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Oyama M, Watanabe S, Iwai T, Tanabe M. Selective inhibition of A-fiber-mediated excitatory transmission underlies the analgesic effects of KCNQ channel opening in the spinal dorsal horn. Neuropharmacology 2024; 254:109994. [PMID: 38750803 DOI: 10.1016/j.neuropharm.2024.109994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 04/11/2024] [Accepted: 05/10/2024] [Indexed: 05/18/2024]
Abstract
Neuronal voltage-gated KCNQ (Kv7) channels, expressed centrally and peripherally, mediate low-threshold and non-inactivating M-currents responsible for the control of tonic excitability of mammalian neurons. Pharmacological opening of KCNQ channels has been reported to generate analgesic effects in animal models of neuropathic pain. Here, we examined the possible involvement of central KCNQ channels in the analgesic effects of retigabine, a KCNQ channel opener. Behaviorally, intraperitoneally applied retigabine exerted analgesic effects on thermal and mechanical hypersensitivity in male mice developing neuropathic pain after partial sciatic nerve ligation, which was antagonized by the KCNQ channel blocker XE991 preadministered intraperitoneally and intrathecally. Intrathecally applied retigabine also exerted analgesic effects that were inhibited by intrathecally injected XE991. We then explored the synaptic mechanisms underlying the analgesic effects of retigabine in the spinal dorsal horn. Whole-cell recordings were made from dorsal horn neurons in spinal slices with attached dorsal roots from adult male mice developing neuropathic pain, and the effects of retigabine on miniature and afferent-evoked postsynaptic currents were examined. Retigabine reduced the amplitude of A-fiber-mediated EPSCs without affecting C-fiber-mediated excitatory synaptic transmission. A-fiber-mediated EPSCs remained unaltered by retigabine in the presence of XE991, consistently with the behavioral findings. The frequency and amplitude of mEPSCs were not affected by retigabine. Thus, opening of KCNQ channels in the central terminals of primary afferent A-fibers inhibits excitatory synaptic transmission in the spinal dorsal horn, most likely contributing to the analgesic effect of retigabine.
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Affiliation(s)
- Misa Oyama
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan; Medicinal Research Laboratories, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Shun Watanabe
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan; Medicinal Research Laboratories, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Takashi Iwai
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan; Medicinal Research Laboratories, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Mitsuo Tanabe
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan; Medicinal Research Laboratories, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan.
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Pastor J, Attali B. Opposite effects of acute and chronic IGF1 on rat dorsal root ganglion neuron excitability. Front Cell Neurosci 2024; 18:1391858. [PMID: 38919332 PMCID: PMC11196413 DOI: 10.3389/fncel.2024.1391858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 05/29/2024] [Indexed: 06/27/2024] Open
Abstract
Insulin-like growth factor-1 (IGF-1) is a polypeptide hormone with a ubiquitous distribution in numerous tissues and with various functions in both neuronal and non-neuronal cells. IGF-1 provides trophic support for many neurons of both the central and peripheral nervous systems. In the central nervous system (CNS), IGF-1R signaling regulates brain development, increases neuronal firing and modulates synaptic transmission. IGF-1 and IGF-IR are not only expressed in CNS neurons but also in sensory dorsal root ganglion (DRG) nociceptive neurons that convey pain signals. DRG nociceptive neurons express a variety of receptors and ion channels that are essential players of neuronal excitability, notably the ligand-gated cation channel TRPV1 and the voltage-gated M-type K+ channel, which, respectively, triggers and dampens sensory neuron excitability. Although many lines of evidence suggest that IGF-IR signaling contributes to pain sensitivity, its possible modulation of TRPV1 and M-type K+ channel remains largely unexplored. In this study, we examined the impact of IGF-1R signaling on DRG neuron excitability and its modulation of TRPV1 and M-type K+ channel activities in cultured rat DRG neurons. Acute application of IGF-1 to DRG neurons triggered hyper-excitability by inducing spontaneous firing or by increasing the frequency of spikes evoked by depolarizing current injection. These effects were prevented by the IGF-1R antagonist NVP-AEW541 and by the PI3Kinase blocker wortmannin. Surprisingly, acute exposure to IGF-1 profoundly inhibited both the TRPV1 current and the spike burst evoked by capsaicin. The Src kinase inhibitor PP2 potently depressed the capsaicin-evoked spike burst but did not alter the IGF-1 inhibition of the hyperexcitability triggered by capsaicin. Chronic IGF-1 treatment (24 h) reduced the spike firing evoked by depolarizing current injection and upregulated the M-current density. In contrast, chronic IGF-1 markedly increased the spike burst evoked by capsaicin. In all, our data suggest that IGF-1 exerts complex effects on DRG neuron excitability as revealed by its dual and opposite actions upon acute and chronic exposures.
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Affiliation(s)
| | - Bernard Attali
- Department of Physiology and Pharmacology, Faculty of Medicine and Health Sciences and Sagol School of Neurosciences-Tel Aviv University, Tel Aviv, Israel
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3
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Dey S, Barkai O, Gokhman I, Suissa S, Haffner-Krausz R, Wigoda N, Feldmesser E, Ben-Dor S, Kovalenko A, Binshtok A, Yaron A. Kinesin family member 2A gates nociception. Cell Rep 2023; 42:113257. [PMID: 37851573 DOI: 10.1016/j.celrep.2023.113257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 08/23/2023] [Accepted: 09/27/2023] [Indexed: 10/20/2023] Open
Abstract
Nociceptive axons undergo remodeling as they innervate their targets during development and in response to environmental insults and pathological conditions. How is nociceptive morphogenesis regulated? Here, we show that the microtubule destabilizer kinesin family member 2A (Kif2a) is a key regulator of nociceptive terminal structures and pain sensitivity. Ablation of Kif2a in sensory neurons causes hyperinnervation and hypersensitivity to noxious stimuli in young adult mice, whereas touch sensitivity and proprioception remain unaffected. Computational modeling predicts that structural remodeling is sufficient to explain the phenotypes. Furthermore, Kif2a deficiency triggers a transcriptional response comprising sustained upregulation of injury-related genes and homeostatic downregulation of highly specific channels and receptors at the late stage. The latter effect can be predicted to relieve the hyperexcitability of nociceptive neurons, despite persisting morphological aberrations, and indeed correlates with the resolution of pain hypersensitivity. Overall, we reveal a critical control node defining nociceptive terminal structure, which is regulating nociception.
