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Analgesic effect of ivabradine against inflammatory pain mediated by hyperpolarization-activated cyclic nucleotide–gated cation channels expressed on primary afferent terminals in the spinal dorsal horn. Pain 2022; 163:1356-1369. [DOI: 10.1097/j.pain.0000000000002523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 10/14/2021] [Indexed: 11/25/2022]
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2
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Ślęczkowska M, Almomani R, Marchi M, de Greef BTA, Sopacua M, Hoeijmakers JGJ, Lindsey P, Salvi E, Bönhof GJ, Ziegler D, Malik RA, Waxman SG, Lauria G, Faber CG, Smeets HJM, Gerrits MM. Peripheral Ion Channel Gene Screening in Painful- and Painless-Diabetic Neuropathy. Int J Mol Sci 2022; 23:ijms23137190. [PMID: 35806193 PMCID: PMC9266298 DOI: 10.3390/ijms23137190] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/21/2022] [Accepted: 06/23/2022] [Indexed: 02/01/2023] Open
Abstract
Neuropathic pain is common in diabetic peripheral neuropathy (DN), probably caused by pathogenic ion channel gene variants. Therefore, we performed molecular inversion probes-next generation sequencing of 5 transient receptor potential cation channels, 8 potassium channels and 2 calcium-activated chloride channel genes in 222 painful- and 304 painless-DN patients. Twelve painful-DN (5.4%) patients showed potentially pathogenic variants (five nonsense/frameshift, seven missense, one out-of-frame deletion) in ANO3 (n = 3), HCN1 (n = 1), KCNK18 (n = 2), TRPA1 (n = 3), TRPM8 (n = 3) and TRPV4 (n = 1) and fourteen painless-DN patients (4.6%-three nonsense/frameshift, nine missense, one out-of-frame deletion) in ANO1 (n = 1), KCNK18 (n = 3), KCNQ3 (n = 1), TRPA1 (n = 2), TRPM8 (n = 1), TRPV1 (n = 3) and TRPV4 (n = 3). Missense variants were present in both conditions, presumably with loss- or gain-of-functions. KCNK18 nonsense/frameshift variants were found in painless/painful-DN, making a causal role in pain less likely. Surprisingly, premature stop-codons with likely nonsense-mediated RNA-decay were more frequent in painful-DN. Although limited in number, painful-DN patients with ion channel gene variants reported higher maximal pain during the night and day. Moreover, painful-DN patients with TRP variants had abnormal thermal thresholds and more severe pain during the night and day. Our results suggest a role of ion channel gene variants in neuropathic pain, but functional validation is required.
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Affiliation(s)
- Milena Ślęczkowska
- Department of Toxicogenomics, Maastricht University, 6229 ER Maastricht, The Netherlands; (R.A.); (P.L.); (H.J.M.S.)
- School of Mental Health and Neuroscience, Maastricht University, 6229 ER Maastricht, The Netherlands
- Correspondence:
| | - Rowida Almomani
- Department of Toxicogenomics, Maastricht University, 6229 ER Maastricht, The Netherlands; (R.A.); (P.L.); (H.J.M.S.)
- Department of Neurology, Maastricht University Medical Centre, 6229 HX Maastricht, The Netherlands; (B.T.A.d.G.); (M.S.); (J.G.J.H.); (C.G.F.)
- Department of Medical Laboratory Sciences, Jordan University of Science and Technology, Irbid 22110, Jordan
| | - Margherita Marchi
- Neuroalgology Unit, IRCCS Foundation “Carlo Besta” Neurological Institute, 20133 Milan, Italy; (M.M.); (E.S.); (G.L.)
| | - Bianca T. A. de Greef
- Department of Neurology, Maastricht University Medical Centre, 6229 HX Maastricht, The Netherlands; (B.T.A.d.G.); (M.S.); (J.G.J.H.); (C.G.F.)
| | - Maurice Sopacua
- Department of Neurology, Maastricht University Medical Centre, 6229 HX Maastricht, The Netherlands; (B.T.A.d.G.); (M.S.); (J.G.J.H.); (C.G.F.)
| | - Janneke G. J. Hoeijmakers
- Department of Neurology, Maastricht University Medical Centre, 6229 HX Maastricht, The Netherlands; (B.T.A.d.G.); (M.S.); (J.G.J.H.); (C.G.F.)
| | - Patrick Lindsey
- Department of Toxicogenomics, Maastricht University, 6229 ER Maastricht, The Netherlands; (R.A.); (P.L.); (H.J.M.S.)
| | - Erika Salvi
- Neuroalgology Unit, IRCCS Foundation “Carlo Besta” Neurological Institute, 20133 Milan, Italy; (M.M.); (E.S.); (G.L.)
| | - Gidon J. Bönhof
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (G.J.B.); (D.Z.)
- Department of Endocrinology and Diabetology, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Dan Ziegler
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany; (G.J.B.); (D.Z.)
| | - Rayaz A. Malik
- Division of Cardiovascular Sciences, University of Manchester, Manchester M13 9PL, UK;
- Department of Medicine, Weill Cornell Medicine-Qatar, Doha P.O. Box 24144, Qatar
| | - Stephen G. Waxman
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT 06510, USA;
- Center for Neuroscience and Regeneration Research, Veterans Affairs Medical Center, West Haven, CT 06516, USA
| | - Giuseppe Lauria
- Neuroalgology Unit, IRCCS Foundation “Carlo Besta” Neurological Institute, 20133 Milan, Italy; (M.M.); (E.S.); (G.L.)
| | - Catharina G. Faber
- Department of Neurology, Maastricht University Medical Centre, 6229 HX Maastricht, The Netherlands; (B.T.A.d.G.); (M.S.); (J.G.J.H.); (C.G.F.)
| | - Hubert J. M. Smeets
- Department of Toxicogenomics, Maastricht University, 6229 ER Maastricht, The Netherlands; (R.A.); (P.L.); (H.J.M.S.)
- School of Mental Health and Neuroscience, Maastricht University, 6229 ER Maastricht, The Netherlands
| | - Monique M. Gerrits
- Department of Clinical Genetics, Maastricht University Medical Centre, 6229 HX Maastricht, The Netherlands;
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Ducza L, Szücs P, Hegedűs K, Bakk E, Gajtkó A, Wéber I, Holló K. NLRP2 Is Overexpressed in Spinal Astrocytes at the Peak of Mechanical Pain Sensitivity during Complete Freund Adjuvant-Induced Persistent Pain. Int J Mol Sci 2021; 22:ijms222111408. [PMID: 34768839 PMCID: PMC8584130 DOI: 10.3390/ijms222111408] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 10/09/2021] [Accepted: 10/17/2021] [Indexed: 12/15/2022] Open
Abstract
Our earlier findings revealed that interleukin-1 receptor type-1 (IL-1R1) was overexpressed in spinal neurons, and IL-1R1-deficient mice showed significant attenuation of thermal and mechanical allodynia during the course of the Complete Freund adjuvant (CFA)-induced persistent pain model. In the present study, we found that a ligand of IL-1R1, termed interleukin-1β (IL-1β), is also significantly overexpressed at the peak of mechanical pain sensitivity in the CFA-evoked pain model. Analysis of cellular distribution and modeling using IMARIS software showed that in the lumbar spinal dorsal horn, IL-1β is significantly elevated by astrocytic expression. Maturation of IL-1β to its active form is facilitated by the formation of the multiprotein complex called inflammasome; thus, we tested the expression of NOD-like receptor proteins (NLRPs) in astrocytes. At the peak of mechanical allodynia, we found expression of the NLRP2 inflammasome sensor and its significantly elevated co-localization with the GFAP astrocytic marker, while NLRP3 was moderately present and NLRP1 showed total segregation from the astrocytic profiles. Our results indicate that peripheral CFA injection induces NLRP2 inflammasome and IL-1β expression in spinal astrocytes. The release of mature IL-1β can contribute to the maintenance of persistent pain by acting on its neuronally expressed receptor, which can lead to altered neuronal excitability.
