1
|
Cathenaut L, Schlichter R, Hugel S. Short-term plasticity in the spinal nociceptive system. Pain 2023; 164:2411-2424. [PMID: 37578501 DOI: 10.1097/j.pain.0000000000002999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 06/08/2023] [Indexed: 08/15/2023]
Abstract
ABSTRACT Somatosensory information is delivered to neuronal networks of the dorsal horn (DH) of the spinal cord by the axons of primary afferent neurons that encode the intensity of peripheral sensory stimuli under the form of a code based on the frequency of action potential firing. The efficient processing of these messages within the DH involves frequency-tuned synapses, a phenomenon linked to their ability to display activity-dependent forms of short-term plasticity (STP). By affecting differently excitatory and inhibitory synaptic transmissions, these STP properties allow a powerful gain control in DH neuronal networks that may be critical for the integration of nociceptive messages before they are forwarded to the brain, where they may be ultimately interpreted as pain. Moreover, these STPs can be finely modulated by endogenous signaling molecules, such as neurosteroids, adenosine, or GABA. The STP properties of DH inhibitory synapses might also, at least in part, participate in the pain-relieving effect of nonpharmacological analgesic procedures, such as transcutaneous electrical nerve stimulation, electroacupuncture, or spinal cord stimulation. The properties of target-specific STP at inhibitory DH synapses and their possible contribution to electrical stimulation-induced reduction of hyperalgesic and allodynic states in chronic pain will be reviewed and discussed.
Collapse
Affiliation(s)
- Lou Cathenaut
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | | | | |
Collapse
|
2
|
Pérez R, Figueredo C, Burgos V, Cabrera-Pardo JR, Schmidt B, Heydenreich M, Koch A, Deuis JR, Vetter I, Paz C. Natural Compounds Purified from the Leaves of Aristotelia chilensis: Makomakinol, a New Alkaloid and the Effect of Aristoteline and Hobartine on Na V Channels. Int J Mol Sci 2023; 24:15504. [PMID: 37958488 PMCID: PMC10650464 DOI: 10.3390/ijms242115504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 10/13/2023] [Accepted: 10/17/2023] [Indexed: 11/15/2023] Open
Abstract
Aristotelia chilensis or "maqui" is a tree native to Chile used in the folk medicine of the Mapuche people as an anti-inflammatory agent for the treatment of digestive ailments, fever, and skin lesions. Maqui fruits are black berries which are considered a "superfruit" with notable potential health benefits, promoted to be an antioxidant, cardioprotective, and anti-inflammatory. Maqui leaves contain non-iridoid monoterpene indole alkaloids which have previously been shown to act on nicotinic acetylcholine receptors, potassium channels, and calcium channels. Here, we isolated a new alkaloid from maqui leaves, now called makomakinol, together with the known alkaloids aristoteline, hobartine, and 3-formylindole. Moreover, the polyphenols quercetine, ethyl caffeate, and the terpenes, dihydro-β-ionone and terpin hydrate, were also obtained. In light of the reported analgesic and anti-nociceptive properties of A. chilensis, in particular a crude mixture of alkaloids containing aristoteline and hobartinol (PMID 21585384), we therefore evaluated the activity of aristoteline and hobartine on NaV1.8, a key NaV isoform involved in nociception, using automated whole-cell patch-clamp electrophysiology. Aristoteline and hobartine both inhibited Nav1.8 with an IC50 of 68 ± 3 µM and 54 ± 1 µM, respectively. Hobartine caused a hyperpolarizing shift of the voltage-dependence of the activation, whereas aristoteline did not change the voltage-dependence of the activation or inactivation. The inhibitory activity of these alkaloids on NaV channels may contribute to the reported analgesic properties of Aristotelia chilensis used by the Mapuche people.
Collapse
Affiliation(s)
- Rebeca Pérez
- Laboratory of Natural Products & Drug Discovery, Center CEBIM, Universidad de La Frontera, Av. Francisco Salazar 01145, Temuco 4780000, Chile; (R.P.); (C.F.)
| | - Claudia Figueredo
- Laboratory of Natural Products & Drug Discovery, Center CEBIM, Universidad de La Frontera, Av. Francisco Salazar 01145, Temuco 4780000, Chile; (R.P.); (C.F.)
| | - Viviana Burgos
- Departamento de Ciencias Biológicas y Químicas, Facultad de Recursos Naturales, Universidad Católica de Temuco, Rudecindo Ortega 02950, Temuco 4780000, Chile;
| | - Jaime R. Cabrera-Pardo
- Laboratorio de Química Aplicada y Sustentable (LabQAS), Departamento de Química, Facultad de Ciencias, Universidad del Bío-Bío, Concepción 4081112, Chile;
| | - Bernd Schmidt
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam, Germany; (B.S.); (A.K.)
| | - Matthias Heydenreich
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam, Germany; (B.S.); (A.K.)
| | - Andreas Koch
- Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam, Germany; (B.S.); (A.K.)
| | - Jennifer R. Deuis
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia; (J.R.D.); (I.V.)
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia; (J.R.D.); (I.V.)
- School of Pharmacy, The University of Queensland, Woolloongabba, QLD 4102, Australia
| | - Cristian Paz
- Laboratory of Natural Products & Drug Discovery, Center CEBIM, Universidad de La Frontera, Av. Francisco Salazar 01145, Temuco 4780000, Chile; (R.P.); (C.F.)
| |
Collapse
|
3
|
Marom S, Marder E. A biophysical perspective on the resilience of neuronal excitability across timescales. Nat Rev Neurosci 2023; 24:640-652. [PMID: 37620600 DOI: 10.1038/s41583-023-00730-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2023] [Indexed: 08/26/2023]
Abstract
Neuronal membrane excitability must be resilient to perturbations that can take place over timescales from milliseconds to months (or even years in long-lived animals). A great deal of attention has been paid to classes of homeostatic mechanisms that contribute to long-term maintenance of neuronal excitability through processes that alter a key structural parameter: the number of ion channel proteins present at the neuronal membrane. However, less attention has been paid to the self-regulating 'automatic' mechanisms that contribute to neuronal resilience by virtue of the kinetic properties of ion channels themselves. Here, we propose that these two sets of mechanisms are complementary instantiations of feedback control, together enabling resilience on a wide range of temporal scales. We further point to several methodological and conceptual challenges entailed in studying these processes - both of which involve enmeshed feedback control loops - and consider the consequences of these mechanisms of resilience.
Collapse
Affiliation(s)
- Shimon Marom
- Faculty of Medicine, Technion - Institute of Technology, Haifa, Israel.
| | - Eve Marder
- Biology Department, Brandeis University, Waltham, MA, USA.
- Volen National Center for Complex Systems, Brandeis University, Waltham, MA, USA.
| |
Collapse
|
4
|
Maksymchuk N, Sakurai A, Cox DN, Cymbalyuk GS. Cold-Temperature Coding with Bursting and Spiking Based on TRP Channel Dynamics in Drosophila Larva Sensory Neurons. Int J Mol Sci 2023; 24:14638. [PMID: 37834085 PMCID: PMC10572325 DOI: 10.3390/ijms241914638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/30/2023] [Accepted: 09/05/2023] [Indexed: 10/15/2023] Open
Abstract
Temperature sensation involves thermosensitive TRP (thermoTRP) and non-TRP channels. Drosophila larval Class III (CIII) neurons serve as the primary cold nociceptors and express a suite of thermoTRP channels implicated in noxious cold sensation. How CIII neurons code temperature remains unclear. We combined computational and electrophysiological methods to address this question. In electrophysiological experiments, we identified two basic cold-evoked patterns of CIII neurons: bursting and spiking. In response to a fast temperature drop to noxious cold, CIII neurons distinctly mark different phases of the stimulus. Bursts frequently occurred along with the fast temperature drop, forming a peak in the spiking rate and likely coding the high rate of the temperature change. Single spikes dominated at a steady temperature and exhibited frequency adaptation following the peak. When temperature decreased slowly to the same value, mainly spiking activity was observed, with bursts occurring sporadically throughout the stimulation. The spike and the burst frequencies positively correlated with the rate of the temperature drop. Using a computational model, we explain the distinction in the occurrence of the two CIII cold-evoked patterns bursting and spiking using the dynamics of a thermoTRP current. A two-parameter activity map (Temperature, constant TRP current conductance) marks parameters that support silent, spiking, and bursting regimes. Projecting on the map the instantaneous TRP conductance, governed by activation and inactivation processes, reflects temperature coding responses as a path across silent, spiking, or bursting domains on the map. The map sheds light on how various parameter sets for TRP kinetics represent various types of cold-evoked responses. Together, our results indicate that bursting detects the high rate of temperature change, whereas tonic spiking could reflect both the rate of change and magnitude of steady cold temperature.
Collapse
Affiliation(s)
- Natalia Maksymchuk
- Neuroscience Institute, Georgia State University, Atlanta, GA 30302-5030, USA; (N.M.); (A.S.); (D.N.C.)
| | - Akira Sakurai
- Neuroscience Institute, Georgia State University, Atlanta, GA 30302-5030, USA; (N.M.); (A.S.); (D.N.C.)
| | - Daniel N. Cox
- Neuroscience Institute, Georgia State University, Atlanta, GA 30302-5030, USA; (N.M.); (A.S.); (D.N.C.)
| | - Gennady S. Cymbalyuk
- Neuroscience Institute, Georgia State University, Atlanta, GA 30302-5030, USA; (N.M.); (A.S.); (D.N.C.)
- Department of Biology, Georgia State University, Atlanta, GA 30302-5030, USA
| |
Collapse
|
5
|
Zhang Y, Gong H, Wang JS, Li MN, Cao DL, Gu J, Zhao LX, Zhang XD, Deng YT, Dong FL, Gao YJ, Sun WX, Jiang BC. Nerve Injury-Induced γH2AX Reduction in Primary Sensory Neurons Is Involved in Neuropathic Pain Processing. Int J Mol Sci 2023; 24:10148. [PMID: 37373296 DOI: 10.3390/ijms241210148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/02/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023] Open
Abstract
Phosphorylation of the serine 139 of the histone variant H2AX (γH2AX) is a DNA damage marker that regulates DNA damage response and various diseases. However, whether γH2AX is involved in neuropathic pain is still unclear. We found the expression of γH2AX and H2AX decreased in mice dorsal root ganglion (DRG) after spared nerve injury (SNI). Ataxia telangiectasia mutated (ATM), which promotes γH2AX, was also down-regulated in DRG after peripheral nerve injury. ATM inhibitor KU55933 decreased the level of γH2AX in ND7/23 cells. The intrathecal injection of KU55933 down-regulated DRG γH2AX expression and significantly induced mechanical allodynia and thermal hyperalgesia in a dose-dependent manner. The inhibition of ATM by siRNA could also decrease the pain threshold. The inhibition of dephosphorylation of γH2AX by protein phosphatase 2A (PP2A) siRNA partially suppressed the down-regulation of γH2AX after SNI and relieved pain behavior. Further exploration of the mechanism revealed that inhibiting ATM by KU55933 up-regulated extracellular-signal regulated kinase (ERK) phosphorylation and down-regulated potassium ion channel genes, such as potassium voltage-gated channel subfamily Q member 2 (Kcnq2) and potassium voltage-gated channel subfamily D member 2 (Kcnd2) in vivo, and KU559333 enhanced sensory neuron excitability in vitro. These preliminary findings imply that the down-regulation of γH2AX may contribute to neuropathic pain.