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Affiliation(s)
- Swagata Dey
- Department of Biomolecular Sciences and Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Omer Barkai
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah School of Medicine, Jerusalem 91120, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel; F.M. Kirby Neurobiology Center, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Irena Gokhman
- Department of Biomolecular Sciences and Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Sapir Suissa
- Department of Biomolecular Sciences and Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Rebecca Haffner-Krausz
- Department of Veterinary Resources, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Noa Wigoda
- Bioinformatics Unit, Life Science Core Facilities, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ester Feldmesser
- Bioinformatics Unit, Life Science Core Facilities, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Shifra Ben-Dor
- Bioinformatics Unit, Life Science Core Facilities, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Andrew Kovalenko
- Department of Biomolecular Sciences and Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Alexander Binshtok
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah School of Medicine, Jerusalem 91120, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Avraham Yaron
- Department of Biomolecular Sciences and Department of Molecular Neuroscience, Weizmann Institute of Science, Rehovot 76100, Israel.
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Encoding of inflammatory hyperalgesia in mouse spinal cord. Pain 2023; 164:443-460. [PMID: 36149026 DOI: 10.1097/j.pain.0000000000002727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 06/21/2022] [Indexed: 02/06/2023]
Abstract
ABSTRACT Inflammation modifies the input-output properties of peripheral nociceptive neurons such that the same stimulus produces enhanced nociceptive firing. This increased nociceptive output enters the superficial dorsal spinal cord (SDH), an intricate neuronal network composed largely of excitatory and inhibitory interneurons and a small percentage of projection neurons. The SDH network comprises the first central nervous system network integrating noxious information. Using in vivo calcium imaging and a computational approach, we characterized the responsiveness of the SDH network in mice to noxious stimuli in normal conditions and investigated the changes in SDH response patterns after acute burn injury-induced inflammation. We show that the application of noxious heat stimuli to the hind paw of naïve mice results in an overall increase in SDH network activity. Single-cell response analysis reveals that 70% of recorded neurons increase or suppress their activity, while ∼30% of neurons remain nonresponsive. After acute burn injury and the development of inflammatory hyperalgesia, application of the same noxious heat stimuli leads to the activation of previously nonresponding neurons and desuppression of suppressed neurons. We further demonstrate that an increase in afferent activity mimics the response of the SDH network to noxious heat stimuli under inflammatory conditions. Using a computational model of the SDH network, we predict that the changes in SDH network activity result in overall increased activity of excitatory neurons, amplifying the output from SDH to higher brain centers. We suggest that during acute local peripheral inflammation, the SDH network undergoes dynamic changes promoting hyperalgesia.
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Antagonism of the Muscarinic Acetylcholine Type 1 Receptor Enhances Mitochondrial Membrane Potential and Expression of Respiratory Chain Components via AMPK in Human Neuroblastoma SH-SY5Y Cells and Primary Neurons. Mol Neurobiol 2022; 59:6754-6770. [PMID: 36002781 PMCID: PMC9525428 DOI: 10.1007/s12035-022-03003-1] [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: 05/05/2022] [Accepted: 08/16/2022] [Indexed: 12/05/2022]
Abstract
Impairments in mitochondrial physiology play a role in the progression of multiple neurodegenerative conditions, including peripheral neuropathy in diabetes. Blockade of muscarinic acetylcholine type 1 receptor (M1R) with specific/selective antagonists prevented mitochondrial dysfunction and reversed nerve degeneration in in vitro and in vivo models of peripheral neuropathy. Specifically, in type 1 and type 2 models of diabetes, inhibition of M1R using pirenzepine or muscarinic toxin 7 (MT7) induced AMP-activated protein kinase (AMPK) activity in dorsal root ganglia (DRG) and prevented sensory abnormalities and distal nerve fiber loss. The human neuroblastoma SH-SY5Y cell line has been extensively used as an in vitro model system to study mechanisms of neurodegeneration in DRG neurons and other neuronal sub-types. Here, we tested the hypothesis that pirenzepine or MT7 enhance AMPK activity and via this pathway augment mitochondrial function in SH-SY5Y cells. M1R expression was confirmed by utilizing a fluorescent dye, ATTO590-labeled MT7, that exhibits great specificity for this receptor. M1R antagonist treatment in SH-SY5Y culture increased AMPK phosphorylation and mitochondrial protein expression (OXPHOS). Mitochondrial membrane potential (MMP) was augmented in pirenzepine and MT7 treated cultured SH-SY5Y cells and DRG neurons. Compound C or AMPK-specific siRNA suppressed pirenzepine or MT7-induced elevation of OXPHOS expression and MMP. Moreover, muscarinic antagonists induced hyperpolarization by activating the M-current and, thus, suppressed neuronal excitability. These results reveal that negative regulation of this M1R-dependent pathway could represent a potential therapeutic target to elevate AMPK activity, enhance mitochondrial function, suppress neuropathic pain, and enhance nerve repair in peripheral neuropathy.