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Zhu M, Yan Y, Cao X, Zeng F, Xu G, Shen W, Li F, Luo L, Wang Z, Zhang Y, Zhang X, Zhang D, Liu T. Electrophysiological and Morphological Features of Rebound Depolarization Characterized Interneurons in Rat Superficial Spinal Dorsal Horn. Front Cell Neurosci 2021; 15:736879. [PMID: 34621158 PMCID: PMC8490703 DOI: 10.3389/fncel.2021.736879] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 08/25/2021] [Indexed: 11/18/2022] Open
Abstract
Substantia gelatinosa (SG) neurons, which are located in the spinal dorsal horn (lamina II), have been identified as the “central gate” for the transmission and modulation of nociceptive information. Rebound depolarization (RD), a biophysical property mediated by membrane hyperpolarization that is frequently recorded in the central nervous system, contributes to shaping neuronal intrinsic excitability and, in turn, contributes to neuronal output and network function. However, the electrophysiological and morphological properties of SG neurons exhibiting RD remain unclarified. In this study, whole-cell patch-clamp recordings were performed on SG neurons from parasagittal spinal cord slices. RD was detected in 44.44% (84 out of 189) of the SG neurons recorded. We found that RD-expressing neurons had more depolarized resting membrane potentials, more hyperpolarized action potential (AP) thresholds, higher AP amplitudes, shorter AP durations, and higher spike frequencies in response to depolarizing current injection than neurons without RD. Based on their firing patterns and morphological characteristics, we propose that most of the SG neurons with RD mainly displayed tonic firing (69.05%) and corresponded to islet cell morphology (58.82%). Meanwhile, subthreshold currents, including the hyperpolarization-activated cation current (Ih) and T-type calcium current (IT), were identified in SG neurons with RD. Blockage of Ih delayed the onset of the first spike in RD, while abolishment of IT significantly blunted the amplitude of RD. Regarding synaptic inputs, SG neurons with RD showed lower frequencies in both spontaneous and miniature excitatory synaptic currents. Furthermore, RD-expressing neurons received either Aδ- or C-afferent-mediated monosynaptic and polysynaptic inputs. However, RD-lacking neurons received afferents from monosynaptic and polysynaptic Aδ fibers and predominantly polysynaptic C-fibers. These findings demonstrate that SG neurons with RD have a specific cell-type distribution, and may differentially process somatosensory information compared to those without RD.
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Affiliation(s)
- Mengye Zhu
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China.,Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, China
| | - Yi Yan
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China.,Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, China
| | - Xuezhong Cao
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China.,Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, China
| | - Fei Zeng
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China.,Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, China
| | - Gang Xu
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China.,Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, China
| | - Wei Shen
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China.,Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, China
| | - Fan Li
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China.,Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, China
| | - Lingyun Luo
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China.,Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, China
| | - Zhijian Wang
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China.,Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, China
| | - Yong Zhang
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China.,Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, China
| | - Xuexue Zhang
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China.,Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, China
| | - Daying Zhang
- Department of Pain Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China.,Institute of Pain Medicine, Jiangxi Academy of Clinical and Medical Sciences, Nanchang, China
| | - Tao Liu
- Center for Experimental Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China
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5
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Ma Y, Chen J, Yu D, Wei B, Jin H, Zeng J, Liu X. cAMP-PKA signaling is involved in regulation of spinal HCN channels function in diabetic neuropathic pain. Neurosci Lett 2021; 750:135763. [PMID: 33617945 DOI: 10.1016/j.neulet.2021.135763] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 02/07/2021] [Accepted: 02/16/2021] [Indexed: 12/23/2022]
Abstract
The cyclic adenosine monophosphate-protein kinase A (cAMP-PKA) signaling acts a pivotal part in hyperpolarization-activated cyclic nucleotide-gated (HCN) channels-mediated neuropathic and inflammatory pain. However, there has been no evidence of cAMP-PKA signaling is involved in regulation of spinal HCN channels function in the occurrence of diabetic neuropathic pain (DNP). The study aimed to elucidate the impact of HCN channels on neuropathic pain in a rat model of diabetes induced by streptozotocin, and whether cAMP-PKA signaling is involved in regulation of HCN channels function. In this report, we evaluated the effect of intrathecal administration of HCN channel blockers ZD7288, cAMP inhibitor SQ22536 and PKA inhibitor H-89 on nociceptive behavior in DNP rats. The mechanical withdrawal threshold (MWT) was measured to evaluate pain behavior in rats. Protein expression levels of HCN2, HCN4 channels and PKA in the spinal dorsal horn of rats were assessed. Furthermore, the levels of cAMP in rat spinal dorsal horn was analyzed. We discovered that DNP rats showed significant mechanical allodynia and are related to the increased HCN2 and HCN4 channels expression, enhanced cAMP production and elevated the expression of PKA protein in the spinal dorsal horn, which were attenuated by intrathecal ZD7288. Furthermore, intrathecal injection of SQ22536 and H-89 significantly reduced the HCN2 and HCN4 channels expression in the spinal dorsal horn of DNP rats. Our findings indicate that HCN channels of the spinal dorsal horn participate in the pathogenesis of allodynia in rats with DNP, which could be regulated by cAMP-PKA signaling. Therefore, HCN channels and cAMP-PKA signaling are potential targets for hyperalgesia treatment in DNP patients.
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Affiliation(s)
- Yanqiao Ma
- Department of Physiology, Zunyi Medical University, Zunyi, 563000, China
| | - Ji Chen
- School of Pharmacy, Qingdao University, Qingdao 266000, China
| | - Deqian Yu
- Department of Physiology, Zunyi Medical University, Zunyi, 563000, China
| | - Bangcong Wei
- Department of Physiology, Zunyi Medical University, Zunyi, 563000, China
| | - Huan Jin
- Department of Physiology, Zunyi Medical University, Zunyi, 563000, China
| | - Junwei Zeng
- Department of Physiology, Zunyi Medical University, Zunyi, 563000, China
| | - Xiaohong Liu
- Department of Physiology, Zunyi Medical University, Zunyi, 563000, China.
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6
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Jansen LAR, Forster LA, Smith XL, Rubaharan M, Murphy AZ, Baro DJ. Changes in peripheral HCN2 channels during persistent inflammation. Channels (Austin) 2021; 15:165-179. [PMID: 33423595 PMCID: PMC7808421 DOI: 10.1080/19336950.2020.1870086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Nociceptor sensitization following nerve injury or inflammation leads to chronic pain. An increase in the nociceptor hyperpolarization-activated current, Ih, is observed in many models of pathological pain. Pharmacological blockade of Ih prevents the mechanical and thermal hypersensitivity that occurs during pathological pain. Alterations in the Hyperpolarization-activated Cyclic Nucleotide-gated ion channel 2 (HCN2) mediate Ih-dependent thermal and mechanical hyperalgesia. Limited knowledge exists regarding the nature of these changes during chronic inflammatory pain. Modifications in HCN2 expression and post-translational SUMOylation have been observed in the Complete Freund’s Adjuvant (CFA) model of chronic inflammatory pain. Intra-plantar injection of CFA into the rat hindpaw induces unilateral hyperalgesia that is sustained for up to 14 days following injection. The hindpaw is innervated by primary afferents in lumbar DRG, L4-6. Adjustments in HCN2 expression and SUMOylation have been well-documented for L5 DRG during the first 7 days of CFA-induced inflammation. Here, we examine bilateral L4 and L6 DRG at day 1 and day 3 post-CFA. Using L4 and L6 DRG cryosections, HCN2 expression and SUMOylation were measured with immunohistochemistry and proximity ligation assays, respectively. Our findings indicate that intra-plantar injection of CFA elicited a bilateral increase in HCN2 expression in L4 and L6 DRG at day 1, but not day 3, and enhanced HCN2 SUMOylation in ipsilateral L6 DRG at day 1 and day 3. Changes in HCN2 expression and SUMOylation were transient over this time course. Our study suggests that HCN2 is regulated by multiple mechanisms during CFA-induced inflammation.