Collapse
Affiliation(s)
- Yan Zhang
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
| | - Hao Gong
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
| | - Ji-Shuai Wang
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
| | - Meng-Na Li
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
| | - De-Li Cao
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
| | - Jun Gu
- Department of Molecular and Cellular Pharmacology, Miller School of Medicine, University of Miami, Coral Gables, FL 33136, USA
| | - Lin-Xia Zhao
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
| | - Xin-Dan Zhang
- The 1st Clinical Department, China Medical University, Shenyang 110122, China
| | - Yu-Tao Deng
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
| | - Fu-Lu Dong
- Department of Pathology, Medical School, Nantong University, Nantong 226001, China
| | - Yong-Jing Gao
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
| | - Wen-Xing Sun
- Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong 226019, China
| | - Bao-Chun Jiang
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong 226019, China
| |
Collapse
|
6
|
Yin JB, Liu HX, Dong QQ, Wu HH, Liang ZW, Fu JT, Zhao WJ, Hu HQ, Guo HW, Zhang T, Lu YC, Jin S, Wang XL, Cao BZ, Wang Z, Ding T. Correlative increasing expressions of KIF5b and Nav1.7 in DRG neurons of rats under neuropathic pain conditions. Physiol Behav 2023; 263:114115. [PMID: 36773735 DOI: 10.1016/j.physbeh.2023.114115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 01/30/2023] [Accepted: 02/08/2023] [Indexed: 02/11/2023]
Abstract
Nav1.7, one of tetrodotoxin-sensitive voltage-gated sodium channels, mainly expressed in the small diameter dorsal root ganglion (DRG) neurons. The expression and accumulation on neuronal membrane of Nav1.7 increased following peripheral tissue inflammation or nerve injury. However, the mechanisms for membrane accumulation of Nav1.7 remained unclear. We report that KIF5b, a highly expressed member of the kinesin-1 family in DRGs, promoted the translocation of Nav1.7 to the plasma membrane in DRG neurons of the rat. Following nociceptive behaviors in rats induced by peripheral spared nerve injury (SNI), synchronously increased KIF5b and Nav1.7 expressions were observed in DRGs. Immunohistochemistry staining demonstrated the co-expressions of KIF5b and Nav1.7 in the same DRG neurons. Immunoprecipitation experiments further confirmed the interactions between KIF5b and Nav1.7. Moreover, intrathecal injections of KIF5b shRNA moderated the SNI-induced both mechanical and thermal hyperalgesia. The rescued analgesic effects also alleviated SNI-induced anxiety-like behaviors. In sum, KIF5b was required for the membrane localizations of Nav1.7, which suggests a novel mechanism for the trafficking of Nav1.7 involved in neuropathic pain.
Collapse
Affiliation(s)
- Jun-Bin Yin
- Department of Neurology, the 960th Hospital of PLA, Jinan 250031, China; Institute of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China; Department of Anatomy, Histology and Embryology, The Fourth Military Medical University, Xi'an 710032, China
| | - Hai-Xia Liu
- Department of Obstetrics and Gynecology, Shandong Provincial Hospital, Jinan 250021, China
| | - Qin-Qin Dong
- Department of Neurology, the 960th Hospital of PLA, Jinan 250031, China; Department of Neurology, Jinzhou Medical University, Jinzhou 121000, China
| | - Huang-Hui Wu
- Department of Anesthesiology, Medical College of Xiamen University, Xiamen 361005, China
| | - Zhuo-Wen Liang
- Institute of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China
| | - Jin-Tao Fu
- Department of Critical Care Medicine, Affiliated Yanzhou District Hospital of Jining Medical College, Jining 272100, China
| | - Wen-Jun Zhao
- Department of Anatomy, Histology and Embryology, The Fourth Military Medical University, Xi'an 710032, China
| | - Huai-Qiang Hu
- Department of Neurology, the 960th Hospital of PLA, Jinan 250031, China
| | - Hong-Wei Guo
- Department of Neurology, the 960th Hospital of PLA, Jinan 250031, China
| | - Ting Zhang
- Department of Anatomy, Histology and Embryology, The Fourth Military Medical University, Xi'an 710032, China
| | - Ya-Cheng Lu
- Department of Anatomy, Histology and Embryology, The Fourth Military Medical University, Xi'an 710032, China
| | - Shan Jin
- Department of Neurology, the 960th Hospital of PLA, Jinan 250031, China
| | - Xiao-Ling Wang
- Department of Neurology, the 960th Hospital of PLA, Jinan 250031, China
| | - Bing-Zhen Cao
- Department of Neurology, the 960th Hospital of PLA, Jinan 250031, China.
| | - Zhe Wang
- Institute of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China.
| | - Tan Ding
- Institute of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China; Department of Anatomy, Histology and Embryology, The Fourth Military Medical University, Xi'an 710032, China.
| |
Collapse
|
7
|
Hyperacusis: Loudness Intolerance, Fear, Annoyance and Pain. Hear Res 2022; 426:108648. [DOI: 10.1016/j.heares.2022.108648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/02/2022] [Accepted: 11/07/2022] [Indexed: 11/10/2022]
|
8
|
Sun Z, Waybright JM, Beldar S, Chen L, Foley CA, Norris‐Drouin JL, Lyu T, Dong A, Min J, Wang Y, James LI, Wang Y. Cdyl Deficiency Brakes Neuronal Excitability and Nociception through Promoting Kcnb1 Transcription in Peripheral Sensory Neurons. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2104317. [PMID: 35119221 PMCID: PMC8981457 DOI: 10.1002/advs.202104317] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 12/28/2021] [Indexed: 05/24/2023]
Abstract
Epigenetic modifications are involved in the onset, development, and maintenance of pain; however, the precise epigenetic mechanism underlying pain regulation remains elusive. Here it is reported that the epigenetic factor chromodomain Y-like (CDYL) is crucial for pain processing. Selective knockout of CDYL in sensory neurons results in decreased neuronal excitability and nociception. Moreover, CDYL facilitates histone 3 lysine 27 trimethylation (H3K27me3) deposition at the Kcnb1 intron region thus silencing voltage-gated potassium channel (Kv ) subfamily member Kv 2.1 transcription. Loss function of CDYL enhances total Kv and Kv 2.1 current density in dorsal root ganglia and knockdown of Kv 2.1 reverses the pain-related phenotypes of Cdyl deficiency mice. Furthermore, focal administration of a novel potent CDYL antagonist blunts nociception and attenuates neuropathic pain. These findings reveal that CDYL is a critical regulator of pain sensation and shed light on the development of novel analgesics targeting epigenetic mechanisms.
Collapse
Affiliation(s)
- Zhao‐Wei Sun
- Neuroscience Research Institute and Department of NeurobiologySchool of Basic Medical SciencesKey Laboratory for NeuroscienceMinistry of Education/National Health Commission and State Key Laboratory of Natural and Biomimetic DrugsPeking UniversityBeijing100083China
- Institute of Military Cognitive and Brain SciencesAcademy of Military Medical SciencesBeijing100039China
| | - Jarod M. Waybright
- Center for Integrative Chemical Biology and Drug DiscoveryDivision of Chemical Biology and Medicinal ChemistryUNC Eshelman School of PharmacyUniversity of North Carolina at Chapel HillChapel HillNC27599USA
| | - Serap Beldar
- Structural Genomics ConsortiumUniversity of Toronto101 College StreetTorontoOntarioM5G 1L7Canada
| | - Lu Chen
- Neuroscience Research Institute and Department of NeurobiologySchool of Basic Medical SciencesKey Laboratory for NeuroscienceMinistry of Education/National Health Commission and State Key Laboratory of Natural and Biomimetic DrugsPeking UniversityBeijing100083China
| | - Caroline A. Foley
- Center for Integrative Chemical Biology and Drug DiscoveryDivision of Chemical Biology and Medicinal ChemistryUNC Eshelman School of PharmacyUniversity of North Carolina at Chapel HillChapel HillNC27599USA
| | - Jacqueline L. Norris‐Drouin
- Center for Integrative Chemical Biology and Drug DiscoveryDivision of Chemical Biology and Medicinal ChemistryUNC Eshelman School of PharmacyUniversity of North Carolina at Chapel HillChapel HillNC27599USA
| | - Tian‐Jie Lyu
- Neuroscience Research Institute and Department of NeurobiologySchool of Basic Medical SciencesKey Laboratory for NeuroscienceMinistry of Education/National Health Commission and State Key Laboratory of Natural and Biomimetic DrugsPeking UniversityBeijing100083China
| | - Aiping Dong
- Structural Genomics ConsortiumUniversity of Toronto101 College StreetTorontoOntarioM5G 1L7Canada
| | - Jinrong Min
- Structural Genomics ConsortiumUniversity of Toronto101 College StreetTorontoOntarioM5G 1L7Canada
- Hubei Key Laboratory of Genetic Regulation and Integrative BiologySchool of Life SciencesCentral China Normal UniversityWuhanHubei430079China
- Department of PhysiologyUniversity of TorontoTorontoOntarioM5S 1A8Canada
| | - Yu‐Pu Wang
- Neuroscience Research Institute and Department of NeurobiologySchool of Basic Medical SciencesKey Laboratory for NeuroscienceMinistry of Education/National Health Commission and State Key Laboratory of Natural and Biomimetic DrugsPeking UniversityBeijing100083China
| | - Lindsey I. James
- Center for Integrative Chemical Biology and Drug DiscoveryDivision of Chemical Biology and Medicinal ChemistryUNC Eshelman School of PharmacyUniversity of North Carolina at Chapel HillChapel HillNC27599USA
| | - Yun Wang
- Neuroscience Research Institute and Department of NeurobiologySchool of Basic Medical SciencesKey Laboratory for NeuroscienceMinistry of Education/National Health Commission and State Key Laboratory of Natural and Biomimetic DrugsPeking UniversityBeijing100083China
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijing100871China
| |
Collapse
|
9
|
Mulpuri Y, Yamamoto T, Nishimura I, Spigelman I. Role of voltage-gated sodium channels in axonal signal propagation of trigeminal ganglion neurons after infraorbital nerve entrapment. NEUROBIOLOGY OF PAIN 2022; 11:100084. [PMID: 35128176 PMCID: PMC8803652 DOI: 10.1016/j.ynpai.2022.100084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/17/2022] [Accepted: 01/17/2022] [Indexed: 11/25/2022]
Abstract
Infraorbital nerve entrapment (IoNE) induces mechanical allodynia and enhances signal propagation in primary afferent A- and C-fibers. IoNE increases sensitivity of A- and C-fibers to conduction block by tetrodotoxin (TTX) and selective voltage-gated sodium channel 1.8 (NaV1.8) inhibitor, A-803467. IoNE increases signal propagation in vibrissal pad Ad -, but not Aβ-fibers, and their sensitivity to conduction block by the selective NaV1.8 inhibitor. IoNE increases membrane excitability of dissociated small and medium sized trigeminal neurons. IoNE increases nerve, but not ganglion, levels of NaV1.3, NaV1.7, and NaV1.8 mRNAs, and NaV1.8 protein.
Chronic pain arising from peripheral nerve injuries represents a significant clinical challenge because even the most efficacious anticonvulsant drug treatments are limited by their side effects profile. We investigated pain behavior, changes in axonal signal conduction and excitability of trigeminal neurons, and expression of voltage-gated sodium channels (NaVs) in the infraorbital nerve and trigeminal ganglion (TG) after infraorbital nerve entrapment (IoNE). Compared to Sham, IoNE rats had increased A- and C-fiber compound action potentials (CAPs) and Aδ component of A-CAP area from fibers innervating the vibrissal pad. After IoNE, A- and C-fiber CAPs were more sensitive to blockade by tetrodotoxin (TTX), and those fibers that were TTX-resistant were more sensitive to blockade by the NaV1.8 selective blocker, A-803467. Although NaV1.7 blocker, ICA-121431 alone, did not affect Aδ-fiber signal propagation, cumulative application with A-803467 and 4,9-anhydro-TTX significantly reduced the Aδ-fiber CAP in IoNE rats. In patch clamp recordings from small- and medium-sized TG neurons, IoNE resulted in reduced action potential (AP) depolarizing current threshold, hyperpolarized AP voltage threshold, increased AP duration, and a more depolarized membrane potential. While the transcripts of most NaVs were reduced in the ipsilateral TG after IoNE, NaV1.3, NaV1.7, and NaV1.8 mRNAs, and NaV1.8 protein, were significantly increased in the nerve. Altogether, our data suggest that axonal redistribution of NaV1.8, and to a lesser extent NaV1.3, and NaV1.7 contributes to enhanced nociceptive signal propagation in peripheral nerve after IoNE.
Collapse
|
10
|
Roy PK, Rajesh Y, Mandal M. Therapeutic targeting of membrane-associated proteins in central nervous system tumors. Exp Cell Res 2021; 406:112760. [PMID: 34339674 DOI: 10.1016/j.yexcr.2021.112760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/28/2021] [Accepted: 07/28/2021] [Indexed: 12/09/2022]
Abstract
The activity of the most complex system, the central nervous system (CNS) is profoundly regulated by a huge number of membrane-associated proteins (MAP). A minor change stimulates immense chemical changes and the elicited response is organized by MAP, which acts as a receptor of that chemical or channel enabling the flow of ions. Slight changes in the activity or expression of these MAPs lead to severe consequences such as cognitive disorders, memory loss, or cancer. CNS tumors are heterogeneous in nature and hard-to-treat due to random mutations in MAPs; like as overexpression of EGFRvIII/TGFβR/VEGFR, change in adhesion molecules α5β3 integrin/SEMA3A, imbalance in ion channel proteins, etc. Extensive research is under process for developing new therapeutic approaches using these proteins such as targeted cytotoxic radiotherapy, drug-delivery, and prodrug activation, blocking of receptors like GluA1, developing viral vector against cell surface receptor. The combinatorial approach of these strategies along with the conventional one might be more potential. Henceforth, our review focuses on in-depth analysis regarding MAPs aiming for a better understanding for developing an efficient therapeutic approach for targeting CNS tumors.