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Evidence for Dual Activation of IK(M) and IK(Ca) Caused by QO-58 (5-(2,6-Dichloro-5-fluoropyridin-3-yl)-3-phenyl-2-(trifluoromethyl)-1H-pyrazolol[1,5-a]pyrimidin-7-one). Int J Mol Sci 2022; 23:ijms23137042. [PMID: 35806047 PMCID: PMC9266432 DOI: 10.3390/ijms23137042] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 06/20/2022] [Accepted: 06/22/2022] [Indexed: 02/06/2023] Open
Abstract
QO-58 (5-(2,6-dichloro-5-fluoropyridin-3-yl)-3-phenyl-2-(trifluoromethyl)-1H-pyrazolol[1,5-a]pyrimidin-7-one) has been regarded to be an activator of KV7 channels with analgesic properties. However, whether and how the presence of this compound can result in any modifications of other types of membrane ion channels in native cells are not thoroughly investigated. In this study, we investigated its perturbations on M-type K+ current (IK(M)), Ca2+-activated K+ current (IK(Ca)), large-conductance Ca2+-activated K+ (BKCa) channels, and erg-mediated K+ current (IK(erg)) identified from pituitary tumor (GH3) cells. Addition of QO-58 can increase the amplitude of IK(M) and IK(Ca) in a concentration-dependent fashion, with effective EC50 of 3.1 and 4.2 μM, respectively. This compound could shift the activation curve of IK(M) toward a leftward direction with being void of changes in the gating charge. The strength in voltage-dependent hysteresis (Vhys) of IK(M) evoked by upright triangular ramp pulse (Vramp) was enhanced by adding QO-58. The probabilities of M-type K+ (KM) channels that will be open increased upon the exposure to QO-58, although no modification in single-channel conductance was seen. Furthermore, GH3-cell exposure to QO-58 effectively increased the amplitude of IK(Ca) as well as enhanced the activity of BKCa channels. Under inside-out configuration, QO-58, applied at the cytosolic leaflet of the channel, activated BKCa-channel activity, and its increase could be attenuated by further addition of verruculogen, but not by linopirdine (10 μM). The application of QO-58 could lead to a leftward shift in the activation curve of BKCa channels with neither change in the gating charge nor in single-channel conductance. Moreover, cell exposure of QO-58 (10 μM) resulted in a minor suppression of IK(erg) amplitude in response to membrane hyperpolarization. The docking results also revealed that there are possible interactions of the QO-58 molecule with the KCNQ or KCa1.1 channel. Overall, dual activation of IK(M) and IK(Ca) caused by the presence of QO-58 eventually may have high impacts on the functional activity (e.g., anti-nociceptive effect) residing in electrically excitable cells. Care must be exercised when interpreting data generated with QO-58 as it is not entirely KCNQ/KV7 selective.
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Wong C, Barkai O, Wang F, Thörn Pérez C, Lev S, Cai W, Tansley S, Yousefpour N, Hooshmandi M, Lister KC, Latif M, Cuello AC, Prager-Khoutorsky M, Mogil JS, Séguéla P, De Koninck Y, Ribeiro-da-Silva A, Binshtok AM, Khoutorsky A. mTORC2 mediates structural plasticity in distal nociceptive endings that contributes to pain hypersensitivity following inflammation. J Clin Invest 2022; 132:152635. [PMID: 35579957 PMCID: PMC9337825 DOI: 10.1172/jci152635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 05/13/2022] [Indexed: 11/29/2022] Open
Abstract
The encoding of noxious stimuli into action potential firing is largely mediated by nociceptive free nerve endings. Tissue inflammation, by changing the intrinsic properties of the nociceptive endings, leads to nociceptive hyperexcitability and thus to the development of inflammatory pain. Here, we showed that tissue inflammation–induced activation of the mammalian target of rapamycin complex 2 (mTORC2) triggers changes in the architecture of nociceptive terminals and leads to inflammatory pain. Pharmacological activation of mTORC2 induced elongation and branching of nociceptor peripheral endings and caused long-lasting pain hypersensitivity. Conversely, nociceptor-specific deletion of the mTORC2 regulatory protein rapamycin-insensitive companion of mTOR (Rictor) prevented inflammation-induced elongation and branching of cutaneous nociceptive fibers and attenuated inflammatory pain hypersensitivity. Computational modeling demonstrated that mTORC2-mediated structural changes in the nociceptive terminal tree are sufficient to increase the excitability of nociceptors. Targeting mTORC2 using a single injection of antisense oligonucleotide against Rictor provided long-lasting alleviation of inflammatory pain hypersensitivity. Collectively, we showed that tissue inflammation–induced activation of mTORC2 causes structural plasticity of nociceptive free nerve endings in the epidermis and inflammatory hyperalgesia, representing a therapeutic target for inflammatory pain.