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Affiliation(s)
- L-A R Jansen
- Department of Biology, Georgia State University , Atlanta, Georgia
| | - L A Forster
- Department of Biology, Georgia State University , Atlanta, Georgia.,Neuroscience Institute, Georgia State University , Atlanta, Georgia
| | - X L Smith
- Department of Biology, Georgia State University , Atlanta, Georgia
| | - M Rubaharan
- Neuroscience Institute, Georgia State University , Atlanta, Georgia
| | - A Z Murphy
- Neuroscience Institute, Georgia State University , Atlanta, Georgia
| | - D J Baro
- Department of Biology, Georgia State University , Atlanta, Georgia.,Neuroscience Institute, Georgia State University , Atlanta, Georgia
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7
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Rivolta I, Binda A, Masi A, DiFrancesco JC. Cardiac and neuronal HCN channelopathies. Pflugers Arch 2020; 472:931-951. [PMID: 32424620 DOI: 10.1007/s00424-020-02384-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/21/2020] [Accepted: 04/24/2020] [Indexed: 12/31/2022]
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are expressed as four different isoforms (HCN1-4) in the heart and in the central and peripheral nervous systems. In the voltage range of activation, HCN channels carry an inward current mediated by Na+ and K+, termed If in the heart and Ih in neurons. Altered function of HCN channels, mainly HCN4, is associated with sinus node dysfunction and other arrhythmias such as atrial fibrillation, ventricular tachycardia, and atrioventricular block. In recent years, several data have also shown that dysfunctional HCN channels, in particular HCN1, but also HCN2 and HCN4, can play a pathogenic role in epilepsy; these include experimental data from animal models, and data collected over genetic mutations of the channels identified and characterized in epileptic patients. In the central nervous system, alteration of the Ih current could predispose to the development of neurodegenerative diseases such as Parkinson's disease; since HCN channels are widely expressed in the peripheral nervous system, their dysfunctional behavior could also be associated with the pathogenesis of neuropathic pain. Given the fundamental role played by the HCN channels in the regulation of the discharge activity of cardiac and neuronal cells, the modulation of their function for therapeutic purposes is under study since it could be useful in various pathological conditions. Here we review the present knowledge of the HCN-related channelopathies in cardiac and neurological diseases, including clinical, genetic, therapeutic, and physiopathological aspects.
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Affiliation(s)
- Ilaria Rivolta
- School of Medicine and Surgery, Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, Monza, Italy
| | - Anna Binda
- School of Medicine and Surgery, Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, Monza, Italy
| | - Alessio Masi
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Jacopo C DiFrancesco
- School of Medicine and Surgery, Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, Monza, Italy. .,Department of Neurology, ASST San Gerardo Hospital, University of Milano-Bicocca, Via Pergolesi, 33, 20900, Monza, MB, Italy.
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8
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Ciotu CI, Tsantoulas C, Meents J, Lampert A, McMahon SB, Ludwig A, Fischer MJM. Noncanonical Ion Channel Behaviour in Pain. Int J Mol Sci 2019; 20:E4572. [PMID: 31540178 PMCID: PMC6770626 DOI: 10.3390/ijms20184572] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/09/2019] [Accepted: 09/12/2019] [Indexed: 12/19/2022] Open
Abstract
Ion channels contribute fundamental properties to cell membranes. Although highly diverse in conductivity, structure, location, and function, many of them can be regulated by common mechanisms, such as voltage or (de-)phosphorylation. Primarily considering ion channels involved in the nociceptive system, this review covers more novel and less known features. Accordingly, we outline noncanonical operation of voltage-gated sodium, potassium, transient receptor potential (TRP), and hyperpolarization-activated cyclic nucleotide (HCN)-gated channels. Noncanonical features discussed include properties as a memory for prior voltage and chemical exposure, alternative ion conduction pathways, cluster formation, and silent subunits. Complementary to this main focus, the intention is also to transfer knowledge between fields, which become inevitably more separate due to their size.
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Affiliation(s)
- Cosmin I Ciotu
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | | | - Jannis Meents
- Institute of Physiology, University Hospital RWTH Aachen, 52074 Aachen, Germany
| | - Angelika Lampert
- Institute of Physiology, University Hospital RWTH Aachen, 52074 Aachen, Germany
| | - Stephen B McMahon
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UR, UK
| | - Andreas Ludwig
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Michael J M Fischer
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria.
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Zhang M, Guo H, Ma Y, Xu F, Bai F, Liang S, Hu H, Wang Q, Deng J, Dong H, Xiong L. Acupoint Sensitization is Associated with Increased Excitability and Hyperpolarization-Activated Current (I h) in C- But Not Aδ-Type Neurons. Neuroscience 2019; 404:499-509. [PMID: 30826524 DOI: 10.1016/j.neuroscience.2019.02.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 10/27/2022]
Abstract
Under pathological conditions, acupoint sensitization is the phenomenon of acupoints transforming from the stable state to the dynamic state. Evidences suggest that hyperpolarization-activated current (Ih), conducted by the hyperpolarization-activated/cyclic nucleotide-gated (HCN) channel, greatly contributes to the peripheral and central sensitization. However, the role of the Ih current in acupoint sensitization has not been explained. In the present study, changes in excitability, Ih density and the HCN channel of dorsal root ganglion (DRG) nociceptive neurons were examined in the later phase of knee osteoarthritis (KOA) rats. To investigate the neuronal specificity of acupoint sensitization, retrograde dyes were injected into the acupoints ST35 and GB37. The results showed that acupoint sensitization occurred in bilateral ST35 but not GB37 acupoints. The excitability and Ih density of C- but not Aδ-type neurons innervating ST35 acupoint increased in bilateral L5 DRG of acupoint sensitized rats than that of sham rats. No obvious changes were found in the excitability or Ih density of C- and Aδ-type neurons innervating the GB37 acupoint in the bilateral L5 DRG. HCN channel subtype 2 (HCN2) expression levels significantly increased after acupoint sensitization. Furthermore, ZD7288, an HCN current (Ih) blocker, attenuated the acupoint sensitization of the ST35 acupoint. Taken together, our findings suggest that the increased excitability of C- but not Aδ-type neurons and the upregulation of Ih/HCN2 channels contribute to the formation of acupoint sensitization.
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Affiliation(s)
- Ming Zhang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, the Fourth Military Medical University, the 127(th) West Changle Road, Xi'an, 710032, Shaanxi, China; Department of Central Laboratory, the General Hospital of Western Theater Command, the 270(th)Tianhui Road, Chengdu, 610083, Sichuan, China
| | - Haiyun Guo
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, the Fourth Military Medical University, the 127(th) West Changle Road, Xi'an, 710032, Shaanxi, China
| | - Yongyuan Ma
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, the Fourth Military Medical University, the 127(th) West Changle Road, Xi'an, 710032, Shaanxi, China
| | - Feifei Xu
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, the Fourth Military Medical University, the 127(th) West Changle Road, Xi'an, 710032, Shaanxi, China
| | - Fuhai Bai
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, the Fourth Military Medical University, the 127(th) West Changle Road, Xi'an, 710032, Shaanxi, China
| | - Shirui Liang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, the Fourth Military Medical University, the 127(th) West Changle Road, Xi'an, 710032, Shaanxi, China
| | - Huimin Hu
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, the Fourth Military Medical University, the 127(th) West Changle Road, Xi'an, 710032, Shaanxi, China
| | - Qi Wang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, the Fourth Military Medical University, the 127(th) West Changle Road, Xi'an, 710032, Shaanxi, China
| | - Jiao Deng
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, the Fourth Military Medical University, the 127(th) West Changle Road, Xi'an, 710032, Shaanxi, China
| | - Hailong Dong
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, the Fourth Military Medical University, the 127(th) West Changle Road, Xi'an, 710032, Shaanxi, China
| | - Lize Xiong
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, the Fourth Military Medical University, the 127(th) West Changle Road, Xi'an, 710032, Shaanxi, China.