Collapse
Affiliation(s)
- Pritam Kumar Roy
- School of Medical Science and Technology, Indian Institute of Technology Kharagpur, India
| | - Yetirajam Rajesh
- Department of Human and Molecular Genetics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Mahitosh Mandal
- School of Medical Science and Technology, Indian Institute of Technology Kharagpur, India.
| |
Collapse
|
11
|
Mehboob R, Marchenkova A, van den Maagdenberg AMJM, Nistri A. Overexpressed Na V 1.7 Channels Confer Hyperexcitability to in vitro Trigeminal Sensory Neurons of Ca V 2.1 Mutant Hemiplegic Migraine Mice. Front Cell Neurosci 2021; 15:640709. [PMID: 34113237 PMCID: PMC8185157 DOI: 10.3389/fncel.2021.640709] [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: 12/11/2020] [Accepted: 04/09/2021] [Indexed: 11/21/2022] Open
Abstract
Trigeminal sensory neurons of transgenic knock-in (KI) mice expressing the R192Q missense mutation in the α1A subunit of neuronal voltage-gated CaV2.1 Ca2+ channels, which leads to familial hemiplegic migraine type 1 (FHM1) in patients, exhibit a hyperexcitability phenotype. Here, we show that the expression of NaV1.7 channels, linked to pain states, is upregulated in KI primary cultures of trigeminal ganglia (TG), as shown by increased expression of its α1 subunit. In the majority of TG neurons, NaV1.7 channels are co-expressed with ATP-gated P2X3 receptors (P2X3R), which are important nociceptive sensors. Reversing the trigeminal phenotype with selective CaV2.1 channel inhibitor ω-agatoxin IVA inhibited NaV1.7 overexpression. Functionally, KI neurons revealed a TTX-sensitive inward current of larger amplitude that was partially inhibited by selective NaV1.7 blocker Tp1a. Under current-clamp condition, Tp1a raised the spike threshold of both wild-type (WT) and KI neurons with decreased firing rate in KI cells. NaV1.7 activator OD1 accelerated firing in WT and KI neurons, a phenomenon blocked by Tp1a. Enhanced expression and function of NaV1.7 channels in KI TG neurons resulted in higher excitability and facilitated nociceptive signaling. Co-expression of NaV1.7 channels and P2X3Rs in TGs may explain how hypersensitivity to local stimuli can be relevant to migraine.
Collapse
Affiliation(s)
- Riffat Mehboob
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy.,Research Unit, Faculty of Allied Health Sciences, University of Lahore, Lahore, Pakistan
| | - Anna Marchenkova
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Arn M J M van den Maagdenberg
- Department of Neurology, Leiden University Medical Center, Leiden, Netherlands.,Department of Human Genetics, University Medical Center, Leiden, Netherlands
| | - Andrea Nistri
- Department of Neuroscience, International School for Advanced Studies (SISSA), Trieste, Italy
| |
Collapse
|
12
|
Qiu J, Zhang L, Hong J, Ni X, Li J, Li G, Zhang G. Magnolol inhibits sodium currents in freshly isolated mouse dorsal root ganglion neurons. Clin Exp Pharmacol Physiol 2021; 48:347-354. [PMID: 33064853 DOI: 10.1111/1440-1681.13422] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 10/10/2020] [Accepted: 10/12/2020] [Indexed: 12/14/2022]
Abstract
The voltage-gated sodium channel (VGSC) currents in dorsal root ganglion (DRG) neurons contain mainly TTX-sensitive (TTX-S) and TTX-resistant (TTX-R) Na+ currents. Magnolol (Mag), a hydroxylated biphenyl compound isolated from the bark of Magnolia officinalis, has been well documented to exhibit analgesic effects, but its mechanism is not yet fully understood. The aim of the present study was to investigate whether the antinociceptive effects of Mag is through inhibition of Na+ currents. Na+ currents in freshly isolated mouse DRG neurons were recorded with the whole cell patch clamp technique. Results showed that Mag inhibited TTX-S and TTX-R Na+ currents in a concentration-dependent manner. The IC50 values for block of TTX-S and TTX-R Na+ currents were 9.4 and 7.0 μmol/L, respectively. Therefore, TTX-R Na+ current was more susceptible to Mag than TTX-S Na+ current. For TTX-S Na+ channel, 10 μmol/L Mag shifted the steady state inactivation curve toward more negative by 9.8 mV, without affecting the activation curve. For TTX-R Na+ channel, 7 μmol/L Mag shifted the steady state activation and inactivation curves toward more positive and negative potentials by 6.5 and 11.7 mV, respectively. In addition, Mag significantly postponed recovery of TTX-S and TTX-R Na+ currents from inactivation, and produced frequency dependent blocks of both subtypes of Na+ currents. These results suggest that the inhibitory effects of Mag on Na+ channels may contribute to its analgesic effect.
Collapse
Affiliation(s)
- Jie Qiu
- Department of Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Lulu Zhang
- Department of Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Jiangru Hong
- Department of Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Xiao Ni
- Key Laboratory of Medical Electrophysiology, Ministry of Education, Institute of Cardiovascular Research of Southwest, Medical University, Luzhou, China
| | - Jun Li
- Key Laboratory of Medical Electrophysiology, Ministry of Education, Institute of Cardiovascular Research of Southwest, Medical University, Luzhou, China
| | - Guang Li
- Key Laboratory of Medical Electrophysiology, Ministry of Education, Institute of Cardiovascular Research of Southwest, Medical University, Luzhou, China
| | - Guangqin Zhang
- Department of Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| |
Collapse
|
13
|
Lengyel M, Hajdu D, Dobolyi A, Rosta J, Czirják G, Dux M, Enyedi P. TRESK background potassium channel modifies the TRPV1-mediated nociceptor excitability in sensory neurons. Cephalalgia 2021; 41:827-838. [PMID: 33525904 DOI: 10.1177/0333102421989261] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND TWIK-related spinal cord potassium channel (TRESK) background potassium channels have a key role in controlling resting membrane potential and excitability of sensory neurons. A frameshift mutation leading to complete loss of TRESK function has been identified in members of a family suffering from migraine with aura. In the present study, we examined the role of TRESK channels on nociceptor function in mice. METHODS Calcium imaging was used to investigate the role of TRESK channels in the modulation of the response evoked by transient receptor potential vanilloid 1 (TRPV1) receptor stimulation in dorsal root ganglion neurons. Release of calcitonin gene-related peptide from trigeminal afferents and changes in meningeal blood flow were also measured. Experiments were performed on wild-type and TRESK knockout animals. RESULTS Inhibition of TRESK increased the TRPV1-mediated calcium signal in dorsal root ganglion neurons and potentiated capsaicin-induced increases in calcitonin gene-related peptide release and meningeal blood flow. Activation of TRESK decreased the capsaicin sensitivity of sensory neurons, leading to an attenuation of capsaicin-induced increase in meningeal blood flow. In TRESK knockout animals, TRPV1-mediated nociceptive reactions were unaffected by pretreatment with TRESK modulators. CONCLUSIONS Pharmacological manipulation of TRESK channels influences the TRPV1-mediated functions of nociceptors. Altered TRESK function might contribute to trigeminal nociceptor sensitization in migraine patients.
Collapse
Affiliation(s)
- Miklós Lengyel
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Dominika Hajdu
- Department of Physiology, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Alice Dobolyi
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Judit Rosta
- Department of Physiology, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Gábor Czirják
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Mária Dux
- Department of Physiology, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Péter Enyedi
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| |
Collapse
|
14
|
Modulations of Na v1.8 and Na v1.9 Channels in Monosodium Urate-Induced Gouty Arthritis in Mice. Inflammation 2021; 44:1405-1415. [PMID: 33515125 DOI: 10.1007/s10753-021-01425-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 01/03/2021] [Accepted: 01/21/2021] [Indexed: 10/22/2022]
Abstract
The aim of the present study was to observe the changes of TTX-R, Nav1.8, and Nav1.9 Na+ currents in MSU-induced gouty arthritis mice, and to explore the possibility of Nav1.8 and Nav1.9 channels as potential targets for gout pain treatment. Acute gouty arthritis was induced by monosodium urate (MSU) in mice. Swelling degree was evaluated by measuring the circumference of the ankle joint. Mechanical allodynia was assessed by applying the electronic von Frey. Na+ currents were recorded by patch-clamp techniques in acute isolated dorsal root ganglion (DRG) neurons. MSU treatment significantly increased the swelling degree of ankle joint and decreased the mechanical pain threshold. The amplitude of TTX-R Na+ current was significantly increased and reached its peak on the 4th day after injection of MSU. For TTX-R Na+ channel subunits, Nav1.8 current density was significantly increased, but Nav1.9 current density was markedly decreased after MSU treatment. MSU treatment shifted the steady-state activation curves of TTX-R Na+ channel, Nav1.8 and Nav1.9 channels, and the inactivation curves of TTX-R Na+ channel and Nav1.8 channels to the depolarizing direction, but did not affect the inactivation curve of Nav1.9 channel. Compared with the normal group, the recovery of Nav1.8 channel was faster, while that of Nav1.9 channel was slower. The recovery of TTX-R Na+ channel remained unchanged after MSU treatment. Additionally, MSU treatment increased DRG neurons excitability by reducing action potential threshold. Nav1.8 channel, not Nav1.9 channel, may be involved in MSU-induced gout pain by increasing nerve excitability.
Collapse
|
15
|
L-bupivacaine Inhibition of Nociceptive Transmission in Rat Peripheral and Dorsal Horn Neurons. Anesthesiology 2021; 134:88-102. [PMID: 33166389 DOI: 10.1097/aln.0000000000003596] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Although the widely used single L-enantiomers of local anesthetics have less toxic effects on the cardiovascular and central nervous systems, the mechanisms mediating their antinociceptive actions are not well understood. The authors hypothesized that significant differences in the ion channel blocking abilities of the enantiomers of bupivacaine would be identified. METHODS The authors performed electrophysiologic analysis on rat dorsal root ganglion neurons in vitro and on spinal transmissions in vivo. RESULTS In the dorsal root ganglion, these anesthetics decreased the amplitudes of action potentials. The half-maximum inhibitory concentrations of D-enantiomer D-bupivacaine were almost equal for Aβ (29.5 μM), Aδ (29.7μM), and C (29.8 μM) neurons. However, the half-maximum inhibitory concentrations of L-bupivacaine was lower for Aδ (19.35 μM) and C (19.5 μM) neurons than for A β (79.4 μM) neurons. Moreover, D-bupivacaine almost equally inhibited tetrodotoxin-resistant (mean ± SD: 15.8 ± 10.9% of the control, n = 14, P < 0.001) and tetrodotoxin-sensitive (15.4 ± 15.6% of the control, n = 11, P = 0.004) sodium currents. In contrast, L-bupivacaine suppressed tetrodotoxin-resistant sodium currents (26.1 ± 19.5% of the control, n = 18, P < 0.001) but not tetrodotoxin-sensitive sodium currents (74.5 ± 18.2% of the control, n = 11, P = 0.477). In the spinal dorsal horn, L-bupivacaine decreased the area of pinch-evoked excitatory postsynaptic currents (39.4 ± 11.3% of the control, n = 7, P < 0.001) but not touch-evoked responses (84.2 ± 14.5% of the control, n = 6, P = 0.826). In contrast, D-bupivacaine equally decreased pinch- and touch-evoked responses (38.8 ± 9.5% of the control, n = 6, P = 0.001, 42.9 ± 11.8% of the control, n = 6, P = 0.013, respectively). CONCLUSIONS These results suggest that the L-enantiomer of bupivacaine (L-bupivacaine) effectively inhibits noxious transmission to the spinal dorsal horn by blocking action potential conduction through C and Aδ afferent fibers. EDITOR’S PERSPECTIVE
Collapse
|
16
|
Johnson AC, Louwies T, Ligon CO, Greenwood-Van Meerveld B. Enlightening the frontiers of neurogastroenterology through optogenetics. Am J Physiol Gastrointest Liver Physiol 2020; 319:G391-G399. [PMID: 32755304 PMCID: PMC7717115 DOI: 10.1152/ajpgi.00384.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Neurogastroenterology refers to the study of the extrinsic and intrinsic nervous system circuits controlling the gastrointestinal (GI) tract. Over the past 5-10 yr there has been an explosion in novel methodologies, technologies and approaches that offer great promise to advance our understanding of the basic mechanisms underlying GI function in health and disease. This review focuses on the use of optogenetics combined with electrophysiology in the field of neurogastroenterology. We discuss how these technologies and tools are currently being used to explore the brain-gut axis and debate the future research potential and limitations of these techniques. Taken together, we consider that the use of these technologies will enable researchers to answer important questions in neurogastroenterology through fundamental research. The answers to those questions will shorten the path from basic discovery to new treatments for patient populations with disorders of the brain-gut axis affecting the GI tract such as irritable bowel syndrome (IBS), functional dyspepsia, achalasia, and delayed gastric emptying.
