therapy approaches have been explored to achieve this. These range from the up- or down-regulation of channels that control excitability endogenously, to the delivery of exogenous channels that permit manipulation of excitability via optical or chemical means. In this review we highlight the key experimental successes of each approach and discuss the challenges facing their clinical translation.
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Affiliation(s)
- Albert Snowball
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Stephanie Schorge
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK.
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Increase in the titer of lentiviral vectors expressing potassium channels by current blockade during viral vector production. BMC Neurosci 2015; 16:30. [PMID: 25940378 PMCID: PMC4425897 DOI: 10.1186/s12868-015-0159-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 04/01/2015] [Indexed: 12/02/2022] Open
Abstract
Background High titers of lentiviral vectors are required for the efficient transduction of a gene of interest. During preparation of lentiviral the vectors, the protein of interest is inevitably expressed in the viral vector-producing cells. This expression may affect the production of the lentiviral vector. Methods We prepared lentiviral vectors expressing inwardly rectifying potassium channel (Lv-Kir2.1), its dominant-negative form (Lv-Kir-DN), and other K+ channels, using the ubiquitously active β-actin and neuron-specific synapsin I promoters. Results The titer of Lv-Kir-DN was higher than that of Lv-Kir2.1, suggesting a negative effect of induced K+ currents on viral titer. We then blocked Kir2.1 currents with the selective blocker Ba2+ during Lv-Kir2.1 production, and obtained about a 5-fold increase in the titer. Higher extracellular K+ concentrations increased the titer of Lv-Kir2.1 about 9-fold. With a synapsin I promoter Ba2+ increased the titer because of the moderate expression of Kir2.1 channel. Channel blockade also increased the titers of the lentivirus expressing Kv1.4 and TREK channels, but not HERG. The increase in titer correlated with the K+ currents generated by the channels expressed. Conclusion In the production of lentivirus expressing K+ channels, titers are increased by blocking K+ currents in the virus-producing cells. This identifies a crucial issue in the production of viruses expressing membrane channels, and should facilitate basic and gene therapeutic research on channelopathies.
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Opening paths to novel analgesics: the role of potassium channels in chronic pain. Trends Neurosci 2014; 37:146-58. [PMID: 24461875 PMCID: PMC3945816 DOI: 10.1016/j.tins.2013.12.002] [Citation(s) in RCA: 183] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 12/13/2013] [Accepted: 12/17/2013] [Indexed: 01/02/2023]
Abstract
Potassium (K+) channels are crucial determinants of neuronal excitability. Nerve injury or inflammation alters K+ channel activity in neurons of the pain pathway. These changes can render neurons hyperexcitable and cause chronic pain. Therapies targeting K+ channels may provide improved pain relief in these states.
Chronic pain is associated with abnormal excitability of the somatosensory system and remains poorly treated in the clinic. Potassium (K+) channels are crucial determinants of neuronal activity throughout the nervous system. Opening of these channels facilitates a hyperpolarizing K+ efflux across the plasma membrane that counteracts inward ion conductance and therefore limits neuronal excitability. Accumulating research has highlighted a prominent involvement of K+ channels in nociceptive processing, particularly in determining peripheral hyperexcitability. We review salient findings from expression, pharmacological, and genetic studies that have untangled a hitherto undervalued contribution of K+ channels in maladaptive pain signaling. These emerging data provide a framework to explain enigmatic pain syndromes and to design novel pharmacological treatments for these debilitating states.
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Boulis NM, Handy CR, Krudy CA, Donnelly EM, Federici T, Franz CK, Barrow EM, Teng Q, Kumar P, Cress D. Regulated Neuronal Neuromodulation via Spinal Cord Expression of the Gene for the Inwardly Rectifying Potassium Channel 2.1 (Kir2.1). Neurosurgery 2013; 72:653-61; discussion 661. [DOI: 10.1227/neu.0b013e318283f59a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Iwase T, Takebayashi T, Tanimoto K, Terashima Y, Miyakawa T, Kobayashi T, Tohse N, Yamashita T. Sympathectomy attenuates excitability of dorsal root ganglion neurons and pain behaviour in a lumbar radiculopathy model. Bone Joint Res 2012; 1:198-204. [PMID: 23610691 PMCID: PMC3626214 DOI: 10.1302/2046-3758.19.2000073] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 07/03/2012] [Indexed: 01/19/2023] Open
Abstract
Objectives In order to elucidate the influence of sympathetic nerves on
lumbar radiculopathy, we investigated whether sympathectomy attenuated
pain behaviour and altered the electrical properties of the dorsal
root ganglion (DRG) neurons in a rat model of lumbar root constriction. Methods Sprague-Dawley rats were divided into three experimental groups.