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10
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He JT, Li XY, Zhao X, Liu X. Hyperpolarization-activated and cyclic nucleotide-gated channel proteins as emerging new targets in neuropathic pain. Rev Neurosci 2019; 30:639-649. [PMID: 30768426 DOI: 10.1515/revneuro-2018-0094] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 10/26/2018] [Indexed: 01/14/2023]
Abstract
Abstract
Hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels are activated during hyperpolarization, and there is an inward flow of current, which is termed as hyperpolarization-activated current, Ih. Initially, these channels were identified on the pacemaker cells of the heart. Nowadays, these are identified on different regions of the nervous system, including peripheral nerves, dorsal root ganglia, dorsal horns, and different parts of the brain. There are four different types of HCN channels (HCN1–HCN4); however, HCN1 and HCN2 are more prominent. A large number of studies have shown that peripheral nerve injury increases the amplitude of Ih current in the neurons of the spinal cord and the brain. Moreover, there is an increase in the expression of HCN1 and HCN2 protein channels in peripheral axons and the spinal cord and brain regions in experimental models of nerve injury. Studies have also documented the pain-attenuating actions of selective HCN inhibitors, such as ivabradine and ZD7288. Moreover, certain drugs with additional HCN-blocking activities have also shown pain-attenuating actions in different pain models. There have been few studies documenting the relationship of HCN channels with other mediators of pain. Nevertheless, it may be proposed that the HCN channel activity is modulated by endogenous opioids and cyclo-oxygenase-2, whereas the activation of these channels may modulate the actions of substance P and the expression of spinal N-methyl-D-aspartate receptor subunit 2B to modulate pain. The present review describes the role and mechanisms of HCN ion channels in the development of neuropathic pain.
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Affiliation(s)
- Jin-Ting He
- Department of Neurology , China-Japan Union Hospital, Jilin University , Changchun 130033, Jilin Province , China
| | - Xiao-Yan Li
- Department of Neurology , China-Japan Union Hospital, Jilin University , Changchun 130033, Jilin Province , China
| | - Xin Zhao
- Department of Paediatrics , The First Hospital of Jilin University , Changchun 130021, Jilin Province , China
| | - Xiaoliang Liu
- Cancer Center, The First Hospital of Jilin University , 126 Xiantai Street , Changchun 130033, Jilin Province , China
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Dini L, Del Lungo M, Resta F, Melchiorre M, Spinelli V, Di Cesare Mannelli L, Ghelardini C, Laurino A, Sartiani L, Coppini R, Mannaioni G, Cerbai E, Romanelli MN. Selective Blockade of HCN1/HCN2 Channels as a Potential Pharmacological Strategy Against Pain. Front Pharmacol 2018; 9:1252. [PMID: 30467478 PMCID: PMC6237106 DOI: 10.3389/fphar.2018.01252] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 10/15/2018] [Indexed: 12/25/2022] Open
Abstract
A prominent role of hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels has been suggested based on their expression and (dys)function in dorsal root ganglion (DRG) neurons, being likely involved in peripheral nociception. Using HCN blockers as antinociceptive drugs is prevented by the widespread distribution of these channels. However, tissue-specific expression of HCN isoforms varies significantly, HCN1 and HCN2 being considered as major players in DRG excitability. We characterized the pharmacological effect of a novel compound, MEL55A, able to block selectively HCN1/HCN2 isoforms, on DRG neuron excitability in-vitro and for its antiallodynic properties in-vivo. HEK293 cells expressing HCN1, HCN2, or HCN4 isoforms were used to verify drug selectivity. The pharmacological profile of MEL55A was tested on mouse DRG neurons by patch-clamp recordings, and in-vivo in oxaliplatin-induced neuropathy by means of thermal hypersensitivity. Results were compared to the non-isoform-selective drug, ivabradine. MEL55A showed a marked preference toward HCN1 and HCN2 isoforms expressed in HEK293, with respect to HCN4. In cultured DRG, MEL55A reduced I h amplitude, both in basic conditions and after stimulation by forskolin, and cell excitability, its effect being quantitatively similar to that observed with ivabradine. MEL55A was able to relieve chemotherapy-induced neuropathic pain. In conclusion, selective blockade of HCN1/HCN2 channels, over HCN4 isoform, was able to modulate electrophysiological properties of DRG neurons similarly to that reported for classical I h blockers, ivabradine, resulting in a pain-relieving activity. The availability of small molecules with selectivity toward HCN channel isoforms involved in nociception might represent a safe and effective strategy against chronic pain.
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Affiliation(s)
- Leonardo Dini
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Martina Del Lungo
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Francesco Resta
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Michele Melchiorre
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Valentina Spinelli
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Lorenzo Di Cesare Mannelli
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Carla Ghelardini
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Annunziatina Laurino
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Laura Sartiani
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Raffaele Coppini
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Guido Mannaioni
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Elisabetta Cerbai
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
| | - Maria Novella Romanelli
- Department of Neurosciences, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Florence, Italy
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Protein kinase A regulates inflammatory pain sensitization by modulating HCN2 channel activity in nociceptive sensory neurons. Pain 2018; 158:2012-2024. [PMID: 28767511 DOI: 10.1097/j.pain.0000000000001005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Several studies implicated cyclic adenosine monophosphate (cAMP) as an important second messenger for regulating nociceptor sensitization, but downstream targets of this signaling pathway which contribute to neuronal plasticity are not well understood. We used a Cre/loxP-based strategy to disable the function of either HCN2 or PKA selectively in a subset of peripheral nociceptive neurons and analyzed the nociceptive responses in both transgenic lines. A near-complete lack of sensitization was observed in both mutant strains when peripheral inflammation was induced by an intradermal injection of 8br-cAMP. The lack of HCN2 as well as the inhibition of PKA eliminated the cAMP-mediated increase of calcium transients in dorsal root ganglion neurons. Facilitation of Ih via cAMP, a hallmark of the Ih current, was abolished in neurons without PKA activity. Collectively, these results show a significant contribution of both genes to inflammatory pain and suggest that PKA-dependent activation of HCN2 underlies cAMP-triggered neuronal sensitization.
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Sartiani L, Mannaioni G, Masi A, Novella Romanelli M, Cerbai E. The Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels: from Biophysics to Pharmacology of a Unique Family of Ion Channels. Pharmacol Rev 2017; 69:354-395. [PMID: 28878030 DOI: 10.1124/pr.117.014035] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 07/07/2017] [Indexed: 12/22/2022] Open
Abstract
Hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels are important members of the voltage-gated pore loop channels family. They show unique features: they open at hyperpolarizing potential, carry a mixed Na/K current, and are regulated by cyclic nucleotides. Four different isoforms have been cloned (HCN1-4) that can assemble to form homo- or heterotetramers, characterized by different biophysical properties. These proteins are widely distributed throughout the body and involved in different physiologic processes, the most important being the generation of spontaneous electrical activity in the heart and the regulation of synaptic transmission in the brain. Their role in heart rate, neuronal pacemaking, dendritic integration, learning and memory, and visual and pain perceptions has been extensively studied; these channels have been found also in some peripheral tissues, where their functions still need to be fully elucidated. Genetic defects and altered expression of HCN channels are linked to several pathologies, which makes these proteins attractive targets for translational research; at the moment only one drug (ivabradine), which specifically blocks the hyperpolarization-activated current, is clinically available. This review discusses current knowledge about HCN channels, starting from their biophysical properties, origin, and developmental features, to (patho)physiologic role in different tissues and pharmacological modulation, ending with their present and future relevance as drug targets.
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Affiliation(s)
- Laura Sartiani
- Department of Neurosciences, Psychology, Drug Research, and Child Health, University of Florence, Firenze, Italy
| | - Guido Mannaioni
- Department of Neurosciences, Psychology, Drug Research, and Child Health, University of Florence, Firenze, Italy
| | - Alessio Masi
- Department of Neurosciences, Psychology, Drug Research, and Child Health, University of Florence, Firenze, Italy
| | - Maria Novella Romanelli
- Department of Neurosciences, Psychology, Drug Research, and Child Health, University of Florence, Firenze, Italy
| | - Elisabetta Cerbai
- Department of Neurosciences, Psychology, Drug Research, and Child Health, University of Florence, Firenze, Italy
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Peng SC, Wu J, Zhang DY, Jiang CY, Xie CN, Liu T. Contribution of presynaptic HCN channels to excitatory inputs of spinal substantia gelatinosa neurons. Neuroscience 2017; 358:146-157. [PMID: 28673721 DOI: 10.1016/j.neuroscience.2017.06.046] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 06/19/2017] [Accepted: 06/23/2017] [Indexed: 01/09/2023]
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are pathological pain-associated voltage-gated ion channels. They are widely expressed in central nervous system including spinal lamina II (also named the substantia gelatinosa, SG). Here, we examined the distribution of HCN channels in glutamatergic synaptic terminals as well as their role in the modulation of synaptic transmission in SG neurons from SD rats and glutamic acid decarboxylase-67 (GAD67)-GFP mice. We found that the expression of the HCN channel isoforms was varied in SG. The HCN4 isoform showed the highest level of co-localization with VGLUT2 (23±3%). In 53% (n=21/40 neurons) of the SG neurons examined in SD rats, application of HCN channel blocker, ZD7288 (10μM), decreased the frequency of spontaneous (s) and miniature (m) excitatory postsynaptic currents (EPSCs) by 37±4% and 33±4%, respectively. Consistently, forskolin (FSK) (an activator of adenylate cyclase) significantly increased the frequency of mEPSCs by 225±34%, which could be partially inhibited by ZD7288. Interestingly, the effects of ZD7288 and FSK on sEPSC frequency were replicated in non-GFP-expressing neurons, but not in GFP-expressing GABAergic SG neurons, in GAD67-GFP transgenic C57/BL6 mice. In summary, our results represent a previously unknown cellular mechanism by which presynaptic HCN channels, especially HCN4, regulate the glutamate release from presynaptic terminals that target excitatory, but not inhibitory SG interneurons.