Collapse
Affiliation(s)
- Anthony C. Johnson
- 1Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,2Oklahoma City Veterans Affairs Health Care System, Oklahoma City, Oklahoma,3Department of Neurology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Tijs Louwies
- 1Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Casey O. Ligon
- 1Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Beverley Greenwood-Van Meerveld
- 1Oklahoma Center for Neuroscience, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma,2Oklahoma City Veterans Affairs Health Care System, Oklahoma City, Oklahoma,4Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| |
Collapse
|
17
|
Li N, Liu B, Wu W, Hong Y, Zhang J, Liu Y, Zhang M, Zhang X, Duan G. Upregulation of transcription factor 4 downregulates Na V1.8 expression in DRG neurons and prevents the development of rat inflammatory and neuropathic hypersensitivity. Exp Neurol 2020; 327:113240. [PMID: 32045596 DOI: 10.1016/j.expneurol.2020.113240] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 01/20/2020] [Accepted: 02/07/2020] [Indexed: 10/25/2022]
Abstract
The voltage sodium channel 1.8 (NaV1.8) in the dorsal root ganglion (DRG) neurons contributes to the initiation and development of chronic inflammatory and neuropathic pain. However, an effective intervention on NaV1.8 remains to be studied in pre-clinical research and clinical trials. In this study, we aimed to investigate whether transcription factor 4 (TCF4) overexpression represses NaV1.8 expression in DRG neurons, thus preventing the development of chronic pain. Using chromatin immunoprecipitation (CHIP), we verified the interaction of TCF4 and sodium voltage-gated channel alpha subunit 10A (SCN10A) enhancer in HEK293 cells and rat DRG neurons. Using a dual luciferase reporter assay, we confirmed the transcriptional inhibition of TCF4 on SCN10A promoter in vitro. To investigate the regulation of TCF4 on Nav1.8, we then upregulated TCF4 expression by intrathecally delivering an overexpression of recombinant adeno-associated virus (rAAV) in the Complete Freund's adjuvant (CFA)-induced inflammatory pain model and spared nerve injury (SNI)-induced neuropathic pain model. By using a quantitative polymerase chain reaction (qPCR), western blot, and immunostaining, we evaluated NaV1.8 expression after a noxious stimulation and the application of the TCF4 overexpression virus. We showed that the intrathecal delivery of TCF4 overexpression virus significantly repressed the increase of NaV1.8 and prevented the development of hyperalgesia in rats. Moreover, we confirmed the efficient role of an overexpressed TCF4 in preventing the CFA- and SNI-induced neuronal hyperexcitability by calcium imaging. Our results suggest that attenuating the dysregulation of NaV1.8 by targeting TCF4 may be a novel therapeutic strategy for chronic inflammatory and neuropathic pain.
Collapse
Affiliation(s)
- Ningbo Li
- Department of Anesthesiology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing 400010, China.; Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Baowen Liu
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Wenyao Wu
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yishun Hong
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jin Zhang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yi Liu
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Mi Zhang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xianwei Zhang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China..
| | - Guangyou Duan
- Department of Anesthesiology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing 400010, China..
| |
Collapse
|
18
|
Xu RJ, Fei SH, Chen LY, Wang G, Liu M, Zhang WS, Yan XW, Lai R, Shen CB. 3'-Methoxydaidzein exerts analgesic activity by inhibiting voltage-gated sodium channels. Chin J Nat Med 2019; 17:413-423. [PMID: 31262454 DOI: 10.1016/s1875-5364(19)30049-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Indexed: 02/05/2023]
Abstract
Isoflavones are widely consumed by people around the world in the form of soy products, dietary supplements and drugs. Many isoflavones or related crude extracts have been reported to exert pain-relief activities, but the mechanism remains unclear. Voltage-gated sodium channels (VGSCs) play important roles in excitability of pain sensing neurons and many of them are important nociceptors. Here, we report that several isoflavones including 3'-methoxydaidzein (3MOD), genistein (GEN) and daidzein (DAI) show abilities to block VGSCs and thus to attenuate chemicals and heat induced acute pain or chronic constriction injury (CCI) induced pain hypersensitivity in mice. Especially, 3MOD shows strong analgesic potential without inducing addiction through inhibiting subtypes NaV1.7, NaV1.8 and NaV1.3 with the IC50 of 181 ± 14, 397 ± 26, and 505 ± 46 nmol·L-1, respectively, providing a promising compound or parent structure for the treatment of pain pathologies. This study reveals a pain-alleviating mechanism of dietary isoflavones and may provide a convenient avenue to alleviate pain.
Collapse
Affiliation(s)
- Run-Jia Xu
- Life Sciences College of Nanjing Agricultural University, Nanjing 210095, China
| | - Shuo-Han Fei
- Life Sciences College of Nanjing Agricultural University, Nanjing 210095, China
| | - Lin-Yan Chen
- Life Sciences College of Nanjing Agricultural University, Nanjing 210095, China
| | - Gan Wang
- Key Laboratory of bioactive peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming 650223, China
| | - Ming Liu
- Department of Molecular and Cell Biology, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Wen-Sheng Zhang
- Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Xiu-Wen Yan
- Life Sciences College of Nanjing Agricultural University, Nanjing 210095, China
| | - Ren Lai
- Life Sciences College of Nanjing Agricultural University, Nanjing 210095, China; Key Laboratory of bioactive peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming 650223, China; Sino-African Joint Research Center, CAS, Kunming Institute of Zoology, Kunming 650223, China.
| | - Chuan-Bin Shen
- Key Laboratory of bioactive peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming 650223, China.
| |
Collapse
|
19
|
McDougall JJ. Osteoarthritis is a neurological disease – an hypothesis. OSTEOARTHRITIS AND CARTILAGE OPEN 2019; 1:100005. [DOI: 10.1016/j.ocarto.2019.100005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 10/17/2019] [Indexed: 12/20/2022] Open
|
20
|
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.
Collapse
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
| |
Collapse
|
21
|
Hameed S. Na v1.7 and Na v1.8: Role in the pathophysiology of pain. Mol Pain 2019; 15:1744806919858801. [PMID: 31172839 PMCID: PMC6589956 DOI: 10.1177/1744806919858801] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/25/2019] [Accepted: 05/30/2019] [Indexed: 01/25/2023] Open
Abstract
Chronic pain is a significant unmet medical problem. Current research regarding sodium channel function in pathological pain is advancing with the hope that it will enable the development of isoform-specific sodium channel blockers, a promising treatment for chronic pain. Before advancements in the pharmacological field, an elucidation of the roles of Nav1.7 and Nav1.8 in the pathophysiology of pain states is required. Thus, the aim of this report is to present what is currently known about the contributions of these sodium channel subtypes in the pathophysiology of neuropathic and inflammatory pain. The electrophysiological properties and localisation of sodium channel isoforms is discussed. Research concerning the genetic links of Nav1.7 and Nav1.8 in acquired neuropathic and inflammatory pain states from the scientific literature in this field is reported. The role of Nav1.7 and Nav1.8 in the generation and maintenance of abnormal neuronal electrogenesis and hyperexcitability highlights the importance of these channels in the development of pathological pain. However, further research in this area is required to fully elucidate the roles of Nav1.7 and Nav1.8 in the pathophysiology of pain for the development of subtype-specific sodium channel blockers.
Collapse
Affiliation(s)
- Shaila Hameed
- Department of Physiology, King’s College London, London, UK
| |
Collapse
|
22
|
Tisné-Versailles S, Fénélon M, Marteau JM, Catros S, Fricain JC. Injection of ropivacaine combined with pregabalin in a patient with post-traumatic trigeminal neuropathic pain. JOURNAL OF ORAL MEDICINE AND ORAL SURGERY 2018. [DOI: 10.1051/mbcb/2018018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Introduction: Post-traumatic painful trigeminal neuropathy is a chronic facial pain secondary to trigeminal nerve injury. The treatment of this pain is a therapeutic issue due to the alteration of quality of life that it generates. Observation: A 58-year-old man whose main history of facial trauma has been consulted in the Odontology Department for bilateral trigeminal neuropathic pain that has been evolving for several months. The interrogation revealed continuous pain like electric shocks in the canine areas and daily painful exacerbations. Hyperesthesia and allodynia were found on clinical examination. The patient had received several treatments, oral and local, without significant improvement. As a last resort, injections of ropivacaine every 2 weeks associated with pregabalin (200 mg/day) were performed. At 6 months, there was a clear decrease in the burning sensation and a complete disappearance of painful exacerbations. Discussion: Two studies have recently shown the benefit of the combination of an antiepileptic and a local analgesic in the treatment of classical trigeminal neuralgia, justifying their use in a context of post-traumatic neuropathic pain. Conclusion: Further studies with higher levels of evidence are needed to confirm these preliminary results.
Collapse
|
23
|
Black BJ, Atmaramani R, Plagens S, Campbell ZT, Dussor G, Price TJ, Pancrazio JJ. Emerging neurotechnology for antinoceptive mechanisms and therapeutics discovery. Biosens Bioelectron 2018; 126:679-689. [PMID: 30544081 DOI: 10.1016/j.bios.2018.11.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 11/01/2018] [Accepted: 11/10/2018] [Indexed: 12/20/2022]
Abstract
The tolerance, abuse, and potential exacerbation associated with classical chronic pain medications such as opioids creates a need for alternative therapeutics. Phenotypic screening provides a complementary approach to traditional target-based drug discovery. Profiling cellular phenotypes enables quantification of physiologically relevant traits central to a disease pathology without prior identification of a specific drug target. For complex disorders such as chronic pain, which likely involves many molecular targets, this approach may identify novel treatments. Sensory neurons, termed nociceptors, are derived from dorsal root ganglia (DRG) and can undergo changes in membrane excitability during chronic pain. In this review, we describe phenotypic screening paradigms that make use of nociceptor electrophysiology. The purpose of this paper is to review the bioelectrical behavior of DRG neurons, signaling complexity in sensory neurons, various sensory neuron models, assays for bioelectrical behavior, and emerging efforts to leverage microfabrication and microfluidics for assay development. We discuss limitations and advantages of these various approaches and offer perspectives on opportunities for future development.