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Affiliation(s)
- Calvin Wong
- Department of Anesthesia, McGill University, Montreal, Canada
| | - Omer Barkai
- Department of Medical Neurobiology, The Hebrew University, Jerusalem, Israel
| | - Feng Wang
- Department of Psychiatry and Neuroscience, Université Laval, Quebec City, Canada
| | | | - Shaya Lev
- Department of Medical Neurobiology, The Hebrew University, Jerusalem, Israel
| | - Weihua Cai
- Department of Anesthesia, McGill University, Montreal, Canada
| | - Shannon Tansley
- Department of Psychology, McGill University, Montreal, Canada
| | - Noosha Yousefpour
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | | | - Kevin C Lister
- Department of Anesthesia, McGill University, Montreal, Canada
| | - Mariam Latif
- Department of Anesthesia, McGill University, Montreal, Canada
| | - A Claudio Cuello
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | | | - Jeffrey S Mogil
- Department of Psychology, McGill University, Montreal, Canada
| | - Philippe Séguéla
- Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
| | - Yves De Koninck
- Department of Psychiatry and Neuroscience, Université Laval, Quebec City, Canada
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Alles SRA, Smith PA. Peripheral Voltage-Gated Cation Channels in Neuropathic Pain and Their Potential as Therapeutic Targets. FRONTIERS IN PAIN RESEARCH 2022; 2:750583. [PMID: 35295464 PMCID: PMC8915663 DOI: 10.3389/fpain.2021.750583] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 11/10/2021] [Indexed: 11/25/2022] Open
Abstract
The persistence of increased excitability and spontaneous activity in injured peripheral neurons is imperative for the development and persistence of many forms of neuropathic pain. This aberrant activity involves increased activity and/or expression of voltage-gated Na+ and Ca2+ channels and hyperpolarization activated cyclic nucleotide gated (HCN) channels as well as decreased function of K+ channels. Because they display limited central side effects, peripherally restricted Na+ and Ca2+ channel blockers and K+ channel activators offer potential therapeutic approaches to pain management. This review outlines the current status and future therapeutic promise of peripherally acting channel modulators. Selective blockers of Nav1.3, Nav1.7, Nav1.8, Cav3.2, and HCN2 and activators of Kv7.2 abrogate signs of neuropathic pain in animal models. Unfortunately, their performance in the clinic has been disappointing; some substances fail to meet therapeutic end points whereas others produce dose-limiting side effects. Despite this, peripheral voltage-gated cation channels retain their promise as therapeutic targets. The way forward may include (i) further structural refinement of K+ channel activators such as retigabine and ASP0819 to improve selectivity and limit toxicity; use or modification of Na+ channel blockers such as vixotrigine, PF-05089771, A803467, PF-01247324, VX-150 or arachnid toxins such as Tap1a; the use of Ca2+ channel blockers such as TTA-P2, TTA-A2, Z 944, ACT709478, and CNCB-2; (ii) improving methods for assessing “pain” as opposed to nociception in rodent models; (iii) recognizing sex differences in pain etiology; (iv) tailoring of therapeutic approaches to meet the symptoms and etiology of pain in individual patients via quantitative sensory testing and other personalized medicine approaches; (v) targeting genetic and biochemical mechanisms controlling channel expression using anti-NGF antibodies such as tanezumab or re-purposed drugs such as vorinostat, a histone methyltransferase inhibitor used in the management of T-cell lymphoma, or cercosporamide a MNK 1/2 inhibitor used in treatment of rheumatoid arthritis; (vi) combination therapy using drugs that are selective for different channel types or regulatory processes; (vii) directing preclinical validation work toward the use of human or human-derived tissue samples; and (viii) application of molecular biological approaches such as clustered regularly interspaced short palindromic repeats (CRISPR) technology.
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Affiliation(s)
- Sascha R A Alles
- Department of Anesthesiology and Critical Care Medicine, University of New Mexico School of Medicine, Albuquerque, NM, United States
| | - Peter A Smith
- Department of Pharmacology, Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
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9
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Nagaraja S, Queme LF, Hofmann MC, Tewari SG, Jankowski MP, Reifman J. In silico Identification of Key Factors Driving the Response of Muscle Sensory Neurons to Noxious Stimuli. Front Neurosci 2021; 15:719735. [PMID: 34566566 PMCID: PMC8461020 DOI: 10.3389/fnins.2021.719735] [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: 06/03/2021] [Accepted: 08/17/2021] [Indexed: 11/13/2022] Open
Abstract
Nociceptive nerve endings embedded in muscle tissue transduce peripheral noxious stimuli into an electrical signal [i.e., an action potential (AP)] to initiate pain sensations. A major contributor to nociception from the muscles is mechanosensation. However, due to the heterogeneity in the expression of proteins, such as ion channels, pumps, and exchangers, on muscle nociceptors, we currently do not know the relative contributions of different proteins and signaling molecules to the neuronal response due to mechanical stimuli. In this study, we employed an integrated approach combining a customized experimental study in mice with a computational model to identify key proteins that regulate mechanical nociception in muscles. First, using newly collected data from somatosensory recordings in mouse hindpaw muscles, we developed and then validated a computational model of a mechanosensitive mouse muscle nociceptor. Next, by performing global sensitivity analyses that simulated thousands of nociceptors, we identified three ion channels (among the 17 modeled transmembrane proteins and four endoplasmic reticulum proteins) as potential regulators of the nociceptor response to mechanical forces in both the innocuous and noxious range. Moreover, we found that simulating single knockouts of any of the three ion channels, delayed rectifier voltage-gated K+ channel (Kv1.1) or mechanosensitive channels Piezo2 or TRPA1, considerably altered the excitability of the nociceptor (i.e., each knockout increased or decreased the number of triggered APs compared to when all channels were present). These results suggest that altering expression of the gene encoding Kv1.1, Piezo2, or TRPA1 might regulate the response of mechanosensitive muscle nociceptors.
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Affiliation(s)
- Sridevi Nagaraja
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD, United States.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - Luis F Queme
- Department of Anesthesia, Division of Pain Management, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Megan C Hofmann
- Department of Anesthesia, Division of Pain Management, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Shivendra G Tewari
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD, United States.,The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - Michael P Jankowski
- Department of Anesthesia, Division of Pain Management, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Department of Pediatrics, University of Cincinnati, College of Medicine, Cincinnati, OH, United States
| | - Jaques Reifman
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD, United States
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Wang J, Liu Y, Hu F, Yang J, Guo X, Hou X, Ju C, Wang K. Activation of Neuronal Voltage-Gated Potassium Kv7/KCNQ/M-Current by a Novel Channel Opener SCR2682 for Alleviation of Chronic Pain. J Pharmacol Exp Ther 2021; 377:20-28. [DOI: 10.1124/jpet.120.000357] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 01/06/2021] [Indexed: 12/20/2022] Open
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11
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Optical Assessment of Nociceptive TRP Channel Function at the Peripheral Nerve Terminal. Int J Mol Sci 2021; 22:ijms22020481. [PMID: 33418928 PMCID: PMC7825137 DOI: 10.3390/ijms22020481] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/01/2021] [Accepted: 01/03/2021] [Indexed: 12/13/2022] Open
Abstract
Free nerve endings are key structures in sensory transduction of noxious stimuli. In spite of this, little is known about their functional organization. Transient receptor potential (TRP) channels have emerged as key molecular identities in the sensory transduction of pain-producing stimuli, yet the vast majority of our knowledge about sensory TRP channel function is limited to data obtained from in vitro models which do not necessarily reflect physiological conditions. In recent years, the development of novel optical methods such as genetically encoded calcium indicators and photo-modulation of ion channel activity by pharmacological tools has provided an invaluable opportunity to directly assess nociceptive TRP channel function at the nerve terminal.