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Affiliation(s)
- S-C Peng
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China
| | - J Wu
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China
| | - D-Y Zhang
- Department of Pain Clinic, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China
| | - C-Y Jiang
- Jisheng Han Academician Workstation for Pain Medicine, Nanshan Hospital, Shenzhen 518052, China
| | - C-N Xie
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China
| | - T Liu
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China; Jisheng Han Academician Workstation for Pain Medicine, Nanshan Hospital, Shenzhen 518052, China; Jiangxi Key Laboratory of Molecular Diagnostics and Precision Medicine, Nanchang, Jiangxi 330006, China.
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Holló K, Ducza L, Hegyi Z, Dócs K, Hegedűs K, Bakk E, Papp I, Kis G, Mészár Z, Bardóczi Z, Antal M. Interleukin-1 receptor type 1 is overexpressed in neurons but not in glial cells within the rat superficial spinal dorsal horn in complete Freund adjuvant-induced inflammatory pain. J Neuroinflammation 2017. [PMID: 28645297 PMCID: PMC5482961 DOI: 10.1186/s12974-017-0902-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Background All known biological functions of the pro-inflammatory cytokine interleukin-1β (IL-1β) are mediated by type 1 interleukin receptor (IL-1R1). IL-1β–IL-1R1 signaling modulates various neuronal functions including spinal pain processing. Although the role of IL-1β in pain processing is generally accepted, there is a discussion in the literature whether IL-1β exerts its effect on spinal pain processing by activating neuronal or glial IL-1R1. To contribute to this debate, here we investigated the expression and cellular distribution of IL-1R1 in the superficial spinal dorsal horn in control animals and also in inflammatory pain. Methods Experiments were performed on rats and wild type as well as IL-1R1-deficient mice. Inflammatory pain was evoked by unilateral intraplantar injection of complete Freund adjuvant (CFA). The nociceptive responsiveness of control and CFA-treated animals were tested daily for withdrawal responses to mechanical and thermal stimuli before and after CFA injection. Changes in the expression of 48 selected genes/mRNAs and in the quantity of IL-1R1 protein during the first 3 days after CFA injection were measured with the TaqMan low-density array method and Western blot analysis, respectively. The cellular localization of IL-1R1 protein was investigated with single and double staining immunocytochemical methods. Results We found a six times and two times increase in IL-1R1 mRNA and protein levels, respectively, in the dorsal horn of CFA-injected animals 3 days after CFA injection, at the time of the summit of mechanical and thermal allodynia. Studying the cellular distribution of IL-1R1, we found an abundant expression of IL-1R1 on the somatodendritic compartment of neurons and an enrichment of the receptor in the postsynaptic membranes of some excitatory synapses. In contrast to the robust neuronal localization, we observed only a moderate expression of IL-1R1 on astrocytes and a negligible one on microglial cells. CFA injection into the hind paw caused a remarkable increase in the expression of IL-1R1 in neurons, but did not alter the glial expression of the receptor. Conclusion The results suggest that IL-1β exerts its effect on spinal pain processing primarily through neuronal IL-1R1, but it can also interact in some extent with IL-1R1 expressed by astrocytes.
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Affiliation(s)
- Krisztina Holló
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary
| | - László Ducza
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary
| | - Zoltán Hegyi
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary
| | - Klaudia Dócs
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary
| | - Krisztina Hegedűs
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary
| | - Erzsébet Bakk
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary
| | - Ildikó Papp
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary.,Department of Anatomy, Histology and Embryology, Faculty of Pharmacy, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary
| | - Gréta Kis
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary
| | - Zoltán Mészár
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary
| | - Zsuzsanna Bardóczi
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Miklós Antal
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary. .,MTA-DE Neuroscience Research Group, Nagyerdei krt. 98, 4012, Debrecen, Hungary.
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16
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Inflammatory Pain Reduces C Fiber Activity-Dependent Slowing in a Sex-Dependent Manner, Amplifying Nociceptive Input to the Spinal Cord. J Neurosci 2017; 37:6488-6502. [PMID: 28576935 PMCID: PMC5511880 DOI: 10.1523/jneurosci.3816-16.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 05/10/2017] [Accepted: 05/13/2017] [Indexed: 11/21/2022] Open
Abstract
C fibers display activity-dependent slowing (ADS), whereby repetitive stimulation (≥1 Hz) results in a progressive slowing of action potential conduction velocity, which manifests as a progressive increase in response latency. However, the impact of ADS on spinal pain processing has not been explored, nor whether ADS is altered in inflammatory pain conditions. To investigate, compound action potentials were made, from dorsal roots isolated from rats with or without complete Freund's adjuvant (CFA) hindpaw inflammation, in response to electrical stimulus trains. CFA inflammation significantly reduced C fiber ADS at 1 and 2 Hz stimulation rates. Whole-cell patch-clamp recordings in the spinal cord slice preparation with attached dorsal roots also demonstrated that CFA inflammation reduced ADS in the monosynaptic C fiber input to lamina I neurokinin 1 receptor-expressing neurons (1–10 Hz stimulus trains) without altering the incidence of synaptic response failures. When analyzed by sex, it was revealed that females display a more pronounced ADS that is reduced by CFA inflammation to a level comparable with males. Cumulative ventral root potentials evoked by long and short dorsal root stimulation lengths, to maximize and minimize the impact of ADS, respectively, demonstrated that reducing ADS facilitates spinal summation, and this was also sex dependent. This finding correlated with the behavioral observation of increased noxious thermal thresholds and enhanced inflammatory thermal hypersensitivity in females. We propose that sex/inflammation-dependent regulation of C fiber ADS can, by controlling the temporal relay of nociceptive inputs, influence the spinal summation of nociceptive signals contributing to sex/inflammation-dependent differences in pain sensitivity. SIGNIFICANCE STATEMENT The intensity of a noxious stimulus is encoded by the frequency of action potentials relayed by nociceptive C fibers to the spinal cord. C fibers conduct successive action potentials at progressively slower speeds, but the impact of this activity-dependent slowing (ADS) is unknown. Here we demonstrate that ADS is more prevalent in females than males and is reduced in an inflammatory pain model in females only. We also demonstrate a progressive delay of C fiber monosynaptic transmission to the spinal cord that is similarly sex and inflammation dependent. Experimentally manipulating ADS strongly influences spinal summation consistent with sex differences in behavioral pain thresholds. This suggests that ADS provides a peripheral mechanism that can regulate spinal nociceptive processing and pain sensation.
