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Zhu H, Tao Y, Wang S, Zhu X, Lin K, Zheng N, Chen LM, Xu F, Wu R. fMRI, LFP, and anatomical evidence for hierarchical nociceptive routing pathway between somatosensory and insular cortices. Neuroimage 2024; 289:120549. [PMID: 38382864 DOI: 10.1016/j.neuroimage.2024.120549] [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: 12/15/2023] [Revised: 02/06/2024] [Accepted: 02/19/2024] [Indexed: 02/23/2024] Open
Abstract
The directional organization of multiple nociceptive regions, particularly within obscure operculoinsular areas, underlying multidimensional pain processing remains elusive. This study aims to establish the fundamental organization between somatosensory and insular cortices in routing nociceptive information. By employing an integrated multimodal approach of high-field fMRI, intracranial electrophysiology, and transsynaptic viral tracing in rats, we observed a hierarchically organized connection of S1/S2 → posterior insula → anterior insula in routing nociceptive information. The directional nociceptive pathway determined by early fMRI responses was consistent with that examined by early evoked LFP, intrinsic effective connectivity, and anatomical projection, suggesting fMRI could provide a valuable facility to discern directional neural circuits in animals and humans non-invasively. Moreover, our knowledge of the nociceptive hierarchical organization of somatosensory and insular cortices and the interface role of the posterior insula may have implications for the development of targeted pain therapies.
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Affiliation(s)
- Hongyan Zhu
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200032, China
| | - Yan Tao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200032, China
| | - Siqi Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Xutao Zhu
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Kunzhang Lin
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Ning Zheng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Li Min Chen
- Vanderbilt University Institute of Imaging Science and Department of Psychology, Vanderbilt University, Nashville, TN 37232, USA.
| | - Fuqiang Xu
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China.
| | - Ruiqi Wu
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai 200032, China; Shanghai Center for Brain Science and Brain-Inspired Technology, Shanghai 200031, China.
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2
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Cathenaut L, Schlichter R, Hugel S. Short-term plasticity in the spinal nociceptive system. Pain 2023; 164:2411-2424. [PMID: 37578501 DOI: 10.1097/j.pain.0000000000002999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 06/08/2023] [Indexed: 08/15/2023]
Abstract
ABSTRACT Somatosensory information is delivered to neuronal networks of the dorsal horn (DH) of the spinal cord by the axons of primary afferent neurons that encode the intensity of peripheral sensory stimuli under the form of a code based on the frequency of action potential firing. The efficient processing of these messages within the DH involves frequency-tuned synapses, a phenomenon linked to their ability to display activity-dependent forms of short-term plasticity (STP). By affecting differently excitatory and inhibitory synaptic transmissions, these STP properties allow a powerful gain control in DH neuronal networks that may be critical for the integration of nociceptive messages before they are forwarded to the brain, where they may be ultimately interpreted as pain. Moreover, these STPs can be finely modulated by endogenous signaling molecules, such as neurosteroids, adenosine, or GABA. The STP properties of DH inhibitory synapses might also, at least in part, participate in the pain-relieving effect of nonpharmacological analgesic procedures, such as transcutaneous electrical nerve stimulation, electroacupuncture, or spinal cord stimulation. The properties of target-specific STP at inhibitory DH synapses and their possible contribution to electrical stimulation-induced reduction of hyperalgesic and allodynic states in chronic pain will be reviewed and discussed.
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Affiliation(s)
- Lou Cathenaut
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
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3
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Iwasaki M, Lefevre A, Althammer F, Clauss Creusot E, Łąpieś O, Petitjean H, Hilfiger L, Kerspern D, Melchior M, Küppers S, Krabichler Q, Patwell R, Kania A, Gruber T, Kirchner MK, Wimmer M, Fröhlich H, Dötsch L, Schimmer J, Herpertz SC, Ditzen B, Schaaf CP, Schönig K, Bartsch D, Gugula A, Trenk A, Blasiak A, Stern JE, Darbon P, Grinevich V, Charlet A. An analgesic pathway from parvocellular oxytocin neurons to the periaqueductal gray in rats. Nat Commun 2023; 14:1066. [PMID: 36828816 PMCID: PMC9958129 DOI: 10.1038/s41467-023-36641-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 02/08/2023] [Indexed: 02/26/2023] Open
Abstract
The hypothalamic neuropeptide oxytocin (OT) exerts prominent analgesic effects via central and peripheral action. However, the precise analgesic pathways recruited by OT are largely elusive. Here we discovered a subset of OT neurons whose projections preferentially terminate on OT receptor (OTR)-expressing neurons in the ventrolateral periaqueductal gray (vlPAG). Using a newly generated line of transgenic rats (OTR-IRES-Cre), we determined that most of the vlPAG OTR expressing cells targeted by OT projections are GABAergic. Ex vivo stimulation of parvocellular OT axons in the vlPAG induced local OT release, as measured with OT sensor GRAB. In vivo, optogenetically-evoked axonal OT release in the vlPAG of as well as chemogenetic activation of OTR vlPAG neurons resulted in a long-lasting increase of vlPAG neuronal activity. This lead to an indirect suppression of sensory neuron activity in the spinal cord and strong analgesia in both female and male rats. Altogether, we describe an OT-vlPAG-spinal cord circuit that is critical for analgesia in both inflammatory and neuropathic pain models.
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Grants
- R01 HL090948 NHLBI NIH HHS
- R01 NS094640 NINDS NIH HHS
- This work was supported by the Centre National de la Recherche Scientifique contract UPR3212, the Université de Strasbourg contract UPR3212; the University of Strasbourg Institute for Advanced Study (USIAS) fellowship 2014-15, Fyssen Foundation research grant 2015, NARSAD Young Investigator Grant 24821, Agence Nationale de la Recherche (ANR, French Research Foundation) grants n° 19-CE16-0011-0 and n° 20-CE18-0031 (to AC); the Graduate School of Pain EURIDOL, ANR-17-EURE-0022 (to AC and ECC); ANR-DFG grant GR 3619/701, PHC PROCOPE and PICS07882 grants (to AC and VG); Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) grants GR 3619/15-1, GR 3619/16-1(to VG); SFB Consortium 1158-2 (to VG, SH and BD); French Japanese governments fellowship B-16012 JM/NH and Subsidy from Nukada Institute for Medical and Biological Research (to MI); Fyssen Foundation fellowship (to AL); Région Grand Est fellowship (to DK); DFG Postdoc Fellowship AL 2466/1-1 (to FA); the Foundation of Prader-Willi Research post-doctoral fellowship (to CPS and FA); DAAD Postdoc Short term research grant 57552337 (to RP); DFG Walter Benjamin Position – Projektnummer 459051339 (to QK). National Heart, Lung, and Blood Institute Grant NIH HL090948, National Institute of Neurological Disorders and Stroke Grant NIH NS094640, and funding provided by the Center for Neuroinflammation and Cardiometabolic Diseases (CNCD) at Georgia State University (to JES). The authors thank Prof. Yulong Li for providing the GRABOTR plasmid, Drs. Romain Goutagny and Vincent Douchamps for in vivo electrophysiology advices, the Chronobiotron UMS 3415 for all animal care and the technical plateau ComptOpt UPR 3212 for behavior technical assistance.