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12
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The Input-Output Relation of Primary Nociceptive Neurons is Determined by the Morphology of the Peripheral Nociceptive Terminals. J Neurosci 2020; 40:9346-9363. [PMID: 33115929 DOI: 10.1523/jneurosci.1546-20.2020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 10/19/2020] [Accepted: 10/21/2020] [Indexed: 12/22/2022] Open
Abstract
The output from the peripheral terminals of primary nociceptive neurons, which detect and encode the information regarding noxious stimuli, is crucial in determining pain sensation. The nociceptive terminal endings are morphologically complex structures assembled from multiple branches of different geometry, which converge in a variety of forms to create the terminal tree. The output of a single terminal is defined by the properties of the transducer channels producing the generation potentials and voltage-gated channels, translating the generation potentials into action potential (AP) firing. However, in the majority of cases, noxious stimuli activate multiple terminals; thus, the output of the nociceptive neuron is defined by the integration and computation of the inputs of the individual terminals. Here, we used a computational model of nociceptive terminal tree to study how the architecture of the terminal tree affects the input-output relation of the primary nociceptive neurons. We show that the input-output properties of the nociceptive neurons depend on the length, the axial resistance (Ra), and location of individual terminals. Moreover, we show that activation of multiple terminals by a capsaicin-like current allows summation of the responses from individual terminals, thus leading to increased nociceptive output. Stimulation of the terminals in simulated models of inflammatory or neuropathic hyperexcitability led to a change in the temporal pattern of AP firing, emphasizing the role of temporal code in conveying key information about changes in nociceptive output in pathologic conditions, leading to pain hypersensitivity.SIGNIFICANCE STATEMENT Noxious stimuli are detected by terminal endings of primary nociceptive neurons, which are organized into morphologically complex terminal trees. The information from multiple terminals is integrated along the terminal tree, computing the neuronal output, which propagates toward the CNS, thus shaping the pain sensation. Here, we revealed that the structure of the nociceptive terminal tree determines the output of nociceptive neurons. We show that the integration of noxious information depends on the morphology of the terminal trees and how this integration and, consequently, the neuronal output change under pathologic conditions. Our findings help to predict how nociceptive neurons encode noxious stimuli and how this encoding changes in pathologic conditions, leading to pain.
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Smith PA. K + Channels in Primary Afferents and Their Role in Nerve Injury-Induced Pain. Front Cell Neurosci 2020; 14:566418. [PMID: 33093824 PMCID: PMC7528628 DOI: 10.3389/fncel.2020.566418] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/21/2020] [Indexed: 12/12/2022] Open
Abstract
Sensory abnormalities generated by nerve injury, peripheral neuropathy or disease are often expressed as neuropathic pain. This type of pain is frequently resistant to therapeutic intervention and may be intractable. Numerous studies have revealed the importance of enduring increases in primary afferent excitability and persistent spontaneous activity in the onset and maintenance of peripherally induced neuropathic pain. Some of this activity results from modulation, increased activity and /or expression of voltage-gated Na+ channels and hyperpolarization-activated cyclic nucleotide–gated (HCN) channels. K+ channels expressed in dorsal root ganglia (DRG) include delayed rectifiers (Kv1.1, 1.2), A-channels (Kv1.4, 3.3, 3.4, 4.1, 4.2, and 4.3), KCNQ or M-channels (Kv7.2, 7.3, 7.4, and 7.5), ATP-sensitive channels (KIR6.2), Ca2+-activated K+ channels (KCa1.1, 2.1, 2.2, 2.3, and 3.1), Na+-activated K+ channels (KCa4.1 and 4.2) and two pore domain leak channels (K2p; TWIK related channels). Function of all K+ channel types is reduced via a multiplicity of processes leading to altered expression and/or post-translational modification. This also increases excitability of DRG cell bodies and nociceptive free nerve endings, alters axonal conduction and increases neurotransmitter release from primary afferent terminals in the spinal dorsal horn. Correlation of these cellular changes with behavioral studies provides almost indisputable evidence for K+ channel dysfunction in the onset and maintenance of neuropathic pain. This idea is underlined by the observation that selective impairment of just one subtype of DRG K+ channel can produce signs of pain in vivo. Whilst it is established that various mediators, including cytokines and growth factors bring about injury-induced changes in DRG function and excitability, evidence presently available points to a seminal role for interleukin 1β (IL-1β) in control of K+ channel function. Despite the current state of knowledge, attempts to target K+ channels for therapeutic pain management have met with limited success. This situation may change with the advent of personalized medicine. Identification of specific sensory abnormalities and genetic profiling of individual patients may predict therapeutic benefit of K+ channel activators.