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Tabuena DR, Solis A, Geraldi K, Moffatt CA, Fuse M. Central neural alterations predominate in an insect model of nociceptive sensitization. J Comp Neurol 2017; 525:1176-1191. [PMID: 27650422 PMCID: PMC5258852 DOI: 10.1002/cne.24124] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 05/20/2016] [Accepted: 09/11/2016] [Indexed: 12/12/2022]
Abstract
Many organisms respond to noxious stimuli with defensive maneuvers. This is noted in the hornworm, Manduca sexta, as a defensive strike response. After tissue damage, organisms typically display sensitized responses to both noxious or normally innocuous stimuli. To further understand this phenomenon, we used novel in situ and in vitro preparations based on paired extracellular nerve recordings and videography to identify central and peripheral nerves responsible for nociception and sensitization of the defensive behavior in M. sexta. In addition, we used the in vivo defensive strike response threshold assayed with von Frey filaments to examine the roles that N-methyl-D-aspartate receptor (NMDAR) and hyperpolarization-activated, cyclic nucleotide-gated (HCN) channels play in this nociceptive sensitization using the inhibitors MK-801 and AP5 (NMDAR), and ivabradine and ZD7288 (HCN). Using our new preparations, we found that afferent activity evoked by noxious pinch in these preparations was conveyed to central ganglia by axons in the anterior- and lateral-dorsal nerve branches, and that sensitization induced by tissue damage was mediated centrally. Furthermore, sensitization was blocked by all inhibitors tested except the inactive isomer L-AP5, and reversed by ivabradine both in vivo and in vitro. Our findings suggest that M. sexta's sensitization occurs through central signal amplification. Due to the relatively natural sensitization method and conserved molecular actions, we suggest that M. sexta may be a valuable model for studying the electrophysiological properties of nociceptive sensitization and potentially related conditions such as allodynia and hyperalgesia in a comparative setting that offers unique experimental advantages. J. Comp. Neurol. 525:1176-1191, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Dennis R Tabuena
- San Francisco State University, Dept. Biology. 1600 Holloway Avenue, San Francisco, CA 94132
| | - Allan Solis
- City College of San Francisco, 50 Phelan Ave, San Francisco, CA 94112
| | - Ken Geraldi
- San Francisco State University, Dept. Biology. 1600 Holloway Avenue, San Francisco, CA 94132
| | - Christopher A Moffatt
- San Francisco State University, Dept. Biology. 1600 Holloway Avenue, San Francisco, CA 94132
| | - Megumi Fuse
- San Francisco State University, Dept. Biology. 1600 Holloway Avenue, San Francisco, CA 94132
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Spisák T, Pozsgay Z, Aranyi C, Dávid S, Kocsis P, Nyitrai G, Gajári D, Emri M, Czurkó A, Kincses ZT. Central sensitization-related changes of effective and functional connectivity in the rat inflammatory trigeminal pain model. Neuroscience 2016; 344:133-147. [PMID: 28003158 DOI: 10.1016/j.neuroscience.2016.12.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 12/09/2016] [Accepted: 12/11/2016] [Indexed: 01/24/2023]
Abstract
Central sensitization is a key mechanism in the pathology of several neuropathic pain disorders. We aimed to investigate the underlying brain connectivity changes in a rat model of chronic pain. Non-noxious whisker stimulation was used to evoke blood-oxygen-level-dependent (BOLD) responses in a block-design functional Magnetic Resonance Imaging (fMRI) experiment on 9.4T. Measurements were repeated two days and one week after injecting complete Freund's adjuvant into the rats' whisker pad. We found that acute pain reduced activation in the barrel cortex, most probably due to a plateau effect. After one week, increased activation of the anterior cingulate cortex was found. Analyses of effective connectivity driven by stimulus-related activation revealed that chronic pain-related central sensitization manifested as a widespread alteration in the activity of the somatosensory network. Changes were mainly mediated by the anterior cingulate cortex and the striatum and affected the somatosensory and motor cortices and the superior colliculus. Functional connectivity analysis of nested BOLD oscillations justified that the anterior cingular-somatosensory interplay is a key element of network changes. Additionally, a decreased cingulo-motor functional connectivity implies that alterations also involve the output tract of the network. Our results extend the knowledge about the role of the cingulate cortex in the chronification of pain and indicate that integration of multiple connectivity analysis could be fruitful in studying the central sensitization in the pain matrix.
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Affiliation(s)
- Tamás Spisák
- Preclinical Imaging Center, Gedeon Richter Plc., Budapest, Hungary.
| | - Zsófia Pozsgay
- Preclinical Imaging Center, Gedeon Richter Plc., Budapest, Hungary
| | - Csaba Aranyi
- Department of Nuclear Medicine, University of Debrecen, Debrecen, Hungary
| | - Szabolcs Dávid
- Preclinical Imaging Center, Gedeon Richter Plc., Budapest, Hungary
| | - Pál Kocsis
- Preclinical Imaging Center, Gedeon Richter Plc., Budapest, Hungary
| | | | - Dávid Gajári
- Preclinical Imaging Center, Gedeon Richter Plc., Budapest, Hungary
| | - Miklós Emri
- Department of Nuclear Medicine, University of Debrecen, Debrecen, Hungary
| | - András Czurkó
- Preclinical Imaging Center, Gedeon Richter Plc., Budapest, Hungary
| | - Zsigmond Tamás Kincses
- Preclinical Imaging Center, Gedeon Richter Plc., Budapest, Hungary; Department of Neurology, University of Szeged, Hungary; International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic
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HCN2 ion channels: basic science opens up possibilities for therapeutic intervention in neuropathic pain. Biochem J 2016; 473:2717-36. [DOI: 10.1042/bcj20160287] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 05/18/2016] [Indexed: 01/22/2023]
Abstract
Nociception — the ability to detect painful stimuli — is an invaluable sense that warns against present or imminent damage. In patients with chronic pain, however, this warning signal persists in the absence of any genuine threat and affects all aspects of everyday life. Neuropathic pain, a form of chronic pain caused by damage to sensory nerves themselves, is dishearteningly refractory to drugs that may work in other types of pain and is a major unmet medical need begging for novel analgesics. Hyperpolarisation-activated cyclic nucleotide (HCN)-modulated ion channels are best known for their fundamental pacemaker role in the heart; here, we review data demonstrating that the HCN2 isoform acts in an analogous way as a ‘pacemaker for pain’, in that its activity in nociceptive neurons is critical for the maintenance of electrical activity and for the sensation of chronic pain in pathological pain states. Pharmacological block or genetic deletion of HCN2 in sensory neurons provides robust pain relief in a variety of animal models of inflammatory and neuropathic pain, without any effect on normal sensation of acute pain. We discuss the implications of these findings for our understanding of neuropathic pain pathogenesis, and we outline possible future opportunities for the development of efficacious and safe pharmacotherapies in a range of chronic pain syndromes.
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Papp T, Hollo K, Meszar-Katona E, Nagy Z, Polyak A, Miko E, Bai P, Felszeghy S. TLR signalling can modify the mineralization of tooth germ. Acta Odontol Scand 2016; 74:307-14. [PMID: 26763602 DOI: 10.3109/00016357.2015.1130853] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE The aim of this work is to investigate the possible role of Toll-like receptor 4 (TLR4) during the development of mouse tooth germ. TLR4 is well known to inhibit mineralization and cause inflammation in mature odontoblasts and dental pulp cells. However, unlike these pathological functions of TLR4, little is known about the developmental function(s) of TLR4 during tooth development. MATERIALS AND METHODS TLR4 expression was studied via Western blot in developing lower mouse incisors from E13.5 to E18.5. To generate functional data about the effects of TLR4, a specific agonist (LPS) was applied to the medium of in vitro tooth germ cultures, followed by Western blot, histochemical staining, ELISA assay, in situ hybridization and RT-qPCR. RESULTS Increased accumulation of biotin-labelled LPS was detected in the enamel organ and in preodontoblasts. LPS treatment induced degradation of the inhibitor molecule (IκB) of the NF-κB signalling pathway. However, no morphological alterations were detected in cultured tissue after LPS addition at the applied dosage. Activation of TLR4 inhibited the mineralization of enamel and dentin, as demonstrated by alizarin red staining and as decreased levels of collagen type X. mRNA expression of ameloblastin was elevated after LPS administration. CONCLUSION These results demonstrate that TLR4 may decrease the mineralization of hard tissues of the tooth germ and may trigger the maturation of ameloblasts; it can give valuable information to understand better congenital tooth abnormalities.