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Affiliation(s)
- Mai Iwasaki
- Centre National de la Recherche Scientifique and University of Strasbourg, Institute of Cellular and Integrative Neuroscience, 67000, Strasbourg, France
| | - Arthur Lefevre
- Centre National de la Recherche Scientifique and University of Strasbourg, Institute of Cellular and Integrative Neuroscience, 67000, Strasbourg, France
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, University of Heidelberg, Mannheim, 68159, Germany
- Cortical Systems and Behavior Laboratory, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Ferdinand Althammer
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, University of Heidelberg, Mannheim, 68159, Germany
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, USA
- Institute of Human Genetics, University Hospital Heidelberg, Heidelberg, Germany
| | - Etienne Clauss Creusot
- Centre National de la Recherche Scientifique and University of Strasbourg, Institute of Cellular and Integrative Neuroscience, 67000, Strasbourg, France
| | - Olga Łąpieś
- Centre National de la Recherche Scientifique and University of Strasbourg, Institute of Cellular and Integrative Neuroscience, 67000, Strasbourg, France
| | - Hugues Petitjean
- Centre National de la Recherche Scientifique and University of Strasbourg, Institute of Cellular and Integrative Neuroscience, 67000, Strasbourg, France
| | - Louis Hilfiger
- Centre National de la Recherche Scientifique and University of Strasbourg, Institute of Cellular and Integrative Neuroscience, 67000, Strasbourg, France
| | - Damien Kerspern
- Centre National de la Recherche Scientifique and University of Strasbourg, Institute of Cellular and Integrative Neuroscience, 67000, Strasbourg, France
| | - Meggane Melchior
- Centre National de la Recherche Scientifique and University of Strasbourg, Institute of Cellular and Integrative Neuroscience, 67000, Strasbourg, France
| | - Stephanie Küppers
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, University of Heidelberg, Mannheim, 68159, Germany
| | - Quirin Krabichler
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, University of Heidelberg, Mannheim, 68159, Germany
| | - Ryan Patwell
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, University of Heidelberg, Mannheim, 68159, Germany
| | - Alan Kania
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, University of Heidelberg, Mannheim, 68159, Germany
| | - Tim Gruber
- Van Andel Institute, Grand Rapids, MI, USA
| | - Matthew K Kirchner
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, USA
| | - Moritz Wimmer
- Institute of Human Genetics, University Hospital Heidelberg, Heidelberg, Germany
| | - Henning Fröhlich
- Institute of Human Genetics, University Hospital Heidelberg, Heidelberg, Germany
| | - Laura Dötsch
- Institute of Human Genetics, University Hospital Heidelberg, Heidelberg, Germany
| | - Jonas Schimmer
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, University of Heidelberg, Mannheim, 68159, Germany
| | - Sabine C Herpertz
- Department of General Psychiatry, Center of Psychosocial Medicine, University of Heidelberg, 69115, Heidelberg, Germany
| | - Beate Ditzen
- Institute of Medical Psychology, Heidelberg University Hospital, 69115, Heidelberg, Germany
- Ruprecht-Karls University Heidelberg, Heidelberg, Germany
| | - Christian P Schaaf
- Institute of Human Genetics, University Hospital Heidelberg, Heidelberg, Germany
- Ruprecht-Karls University Heidelberg, Heidelberg, Germany
| | - Kai Schönig
- Department of Molecular Biology, Central Institute of Mental Health, University of Heidelberg, Mannheim, 68159, Germany
| | - Dusan Bartsch
- Department of Molecular Biology, Central Institute of Mental Health, University of Heidelberg, Mannheim, 68159, Germany
| | - Anna Gugula
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow, 30-387, Poland
| | - Aleksandra Trenk
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow, 30-387, Poland
| | - Anna Blasiak
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University, Krakow, 30-387, Poland
| | - Javier E Stern
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, USA
| | - Pascal Darbon
- Centre National de la Recherche Scientifique and University of Strasbourg, Institute of Cellular and Integrative Neuroscience, 67000, Strasbourg, France
| | - Valery Grinevich
- Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, University of Heidelberg, Mannheim, 68159, Germany.
- Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, USA.
| | - Alexandre Charlet
- Centre National de la Recherche Scientifique and University of Strasbourg, Institute of Cellular and Integrative Neuroscience, 67000, Strasbourg, France.
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4
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Christensen NR, De Luca M, Lever MB, Richner M, Hansen AB, Noes-Holt G, Jensen KL, Rathje M, Jensen DB, Erlendsson S, Bartling CR, Ammendrup-Johnsen I, Pedersen SE, Schönauer M, Nissen KB, Midtgaard SR, Teilum K, Arleth L, Sørensen AT, Bach A, Strømgaard K, Meehan CF, Vaegter CB, Gether U, Madsen KL. A high-affinity, bivalent PDZ domain inhibitor complexes PICK1 to alleviate neuropathic pain. EMBO Mol Med 2020; 12:e11248. [PMID: 32352640 PMCID: PMC7278562 DOI: 10.15252/emmm.201911248] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 04/01/2020] [Accepted: 04/07/2020] [Indexed: 12/13/2022] Open
Abstract
Maladaptive plasticity involving increased expression of AMPA-type glutamate receptors is involved in several pathologies, including neuropathic pain, but direct inhibition of AMPARs is associated with side effects. As an alternative, we developed a cell-permeable, high-affinity (~2 nM) peptide inhibitor, Tat-P4 -(C5)2 , of the PDZ domain protein PICK1 to interfere with increased AMPAR expression. The affinity is obtained partly from the Tat peptide and partly from the bivalency of the PDZ motif, engaging PDZ domains from two separate PICK1 dimers to form a tetrameric complex. Bivalent Tat-P4 -(C5)2 disrupts PICK1 interaction with membrane proteins on supported cell membrane sheets and reduce the interaction of AMPARs with PICK1 and AMPA-receptor surface expression in vivo. Moreover, Tat-P4 -(C5)2 administration reduces spinal cord transmission and alleviates mechanical hyperalgesia in the spared nerve injury model of neuropathic pain. Taken together, our data reveal Tat-P4 -(C5)2 as a novel promising lead for neuropathic pain treatment and expand the therapeutic potential of bivalent inhibitors to non-tandem protein-protein interaction domains.