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Affiliation(s)
- Peter A Smith
- Department of Pharmacology and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
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14
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Mecklenburg J, Zou Y, Wangzhou A, Garcia D, Lai Z, Tumanov AV, Dussor G, Price TJ, Akopian AN. Transcriptomic sex differences in sensory neuronal populations of mice. Sci Rep 2020; 10:15278. [PMID: 32943709 PMCID: PMC7499251 DOI: 10.1038/s41598-020-72285-z] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 08/24/2020] [Indexed: 12/24/2022] Open
Abstract
Many chronic pain conditions show sex differences in their epidemiology. This could be attributed to sex-dependent differential expression of genes (DEGs) involved in nociceptive pathways, including sensory neurons. This study aimed to identify sex-dependent DEGs in estrous female versus male sensory neurons, which were prepared by using different approaches and ganglion types. RNA-seq on non-purified sensory neuronal preparations, such as whole dorsal root ganglion (DRG) and hindpaw tissues, revealed only a few sex-dependent DEGs. Sensory neuron purification increased numbers of sex-dependent DEGs. These DEG sets were substantially influenced by preparation approaches and ganglion types [DRG vs trigeminal ganglia (TG)]. Percoll-gradient enriched DRG and TG neuronal fractions produced distinct sex-dependent DEG groups. We next isolated a subset of sensory neurons by sorting DRG neurons back-labeled from paw and thigh muscle. These neurons have a unique sex-dependent DEG set, yet there is similarity in biological processes linked to these different groups of sex-dependent DEGs. Female-predominant DEGs in sensory neurons relate to inflammatory, synaptic transmission and extracellular matrix reorganization processes that could exacerbate neuro-inflammation severity, especially in TG. Male-selective DEGs were linked to oxidative phosphorylation and protein/molecule metabolism and production. Our findings catalog preparation-dependent sex differences in neuronal gene expressions in sensory ganglia.
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Affiliation(s)
- Jennifer Mecklenburg
- Department of Endodontics, University of Texas Health Science Center at San Antonio (UTHSCSA), San Antonio, TX, 78229, USA
| | - Yi Zou
- Greehey Children's Cancer Research Institute, UTHSCSA, San Antonio, TX, USA
| | - Andi Wangzhou
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas School of Behavioral and Brain Sciences, Richardson, TX, 75080, USA
| | - Dawn Garcia
- Greehey Children's Cancer Research Institute, UTHSCSA, San Antonio, TX, USA
| | - Zhao Lai
- Greehey Children's Cancer Research Institute, UTHSCSA, San Antonio, TX, USA
- Department of Molecular Medicine, University of Texas Health Science Center at San Antonio (UTHSCSA), San Antonio, TX, 78229, USA
| | - Alexei V Tumanov
- Departments of Microbiology, Immunology & Molecular Genetics, University of Texas Health Science Center at San Antonio (UTHSCSA), San Antonio, TX, 78229, USA
| | - Gregory Dussor
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas School of Behavioral and Brain Sciences, Richardson, TX, 75080, USA
| | - Theodore J Price
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas School of Behavioral and Brain Sciences, Richardson, TX, 75080, USA
| | - Armen N Akopian
- Department of Endodontics, University of Texas Health Science Center at San Antonio (UTHSCSA), San Antonio, TX, 78229, USA.
- Department of Pharmacology, The School of Dentistry, University of Texas Health Science Center at San Antonio (UTHSCSA), 7703 Floyd Curl Drive, San Antonio, TX, 78229-3900, USA.
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Djouhri L, Zeidan A, Abd El-Aleem SA, Smith T. Cutaneous Aβ-Non-nociceptive, but Not C-Nociceptive, Dorsal Root Ganglion Neurons Exhibit Spontaneous Activity in the Streptozotocin Rat Model of Painful Diabetic Neuropathy in vivo. Front Neurosci 2020; 14:530. [PMID: 32528247 PMCID: PMC7263321 DOI: 10.3389/fnins.2020.00530] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/29/2020] [Indexed: 12/30/2022] Open
Abstract
Diabetic peripheral neuropathic pain (DPNP) is the most devastating complication of diabetes mellitus. Unfortunately, successful therapy for DPNP remains a challenge because its pathogenesis is still elusive. However, DPNP is believed to be due partly to abnormal hyperexcitability of dorsal root ganglion (DRG) neurons, but the relative contributions of specific functional subtypes remain largely unknown. Here, using the strepotozotocin (STZ) rat model of DPNP induced by a STZ injection (60 mg/kg, i.p), and intracellular recordings of action potentials (APs) from DRG neurons in anesthetized rats, we examined electrophysiological changes in C-and Aβ-nociceptive and Aβ-low threshold mechanoreceptive (LTM) neurons that may contribute to DPNP. Compared with control, we found in STZ-rats with established pain hypersensitivity (5 weeks post-STZ) several significant changes including: (a) A 23% increase in the incidence of spontaneous activity (SA) in Aβ-LTMs (but not C-mechanosensitive nociceptors) that may cause dysesthesias/paresthesia suffered by DPNP patients, (b) membrane hyperpolarization and a ∼85% reduction in SA rate in Aβ-LTMs by Kv7 channel activation with retigabine (6 mg/kg, i.v.) suggesting that Kv7/M channels may be involved in mechanisms of SA generation in Aβ-LTMs, (c) decreases in AP duration and in duration and amplitude of afterhyperpolarization (AHP) in C-and/or Aβ-nociceptors. These faster AP and AHP kinetics may lead to repetitive firing and an increase in afferent input to the CNS and thereby contribute to DPNP development, and (d) a decrease in the electrical thresholds of Aβ-nociceptors that may contribute to their sensitization, and thus to the resulting hypersensitivity associated with DPNP.