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Affiliation(s)
- Tamas Papp
- a Department of Anatomy, Histology and Embryology; Faculty of Medicine , University of Debrecen , Debrecen , Hungary
| | - Krisztina Hollo
- a Department of Anatomy, Histology and Embryology; Faculty of Medicine , University of Debrecen , Debrecen , Hungary
| | - Eva Meszar-Katona
- a Department of Anatomy, Histology and Embryology; Faculty of Medicine , University of Debrecen , Debrecen , Hungary
| | - Zoltan Nagy
- a Department of Anatomy, Histology and Embryology; Faculty of Medicine , University of Debrecen , Debrecen , Hungary
| | - Angela Polyak
- a Department of Anatomy, Histology and Embryology; Faculty of Medicine , University of Debrecen , Debrecen , Hungary
| | - Edit Miko
- b Department of Medical Chemistry , University of Debrecen , Debrecen , Hungary
- c MTA-DE Lendület Laboratory of Cellular Metabolism Research Group , Debrecen , Hungary
- d Research Center for Molecular Medicine, University of Debrecen , Debrecen , Hungary
| | - Peter Bai
- b Department of Medical Chemistry , University of Debrecen , Debrecen , Hungary
- c MTA-DE Lendület Laboratory of Cellular Metabolism Research Group , Debrecen , Hungary
- d Research Center for Molecular Medicine, University of Debrecen , Debrecen , Hungary
| | - Szabolcs Felszeghy
- a Department of Anatomy, Histology and Embryology; Faculty of Medicine , University of Debrecen , Debrecen , Hungary
- e Department of Oral Anatomy, Faculty of Dentistry , University of Debrecen , Debrecen , Hungary
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21
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Smith T, Al Otaibi M, Sathish J, Djouhri L. Increased expression of HCN2 channel protein in L4 dorsal root ganglion neurons following axotomy of L5- and inflammation of L4-spinal nerves in rats. Neuroscience 2015; 295:90-102. [DOI: 10.1016/j.neuroscience.2015.03.041] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 02/28/2015] [Accepted: 03/19/2015] [Indexed: 12/31/2022]
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22
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Liu N, Zhang D, Zhu M, Luo S, Liu T. Minocycline inhibits hyperpolarization-activated currents in rat substantia gelatinosa neurons. Neuropharmacology 2015; 95:110-20. [PMID: 25777286 DOI: 10.1016/j.neuropharm.2015.03.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Revised: 03/04/2015] [Accepted: 03/05/2015] [Indexed: 12/30/2022]
Abstract
Minocycline is a widely used glial activation inhibitor that could suppress pain-related behaviors in a number of different pain animal models, yet, its analgesic mechanisms are not fully understood. Hyperpolarization-activated cation channel-induced Ih current plays an important role in neuronal excitability and pathological pain. In this study, we investigated the possible effect of minocycline on Ih of substantia gelatinosa neuron in superficial spinal dorsal horn by using whole-cell patch-clamp recording. We found that extracellular minocycline rapidly decreases Ih amplitude in a reversible and concentration-dependent manner (IC50 = 41 μM). By contrast, intracellular minocycline had no effect. Minocycline-induced inhibition of Ih was not affected by Na(+) channel blocker tetrodotoxin, glutamate-receptor antagonists (CNQX and D-APV), GABAA receptor antagonist (bicuculine methiodide), or glycine receptor antagonist (strychnine). Minocycline also caused a negative shift in the activation curve of Ih, but did not alter the reversal potential. Moreover, minocycline slowed down the inter-spike depolarizing slope and produced a robust decrease in the rate of action potential firing. Together, these results illustrate a novel cellular mechanism underlying minocycline's analgesic effect by inhibiting Ih currents of spinal dorsal horn neurons.
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Affiliation(s)
- Nana Liu
- Department of Pediatrics, the First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Daying Zhang
- Department of Pain Clinic, the First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Mengye Zhu
- Department of Pain Clinic, the First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Shiwen Luo
- Center for Laboratory Medicine, the First Affiliated Hospital of Nanchang University, Nanchang, 330006, China
| | - Tao Liu
- Department of Pediatrics, the First Affiliated Hospital of Nanchang University, Nanchang, 330006, China; Center for Laboratory Medicine, the First Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
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23
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Herrmann S, Schnorr S, Ludwig A. HCN channels--modulators of cardiac and neuronal excitability. Int J Mol Sci 2015; 16:1429-47. [PMID: 25580535 PMCID: PMC4307311 DOI: 10.3390/ijms16011429] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 12/31/2014] [Indexed: 01/06/2023] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels comprise a family of cation channels activated by hyperpolarized membrane potentials and stimulated by intracellular cyclic nucleotides. The four members of this family, HCN1-4, show distinct biophysical properties which are most evident in the kinetics of activation and deactivation, the sensitivity towards cyclic nucleotides and the modulation by tyrosine phosphorylation. The four isoforms are differentially expressed in various excitable tissues. This review will mainly focus on recent insights into the functional role of the channels apart from their classic role as pacemakers. The importance of HCN channels in the cardiac ventricle and ventricular hypertrophy will be discussed. In addition, their functional significance in the peripheral nervous system and nociception will be examined. The data, which are mainly derived from studies using transgenic mice, suggest that HCN channels contribute significantly to cellular excitability in these tissues. Remarkably, the impact of the channels is clearly more pronounced in pathophysiological states including ventricular hypertrophy as well as neural inflammation and neuropathy suggesting that HCN channels may constitute promising drug targets in the treatment of these conditions. This perspective as well as the current therapeutic use of HCN blockers will also be addressed.
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Affiliation(s)
- Stefan Herrmann
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
| | - Sabine Schnorr
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
| | - Andreas Ludwig
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
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24
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Tanabe M. [Electrophysiological evaluation of pathophysiological and pharmacological characteristics of chronic pain]. YAKUGAKU ZASSHI 2014; 134:405-12. [PMID: 24584022 DOI: 10.1248/yakushi.13-00236-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent studies have revealed considerable evidence for our understanding of the mechanisms underlying the development and maintenance of chronic pain including neuropathic and inflammatory pain. It is considered that plastic changes in the spinal dorsal horn contribute to the amplification of pain signaling. Moreover, persistent pain affects brain function and also the endogenous descending pain regulatory system. To characterize these pathophysiological changes and pharmacological properties in chronic pain conditions at the synaptic level, we have employed in vitro electrophysiology in slices of the spinal cord and supraspinal regions such as brainstem and hippocampus of adult mice and in vivo electrophysiology in anesthetized rats. In particular, we have successfully prepared spinal slices with an attached dorsal root, where A-fiber- or C-fiber-evoked monosynaptic excitatory postsynaptic currents or miniature excitatory postsynaptic currents were recorded from voltage-clamped dorsal horn neurons. In anesthetized rats, C-fiber-evoked field potentials were recorded from the spinal dorsal horn in response to electrical stimulation of the sciatic nerve fibers, and their long-term potentiation was elicited to mimic increased synaptic efficacy after peripheral nerve injury. Of interest is the finding that some drugs exerted the injury-specific effects on synaptic transmission, thus strongly suggesting the importance of pharmacological analysis at the synaptic level combined with electrophysiological techniques to obtain pathophysiological information and new insights into drug research in this field.