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Affiliation(s)
- Nikolaj R Christensen
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Center for Biopharmaceuticals, Department of Drug Design and Pharmacology, Faculty of Health and Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Marta De Luca
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael B Lever
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette Richner
- Danish Research Institute of Translational Neuroscience (DANDRITE), Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | - Astrid B Hansen
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Gith Noes-Holt
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kathrine L Jensen
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette Rathje
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Dennis Bo Jensen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Simon Erlendsson
- Structural biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Christian Ro Bartling
- Center for Biopharmaceuticals, Department of Drug Design and Pharmacology, Faculty of Health and Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Ina Ammendrup-Johnsen
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sofie E Pedersen
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michèle Schönauer
- Center for Biopharmaceuticals, Department of Drug Design and Pharmacology, Faculty of Health and Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Klaus B Nissen
- Center for Biopharmaceuticals, Department of Drug Design and Pharmacology, Faculty of Health and Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Søren R Midtgaard
- Structural Biophysics, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Kaare Teilum
- Structural biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Lise Arleth
- Structural Biophysics, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - Andreas T Sørensen
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anders Bach
- Center for Biopharmaceuticals, Department of Drug Design and Pharmacology, Faculty of Health and Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Kristian Strømgaard
- Center for Biopharmaceuticals, Department of Drug Design and Pharmacology, Faculty of Health and Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Claire F Meehan
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christian B Vaegter
- Danish Research Institute of Translational Neuroscience (DANDRITE), Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | - Ulrik Gether
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kenneth L Madsen
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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de la Coba P, Bruehl S, Garber J, Smith CA, Walker LS. Is Resolution of Chronic Pain Associated With Changes in Blood Pressure-related Hypoalgesia? Ann Behav Med 2019; 52:552-559. [PMID: 29860365 DOI: 10.1093/abm/kax021] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Background In healthy individuals, elevated resting blood pressure (BP) is associated with reduced pain responsiveness and lower temporal summation. Prior work indicates that this BP-related hypoalgesia is reduced in individuals with chronic pain. Purpose This study evaluated whether resolution of chronic pain was associated with greater BP-related hypoalgesia compared to nonresolution. Methods From a prospective sample of adolescents and young adults diagnosed with chronic functional abdominal pain an average of 9 years earlier, 99 individuals in whom the condition had resolved and 51 individuals with ongoing abdominal pain were studied. Resting systolic BP was assessed, followed by evaluation of thermal pain threshold and tolerance, and assessment of temporal summation to thermal pain stimuli. Results Higher resting systolic BP was significantly associated with higher pain threshold and tolerance, and lower temporal summation only in the group with resolved functional abdominal pain (p < .05). Hierarchical regressions revealed that interactions between BP and resolution of chronic pain were significant only for pain tolerance (p < .05). Analyses by sex indicated that interactions between BP and resolution status were significant for the temporal summation outcome in males but not in females. Conclusions Results suggest that BP-related hypoalgesic mechanisms may be more effective in individuals in whom chronic pain has resolved compared to those with ongoing chronic pain. Findings hint at sex differences in the extent to which resolution of chronic pain is associated with BP-related hypoalgesia. Whether greater BP-related hypoalgesia is a consequence of, or alternatively a contributor to, resolution of chronic pain warrants further investigation.
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Affiliation(s)
| | - Stephen Bruehl
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Judy Garber
- Department of Psychology and Human Development, Vanderbilt University, Nashville, TN, USA
| | - Craig A Smith
- Department of Psychology and Human Development, Vanderbilt University, Nashville, TN, USA
| | - Lynn S Walker
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
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6
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Janner H, Klausenitz C, Gürtler N, Hahnenkamp K, Usichenko TI. Effects of Electrical Transcutaneous Vagus Nerve Stimulation on the Perceived Intensity of Repetitive Painful Heat Stimuli: A Blinded Placebo- and Sham-Controlled Randomized Crossover Investigation. Anesth Analg 2019; 126:2085-2092. [PMID: 29337730 DOI: 10.1213/ane.0000000000002820] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Transcutaneous vagus nerve stimulation (TVNS) is a promising treatment for acute and chronic pain. However, experimental studies yielded controversial results. We examined if TVNS reduces the perceived intensity of repetitive painful heat stimulation and temporal summation of pain (TSP) in healthy volunteers in comparison with placebo and sham stimulation, as well as no intervention. METHODS In 4 sessions, 90 heat pulse stimuli at individual pain tolerance temperature were applied to the ventral forearm of 49 healthy volunteers (25 women) using a Contact Heat Evoked Potential Stimulator thermode (Medoc, Ramat Yishai, Israel). Pain intensity was assessed with verbal ratings on a numeric pain scale (0-100) at every tenth heat pulse. After the first session in which pain intensities without intervention were evaluated, participants completed 3 sessions in a single-blinded randomized crossover manner: (1) sham stimulation applied at the earlobes, (2) placebo stimulation (inactive device), or (3) TVNS applied at the cymbas conchae. Primary data were analyzed using analysis of variance for repeated measures and t test for paired samples. RESULTS Pain intensity decreased during all interventions as compared to no intervention (ηp = 0.22, P < .001; mean difference TVNS versus no intervention 9.5; 95% confidence interval [CI], 3.6-15.4; P < .001). Hypoalgesic effect of TVNS was better than that of placebo and sham in men before the onset of TSP (mean differences for TVNS versus placebo 6.2; 95% CI, 0.2-12.1; TVNS versus sham 6.2; 95% CI, 0.2-12.1; P < .05). In women, TSP response under TVNS was decreased if compared to no intervention (median difference, 7.5; 95% CI, 3.5-15.0; P = .003). CONCLUSIONS TVNS, placebo, and sham stimulation exerted comparable effects under experimental heat pain stimulation. Only in male participants, TVNS was superior to sham and placebo conditions in the reduction of heat pain before the onset of TSP.
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Affiliation(s)
| | - Catharina Klausenitz
- Institute of Diagnostic Radiology and Neuroradiology, University Medicine of Greifswald, Greifswald, Germany
| | | | | | - Taras I Usichenko
- From the Department of Anesthesiology.,Department of Anesthesia, McMaster University, Hamilton, Ontario, Canada
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7
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Measurements of Temporal Summation of Heat Pain: a Pilot Investigation in Healthy Humans. NEUROPHYSIOLOGY+ 2019. [DOI: 10.1007/s11062-019-09773-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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8
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Taheriyan F, Teshnehlab M, Gharibzadeh S. Presenting a Neuroid model of wind-up based on dynamic synapse. J Theor Biol 2019; 465:45-50. [PMID: 30639573 DOI: 10.1016/j.jtbi.2019.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 01/05/2019] [Accepted: 01/10/2019] [Indexed: 10/27/2022]
Abstract
The treatment of chronic pain depends mainly on our understanding of the mechanisms such as central sensitization which is involved in it. Wind-up of spinal cord is one of the most important phenomena in the study of central sensitization which has received considerable attention in recent years. Wind-up is a form of short-term synaptic plasticity (STP) that can lead to central sensitivity. Although several models have been proposed for wind-up, none of them are based on the experimental evidence. In this study, a new network model is introduced according to the gate control theory of pain. Neuroids are used as neuron models in which their parameters are captured from available experimental data. Adjusting the weights of the network is based on the short-term synaptic plasticity. The results of the time and frequency domain show that the model can well simulate wind-up behavior. This model can be used for analyzing, predicting and controlling chronic pain in the future.
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Affiliation(s)
- Fatemeh Taheriyan
- Department of Electrical Engineering, K. N. Toosi University of Technology, Tehran, Iran.
| | - Mohammad Teshnehlab
- Department of Electrical Engineering, K. N. Toosi University of Technology, Tehran, Iran.
| | - Shahriar Gharibzadeh
- Institute for Cognitive & Brain Sciences (ICBS), Department of Cognitive Modeling and Cognitive Rehabilitation, Shahid Beheshti University, Basir Eye Health Research Center, Tehran, Iran.