In the root constriction group, the left L5 spinal nerve root was
ligated proximal to the DRG as a lumbar radiculopathy model. In
the root constriction + sympathectomy group, sympathectomy was performed
after the root constriction procedure. In the control group, no
procedures were performed. In order to evaluate the pain relief
effect of sympathectomy, behavioural analysis using mechanical and
thermal stimulation was performed. In order to evaluate the excitability
of the DRG neurons, we recorded action potentials of the isolated
single DRG neuron by the whole-cell patch-clamp method. Results In behavioural analysis, sympathectomy attenuated the mechanical
allodynia and thermal hyperalgesia caused by lumbar root constriction.
In electrophysiological analysis, single isolated DRG neurons with
root constriction exhibited lower threshold current, more depolarised
resting membrane potential, prolonged action potential duration,
and more depolarisation frequency. These hyperexcitable alterations
caused by root constriction were significantly attenuated in rats
treated with surgical sympathectomy. Conclusion The present results suggest that sympathectomy attenuates lumbar
radicular pain resulting from root constriction by altering the
electrical property of the DRG neuron itself. Thus, the sympathetic
nervous system was closely associated with lumbar radicular pain,
and suppressing the activity of the sympathetic nervous system may therefore
lead to pain relief.
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Affiliation(s)
- T Iwase
- Sapporo Medical University School of Medicine, Department of Orthopaedic Surgery, South 1, West 16, Chuo-ku, Sapporo 060-8543, Japan
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Gupta R, Nassiri N, Hazel A, Bathen M, Mozaffar T. Chronic nerve compression alters Schwann cell myelin architecture in a murine model. Muscle Nerve 2012; 45:231-41. [PMID: 22246880 DOI: 10.1002/mus.22276] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Myelinating Schwann cells compartmentalize their outermost layer to form actin-rich channels known as Cajal bands. Herein we investigate changes in Schwann cell architecture and cytoplasmic morphology in a novel mouse model of carpal tunnel syndrome. METHODS Chronic nerve compression (CNC) injury was created in wild-type and slow-Wallerian degeneration (Wld(S) ) mice. Over 12 weeks, nerves were electrodiagnostically assessed, and Schwann cell morphology was thoroughly evaluated. RESULTS A decline in nerve conduction velocity and increase in g-ratio is observed without early axonal damage. Schwann cells display shortened internodal lengths and severely disrupted Cajal bands. Quite surprisingly, the latter is reconstituted without improvements to nerve conduction velocity. CONCLUSIONS Chronic entrapment injuries like carpal tunnel syndrome are primarily mediated by the Schwann cell response, where decreases in internodal length and myelin thickness disrupt the efficiency of impulse propagation. Restitution of Cajal bands is not sufficient for remyelination after CNC injury.
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Affiliation(s)
- Ranjan Gupta
- Department of Orthopaedic Surgery, University of California at Irvine, 2226 Gillespie Neuroscience Research Facility, Irvine, California 92697, USA.
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Fischer G, Kostic S, Nakai H, Park F, Sapunar D, Yu H, Hogan Q. Direct injection into the dorsal root ganglion: technical, behavioral, and histological observations. J Neurosci Methods 2011; 199:43-55. [PMID: 21540055 DOI: 10.1016/j.jneumeth.2011.04.021] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Revised: 04/12/2011] [Accepted: 04/14/2011] [Indexed: 10/18/2022]
Abstract
Direct injection of agents into the dorsal root ganglia (DRGs) offers the opportunity to manipulate sensory neuron function at a segmental level to explore pathophysiology of painful conditions. However, there is no described method that has been validated in detail for such injections in adult rats. We have found that 2 μl of dye injected through a pulled glass pipette directly into the distal DRG, exposed by a minimal foraminotomy, produces complete filling of the DRG with limited extension into the spinal roots. Injection into the spinal nerve required 3 μl to achieve comparable DRG filling, produced preferential spread into the ventral root, and was accompanied by substantial leakage of injected solution from the injection site. Injections into the sciatic nerve of volumes up to 10 μl did not reach the DRG. Transient hypersensitivity to mechanical stimulation at threshold (von Frey) and noxious levels (pin) developed after 2 μl saline injection directly into the DRG that was in part attributable to the surgical exposure procedure alone. Only minimal astrocyte activation in the spinal dorsal horn was evident after DRG saline injections. Injection of adeno-associated virus (AAV) vector conveying green fluorescent protein (GFP) transgene resulted in expression as soon as 1 day after injection into the DRG, including fibers in the spinal dorsal horn and columns. AAV injection into the DRG produced additional thermal hypersensitivity and withdrawal from the stroke of a brush and compromised motor performance. These findings demonstrate a method for selective injection of agents into single DRGs for anatomically restricted actions.
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Affiliation(s)
- Gregory Fischer
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, 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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