Collapse
Affiliation(s)
- Bryan J Black
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA.
| | - Rahul Atmaramani
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA
| | - Sarah Plagens
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA
| | - Zachary T Campbell
- Department of Biological Sciences, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA
| | - Gregory Dussor
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA
| | - Theodore J Price
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA
| | - Joseph J Pancrazio
- Department of Bioengineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, TX 75080, USA
| |
Collapse
|
24
|
Guha D, Shamji MF. The Dorsal Root Ganglion in the Pathogenesis of Chronic Neuropathic Pain. Neurosurgery 2018; 63 Suppl 1:118-126. [PMID: 27399376 DOI: 10.1227/neu.0000000000001255] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Affiliation(s)
| | - Mohammed F Shamji
- Department of Surgery and.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.,Division of Neurosurgery, Toronto Western Hospital, Toronto, Ontario, Canada
| |
Collapse
|
25
|
Black BJ, Atmaramani R, Kumaraju R, Plagens S, Romero-Ortega M, Dussor G, Price TJ, Campbell ZT, Pancrazio JJ. Adult mouse sensory neurons on microelectrode arrays exhibit increased spontaneous and stimulus-evoked activity in the presence of interleukin-6. J Neurophysiol 2018; 120:1374-1385. [PMID: 29947589 DOI: 10.1152/jn.00158.2018] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Following inflammation or injury, sensory neurons located in the dorsal root ganglia (DRG) may exhibit increased spontaneous and/or stimulus-evoked activity, contributing to chronic pain. Current treatment options for peripherally mediated chronic pain are highly limited, driving the development of cell- or tissue-based phenotypic (function-based) screening assays for peripheral analgesic and mechanistic lead discovery. Extant assays are often limited by throughput, content, use of tumorigenic cell lines, or tissue sources from immature developmental stages (i.e., embryonic or postnatal). Here, we describe a protocol for culturing adult mouse DRG neurons on substrate-integrated multiwell microelectrode arrays (MEAs). This approach enables multiplexed measurements of spontaneous as well as stimulus-evoked extracellular action potentials from large populations of cells. The DRG cultures exhibit stable spontaneous activity from 9 to 21 days in vitro. Activity is readily evoked by known chemical and physical agonists of sensory neuron activity such as capsaicin, bradykinin, PGE2, heat, and electrical field stimulation. Most importantly, we demonstrate that both spontaneous and stimulus-evoked activity may be potentiated by incubation with the inflammatory cytokine interleukin-6 (IL-6). Acute responsiveness to IL-6 is inhibited by treatment with a MAPK-interacting kinase 1/2 inhibitor, cercosporamide. In total, these findings suggest that adult mouse DRG neurons on multiwell MEAs are applicable to ongoing efforts to discover peripheral analgesic and their mechanisms of action. NEW & NOTEWORTHY This work describes methodologies for culturing spontaneously active adult mouse dorsal root ganglia (DRG) sensory neurons on microelectrode arrays. We characterize spontaneous and stimulus-evoked adult DRG activity over durations consistent with pharmacological interventions. Furthermore, persistent hyperexcitability could be induced by incubation with inflammatory cytokine IL-6 and attenuated with cercosporamide, an inhibitor of the IL-6 sensitization pathway. This constitutes a more physiologically relevant, moderate-throughput in vitro model for peripheral analgesic screening as well as mechanistic lead discovery.
Collapse
Affiliation(s)
- Bryan J Black
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas
| | - Rahul Atmaramani
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas
| | - Rajeshwari Kumaraju
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas
| | - Sarah Plagens
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas
| | - Mario Romero-Ortega
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas
| | - Gregory Dussor
- School of Behavioral and Brain Sciences, The University of Texas at Dallas , Richardson, Texas
| | - Theodore J Price
- School of Behavioral and Brain Sciences, The University of Texas at Dallas , Richardson, Texas
| | - Zachary T Campbell
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, Richardson, Texas
| | - Joseph J Pancrazio
- Department of Bioengineering, The University of Texas at Dallas , Richardson, Texas
| |
Collapse
|
26
|
Wang G, Long C, Liu W, Xu C, Zhang M, Li Q, Lu Q, Meng P, Li D, Rong M, Sun Z, Luo X, Lai R. Novel Sodium Channel Inhibitor From Leeches. Front Pharmacol 2018; 9:186. [PMID: 29559913 PMCID: PMC5845541 DOI: 10.3389/fphar.2018.00186] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 02/19/2018] [Indexed: 12/16/2022] Open
Abstract
Considering blood-sucking habits of leeches from surviving strategy of view, it can be hypothesized that leech saliva has analgesia or anesthesia functions for leeches to stay undetected by the host. However, no specific substance with analgesic function has been reported from leech saliva although clinical applications strongly indicated that leech therapy produces a strong and long lasting pain-reducing effect. Herein, a novel family of small peptides (HSTXs) including 11 members which show low similarity with known peptides was identified from salivary glands of the leech Haemadipsa sylvestris. A typical HSTX is composed of 22-25 amino acid residues including four half-cysteines, forming two intra-molecular disulfide bridges, and an amidated C-terminus. HSTX-I exerts significant analgesic function by specifically inhibiting voltage-gated sodium (NaV) channels (NaV1.8 and NaV1.9) which contribute to action potential electrogenesis in neurons and potential targets to develop analgesics. This study reveals that sodium channel inhibitors are analgesic substances in the leech. HSTXs are excellent candidates or templates for development of analgesics.
Collapse
Affiliation(s)
- Gan Wang
- Key Laboratory of Bioactive Peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, China
| | - Chengbo Long
- Key Laboratory of Bioactive Peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, China
| | - Weihui Liu
- Key Laboratory of Bioactive Peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, China
| | - Cheng Xu
- Key Laboratory of Bioactive Peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, China
| | - Min Zhang
- Key Laboratory of Bioactive Peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, China.,Graduate School of University of Chinese Academy of Sciences, Beijing, China
| | - Qiong Li
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Qiumin Lu
- Key Laboratory of Bioactive Peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, China.,Sino-African Joint Research Center, Chinese Academy of Sciences, Wuhan, China
| | - Ping Meng
- Key Laboratory of Bioactive Peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, China
| | - Dongsheng Li
- Key Laboratory of Bioactive Peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, China
| | - Mingqiang Rong
- Key Laboratory of Bioactive Peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, China.,Sino-African Joint Research Center, Chinese Academy of Sciences, Wuhan, China
| | - Zhaohui Sun
- Department of Clinical Laboratory, Guangzhou General Hospital of Guangzhou Military Command of PLA, Guangzhou, China
| | - Xiaodong Luo
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Ren Lai
- Key Laboratory of Bioactive Peptides of Yunnan Province/Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming, China.,Life Sciences College of Nanjing Agricultural University, Nanjing, China
| |
Collapse
|
27
|
Na V 1.7 as a Pharmacogenomic Target for Pain: Moving Toward Precision Medicine. Trends Pharmacol Sci 2018; 39:258-275. [DOI: 10.1016/j.tips.2017.11.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 11/27/2017] [Accepted: 11/29/2017] [Indexed: 01/15/2023]
|
28
|
Masuoka T, Gallar J, Belmonte C. Inhibitory Effect of Amitriptyline on the Impulse Activity of Cold Thermoreceptor Terminals of Intact and Tear-Deficient Guinea Pig Corneas. J Ocul Pharmacol Ther 2017; 34:195-203. [PMID: 29185841 DOI: 10.1089/jop.2017.0066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
PURPOSE Chronic dryness of the ocular surface evokes sensitization of corneal cold-sensitive neurons through an increase of sodium currents and a decrease of potassium currents, leading to the unpleasant dryness and pain sensations typical of dry eye disease. Here, we explored the effects of amitriptyline, a voltage-gated Na+ channel blocker used for the treatment of depression and chronic pain, on nerve terminal impulse (NTI) activity of cold-sensitive nerve terminals recorded in intact and tear-deficient guinea pig corneas. METHODS Main lachrymal gland was surgically removed in anesthetized guinea pigs to induce chronic tear deficiency. Four to 6 weeks afterward, animals were sacrificed and both corneas placed in a perfusion chamber superfused at 34°C. Thermal stimuli were induced by changing the solution temperature from 34°C to 20°C (cooling ramp) and from 34°C to 50°C (heating ramp). Spontaneous and stimulus-evoked NTIs of cold-sensitive nerve terminals were recorded before, during, and after perfusion with solutions containing amitriptyline at different concentrations (3-30 μM). RESULTS Perfusion with amitriptyline inhibited irreversibly and in a concentration-dependent manner the spontaneous NTI activity of cold thermoreceptors of intact corneas. This effect was less evident in tear-deficient corneas. In addition, amitriptyline (10 μM) attenuated the maximal response to cooling ramps without changing cold threshold in intact but not in tear-deficient corneas. Only cold thermoreceptors with low cooling threshold values were sensitive to amitriptyline. CONCLUSION Amitriptyline effectively reduces the activity of cold thermoreceptors, although its efficacy is different in intact and tear-deficient corneas, which might be due to the changes induced by ocular dryness in the expression of the various voltage-gated Na+ channels responsible of the action potential generation and propagation.
Collapse
Affiliation(s)
- Takayoshi Masuoka
- 1 Instituto de Neurociencias, Universidad Miguel Hernandez-CSIC , Alicante, Spain .,2 Department of Pharmacology, Kanazawa Medical University , Uchinada, Ishikawa, Japan
| | - Juana Gallar
- 1 Instituto de Neurociencias, Universidad Miguel Hernandez-CSIC , Alicante, Spain
| | - Carlos Belmonte
- 1 Instituto de Neurociencias, Universidad Miguel Hernandez-CSIC , Alicante, Spain
| |
Collapse
|
29
|
Vancamp T, Levy RM, Peña I, Pajuelo A. Relevant Anatomy, Morphology, and Implantation Techniques of the Dorsal Root Ganglia at the Lumbar Levels. Neuromodulation 2017; 20:690-702. [PMID: 28895256 DOI: 10.1111/ner.12651] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 06/30/2017] [Accepted: 07/17/2017] [Indexed: 12/30/2022]
Abstract
OBJECTIVES While dorsal root ganglion (DRG) stimulation has been available in Europe and Australia for the past five years and in the United States for the past year, there are no published details concerning the optimal procedures for DRG lead implantation. MATERIALS AND METHODS We describe several techniques that can be applied to implant cylindrical leads over the DRG, highlighting some tips and tricks according to our experiences. Focus is mainly shifted toward implantations in the lumbar area. We furthermore give some insights in the results we experienced in Spain as well as some worldwide numbers. IMPLANT TECHNIQUES AND RESULTS A 14-gauge needle is placed using a "2-Level Technique (2-LT)" or exceptionally a "1-Level Technique (1-LT)" or a "Primary- or Secondary Technique" at the level of L5. The delivery sheath, loaded with the lead, is advanced toward the targeted neural foramen. The lead is placed over the dorsal aspect of the DRG. A strain relief loop is created in the epidural space. Sheath and needle are retracted and the lead is secured using an anchor or anchorless technique. In Spain, 87.2% (N = 78) of the selected patients have been successfully implanted. Seven (8.9%) had a negative trial and three (4.2%) were explanted. Average VAS score decreased from 8.8 to 3.3 and on average 94.5% of the pain area was covered. In our center's subjects (N = 47 patients, 60.3% of all implanted patients in Spain), VAS scores decreased from an average of 8.8-1.7 and pain coverage averaged 96.4%. We used an average of 1.8 electrodes. Worldwide more than 4000 permanent cases have been successfully performed. CONCLUSIONS We present implantation techniques whereby a percutaneous lead is placed over the DRG through the use of a special designed delivery sheath. Further investigation of the safety, efficacy, and sustainability of clinical outcomes using these devices is warranted.
Collapse
Affiliation(s)
- Tim Vancamp
- BRAI2N, St. Augustinus Hospital, Wilrijk, Belgium
| | | | - Isaac Peña
- Department of Anesthesiology and Pain Management, Virgen del Rocio University Hospital, Sevilla, Spain
| | - Antonio Pajuelo
- Department of Anesthesiology and Pain Management, Virgen del Rocio University Hospital, Sevilla, Spain
| |
Collapse
|
30
|
Qin S, Jiang F, Zhou Y, Zhou G, Ye P, Ji Y. Local knockdown of Nav1.6 relieves pain behaviors induced by BmK I. Acta Biochim Biophys Sin (Shanghai) 2017; 49:713-721. [PMID: 28655185 DOI: 10.1093/abbs/gmx064] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 06/05/2017] [Indexed: 12/13/2022] Open
Abstract
Voltage-gated sodium channels (VGSCs) in peripheral nociceptive sensory neurons are critical to transmit pain signals. BmK I purified from the venom of scorpion Buthus martensi Karsch (BmK) has been demonstrated to be the primary contributor of envenomation-associated pain. However, the role of distinct VGSCs such as Nav1.6 in the induction and maintenance of pain behaviors induced by BmK I was ambiguous. Herein, using molecular and behavioral approaches we investigated the mRNA and protein expression profiles of Nav1.6 in rat DRG after intraplantar injection of BmK I and tested the pain behaviors after knockdown of Nav1.6 in BmK I-treated rats. It was shown that during induction and maintenance of pain responses induced by BmK I, the expression of Nav1.6 in DRG was found to be significantly increased at both mRNA and protein levels. The percentage of co-localization of Nav1.6 and Isolectin B4, a molecular marker of small diameter non-peptidergic DRG neurons, was increased at the maintenance phase of pain responses. Furthermore, spontaneous pain and mechanical allodynia, but not thermal hyperalgesia induced by BmK I, were significantly alleviated after knockdown of Nav1.6. These data strongly suggest that Nav1.6 plays an indispensable role in the peripheral pain hypersensitivity induced by BmK I.