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9
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Greenspon CM, Battell EE, Devonshire IM, Donaldson LF, Chapman V, Hathway GJ. Lamina-specific population encoding of cutaneous signals in the spinal dorsal horn using multi-electrode arrays. J Physiol 2018; 597:377-397. [PMID: 30390415 PMCID: PMC6332738 DOI: 10.1113/jp277036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 10/31/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Traditional, widely used in vivo electrophysiological techniques for the investigation of spinal processing of somatosensory information fail to account for the diverse functions of each lamina. To overcome this oversimplification, we have used multi-electrode arrays, in vivo, to simultaneously record neuronal activity across all laminae of the spinal dorsal horn. Multi-electrode arrays are sensitive enough to detect lamina- and region-specific encoding of different subtypes of afferent fibres and to detect short-lived changes in synaptic plasticity as measured by the application of cutaneous electrical stimulation of varying intensity and frequency. Differential encoding of innocuous and noxious thermal and mechanical stimuli were also detected across the laminae with the technique, as were the effects of the application of capsaicin. This new approach to the study of the dorsal spinal cord produces significantly more information per experiment, permitting accelerated research whilst also permitting the effects of pharmacological tools to modulate network responses. ABSTRACT The dorsal horn (DH) of the spinal cord is a complex laminar structure integrating peripheral signals into the central nervous system. Spinal somatosensory processing is commonly measured electrophysiologically in vivo by recording the activity of individual wide-dynamic-range neurons in the deep DH and extrapolating their behaviour to all cells in every lamina. This fails to account for the specialized processes that occur in each lamina and the considerable heterogeneity in cellular phenotype within and between laminae. Here we overcome this oversimplification by employing linear multi-electrode arrays (MEAs) in the DH of anaesthetized rats to simultaneously measure activity across all laminae. The MEAs, comprising 16 channels, were inserted into the lumbar dorsal horn and peripheral neurons activated electrically via transcutaneous electrodes and ethologically with von Frey hairs (vFHs) or an aluminium heating block. Ascending electrical stimuli showed fibre thresholds with distinct dorsoventral innervation profiles. Wind up was observed across the DH during the C-fibre and post-discharge latencies following 0.5 Hz stimulation. Intrathecal application of morphine (5 ng/50 μl) significantly reduced Aδ- and C-fibre-evoked activity in deep and superficial DH. Light vFHs (≤10 g) predominantly activated intermediate and deep laminae whereas noxious vFHs (26 g) also activated the superficial laminae. Noxious heat (55°C) induced significantly greater activity in the superficial and deep laminae than the innocuous control (30°C). The application of these arrays produced the first description of the processing of innocuous and noxious stimuli throughout the intact DH.
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Affiliation(s)
- Charles M Greenspon
- School of Life Sciences, The University of Nottingham, Nottingham, NG7 2UH, UK
| | - Emma E Battell
- School of Life Sciences, The University of Nottingham, Nottingham, NG7 2UH, UK
| | - Ian M Devonshire
- Bio-Support Unit, The University of Nottingham, Nottingham, NG7 2UH, UK
| | - Lucy F Donaldson
- School of Life Sciences, The University of Nottingham, Nottingham, NG7 2UH, UK.,Arthritis Research UK Pain Centre, The University of Nottingham, Nottingham, NG7 2UH, UK
| | - Victoria Chapman
- School of Life Sciences, The University of Nottingham, Nottingham, NG7 2UH, UK.,Arthritis Research UK Pain Centre, The University of Nottingham, Nottingham, NG7 2UH, UK
| | - Gareth J Hathway
- School of Life Sciences, The University of Nottingham, Nottingham, NG7 2UH, UK
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10
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Kissiwaa SA, Bagley EE. Central sensitization of the spino-parabrachial-amygdala pathway that outlasts a brief nociceptive stimulus. J Physiol 2018; 596:4457-4473. [PMID: 30004124 PMCID: PMC6138295 DOI: 10.1113/jp273976] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 06/29/2018] [Indexed: 12/22/2022] Open
Abstract
KEY POINTS Chronic pain is disabling because sufferers form negative associations between pain and activities, such as work, leading to the sufferer limiting these activities. Pain information arriving in the amygdala is responsible for forming these associations and contributes to us feeling bad when we are in pain. Ongoing injuries enhance the delivery of pain information to the amygdala. If we want to understand why chronic pain can continue without ongoing injury, it is important to know whether this facilitation continues once the injury has healed. In the present study, we show that a 2 min noxious heat stimulus, without ongoing injury, is able to enhance delivery of pain information to the amygdala for 3 days. If the noxious heat stimulus is repeated, this enhancement persists even longer. These changes may prime this information pathway so that subsequent injuries may feel even worse and the associative learning that results in pain-related avoidance may be promoted. ABSTRACT Pain is an important defence against dangers in our environment; however, some clinical conditions produce pain that outlasts this useful role and persists even after the injury has healed. The experience of pain consists of somatosensory elements of intensity and location, negative emotional/aversive feelings and subsequent restrictions on lifestyle as a result of a learned association between certain activities and pain. The amygdala contributes negative emotional value to nociceptive sensory information and forms the association between an aversive response and the environment in which it occurs. It is able to form this association because it receives nociceptive information via the spino-parabrachio-amygdaloid pathway and polymodal sensory information via cortical and thalamic inputs. Synaptic plasticity occurs at the parabrachial-amygdala synapse and other brain regions in chronic pain conditions with ongoing injury; however, very little is known about how plasticity occurs in conditions with no ongoing injury. Using immunohistochemistry, electrophysiology and behavioural assays, we show that a brief nociceptive stimulus with no ongoing injury is able to produce long-lasting synaptic plasticity at the rat parabrachial-amygdala synapse. We show that this plasticity is caused by an increase in postsynaptic AMPA receptors with a transient change in the AMPA receptor subunit, similar to long-term potentiation. Furthermore, this synaptic potentiation primes the synapse so that a subsequent noxious stimulus causes prolonged potentiation of the nociceptive information flow into the amygdala. As a result, a second injury could have an increased negative emotional value and promote associative learning that results in pain-related avoidance.
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Affiliation(s)
- Sarah A Kissiwaa
- Discipline of Pharmacology and Charles Perkins CentreUniversity of SydneySydneyNSW2006Australia
| | - Elena E Bagley
- Discipline of Pharmacology and Charles Perkins CentreUniversity of SydneySydneyNSW2006Australia
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11
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Yu F, Zhao ZY, He T, Yu YQ, Li Z, Chen J. Temporal and spatial dynamics of peripheral afferent-evoked activity in the dorsal horn recorded in rat spinal cord slices. Brain Res Bull 2017; 131:183-191. [PMID: 28458040 DOI: 10.1016/j.brainresbull.2017.04.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 02/13/2017] [Accepted: 04/21/2017] [Indexed: 01/07/2023]
Abstract
In the present study, multi-electrode array recording was used to examine dorsal horn activity following stimulation of primary afferents in a rat dorsal root attached-spinal cord slice preparation. The multi-electrode array probe was placed under the dorsal horn slice and local field potentials evoked by stimulation on the dorsal root were analyzed. Three kinds of dorsal root-evoked responses were identified. In lamina IIo, local field potentials exhibited P1 (peak latency 1.46±0.08ms), N1 (2.77±0.18ms, n=12), N2 (7.31±0.48ms), N3 (12.12±0.73ms) and P2(18.30±0.80ms) waves. In lamina IIi local field potentials exhibited P (1.99±0.10ms), N1 (3.35±0.17ms) and N2 (8.58±0.44ms) waves. In laminae III-VI, local field potentials exhibited P1 (3.01±0.07ms), P2 (7.02±0.21ms) and N waves (22.57±0.79ms). Sweep spread was calculated by two dimensional current source density (2D-CSD) analysis. Both α-amino-3-hydroxy-5-methylisoxazole-4-propionic a/kainate and N-methyl-d-aspartate-type glutamate receptors participated in this neuronal circuitry. Morphine diminished local field potentials. Gabapentin diminished the negative components in lamina II and P2 component in lamina IIo, but increased the positive components in lamina IIi and laminae III-VI. The present study revealed that functional dorsal horn activity was preserved in the spinal cord slice preparation. Glutamatergic synapses were crucially involved in information processing. Opioid interneurons and gabapentin may play a modulatory role in regulating signal flows in the dorsal horn. Taken together, these results identify a spatio-temporal profile of dorsal horn activity evoked by dorsal root stimulation, and implicate glutamatergic and opioidergic receptors and gabapentin in this activity.