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Affiliation(s)
- Laiche Djouhri
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Asad Zeidan
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Seham A. Abd El-Aleem
- Department of Histology and Cell Biology, University of Manchester, Manchester, United Kingdom
- Department of Pathology, Faculty of Medicine, Minia University, Minya, Egypt
| | - Trevor Smith
- Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
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16
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Platelet-derived growth factor activates nociceptive neurons by inhibiting M-current and contributes to inflammatory pain. Pain 2020; 160:1281-1296. [PMID: 30933959 PMCID: PMC6553959 DOI: 10.1097/j.pain.0000000000001523] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Supplemental Digital Content is Available in the Text. Our work reveals that the platelet-derived growth factor-BB, by inhibiting nociceptive M-type potassium channels, acts as a pain-inducing proinflammatory factor that significantly contributes to inflammatory pain. Endogenous inflammatory mediators contribute to the pathogenesis of pain by acting on nociceptors, specialized sensory neurons that detect noxious stimuli. Here, we describe a new factor mediating inflammatory pain. We show that platelet-derived growth factor (PDGF)-BB applied in vitro causes repetitive firing of dissociated nociceptor-like rat dorsal root ganglion neurons and decreased their threshold for action potential generation. Injection of PDGF-BB into the paw produced nocifensive behavior in rats and led to thermal and mechanical pain hypersensitivity. We further detailed the biophysical mechanisms of these PDGF-BB effects and show that PDGF receptor–induced inhibition of nociceptive M-current underlies PDGF-BB–mediated nociceptive hyperexcitability. Moreover, in vivo sequestration of PDGF or inhibition of the PDGF receptor attenuates acute formalin-induced inflammatory pain. Our discovery of a new pain-facilitating proinflammatory mediator, which by inhibiting M-current activates nociceptive neurons and thus contributes to inflammatory pain, improves our understanding of inflammatory pain pathophysiology and may have important clinical implications for pain treatment.
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17
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Hsiao HT, Liu YC, Liu PY, Wu SN. Concerted suppression of I h and activation of I K(M) by ivabradine, an HCN-channel inhibitor, in pituitary cells and hippocampal neurons. Brain Res Bull 2019; 149:11-20. [PMID: 30951796 DOI: 10.1016/j.brainresbull.2019.03.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 03/29/2019] [Accepted: 03/29/2019] [Indexed: 11/24/2022]
Abstract
Ivabradine (IVA), a heart-rate reducing agent, is recognized as an inhibitor of hyperpolarization-activated cation current (Ih) and also reported to ameliorate inflammatory or neuropathic pain. However, to what extent this agent can perturb another types of membrane ion currents in neurons or endocrine cells remains to be largely unknown. Therefore, the Ih or other types of ionic currents in pituitary tumor (GH3) cells and in hippocampal mHippoE-14 neurons was studied with or without the presence of IVA or other related compounds. The IVA addition caused a time- and concentration-dependent reduction in the amplitude of Ih with an IC50 value of 0.64 μM and a KD value of 0.68 μM. IVA (0.3 μM) shifted the Ih activation curve to a more negative potential by approximately 8 mV, despite no concomitant change in the gating charge. Additionally, IVA was found to increase M-type K+ current (IK(M)) together with a rightward shift in the activation curve. In cell-attached current recordings, IVA (3 μM) applied to the bath increased the open probability of M-type K+ channels; however, it did not modify single-channel conductance of the channel. In current-clamp voltage recordings, IVA suppressed the firing of spontaneous action potentials in GH3 cells; and, further addition of linopirdine attenuated its suppression of firing. In hippocampal mHippoE-14 neurons, IVA also effectively increased IK(M) amplitude. In summary, both inhibition of Ih and activation of IK(M) caused by IVA can synergistically combine to influence electrical behaviors in different types of electrically excitable cells occurring in vivo.
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Affiliation(s)
- Hung-Tsung Hsiao
- Department of Anesthesiology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Taiwan
| | - Yen-Chin Liu
- Department of Anesthesiology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Taiwan
| | - Ping-Yen Liu
- Division of Cardiovascular Medicine, National Cheng Kung University Medical College, Tainan City, Taiwan
| | - Sheng-Nan Wu
- Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan City, Taiwan; Department of Physiology, National Cheng Kung University Medical College, Tainan City, Taiwan.
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18
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Goldstein RH, Barkai O, Íñigo-Portugués A, Katz B, Lev S, Binshtok AM. Location and Plasticity of the Sodium Spike Initiation Zone in Nociceptive Terminals In Vivo. Neuron 2019; 102:801-812.e5. [PMID: 30926280 DOI: 10.1016/j.neuron.2019.03.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 01/15/2019] [Accepted: 03/01/2019] [Indexed: 11/18/2022]
Abstract
Nociceptive terminals possess the elements for detecting, transmitting, and modulating noxious signals, thus being pivotal for pain sensation. Despite this, a functional description of the transduction process by the terminals, in physiological conditions, has not been fully achieved. Here, we studied how nociceptive terminals in vivo convert noxious stimuli into propagating signals. By monitoring noxious-stimulus-induced Ca2+ dynamics from mouse corneal terminals, we found that initiation of Na+ channel (Nav)-dependent propagating signals takes place away from the terminal and that the starting point for Nav-mediated propagation depends on Nav functional availability. Acute treatment with the proinflammatory cytokines tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) resulted in a shift of the location of Nav involvement toward the terminal, thus increasing nociceptive excitability. Moreover, a shift of Nav involvement toward the terminal occurs in corneal hyperalgesia resulting from acute photokeratitis. This dynamic change in the location of Nav-mediated propagation initiation could underlie pathological pain hypersensitivity.