Collapse
Affiliation(s)
- Shichao Qin
- Laboratory of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai 200444, China
| | - Feng Jiang
- Shanghai Chongming Xinhua Translational Medical Institute for Cancer Pain, Shanghai 202150, China
| | - You Zhou
- Laboratory of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai 200444, China
| | - Guokun Zhou
- Laboratory of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai 200444, China
| | - Pin Ye
- Laboratory of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai 200444, China
| | - Yonghua Ji
- Laboratory of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai 200444, China
- Shanghai Chongming Xinhua Translational Medical Institute for Cancer Pain, Shanghai 202150, China
| |
Collapse
|
31
|
Barbosa C, Xiao Y, Johnson AJ, Xie W, Strong JA, Zhang JM, Cummins TR. FHF2 isoforms differentially regulate Nav1.6-mediated resurgent sodium currents in dorsal root ganglion neurons. Pflugers Arch 2016; 469:195-212. [PMID: 27999940 DOI: 10.1007/s00424-016-1911-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 10/19/2016] [Accepted: 11/20/2016] [Indexed: 10/20/2022]
Abstract
Nav1.6 and Nav1.6-mediated resurgent currents have been implicated in several pain pathologies. However, our knowledge of how fast resurgent currents are modulated in neurons is limited. Our study explored the potential regulation of Nav1.6-mediated resurgent currents by isoforms of fibroblast growth factor homologous factor 2 (FHF2) in an effort to address the gap in our knowledge. FHF2 isoforms colocalize with Nav1.6 in peripheral sensory neurons. Cell line studies suggest that these proteins differentially regulate inactivation. In particular, FHF2A mediates long-term inactivation, a mechanism proposed to compete with the open-channel blocker mechanism that mediates resurgent currents. On the other hand, FHF2B lacks the ability to mediate long-term inactivation and may delay inactivation favoring open-channel block. Based on these observations, we hypothesized that FHF2A limits resurgent currents, whereas FHF2B enhances resurgent currents. Overall, our results suggest that FHF2A negatively regulates fast resurgent current by enhancing long-term inactivation and delaying recovery. In contrast, FHF2B positively regulated resurgent current and did not alter long-term inactivation. Chimeric constructs of FHF2A and Navβ4 (likely the endogenous open channel blocker in sensory neurons) exhibited differential effects on resurgent currents, suggesting that specific regions within FHF2A and Navβ4 have important regulatory functions. Our data also indicate that FHFAs and FHF2B isoform expression are differentially regulated in a radicular pain model and that associated neuronal hyperexcitability is substantially attenuated by a FHFA peptide. As such, these findings suggest that FHF2A and FHF2B regulate resurgent current in sensory neurons and may contribute to hyperexcitability associated with some pain pathologies.
Collapse
Affiliation(s)
- Cindy Barbosa
- Department of Pharmacology and Toxicology, Indiana University, Indianapolis, IN, USA.,Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Yucheng Xiao
- Department of Pharmacology and Toxicology, Indiana University, Indianapolis, IN, USA.,Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Andrew J Johnson
- Department of Pharmacology and Toxicology, Indiana University, Indianapolis, IN, USA.,Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Wenrui Xie
- Department of Anesthesiology, University of Cincinnati, Cincinnati, OH, USA
| | - Judith A Strong
- Department of Anesthesiology, University of Cincinnati, Cincinnati, OH, USA
| | - Jun-Ming Zhang
- Department of Anesthesiology, University of Cincinnati, Cincinnati, OH, USA
| | - Theodore R Cummins
- Department of Pharmacology and Toxicology, Indiana University, Indianapolis, IN, USA. .,Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA. .,Department of Biology, Indiana University - Purdue University Indianapolis, Indianapolis, IN, USA.
| |
Collapse
|
32
|
Benoliel R, Epstein J, Eliav E, Jurevic R, Elad S. Orofacial Pain in Cancer: Part I—Mechanisms. J Dent Res 2016; 86:491-505. [PMID: 17525348 DOI: 10.1177/154405910708600604] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The mechanisms involved, and possible treatment targets, in orofacial pain due to cancer are poorly understood. The aim of the first of this two-part series is to review the involved pathophysiological mechanisms and explore their possible roles in the orofacial region. However, there is a lack of relevant research in the trigeminal region, and we have therefore applied data accumulated from experiments on cancer pain mechanisms in rodent spinal models. In the second part, we review the clinical presentation of cancer-associated orofacial pain at various stages: initial diagnosis, during therapy (chemo-, radiotherapy, surgery), and in the post-therapy period. In the present article, we provide a brief outline of trigeminal functional neuro-anatomy and pain-modulatory pathways. Tissue destruction by invasive tumors (or metastases) induces inflammation and nerve damage, with attendant acute pain. In some cases, chronic pain, involving inflammatory and neuropathic mechanisms, may ensue. Distant, painful effects of tumors include paraneoplastic neuropathic syndromes and effects secondary to the release of factors by the tumor (growth factors, cytokines, and enzymes). Additionally, pain is frequent in cancer management protocols (surgery, chemotherapy, and radiotherapy). Understanding the mechanisms involved in cancer-related orofacial pain will enhance patient management.
Collapse
Affiliation(s)
- R Benoliel
- Department of Oral Medicine, The Hebrew University, Hadassah Faculty of Dental Medicine, PO Box 12272, Jerusalem 91120, Israel.
| | | | | | | | | |
Collapse
|
33
|
Gong K, Ohara PT, Jasmin L. Patch Clamp Recordings on Intact Dorsal Root Ganglia from Adult Rats. J Vis Exp 2016. [PMID: 27768031 DOI: 10.3791/54287] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Patch clamp studies from dorsal root ganglia (DRGs) neurons have increased our understanding of the peripheral nervous system. Currently, the majority of recordings are conducted on dissociated DRG neurons, which is a standard preparation for most laboratories. Neuronal properties, however, can be altered by axonal injury resulting from enzyme digestion used in acquiring dissociated neurons. Further, dissociated neuron preparations cannot fully represent the microenvironment of the DRG since loss of contact with satellite glial cells that surround the primary sensory neurons is an unavoidable consequence of this method. To overcome the limitations in using conventional dissociated DRG neurons for patch clamp recordings, in this report we describe a method to prepare intact DRGs and conduct patch clamp recordings on individual primary sensory neurons ex vivo. This approach permits the fast and straightforward preparation of intact DRGs, mimicking in vivo conditions by keeping DRG neurons associated with their surrounding satellite glial cells and basement membrane. Furthermore, the method avoids axonal injury from manipulation and enzyme digestion such as when dissociating DRGs. This ex vivo preparation can additionally be used to study the interaction between primary sensory neurons and satellite glial cells.
Collapse
Affiliation(s)
- Kerui Gong
- Department of Oral and Maxillofacial Surgery, University of California, San Francisco;
| | - Peter T Ohara
- Department of Anatomy, University of California, San Francisco
| | - Luc Jasmin
- Department of Oral and Maxillofacial Surgery, University of California, San Francisco;
| |
Collapse
|
34
|
Rolke R, Rolke S, Hiddemann S, Mücke M, Cuhls H, Radbruch L, Elsner F, Peuckmann-Post V. [Update palliative pain therapy]. Internist (Berl) 2016; 57:959-970. [PMID: 27631529 DOI: 10.1007/s00108-016-0126-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Cancer pain and pain associated with non-neoplastic diseases can be associated with pain mechanisms, such as a peripheral or central sensitization or deafferentation. The clarification allows indirect conclusions about the underlying mechanisms based on clinical signs, such as allodynia or hyperalgesia. Non-opioid analgesics are the basis of cancer pain therapy according to the World Health Organization (WHO) pain ladder. In the case of severe cancer pain, treatment can be escalated directly from level 1 to level 3. Opioids are highly effective for the treatment of cancer pain even with a neuropathic component, which can occur in up to 40 % of cases as amixed pain syndrome. Coanalgesics represent a valuable therapeutic adjunct for better pain control and can address treatment of comorbidities, such as anxiety, depression and sleep disorders. When liver and/or renal function is reduced, the dosage of many drugs has to be adapted. Treatment of multimorbid or critically ill patients with opioids and antidepressants/anticonvulsants requires consideration of numerous possible pharmacodynamic and pharmacokinetic interactions.
Collapse
Affiliation(s)
- R Rolke
- Klinik für Palliativmedizin, Universitätsklinikum RWTH Aachen, Pauwelsstr. 30, 52074, Aachen, Deutschland.
| | - S Rolke
- Klinik für Kardiologie, Pneumologie, Angiologie und Internistische Intensivmedizin, Universitätsklinikum RWTH Aachen, Aachen, Deutschland
| | - S Hiddemann
- Klinik für Palliativmedizin, Universitätsklinikum RWTH Aachen, Pauwelsstr. 30, 52074, Aachen, Deutschland
| | - M Mücke
- Klinik für Palliativmedizin, Universitätsklinikum Bonn, Bonn, Deutschland.,Institut für Hausarztmedizin, Medizinische Fakultät, Universität Bonn, Bonn, Deutschland.,Zentrum für Seltene Erkrankungen Bonn (ZSEB), Universitätsklinikum Bonn, Bonn, Deutschland
| | - H Cuhls
- Klinik für Palliativmedizin, Universitätsklinikum Bonn, Bonn, Deutschland
| | - L Radbruch
- Klinik für Palliativmedizin, Universitätsklinikum Bonn, Bonn, Deutschland
| | - F Elsner
- Klinik für Palliativmedizin, Universitätsklinikum RWTH Aachen, Pauwelsstr. 30, 52074, Aachen, Deutschland
| | - V Peuckmann-Post
- Klinik für Palliativmedizin, Universitätsklinikum RWTH Aachen, Pauwelsstr. 30, 52074, Aachen, Deutschland
| |
Collapse
|
35
|
Chambers C, Witton I, Adams C, Marrington L, Kammonen J. High-Throughput Screening of NaV1.7 Modulators Using a Giga-Seal Automated Patch Clamp Instrument. Assay Drug Dev Technol 2016; 14:93-108. [DOI: 10.1089/adt.2016.700] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Chris Chambers
- Neuroscience and Pain Research Unit, Pfizer Inc., Cambridge, United Kingdom
| | - Ian Witton
- Neuroscience and Pain Research Unit, Pfizer Inc., Cambridge, United Kingdom
| | - Cathryn Adams
- Neuroscience and Pain Research Unit, Pfizer Inc., Cambridge, United Kingdom
| | - Luke Marrington
- Neuroscience and Pain Research Unit, Pfizer Inc., Cambridge, United Kingdom
| | - Juha Kammonen
- Neuroscience and Pain Research Unit, Pfizer Inc., Cambridge, United Kingdom
| |
Collapse
|
36
|
Li N, Liu Z, Wang G, Wang S. Downregulation of the sodium channel Nav1.6 by potential transcriptomic deregulation may explain sensory deficits in critical illness neuropathy. Life Sci 2015; 143:231-6. [PMID: 26562765 DOI: 10.1016/j.lfs.2015.11.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 10/08/2015] [Accepted: 11/07/2015] [Indexed: 11/24/2022]
Abstract
AIMS Sepsis patients and other patients in the critical care settings are at very high risk of mortality due to the primary illness. However, a fraction of patients, even after showing initial clinical improvement, deteriorates relentlessly at later stages. Increasingly, it is being identified that this is mostly due to dysfunction of the neurological system. MAIN METHODS We obtained peripheral nerve biopsies from the sural nerve from ICU patients. Nav1.6 expression was significantly diminished. The expression of cellular membrane anchoring protein for Nav1.6, ankyrin, remained unaffected, suggesting that genomic repression may be responsible for the diminished expression of the sodium channels. We examined the expression of two regulatory transcription factors: (a) a positive regulator YY1 that binds to the promoter region of sodium channels and (b) an upstream negative neuronal regulator REST. KEY FINDINGS REST expression was significantly elevated, while YY1 expression was diminished. Finally, we also observed that the cholinergic synthetic enzyme acyltransferase was also significantly diminished in sensory nerve lysates. Finally, circulating antibodies was detected in the peripheral blood against all the major sodium channels Nav1.6, 1.8 and 1.9, which contribute to the development and propagation of action potentials. SIGNIFICANCE This may potentially explain why its dysfunction affects neurological functions across all systems of the body during critical illness. The underlying mechanism of why the expression of the REST transcriptional factor is affected in critical illnesses remains our future goals of investigation.