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Affiliation(s)
- Fang Yu
- State Key Laboratory of Cancer Biology & Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, Shaanxi Province, 710038, PR China; Jinan Military General Hospital, Jinan, Shandong Province, 250031, PR China
| | - Zhen-Yu Zhao
- Institute for Biomedical Sciences of Pain and Institute for Functional Brain Disorders, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi Province, 710038, PR China; Jinan Military General Hospital, Jinan, Shandong Province, 250031, PR China
| | - Ting He
- Institute for Biomedical Sciences of Pain and Institute for Functional Brain Disorders, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi Province, 710038, PR China
| | - Yao-Qing Yu
- Institute for Biomedical Sciences of Pain and Institute for Functional Brain Disorders, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi Province, 710038, PR China
| | - Zhen Li
- Institute for Biomedical Sciences of Pain and Institute for Functional Brain Disorders, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi Province, 710038, PR China
| | - Jun Chen
- Institute for Biomedical Sciences of Pain and Institute for Functional Brain Disorders, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi Province, 710038, PR China.
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12
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Melin C, Jacquot F, Vitello N, Dallel R, Artola A. Different processing of meningeal and cutaneous pain information in the spinal trigeminal nucleus caudalis. Cephalalgia 2016; 37:1189-1201. [DOI: 10.1177/0333102416673204] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Introduction Within superficial trigeminal nucleus caudalis (Sp5C) (laminae I/II), meningeal primary afferents project exclusively to lamina I, whereas nociceptive cutaneous ones distribute in both lamina I and outer lamina II. Whether such a relative absence of meningeal inputs to lamina II represents a fundamental difference from cutaneous pathways in the central processing of sensory information is still unknown. Methods We recorded extracellular field potentials in the superficial Sp5C of anesthetised rats evoked by electrically stimulating the dura mater, to selectively assess the synaptic transmission between meningeal primary afferents and second-order Sp5C neurons, the first synapse in trigeminovascular pathways. We tested the effect of systemic morphine and local glycinergic and GABAAergic disinhibition. Results Meningeal stimulation evokes two negative field potentials in superficial Sp5C. The conduction velocities of the activated primary afferents are within the Aδ- and C-fibre ranges. Systemic morphine specifically suppresses meningeal C-fibre-evoked field potentials, and this effect is reversed by systemic naloxone. Segmental glycinergic or GABAAergic disinhibition strongly potentiates meningeal C-fibre-evoked field potentials but not Aδ-fibre ones. Interestingly, the same segmental disinhibition conversely potentiates cutaneous Aδ-fibre-evoked field potentials and suppresses C-fibre ones. Conclusion These findings reveal that the different anatomical organization of meningeal and cutaneous inputs into superficial Sp5C is associated with a different central processing of meningeal and cutaneous pain information within Sp5C. Moreover, they suggest that the potentiation upon local disinhibition of the first synapse in trigeminovascular pathways may contribute to the generation of headache pain.
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Affiliation(s)
- Céline Melin
- Clermont University, University of Auvergne, Clermont-Ferrand, France
- Clermont-Ferrand University Hospital, Department of Odontology, Clermont-Ferrand, France
| | - Florian Jacquot
- Clermont University, University of Auvergne, Clermont-Ferrand, France
| | - Nicolas Vitello
- Clermont University, University of Auvergne, Clermont-Ferrand, France
| | - Radhouane Dallel
- Clermont University, University of Auvergne, Clermont-Ferrand, France
- Clermont-Ferrand University Hospital, Department of Odontology, Clermont-Ferrand, France
| | - Alain Artola
- Clermont University, University of Auvergne, Clermont-Ferrand, France
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13
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Sherman AL, Morris MC, Bruehl S, Westbrook TD, Walker LS. Heightened Temporal Summation of Pain in Patients with Functional Gastrointestinal Disorders and History of Trauma. Ann Behav Med 2016; 49:785-92. [PMID: 25967582 DOI: 10.1007/s12160-015-9712-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Individuals with functional gastrointestinal disorders (FGIDs) report experiencing trauma more often than healthy controls, but little is known regarding psychophysical correlates. PURPOSE The purpose of this study was to test the hypothesis that adolescents and young adults with FGIDs since childhood and a trauma history (n = 38) would exhibit heightened temporal summation to thermal pain stimuli, an index of central sensitization, and greater clinical symptoms compared to patients with FGIDs and no trauma history (n = 95) and healthy controls (n = 135). METHODS Participants completed self-report measures, an experimental pain protocol, and psychiatric diagnostic interview as part of a larger longitudinal study. RESULTS FGID + Trauma patients exhibited greater temporal summation than FGID + No Trauma patients and healthy controls. Additionally, FGID + Trauma patients exhibited greater gastrointestinal and non-gastrointestinal symptom severity, number of chronic pain sites, and disability. CONCLUSIONS Assessing for trauma history in patients with FGIDs could identify a subset at risk for greater central sensitization and pain-related symptoms.
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Affiliation(s)
- Amanda L Sherman
- Department of Psychology and Human Development, Vanderbilt University, Nashville, TN, USA
| | - Matthew C Morris
- Department of Family and Community Medicine, Meharry Medical College, Nashville, TN, USA
| | - Stephen Bruehl
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | | | - Lynn S Walker
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN, USA. .,Division of Adolescent and Young Adult Health, Monroe Carell Jr. Children's Hospital at Vanderbilt, 2146 Belcourt Ave., Nashville, TN, 37212, USA.
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14
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A spinal analog of memory reconsolidation enables reversal of hyperalgesia. Nat Neurosci 2014; 17:1043-5. [PMID: 24997764 PMCID: PMC4978538 DOI: 10.1038/nn.3758] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 06/06/2014] [Indexed: 01/21/2023]
Abstract
Hyperalgesia arising from sensitization of pain relays in the spinal dorsal horn shares many mechanistic and phenotypic parallels with memory formation. We discover that mechanical hyperalgesia can be rendered labile and reversible in mice after reactivation of spinal pain pathways in a process analogous to memory reconsolidation. These findings reveal a novel regulatory mechanism underlying hyperalgesia and demonstrate the existence of reconsolidation-like processes in a sensory system.