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Affiliation(s)
- Mitsuo Tanabe
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, Kitasato University
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25
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Noh S, Kumar N, Bukhanova N, Chen Y, Stemkowsi P, Smith P. The heart-rate-reducing agent, ivabradine, reduces mechanical allodynia in a rodent model of neuropathic pain. Eur J Pain 2014; 18:1139-47. [DOI: 10.1002/j.1532-2149.2014.00460.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2014] [Indexed: 11/07/2022]
Affiliation(s)
- S. Noh
- Department of Pharmacology and Centre for Neuroscience; University of Alberta; Edmonton Canada
| | - N. Kumar
- Department of Pharmacology and Centre for Neuroscience; University of Alberta; Edmonton Canada
| | - N. Bukhanova
- Department of Pharmacology and Centre for Neuroscience; University of Alberta; Edmonton Canada
| | - Y. Chen
- Department of Pharmacology and Centre for Neuroscience; University of Alberta; Edmonton Canada
| | - P.L. Stemkowsi
- Department of Pharmacology and Centre for Neuroscience; University of Alberta; Edmonton Canada
| | - P.A. Smith
- Department of Pharmacology and Centre for Neuroscience; University of Alberta; Edmonton Canada
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26
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Schnorr S, Eberhardt M, Kistner K, Rajab H, Käer J, Hess A, Reeh P, Ludwig A, Herrmann S. HCN2 channels account for mechanical (but not heat) hyperalgesia during long-standing inflammation. Pain 2014; 155:1079-1090. [PMID: 24525276 DOI: 10.1016/j.pain.2014.02.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 01/28/2014] [Accepted: 02/06/2014] [Indexed: 11/29/2022]
Abstract
There is emerging evidence that hyperpolarization-activated cation (HCN) channels are involved in the development of pathological pain, including allodynia and hyperalgesia. Mice lacking the HCN isoform 2 display reduced heat but unchanged mechanical pain behavior, as recently shown in preclinical models of acute inflammatory pain. However, the impact of HCN2 to chronic pain conditions is less clear and has not been examined so far. In this report, we study the role of HCN2 in the complete Freund's adjuvant inflammation model reflecting chronic pain conditions. We used sensory neuron-specific as well as inducible global HCN2 mutants analyzing pain behavior in persistent inflammation and complemented this by region-specific administration of an HCN channel blocker. Our results demonstrate that the absence of HCN2 in primary sensory neurons reduces tactile hypersensitivity in chronic inflammatory conditions but leaves heat hypersensitivity unaffected. This result is in remarkable contrast to the recently described role of HCN2 in acute inflammatory conditions. We show that chronic inflammation results in an increased expression of HCN2 and causes sensitization in peripheral and spinal terminals of the pain transduction pathway. The contribution of HCN2 to peripheral sensitization mechanisms was further supported by single-fiber recordings from isolated skin-nerve preparations and by conduction velocity measurements of saphenous nerve preparations. Global HCN2 mutants revealed that heat hypersensitivity-unaffected in peripheral HCN2 mutants-was diminished by the additional disruption of central HCN2 channels, suggesting that thermal hyperalgesia under chronic inflammatory conditions is mediated by HCN2 channels beyond primary sensory afferents.
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Affiliation(s)
- Sabine Schnorr
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany Institut für Physiologie und Pathophysiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany Klinik für Anästhesiologie und Intensivmedizin, Medizinische Hochschule Hannover, Hannover, Germany
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27
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Waxman SG, Zamponi GW. Regulating excitability of peripheral afferents: emerging ion channel targets. Nat Neurosci 2014; 17:153-63. [DOI: 10.1038/nn.3602] [Citation(s) in RCA: 285] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 11/08/2013] [Indexed: 12/13/2022]
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28
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Hatch RJ, Jennings EA, Ivanusic JJ. Peripheral hyperpolarization-activated cyclic nucleotide-gated channels contribute to inflammation-induced hypersensitivity of the rat temporomandibular joint. Eur J Pain 2012; 17:972-82. [PMID: 23255289 DOI: 10.1002/j.1532-2149.2012.00261.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/12/2012] [Indexed: 01/09/2023]
Abstract
BACKGROUND Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels conduct an inward cation current (Ih ) that contributes to the maintenance of neuronal membrane potential and have been implicated in a number of animal models of neuropathic and inflammatory pain. In the current study, we investigated HCN channel involvement in inflammatory pain of the temporomandibular joint (TMJ). METHODS The contribution of HCN channels to inflammation (complete Freund's adjuvant; CFA)-induced mechanical hypersensitivity of the rat TMJ was tested with injections of the HCN channel blocker ZD7288. Retrograde labelling and immunohistochemistry was used to explore HCN channel expression in sensory neurons that innervate the TMJ. RESULTS Injection of CFA into the TMJ (n = 7) resulted in a significantly increased mechanical sensitivity relative to vehicle injection (n = 7) (p < 0.05). The mechanical hypersensitivity generated by CFA injection was blocked by co-injection of ZD7288 with the CFA (n = 7). Retrograde labelling and immunohistochemistry experiments revealed expression predominantly of HCN1 and HCN2 channel subunits in trigeminal ganglion neurons that innervate the TMJ (n = 3). No change in the proportion or intensity of HCN channel expression was found in inflamed (n = 6) versus control (n = 5) animals at the time point tested. CONCLUSIONS Our findings suggest a role for peripheral HCN channels in inflammation-induced pain of the TMJ. Peripheral application of a HCN channel blocker could provide therapeutic benefit for inflammatory TMJ pain and avoid side effects associated with activation of HCN channels in the central nervous system.
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Affiliation(s)
- R J Hatch
- Department of Anatomy and Neuroscience, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Australia
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29
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Cocaine sensitization increases I h current channel subunit 2 (HCN₂) protein expression in structures of the mesocorticolimbic system. J Mol Neurosci 2012. [PMID: 23203153 DOI: 10.1007/s12031-012-9920-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Alteration of the biological activity among neuronal components of the mesocorticolimbic (MCL) system has been implicated in the pathophysiology of drug abuse. Changes in the electrophysiological properties of neurons involved in the reward circuit seem to be of utmost importance in addiction. The hyperpolarization-activated cyclic nucleotide current, I h, is a prominent mixed cation current present in neurons. The biophysical properties of the I h and its potential modulatory role in cell excitability depend on the expression profile of the hyperpolarization-activated cyclic nucleotide gated channel (HCN) subunits. We investigated whether cocaine-induced behavioral sensitization, an animal model of drug addiction, elicits region-specific changes in the expression of the HCN₂ channel's subunit in the MCL system. Tissue samples from the ventral tegmental area, prefrontal cortex, nucleus accumbens, and hippocampus were analyzed using Western blot. Our findings demonstrate that cocaine treatment induced a significant increase in the expression profile of the HCN₂ subunit in both its glycosylated and non-glycosylated protein isoforms in all areas tested. The increase in the glycosylated isoform was only observed in the ventral tegmental area. Together, these data suggest that the observed changes in MCL excitability during cocaine addiction might be associated with alterations in the subunit composition of their HCN channels.
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30
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Weng X, Smith T, Sathish J, Djouhri L. Chronic inflammatory pain is associated with increased excitability and hyperpolarization-activated current (Ih) in C- but not Aδ-nociceptors. Pain 2012; 153:900-914. [PMID: 22377439 DOI: 10.1016/j.pain.2012.01.019] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 11/30/2011] [Accepted: 01/18/2012] [Indexed: 01/30/2023]
Abstract
Inflammatory pain hypersensitivity results partly from hyperexcitability of nociceptive (damage-sensing) dorsal root ganglion (DRG) neurons innervating inflamed tissue. However, most of the evidence for this is derived from experiments using acute inflammatory states. Herein, we used several approaches to examine the impact of chronic or persistent inflammation on the excitability of nociceptive DRG neurons and on their expression of I(h) and the underlying hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, which regulate neuronal excitability. Using in vivo intracellular recordings of somatic action potentials from L4/L5 DRG neurons in normal rats and rats with hindlimb inflammation induced by complete Freund's adjuvant (CFA), we demonstrate increased excitability of C- but not Aδ-nociceptors, 5 to 7 days after CFA. This included an afterdischarge response to noxious pinch, which may contribute to inflammatory mechanohyperalgesia, and increased incidence of spontaneous activity (SA) and decreased electrical thresholds, which are likely to contribute to spontaneous pain and nociceptor sensitization, respectively. We also show, using voltage clamp in vivo, immunohistochemistry and behavioral assays that (1) the inflammation-induced nociceptor hyperexcitability is associated, in C- but not Aδ-nociceptors, with increases in the mean I(h) amplitude/density and in the proportion of I(h) expressing neurons, (2) increased proportion of small DRG neurons (mainly IB4-negative) expressing HCN2 but not HCN1 or HCN3 channel protein, (3) increased HCN2- immunoreactivity in the spinal dorsal horn, and (4) attenuation of inflammatory mechanoallodynia with the selective I(h) antagonist, ZD7288. Taken together, the findings suggest that C- but not Aδ-nociceptors sustain chronic inflammatory pain and that I(h)/HCN2 channels contribute to inflammation-induced C-nociceptor hyperexcitability.
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Affiliation(s)
- Xiechuan Weng
- Department of Clinical and Molecular Pharmacology, Institute of Translational Medicine, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
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