Collapse
Affiliation(s)
- Nan Li
- Department of Intensive Care Unit, The First Hospital of Jilin University, Jilin 130021, China
| | - Zhongmin Liu
- Department of Intensive Care Unit, The First Hospital of Jilin University, Jilin 130021, China
| | - Guang Wang
- Department of Intensive Care Unit, The First Hospital of Jilin University, Jilin 130021, China
| | - Shiji Wang
- Department of Intensive Care Unit, The First Hospital of Jilin University, Jilin 130021, China.
| |
Collapse
|
37
|
Barbosa C, Tan ZY, Wang R, Xie W, Strong JA, Patel RR, Vasko MR, Zhang JM, Cummins TR. Navβ4 regulates fast resurgent sodium currents and excitability in sensory neurons. Mol Pain 2015; 11:60. [PMID: 26408173 PMCID: PMC4582632 DOI: 10.1186/s12990-015-0063-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 09/10/2015] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Increased electrical activity in peripheral sensory neurons including dorsal root ganglia (DRG) and trigeminal ganglia neurons is an important mechanism underlying pain. Voltage gated sodium channels (VGSC) contribute to the excitability of sensory neurons and are essential for the upstroke of action potentials. A unique type of VGSC current, resurgent current (INaR), generates an inward current at repolarizing voltages through an alternate mechanism of inactivation referred to as open-channel block. INaRs are proposed to enable high frequency firing and increased INaRs in sensory neurons are associated with pain pathologies. While Nav1.6 has been identified as the main carrier of fast INaR, our understanding of the mechanisms that contribute to INaR generation is limited. Specifically, the open-channel blocker in sensory neurons has not been identified. Previous studies suggest Navβ4 subunit mediates INaR in central nervous system neurons. The goal of this study was to determine whether Navβ4 regulates INaR in DRG sensory neurons. RESULTS Our immunocytochemistry studies show that Navβ4 expression is highly correlated with Nav1.6 expression predominantly in medium-large diameter rat DRG neurons. Navβ4 knockdown decreased endogenous fast INaR in medium-large diameter neurons as measured with whole-cell voltage clamp. Using a reduced expression system in DRG neurons, we isolated recombinant human Nav1.6 sodium currents in rat DRG neurons and found that overexpression of Navβ4 enhanced Nav1.6 INaR generation. By contrast neither overexpression of Navβ2 nor overexpression of a Navβ4-mutant, predicted to be an inactive form of Navβ4, enhanced Nav1.6 INaR generation. DRG neurons transfected with wild-type Navβ4 exhibited increased excitability with increases in both spontaneous activity and evoked activity. Thus, Navβ4 overexpression enhanced INaR and excitability, whereas knockdown or expression of mutant Navβ4 decreased INaR generation. CONCLUSION INaRs are associated with inherited and acquired pain disorders. However, our ability to selectively target and study this current has been hindered due to limited understanding of how it is generated in sensory neurons. This study identified Navβ4 as an important regulator of INaR and excitability in sensory neurons. As such, Navβ4 is a potential target for the manipulation of pain sensations.
Collapse
Affiliation(s)
- Cindy Barbosa
- Department of Pharmacology and Toxicology, Indiana University, Indianapolis, IN, USA. .,Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, 320 West 25th Street, NB-414F, Indianapolis, IN, 46202-2266, USA.
| | - Zhi-Yong Tan
- Department of Pharmacology and Toxicology, Indiana University, Indianapolis, IN, USA. .,Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, 320 West 25th Street, NB-414F, Indianapolis, IN, 46202-2266, USA.
| | - Ruizhong Wang
- Department of Pharmacology and Toxicology, Indiana University, Indianapolis, IN, USA.
| | - Wenrui Xie
- Department of Anesthesiology, University of Cincinnati, Cincinnati, OH, USA.
| | - Judith A Strong
- Department of Anesthesiology, University of Cincinnati, Cincinnati, OH, USA.
| | - Reesha R Patel
- Medical Neuroscience Graduate Program, Indiana University School of Medicine, Indianapolis, IN, USA. .,Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, 320 West 25th Street, NB-414F, Indianapolis, IN, 46202-2266, USA.
| | - Michael R Vasko
- Department of Pharmacology and Toxicology, Indiana University, Indianapolis, IN, USA. .,Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, 320 West 25th Street, NB-414F, Indianapolis, IN, 46202-2266, USA.
| | - Jun-Ming Zhang
- Department of Anesthesiology, University of Cincinnati, Cincinnati, OH, USA.
| | - Theodore R Cummins
- Department of Pharmacology and Toxicology, Indiana University, Indianapolis, IN, USA. .,Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, 320 West 25th Street, NB-414F, Indianapolis, IN, 46202-2266, USA.
| |
Collapse
|
38
|
Back SK, Kam YL, Oh JA, Na HS, Ih U, Park Choo HY. Synthesis and Evaluation of (4-Chlorobenzhydryl) Piperazine Amides as Sodium Channel Nav1.7 Inhibitors. B KOREAN CHEM SOC 2015. [DOI: 10.1002/bkcs.10446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Seung Keun Back
- Pharmaceutics & Biotechnology, College of Medical Engineering; Konyang University; Chungnam 320-711 Republic of Korea
| | - Yoo Lim Kam
- College of Pharmacy and Graduate School of Pharmaceutical Sciences; Ewha Womans University; Seoul 120-750 Republic of Korea
| | - Jung Ae Oh
- College of Pharmacy and Graduate School of Pharmaceutical Sciences; Ewha Womans University; Seoul 120-750 Republic of Korea
| | - Heung Sik Na
- Department of Physiology; Korea University College of Medicine; Seoul 136-705 Republic of Korea
| | - Uhtaek Ih
- Sensory Research Center, CRI, College of Pharmacy; Seoul National University; Seoul 151-742 Republic of Korea
| | - Hea-Young Park Choo
- College of Pharmacy and Graduate School of Pharmaceutical Sciences; Ewha Womans University; Seoul 120-750 Republic of Korea
| |
Collapse
|
39
|
Krames ES. The Dorsal Root Ganglion in Chronic Pain and as a Target for Neuromodulation: A Review. Neuromodulation 2014; 18:24-32; discussion 32. [DOI: 10.1111/ner.12247] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 11/08/2013] [Accepted: 02/04/2014] [Indexed: 11/29/2022]
|
40
|
Figley SA, Liu Y, Karadimas SK, Satkunendrarajah K, Fettes P, Spratt SK, Lee G, Ando D, Surosky R, Giedlin M, Fehlings MG. Delayed administration of a bio-engineered zinc-finger VEGF-A gene therapy is neuroprotective and attenuates allodynia following traumatic spinal cord injury. PLoS One 2014; 9:e96137. [PMID: 24846143 PMCID: PMC4028194 DOI: 10.1371/journal.pone.0096137] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 04/03/2014] [Indexed: 02/01/2023] Open
Abstract
Following spinal cord injury (SCI) there are drastic changes that occur in the spinal microvasculature, including ischemia, hemorrhage, endothelial cell death and blood-spinal cord barrier disruption. Vascular endothelial growth factor-A (VEGF-A) is a pleiotropic factor recognized for its pro-angiogenic properties; however, VEGF has recently been shown to provide neuroprotection. We hypothesized that delivery of AdV-ZFP-VEGF--an adenovirally delivered bio-engineered zinc-finger transcription factor that promotes endogenous VEGF-A expression--would result in angiogenesis, neuroprotection and functional recovery following SCI. This novel VEGF gene therapy induces the endogenous production of multiple VEGF-A isoforms; a critical factor for proper vascular development and repair. Briefly, female Wistar rats--under cyclosporin immunosuppression--received a 35 g clip-compression injury and were administered AdV-ZFP-VEGF or AdV-eGFP at 24 hours post-SCI. qRT-PCR and Western Blot analysis of VEGF-A mRNA and protein, showed significant increases in VEGF-A expression in AdV-ZFP-VEGF treated animals (p<0.001 and p<0.05, respectively). Analysis of NF200, TUNEL, and RECA-1 indicated that AdV-ZFP-VEGF increased axonal preservation (p<0.05), reduced cell death (p<0.01), and increased blood vessels (p<0.01), respectively. Moreover, AdV-ZFP-VEGF resulted in a 10% increase in blood vessel proliferation (p<0.001). Catwalk™ analysis showed AdV-ZFP-VEGF treatment dramatically improves hindlimb weight support (p<0.05) and increases hindlimb swing speed (p<0.02) when compared to control animals. Finally, AdV-ZFP-VEGF administration provided a significant reduction in allodynia (p<0.01). Overall, the results of this study indicate that AdV-ZFP-VEGF administration can be delivered in a clinically relevant time-window following SCI (24 hours) and provide significant molecular and functional benefits.
Collapse
Affiliation(s)
- Sarah A Figley
- Department of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Centre, University Health Network, Toronto, Ontario, Canada; Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Yang Liu
- Department of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Centre, University Health Network, Toronto, Ontario, Canada
| | - Spyridon K Karadimas
- Department of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Centre, University Health Network, Toronto, Ontario, Canada; Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Kajana Satkunendrarajah
- Department of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Centre, University Health Network, Toronto, Ontario, Canada
| | - Peter Fettes
- Department of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Centre, University Health Network, Toronto, Ontario, Canada
| | - S Kaye Spratt
- Department of Therapeutic Development, Sangamo BioSciences, Pt. Richmond, California, United States of America
| | - Gary Lee
- Department of Therapeutic Development, Sangamo BioSciences, Pt. Richmond, California, United States of America
| | - Dale Ando
- Department of Therapeutic Development, Sangamo BioSciences, Pt. Richmond, California, United States of America
| | - Richard Surosky
- Department of Therapeutic Development, Sangamo BioSciences, Pt. Richmond, California, United States of America
| | - Martin Giedlin
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Michael G Fehlings
- Department of Genetics and Development, Toronto Western Research Institute, and Spinal Program, Krembil Neuroscience Centre, University Health Network, Toronto, Ontario, Canada; Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
41
|
Krames ES. The role of the dorsal root ganglion in the development of neuropathic pain. PAIN MEDICINE 2014; 15:1669-85. [PMID: 24641192 DOI: 10.1111/pme.12413] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND The dorsal root ganglion (DRG), in the not too distant past, had been thought of as a passive organ not involved in the development of abnormal aberrent neuropathic pain (NP), but merely metabolically "supporting" physiologic functions between the peripheral nervous system (PNS) and the central nervous system (CNS). New information regarding metabolic change within the DRG has dispelled this supportive passive role and suggests that the DRG is an active, not a passive, organ, in the process of the development of chronic pain. METHODS A review of the anatomic and physiologic literature utilizing PubMed and Google Scholar was performed to create a review of the anatomic and physiologic foundations for the development of NP after peripheral afferent fiber injury. CONCLUSIONS The DRG is as involved in the process of generating NP as is the nociceptor and the dorsal horn of the spinal cord.
Collapse
|
42
|
Chen L, Mao J. Update on neuropathic pain treatment: ion channel blockers and gabapentinoids. Curr Pain Headache Rep 2014; 17:359. [PMID: 23888370 DOI: 10.1007/s11916-013-0359-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Neuropathic pain is a debilitating chronic pain condition, which remains difficult to treat. The current mainstays of treatment include physical therapy, interventional procedures and medications. Among medications, ion channel blockers and gabapentinoids are the 2 classes of drugs commonly used to treat neuropathic pain. It has been suggested that these medications may be useful to treat a variety of neuropathic pain conditions. This article provides several updates on the utility of both ion channel blockers and gabapentinoids for the treatment of neuropathic pain.