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15
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Cortical presynaptic control of dorsal horn C-afferents in the rat. PLoS One 2013; 8:e69063. [PMID: 23935924 PMCID: PMC3728294 DOI: 10.1371/journal.pone.0069063] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 06/10/2013] [Indexed: 12/01/2022] Open
Abstract
Lamina 5 sensorimotor cortex pyramidal neurons project to the spinal cord, participating in the modulation of several modalities of information transmission. A well-studied mechanism by which the corticospinal projection modulates sensory information is primary afferent depolarization, which has been characterized in fast muscular and cutaneous, but not in slow-conducting nociceptive skin afferents. Here we investigated whether the inhibition of nociceptive sensory information, produced by activation of the sensorimotor cortex, involves a direct presynaptic modulation of C primary afferents. In anaesthetized male Wistar rats, we analyzed the effects of sensorimotor cortex activation on post tetanic potentiation (PTP) and the paired pulse ratio (PPR) of dorsal horn field potentials evoked by C–fiber stimulation in the sural (SU) and sciatic (SC) nerves. We also explored the time course of the excitability changes in nociceptive afferents produced by cortical stimulation. We observed that the development of PTP was completely blocked when C-fiber tetanic stimulation was paired with cortex stimulation. In addition, sensorimotor cortex activation by topical administration of bicuculline (BIC) produced a reduction in the amplitude of C–fiber responses, as well as an increase in the PPR. Furthermore, increases in the intraspinal excitability of slow-conducting fiber terminals, produced by sensorimotor cortex stimulation, were indicative of primary afferent depolarization. Topical administration of BIC in the spinal cord blocked the inhibition of C–fiber neuronal responses produced by cortical stimulation. Dorsal horn neurons responding to sensorimotor cortex stimulation also exhibited a peripheral receptive field and responded to stimulation of fast cutaneous myelinated fibers. Our results suggest that corticospinal inhibition of nociceptive responses is due in part to a modulation of the excitability of primary C–fibers by means of GABAergic inhibitory interneurons.
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16
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Melin C, Jacquot F, Dallel R, Artola A. Segmental disinhibition suppresses C-fiber inputs to the rat superficial medullary dorsal horn via the activation of GABABreceptors. Eur J Neurosci 2012; 37:417-28. [DOI: 10.1111/ejn.12048] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 09/13/2012] [Accepted: 09/27/2012] [Indexed: 12/17/2022]
Affiliation(s)
| | - Florian Jacquot
- Clermont Université; Université d'Auvergne; Neuro-Dol, BP 10448, F-63000, Clermont-Ferrand & Inserm U1107; F-63001 Clermont-Ferrand; France
| | | | - Alain Artola
- Clermont Université; Université d'Auvergne; Neuro-Dol, BP 10448, F-63000, Clermont-Ferrand & Inserm U1107; F-63001 Clermont-Ferrand; France
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17
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Temporal regularity determines the impact of electrical stimulation on tactile reactivity and response to capsaicin in spinally transected rats. Neuroscience 2012; 227:119-33. [PMID: 23036621 DOI: 10.1016/j.neuroscience.2012.09.054] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 09/21/2012] [Accepted: 09/22/2012] [Indexed: 01/20/2023]
Abstract
Nociceptive plasticity and central sensitization within the spinal cord depend on neurobiological mechanisms implicated in learning and memory in higher neural systems, suggesting that the factors that impact brain-mediated learning and memory could modulate how stimulation affects spinal systems. One such factor is temporal regularity (predictability). The present paper shows that intermittent hindleg shock has opposing effects in spinally transected rats depending upon whether shock is presented in a regular or irregular (variable) manner. Variable intermittent legshock (900 shocks) enhanced mechanical reactivity to von Frey stimuli (hyperreactivity), whereas 900 fixed-spaced legshocks produced hyporeactivity. The impact of fixed-spaced shock depended upon the duration of exposure; a brief exposure (36 shocks) induced hyperreactivity whereas an extended exposure (900 shocks) produced hyporeactivity. The enhanced reactivity observed after variable shock was most evident 60-180 min after treatment. Fixed and variable intermittent stimulation applied to the sciatic nerve, or the tail, yielded a similar pattern of results. Stimulation had no effect on thermal reactivity. Exposure to fixed-spaced shock, but not variable shock, attenuated the enhanced mechanical reactivity (EMR) produced by treatment with hindpaw capsaicin. The effect of fixed-spaced stimulation lasted 24h. Treatment with fixed-spaced shock also attenuated the maintenance of capsaicin-induced EMR. The results show that variable intermittent shock enhances mechanical reactivity, while an extended exposure to fixed-spaced shock has the opposite effect on mechanical reactivity and attenuates capsaicin-induced EMR.
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18
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Buesa I, Urrutia A, Bilbao J, Aguilera L, Zimmermann M, Azkue JJ. Morphine-induced depression of spinal excitation is not altered following acute disruption of GABAA or GABAB receptor activity. Eur J Pain 2012; 12:677-85. [DOI: 10.1016/j.ejpain.2007.10.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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19
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Jergova S, Hentall ID, Gajavelli S, Varghese MS, Sagen J. Intraspinal transplantation of GABAergic neural progenitors attenuates neuropathic pain in rats: a pharmacologic and neurophysiological evaluation. Exp Neurol 2011; 234:39-49. [PMID: 22193109 DOI: 10.1016/j.expneurol.2011.12.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 10/27/2011] [Accepted: 12/05/2011] [Indexed: 02/03/2023]
Abstract
Dysfunctional γ-aminobutyric acid (GABA)-ergic inhibitory neurotransmission is hypothesized to underlie chronic neuropathic pain. Intraspinal transplantation of GABAergic neural progenitor cells (NPCs) may reduce neuropathic pain by restoring dorsal horn inhibition. Rat NPCs pre-differentiated to a GABAergic phenotype were transplanted into the dorsal horn of rats with unilateral chronic constriction injury (CCI) of the sciatic nerve. GABA signaling in antinociceptive effects of NPC grafts was tested with the GABA(A) receptor antagonist bicuculline (BIC), GABA(B) receptor antagonist CGP35348 (CGP) and GABA reuptake inhibitor SKF 89976A (SKF). NPC-treated animals showed decreased hyperalgesia and allodynia 1-3week post-transplantation; vehicle-injected CCI rats continued displaying pain behaviors. Intrathecal application of BIC or CGP attenuated the antinociceptive effects of the NPC transplants while SKF injection induced analgesia in control rats. Electrophysiological recordings in NPC treated rats showed reduced responses of wide dynamic range (WDR) neurons to peripheral stimulation compared to controls. A spinal application of BIC or CGP increased wind-up response and post-discharges of WDR neurons in NPC treated animals. Results suggest that transplantation of GABAergic NPCs attenuate pain behaviors and reduce exaggerated dorsal horn neuronal firing induced by CCI. The effects of GABA receptor inhibitors suggest participation of continuously released GABA in the grafted animals.
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Affiliation(s)
- Stanislava Jergova
- University of Miami, Miller School of Medicine, Miami Project to Cure Paralysis, 1095 NW 14 Terrace, Miami, Florida 33136, USA.
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Activation of anterior cingulate cortex produces inhibitory effects on noxious mechanical and electrical stimuli-evoked responses in rat spinal WDR neurons. Eur J Pain 2011; 15:895-9. [PMID: 21600816 DOI: 10.1016/j.ejpain.2011.04.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Revised: 03/25/2011] [Accepted: 04/05/2011] [Indexed: 11/22/2022]
Abstract
In present study, in vivo electrophysiological techniques were applied to examine the effects of anterior cingulate cortex (ACC) activation on mechanical and electrical stimuli-evoked responses in rat spinal cord wide-dynamic-range (WDR) neurons. We found that bilateral ACC electrical stimulation (100Hz, 20V, 20s) had different effects on neuronal responses to brush, pressure and pinch stimuli (10s). The brush-evoked neuronal responses at baseline, post 1min and post 5min were 60.8±15.0, 59.2±15.4 and 60.0±19.3 spikes/10s, respectively (n=10, P>0.05 vs. baseline). The pressure-evoked neuronal responses at baseline, post 1min and post 5min were 77.8±11.9, 38.0±7.8 and 45.8±7.6 spikes/10s, respectively (n=10, P<0.05 vs. baseline). The pinch-evoked neuronal responses at baseline, post 1min and post 5min were 137.6±16.7, 62.6±17.5 and 68.8±15.0 spikes/10s, respectively (n=10, P<0.05 vs. baseline). Furthermore, ACC stimulation generated distinct effects on the different components of wind-up response. The total numbers of late response (LR) and after-discharge (AD), but not early response (ER), significantly decreased. Collectively, the present study demonstrated that short-term ACC activation could generate long-term inhibitory effects on the responses of WDR neurons to noxious mechanical (pressure and pinch) and electrical stimuli. The results indicated that ACC activation could negatively regulate noxious information ascending from spinal cord with long-term effect, providing potential neuronal substrate for the modulation of ACC activation on nociception.