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Affiliation(s)
- Robert H Goldstein
- Department of Medical Neurobiology, Institute for Medical Research Israel Canada, Faculty of Medicine, The Hebrew University, 9112001 Jerusalem, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University, 9112001 Jerusalem, Israel
| | - Omer Barkai
- Department of Medical Neurobiology, Institute for Medical Research Israel Canada, Faculty of Medicine, The Hebrew University, 9112001 Jerusalem, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University, 9112001 Jerusalem, Israel
| | - Almudena Íñigo-Portugués
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, 03550 San Juan de Alicante, Spain
| | - Ben Katz
- Department of Medical Neurobiology, Institute for Medical Research Israel Canada, Faculty of Medicine, The Hebrew University, 9112001 Jerusalem, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University, 9112001 Jerusalem, Israel
| | - Shaya Lev
- Department of Medical Neurobiology, Institute for Medical Research Israel Canada, Faculty of Medicine, The Hebrew University, 9112001 Jerusalem, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University, 9112001 Jerusalem, Israel
| | - Alexander M Binshtok
- Department of Medical Neurobiology, Institute for Medical Research Israel Canada, Faculty of Medicine, The Hebrew University, 9112001 Jerusalem, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University, 9112001 Jerusalem, Israel.
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19
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Sun H, Lin AH, Ru F, Patil MJ, Meeker S, Lee LY, Undem BJ. KCNQ/M-channels regulate mouse vagal bronchopulmonary C-fiber excitability and cough sensitivity. JCI Insight 2019; 4:124467. [PMID: 30721152 DOI: 10.1172/jci.insight.124467] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 01/29/2019] [Indexed: 01/06/2023] Open
Abstract
Increased airway vagal sensory C-fiber activity contributes to the symptoms of inflammatory airway diseases. The KCNQ/Kv7/M-channel is a well-known determinant of neuronal excitability, yet whether it regulates the activity of vagal bronchopulmonary C-fibers and airway reflex sensitivity remains unknown. Here we addressed this issue using single-cell RT-PCR, patch clamp technique, extracellular recording of single vagal nerve fibers innervating the mouse lungs, and telemetric recording of cough in free-moving mice. Single-cell mRNA analysis and biophysical properties of M-current (IM) suggest that KCNQ3/Kv7.3 is the major M-channel subunit in mouse nodose neurons. The M-channel opener retigabine negatively shifted the voltage-dependent activation of IM, leading to membrane hyperpolarization, increased rheobase, and suppression of both evoked and spontaneous action potential (AP) firing in nodose neurons in an M-channel inhibitor XE991-sensitive manner. Retigabine also markedly suppressed the α,β-methylene ATP-induced AP firing in nodose C-fiber terminals innervating the mouse lungs, and coughing evoked by irritant gases in awake mice. In conclusion, KCNQ/M-channels play a role in regulating the excitability of vagal airway C-fibers at both the cell soma and nerve terminals. Drugs that open M-channels in airway sensory afferents may relieve the sufferings associated with pulmonary inflammatory diseases such as chronic coughing.
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Affiliation(s)
- Hui Sun
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - An-Hsuan Lin
- Department of Physiology, University of Kentucky, Lexington, Kentucky, USA
| | - Fei Ru
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Mayur J Patil
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Sonya Meeker
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Lu-Yuan Lee
- Department of Physiology, University of Kentucky, Lexington, Kentucky, USA
| | - Bradley J Undem
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Du X, Gao H, Jaffe D, Zhang H, Gamper N. M-type K + channels in peripheral nociceptive pathways. Br J Pharmacol 2018; 175:2158-2172. [PMID: 28800673 PMCID: PMC5980636 DOI: 10.1111/bph.13978] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 07/17/2017] [Accepted: 08/03/2017] [Indexed: 12/22/2022] Open
Abstract
Pathological pain is a hyperexcitability disorder. Since the excitability of a neuron is set and controlled by a complement of ion channels it expresses, in order to understand and treat pain, we need to develop a mechanistic insight into the key ion channels controlling excitability within the mammalian pain pathways and how these ion channels are regulated and modulated in various physiological and pathophysiological settings. In this review, we will discuss the emerging data on the expression in pain pathways, functional role and modulation of a family of voltage-gated K+ channels called 'M channels' (KCNQ, Kv 7). M channels are increasingly recognized as important players in controlling pain signalling, especially within the peripheral somatosensory system. We will also discuss the therapeutic potential of M channels as analgesic drug targets. LINKED ARTICLES This article is part of a themed section on Recent Advances in Targeting Ion Channels to Treat Chronic Pain. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.12/issuetoc/.
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Affiliation(s)
- Xiaona Du
- Department of Pharmacology, The Key Laboratory of Neural and Vascular Biology, Ministry of EducationHebei Medical UniversityShijiazhuangChina
- The Key Laboratory of New Drug Pharmacology and ToxicologyShijiazhuangHebei ProvinceChina
| | - Haixia Gao
- Department of Pharmacology, The Key Laboratory of Neural and Vascular Biology, Ministry of EducationHebei Medical UniversityShijiazhuangChina
- The Key Laboratory of New Drug Pharmacology and ToxicologyShijiazhuangHebei ProvinceChina
- School of Biomedical Sciences, Faculty of Biological SciencesUniversity of LeedsLeedsUK
| | - David Jaffe
- Department of Biology, UTSA Neurosciences InstituteUniversity of Texas at San AntonioSan AntonioTXUSA
| | - Hailin Zhang
- Department of Pharmacology, The Key Laboratory of Neural and Vascular Biology, Ministry of EducationHebei Medical UniversityShijiazhuangChina
- The Key Laboratory of New Drug Pharmacology and ToxicologyShijiazhuangHebei ProvinceChina
| | - Nikita Gamper
- Department of Pharmacology, The Key Laboratory of Neural and Vascular Biology, Ministry of EducationHebei Medical UniversityShijiazhuangChina
- The Key Laboratory of New Drug Pharmacology and ToxicologyShijiazhuangHebei ProvinceChina
- School of Biomedical Sciences, Faculty of Biological SciencesUniversity of LeedsLeedsUK
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