Collapse
Affiliation(s)
- Lucy Chen
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | |
Collapse
|
43
|
Endocannabinoid 2-arachidonylglycerol protects primary cultured neurons against LPS-induced impairments in rat caudate nucleus. J Mol Neurosci 2014; 54:49-58. [PMID: 24510751 DOI: 10.1007/s12031-014-0246-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 01/21/2014] [Indexed: 10/25/2022]
Abstract
Inflammation plays a pivotal role in the pathogenesis of many diseases in the central nervous system. Caudate nucleus (CN), the largest nucleus in the brain, is also implicated in many neurological disorders. 2-Arachidonoylglycerol (2-AG), the most abundant endogenous cannabinoid and the true natural ligand for CB1 receptors, has been shown to exhibit neuroprotective effects through its anti-inflammatory action from proinflammatory stimuli in hippocampus. However, it is still not clear whether 2-AG is also able to protect CN neurons from proinflammation stimuli. In the present study, we discovered that 2-AG significantly protects CN neurons in culture against lipopolysaccharide (LPS)-induced inflammatory response. 2-AG is capable of suppressing elevation of LPS-induced cyclooxygenase-2 expression associated with ERK/p38MAPK/NF-κB signaling pathway in CB1 receptor-dependant manner in primary cultured CN neurons. Moreover, 2-AG inhibits LPS-induced increase in voltage-gated sodium channel currents and hyperpolarizing shift of activation curves through CB1 receptor-dependant pathway. Our study suggests the therapeutic potential of 2-AG for the treatment of some inflammation-induced neurological disorders and pain.
Collapse
|
44
|
KIF5B promotes the forward transport and axonal function of the voltage-gated sodium channel Nav1.8. J Neurosci 2013; 33:17884-96. [PMID: 24198377 DOI: 10.1523/jneurosci.0539-13.2013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Nav1.8 is a tetrodotoxin-resistant voltage-gated sodium channel selectively expressed in primary sensory neurons. Peripheral inflammation and nerve injury induce Nav1.8 accumulation in peripheral nerves. However, the mechanisms and related significance of channel accumulation in nerves remains unclear. Here we report that KIF5B promotes the forward transport of Nav1.8 to the plasma membrane and axons in dorsal root ganglion (DRG) neurons of the rat. In peripheral inflammation induced through the intraplantar injection of complete Freund's adjuvant, increased KIF5 and Nav1.8 accumulation were observed in the sciatic nerve. The knock-down of KIF5B, a highly expressed member of the KIF5 family in DRGs, reduced the current density of Nav1.8 in both cultured DRG neurons and ND7-23 cells. Overexpression of KIF5B in ND7-23 cells increased the current density and surface expression of Nav1.8, which were abolished through brefeldin A treatment, whereas the increases were lost in KIF5B mutants defective in ATP hydrolysis or cargo binding. Overexpression of KIF5B also decreased the proteasome-associated degradation of Nav1.8. In addition, coimmunoprecipitation experiments showed interactions between the N terminus of Nav1.8 and the 511-620 aa sequence in the stalk domain of KIF5B. Furthermore, KIF5B increased Nav1.8 accumulation, Nav1.8 current, and neuronal excitability detected in the axons of cultured DRG neurons, which were completely abolished by the disruption of interactions between KIF5B and the N terminus of Nav1.8. Therefore, our results reveal that KIF5B is required for the forward transport and axonal function of Nav1.8, suggesting a mechanism for axonal accumulation of Nav1.8 in inflammatory pain.
Collapse
|
45
|
Zha C, Brown GB, Brouillette WJ. A highly predictive 3D-QSAR model for binding to the voltage-gated sodium channel: design of potent new ligands. Bioorg Med Chem 2013; 22:95-104. [PMID: 24332655 DOI: 10.1016/j.bmc.2013.11.049] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Revised: 11/17/2013] [Accepted: 11/25/2013] [Indexed: 12/01/2022]
Abstract
A comprehensive comparative molecular field analysis (CoMFA) model for the binding of ligands to the neuronal voltage-gated sodium channel was generated based on 67 diverse compounds. Earlier published CoMFA models for this target provided μM ligands, but the improved model described here provided structurally novel compounds with low nM IC₅₀. For example, new compounds 94 and 95 had IC₅₀ values of 129 and 119 nM, respectively.
Collapse
Affiliation(s)
- Congxiang Zha
- Department of Chemistry, The University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - George B Brown
- Department of Psychiatry and Behavioral Neurobiology, The University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Wayne J Brouillette
- Department of Chemistry, The University of Alabama at Birmingham, Birmingham, AL 35294, United States.
| |
Collapse
|
46
|
Bird EV, Christmas CR, Loescher AR, Smith KG, Robinson PP, Black JA, Waxman SG, Boissonade FM. Correlation of Nav1.8 and Nav1.9 sodium channel expression with neuropathic pain in human subjects with lingual nerve neuromas. Mol Pain 2013; 9:52. [PMID: 24144460 PMCID: PMC4016210 DOI: 10.1186/1744-8069-9-52] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 10/07/2013] [Indexed: 12/22/2022] Open
Abstract
Background Voltage-gated sodium channels Nav1.8 and Nav1.9 are expressed preferentially in small diameter sensory neurons, and are thought to play a role in the generation of ectopic activity in neuronal cell bodies and/or their axons following peripheral nerve injury. The expression of Nav1.8 and Nav1.9 has been quantified in human lingual nerves that have been previously injured inadvertently during lower third molar removal, and any correlation between the expression of these ion channels and the presence or absence of dysaesthesia investigated. Results Immunohistochemical processing and quantitative image analysis revealed that Nav1.8 and Nav1.9 were expressed in human lingual nerve neuromas from patients with or without symptoms of dysaesthesia. The level of Nav1.8 expression was significantly higher in patients reporting pain compared with no pain, and a significant positive correlation was observed between levels of Nav1.8 expression and VAS scores for the symptom of tingling. No significant differences were recorded in the level of expression of Nav1.9 between patients with or without pain. Conclusions These results demonstrate that Nav1.8 and Nav1.9 are present in human lingual nerve neuromas, with significant correlations between the level of expression of Nav1.8 and symptoms of pain. These data provide further evidence that changes in expression of Nav1.8 are important in the development and/or maintenance of nerve injury-induced pain, and suggest that Nav1.8 may be a potential therapeutic target.
Collapse
Affiliation(s)
- Emma V Bird
- Academic Unit of Oral and Maxillofacial Medicine and Surgery, School of Clinical Dentistry, University of Sheffield, Claremont Crescent, Sheffield S10 2TA, UK.
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Waszkielewicz AM, Gunia A, Szkaradek N, Słoczyńska K, Krupińska S, Marona H. Ion channels as drug targets in central nervous system disorders. Curr Med Chem 2013; 20:1241-85. [PMID: 23409712 PMCID: PMC3706965 DOI: 10.2174/0929867311320100005] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 01/14/2013] [Accepted: 01/18/2013] [Indexed: 12/27/2022]
Abstract
Ion channel targeted drugs have always been related with either the central nervous system (CNS), the peripheral nervous system, or the cardiovascular system. Within the CNS, basic indications of drugs are: sleep disorders, anxiety, epilepsy, pain, etc. However, traditional channel blockers have multiple adverse events, mainly due to low specificity of mechanism of action. Lately, novel ion channel subtypes have been discovered, which gives premises to drug discovery process led towards specific channel subtypes. An example is Na(+) channels, whose subtypes 1.3 and 1.7-1.9 are responsible for pain, and 1.1 and 1.2 - for epilepsy. Moreover, new drug candidates have been recognized. This review is focusing on ion channels subtypes, which play a significant role in current drug discovery and development process. The knowledge on channel subtypes has developed rapidly, giving new nomenclatures of ion channels. For example, Ca(2+)s channels are not any more divided to T, L, N, P/Q, and R, but they are described as Ca(v)1.1-Ca(v)3.3, with even newer nomenclature α1A-α1I and α1S. Moreover, new channels such as P2X1-P2X7, as well as TRPA1-TRPV1 have been discovered, giving premises for new types of analgesic drugs.
Collapse
Affiliation(s)
- A M Waszkielewicz
- Department of Bioorganic Chemistry, Chair of Organic Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Krakow, Poland.
| | | | | | | | | | | |
Collapse
|
48
|
Abstract
A number of agents from diverse pharmacological classes are used to treat neuropathic pain associated with diabetic peripheral neuropathy. Only three of these have regulatory approval for this indication in the U.S. In this focused article, I will discuss selected drugs, newly approved or in development, to treat neuropathic pain in patients with diabetic neuropathy. These will include agonists and antagonists of the transient receptor potential channels, a family of receptor proteins that play a role in the transduction of physical stress; sodium channel isoform specific antagonists; a recently approved dual-action opioid receptor agonist-norepinephrine reuptake inhibitor; gene therapy for neuropathic pain; and anti-nerve growth factor molecules. Mechanisms of action, preclinical supporting data, clinical trial evidence, and adverse effects will be reviewed.
Collapse
Affiliation(s)
- Roy Freeman
- Center for Autonomic and Peripheral Nerve Disorders, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
| |
Collapse
|
49
|
Zhang Y, Jia YY, Guo JL, Liu PQ, Jiang JM. Effects of (-)-gallocatechin-3-gallate on tetrodotoxin-resistant voltage-gated sodium channels in rat dorsal root ganglion neurons. Int J Mol Sci 2013; 14:9779-89. [PMID: 23652835 PMCID: PMC3676812 DOI: 10.3390/ijms14059779] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 04/10/2013] [Accepted: 04/24/2013] [Indexed: 11/17/2022] Open
Abstract
The (−)-gallocatechin-3-gallate (GCG) concentration in some tea beverages can account for as much as 50% of the total catechins. It has been shown that catechins have analgesic properties. Voltage-gated sodium channels (Nav) mediate neuronal action potentials. Tetrodotoxin inhibits all Nav isoforms, but Nav1.8 and Nav1.9 are relatively tetrodotoxin-resistant compared to other isoforms and functionally linked to nociception. In this study, the effects of GCG on tetrodotoxin-resistant Na+ currents were investigated in rat primary cultures of dorsal root ganglion neurons via the whole-cell patch-clamp technique. We found that 1 μM GCG reduced the amplitudes of peak current density of tetrodotoxin-resistant Na+ currents significantly. Furthermore, the inhibition was accompanied by a depolarizing shift of the activation voltage and a hyperpolarizing shift of steady-state inactivation voltage. The percentage block of GCG (1 μM) on tetrodotoxin-resistant Na+ current was 45.1% ± 1.1% in 10 min. In addition, GCG did not produce frequency-dependent block of tetrodotoxin-resistant Na+ currents at stimulation frequencies of 1 Hz, 2 Hz and 5 Hz. On the basis of these findings, we propose that GCG may be a potential analgesic agent.
Collapse
Affiliation(s)
- Yan Zhang
- Laboratory of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, China.
| | | | | | | | | |
Collapse
|
50
|
Liang L, Fan L, Tao B, Yaster M, Tao YX. Protein kinase B/Akt is required for complete Freund's adjuvant-induced upregulation of Nav1.7 and Nav1.8 in primary sensory neurons. THE JOURNAL OF PAIN 2013; 14:638-47. [PMID: 23642408 DOI: 10.1016/j.jpain.2013.01.778] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2012] [Revised: 12/18/2012] [Accepted: 01/25/2013] [Indexed: 01/08/2023]
Abstract
UNLABELLED Voltage-gated sodium channels (Nav) are essential for the generation and conduction of action potentials. Peripheral inflammation increases the expression of Nav1.7 and Nav1.8 in dorsal root ganglion (DRG) neurons, suggesting that they participate in the induction and maintenance of chronic inflammatory pain. However, how Nav1.7 and Nav1.8 are regulated in the DRG under inflammatory pain conditions remains unclear. Using a complete Freund's adjuvant (CFA)-induced chronic inflammatory pain model and Western blot analysis, we found that phosphorylated Akt (p-Akt) was significantly increased in the ipsilateral L4/5 DRGs of rats on days 3 and 7 after intraplantar CFA injection. Immunohistochemistry showed that the percentage of p-Akt-positive neurons in the DRG was also significantly increased in the ipsilateral L4/5 DRGs at these time points. Moreover, CFA injection increased the colocalization of p-Akt with Nav1.7 and Nav1.8 in L4/5 DRG neurons. Pretreatment of rats with an intrathecal injection of Akt inhibitor IV blocked CFA-induced thermal hyperalgesia and CFA-induced increases in Nav1.7 and Nav1.8 in the L4/5 DRGs on day 7 after CFA injection. Our findings suggest that the Akt pathway participates in inflammation-induced upregulation of Nav1.7 and Nav1.8 expression in DRG neurons. This participation might contribute to the maintenance of chronic inflammatory pain. PERSPECTIVE This article presents that inhibition of Akt blocks CFA-induced thermal hyperalgesia and CFA-induced increases in dorsal root ganglion Nav1.7 and Nav1.8. These findings have potential implications for use of Akt inhibitors to prevent and/or treat persistent inflammatory pain.
Collapse
Affiliation(s)
- Lingli Liang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | | | | | | | | |
Collapse
|