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21
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Ruscheweyh R, Wilder-Smith O, Drdla R, Liu XG, Sandkühler J. Long-term potentiation in spinal nociceptive pathways as a novel target for pain therapy. Mol Pain 2011; 7:20. [PMID: 21443797 PMCID: PMC3078873 DOI: 10.1186/1744-8069-7-20] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 03/28/2011] [Indexed: 01/19/2023] Open
Abstract
Long-term potentiation (LTP) in nociceptive spinal pathways shares several features with hyperalgesia and has been proposed to be a cellular mechanism of pain amplification in acute and chronic pain states. Spinal LTP is typically induced by noxious input and has therefore been hypothesized to contribute to acute postoperative pain and to forms of chronic pain that develop from an initial painful event, peripheral inflammation or neuropathy. Under this assumption, preventing LTP induction may help to prevent the development of exaggerated postoperative pain and reversing established LTP may help to treat patients who have an LTP component to their chronic pain. Spinal LTP is also induced by abrupt opioid withdrawal, making it a possible mechanism of some forms of opioid-induced hyperalgesia. Here, we give an overview of targets for preventing LTP induction and modifying established LTP as identified in animal studies. We discuss which of the various symptoms of human experimental and clinical pain may be manifestations of spinal LTP, review the pharmacology of these possible human LTP manifestations and compare it to the pharmacology of spinal LTP in rodents.
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Affiliation(s)
- Ruth Ruscheweyh
- Department of Neurophysiology, Center for Brain Research, Medical University of Vienna, Vienna, Austria
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22
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Aguiar P, Sousa M, Lima D. NMDA Channels Together With L-Type Calcium Currents and Calcium-Activated Nonspecific Cationic Currents Are Sufficient to Generate Windup in WDR Neurons. J Neurophysiol 2010; 104:1155-66. [DOI: 10.1152/jn.00834.2009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Windup is characterized as a frequency-dependent increase in the number of evoked action potentials in dorsal horn neurons in response to electrical stimulation of afferent C-fibers. This phenomenon was first described in the mid-60s, but the core mechanisms behind it still remain elusive. Several factors affecting its dynamics have been identified, but the distinction between modulating mechanisms from generating mechanisms is not always clear. Several mechanisms contribute to the excitation of dorsal horn neurons exhibiting windup, and one of our main aims was to help making this distinction. The approach presented here relies on mathematical and computational analysis to study the mechanism(s) underlying windup. From experimentally obtained windup profiles, we extract the time scale of the facilitation mechanisms that may support the characteristics of windup. Guided by these values and using simulations of a biologically realistic compartmental model of a wide dynamic range (WDR) neuron, we are able to assess the contribution of each mechanism for the generation of action potentials windup. We show that the key mechanisms giving rise to windup is the temporal summation of N-methyl-d-aspartate (NMDA) long-lasting postsynaptic responses taking place on top of a membrane potential cumulative depolarization. Calcium-activated nonspecific cationic currents driven by calcium influx from L-type calcium channels and synaptic currents support this cumulative depolarization and plateau formation in WDR neuron membrane potential. The effects of different nonhomogeneous stimulation protocols are explored, and their important role in clarifying many aspects of the windup generation is shown. The models are used to produce several predictions that can be tested experimentally.
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Affiliation(s)
- P. Aguiar
- Centro de Matemática da Universidade do Porto
- Instituto de Biologia Molecular e Celular, Universidade do Porto; and
| | - M. Sousa
- Instituto de Biologia Molecular e Celular, Universidade do Porto; and
| | - D. Lima
- Instituto de Biologia Molecular e Celular, Universidade do Porto; and
- Laboratório de Biologia Celular e Molecular, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
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Larsson M. Ionotropic glutamate receptors in spinal nociceptive processing. Mol Neurobiol 2009; 40:260-88. [PMID: 19876771 DOI: 10.1007/s12035-009-8086-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Accepted: 09/29/2009] [Indexed: 02/07/2023]
Abstract
Glutamate is the predominant excitatory transmitter used by primary afferent synapses and intrinsic neurons in the spinal cord dorsal horn. Accordingly, ionotropic glutamate receptors mediate basal spinal transmission of sensory, including nociceptive, information that is relayed to supraspinal centers. However, it has become gradually more evident that these receptors are also crucially involved in short- and long-term plasticity of spinal nociceptive transmission, and that such plasticity have an important role in the pain hypersensitivity that may result from tissue or nerve injury. This review will cover recent findings on pre- and postsynaptic regulation of synaptic function by ionotropic glutamate receptors in the dorsal horn and how such mechanisms contribute to acute and chronic pain.
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Affiliation(s)
- Max Larsson
- Department of Anatomy and Centre for Molecular Biology and Neuroscience, University of Oslo, Norway.
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Liu WT, Han Y, Li HC, Adams B, Zheng JH, Wu YP, Henkemeyer M, Song XJ. An in vivo mouse model of long-term potentiation at synapses between primary afferent C-fibers and spinal dorsal horn neurons: essential role of EphB1 receptor. Mol Pain 2009; 5:29. [PMID: 19523204 PMCID: PMC2704201 DOI: 10.1186/1744-8069-5-29] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Accepted: 06/12/2009] [Indexed: 11/10/2022] Open
Abstract
Background Long-term potentiation (LTP), a much studied cellular model of synaptic plasticity, has not been demonstrated at synapses between primary afferent C-fibers and spinal dorsal horn (DH) neurons in mice in vivo. EphrinB-EphB receptor signaling plays important roles in synaptic connection and plasticity in the nervous system, but its role in spinal synaptic plasticity remains unclear. Results This study characterizes properties of LTP at synapses of C-fibers onto neurons in the superficial DH following high-frequency stimulation (HFS) of a peripheral nerve at an intensity that activates C-fibers and examines associated activation of Ca2+/calmodulin-activated protein kinase II (p-CaMKII), extracellular signal-regulated kinase (p-ERK) and the cyclic AMP response element binding protein (p-CREB) and expression of c-Fos, and it investigates further roles for the EphB1 receptor in LTP. HFS induced LTP within 5 min and lasts for 3–8 h during the period of recording and resulted in upregulation of p-CaMKII, p-ERK and p-CREB protein levels in the spinal cord and expression of c-Fos in DH. Intrathecal pretreatment of MK-801 or EphB2-Fc prevented LTP and significantly reduced upregulation of p-CaMKII, p-ERK, p-CREB and c-Fos. Further, targeted mutation of EphB1 receptor prevented induction of LTP and associated increases in phosphorylation of CaMKII, ERK, and CREB. Conclusion This study provides an in vivo mouse model of LTP at synapses of C-fibers onto the superficial DH neurons that will be valuable for studying the DH neuron excitability and their synaptic plasticity and hyperalgesia. It further takes advantage of examining functional implications of a specific gene targeted mice and demonstrates that the EphB1 receptor is essential for development of LTP.
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Affiliation(s)
- Wen-Tao Liu
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical College, Xuzhou, Jiangsu, PR China.
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25
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Abstract
Hyperalgesia and allodynia are frequent symptoms of disease and may be useful adaptations to protect vulnerable tissues. Both may, however, also emerge as diseases in their own right. Considerable progress has been made in developing clinically relevant animal models for identifying the most significant underlying mechanisms. This review deals with experimental models that are currently used to measure (sect. II) or to induce (sect. III) hyperalgesia and allodynia in animals. Induction and expression of hyperalgesia and allodynia are context sensitive. This is discussed in section IV. Neuronal and nonneuronal cell populations have been identified that are indispensable for the induction and/or the expression of hyperalgesia and allodynia as summarized in section V. This review focuses on highly topical spinal mechanisms of hyperalgesia and allodynia including intrinsic and synaptic plasticity, the modulation of inhibitory control (sect. VI), and neuroimmune interactions (sect. VII). The scientific use of language improves also in the field of pain research. Refined definitions of some technical terms including the new definitions of hyperalgesia and allodynia by the International Association for the Study of Pain are illustrated and annotated in section I.
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Affiliation(s)
- Jürgen Sandkühler
- Department of Neurophysiology, Center for Brain Research, Medical University of Vienna, Vienna, Austria
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26
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Yu YQ, Zhao F, Chen J. Activation of ERK1/2 in the primary injury site is required to maintain melittin-enhanced wind-up of rat spinal wide-dynamic-range neurons. Neurosci Lett 2009; 459:137-41. [PMID: 19427362 DOI: 10.1016/j.neulet.2009.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2008] [Revised: 04/10/2009] [Accepted: 05/04/2009] [Indexed: 01/07/2023]
Abstract
Peripheral modulation of wind-up enhancement induced by peripheral tissue injury is investigated in rat spinal wide-dynamic-range (WDR) neurons. After subcutaneous (s.c.) injection of melittin, a pain-related peptidergic component separated from bee venom, the responsiveness of spinal cord WDR neuron to repeated suprathreshold (1.5T, the intensity threshold) electrical stimuli is enhanced. Comparing with the less effects on early response (0-100 ms), melittin significantly increases late response (100 ms to the next stimulus artifact) and after-discharge (starting from 2s after the last stimulus artifact) with 189% and 546%, respectively. Peripheral administration of a specific MEK inhibitor, 1,4-diamino-2,3-dicyano-1,4-bis-[o-aminophenylmercapto] butadiene (U0126, 1 microg) gradually suppresses, but not completely blocks melittin-enhanced wind-up to the similar level of baseline. The inhibitions of U0126 are mainly on late response and after-discharge with 49% and 65%, respectively. Peripheral administration of three doses of U0126 (0.1, 1, 10 microg) has no effects on melittin-induced local paw edema regardless of either pre- or post-treatment of the drug. We conclude that peripheral ERKs pathway in the primary injury site is required to maintain melittin-enhanced wind-up of rat spinal cord wide-dynamic-range neurons.
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Affiliation(s)
- Yao-Qing Yu
- Institute for Biomedical Sciences of Pain and Institute for Functional Brain Disorders, Tangdu Hospital, Fourth Military Medical University, Xi'an 710038, PR China
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27
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Baumbauer KM, Hoy KC, Huie JR, Hughes AJ, Woller SA, Puga DA, Setlow B, Grau JW. Timing in the absence of supraspinal input I: variable, but not fixed, spaced stimulation of the sciatic nerve undermines spinally-mediated instrumental learning. Neuroscience 2008; 155:1030-47. [PMID: 18674601 DOI: 10.1016/j.neuroscience.2008.07.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Revised: 06/27/2008] [Accepted: 07/02/2008] [Indexed: 10/21/2022]
Abstract
Rats with complete spinal transections are capable of acquiring a simple instrumentally trained response. If rats receive shock to one hind limb when the limb is extended (controllable shock), the spinal cord will learn to hold the leg in a flexed position that minimizes shock exposure. If shock is delivered irrespective of leg position, subjects do not exhibit an increase in flexion duration and subsequently fail to learn when tested with controllable shock (learning deficit). Just 6 min of variable intermittent shock produces a learning deficit that lasts 24 h. Evidence suggests that the neural mechanisms underlying the learning deficit may be related to those involved in other instances of spinal plasticity (e.g. windup, long-term potentiation). The present paper begins to explore these relations by demonstrating that direct stimulation of the sciatic nerve also impairs instrumental learning. Six minutes of electrical stimulation (mono- or biphasic direct current [DC]) of the sciatic nerve in spinally transected rats produced a voltage-dependent learning deficit that persisted for 24 h (experiments 1-2) and was dependent on C-fiber activation (experiment 7). Exposure to continuous stimulation did not produce a deficit, but intermittent burst or single pulse (as short as 0.1 ms) stimulation (delivered at a frequency of 0.5 Hz) did, irrespective of the pattern (fixed or variable) of stimulus delivery (experiments 3-6, 8). When the duration of stimulation was extended from 6 to 30 min, a surprising result emerged; shocks applied in a random (variable) fashion impaired subsequent learning whereas shocks given in a regular pattern (fixed spacing) did not (experiments 9-10). The results imply that spinal neurons are sensitive to temporal relations and that stimulation at regular intervals can have a restorative effect.
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Affiliation(s)
- K M Baumbauer
- Department of Psychology, Texas A&M University, College Station, TX 77843-4325, USA.
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28
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Drdla R, Sandkühler J. Long-term potentiation at C-fibre synapses by low-level presynaptic activity in vivo. Mol Pain 2008; 4:18. [PMID: 18507818 PMCID: PMC2424039 DOI: 10.1186/1744-8069-4-18] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Accepted: 05/28/2008] [Indexed: 11/10/2022] Open
Abstract
Inflammation, trauma or nerve injury trigger low-level activity in C-fibres and may cause long-lasting hyperalgesia. Long-term potentiation (LTP) at synapses of primary afferent C-fibres is considered to underlie some forms of hyperalgesia. In previous studies, high- but not low-frequency conditioning stimulation of C-fibres has, however, been used to induce LTP in pain pathways. Recently we could show that also conditioning low-frequency stimulation (LFS) at C-fibre intensity induces LTP in vitro as well as in the intact animal, i.e. with tonic descending inhibition fully active. In the slice preparation, this form of LTP requires a rise in postsynaptic Ca2+-concentration and activation of Ca2+-dependent signalling pathways. Here, we investigated the signalling mechanisms underlying this novel form of LTP in vivo. We found that the signal transduction pathways causing LFS-induced LTP in vivo include activation of neurokinin 1 and N-methyl-D-aspartate receptors, rise of [Ca2+]i from intracellular stores and via T-type voltage-dependent Ca2+ channels, activation of phospholipase C, protein kinase C and Ca2+-calmodulin dependent kinase II. These pathways match those leading to hyperalgesia in behaving animals and humans. We thus propose that LTP induced by low-level activity in C-fibres may underlie some forms of hyperalgesia.
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Affiliation(s)
- Ruth Drdla
- Department of Neurophysiology, Center for Brain Research, Medical University of Vienna, Vienna, Austria.
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29
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Lambertz D, Hoheisel U, Mense S. Influence of a chronic myositis on rat spinal field potentials evoked by TTX-resistant unmyelinated skin and muscle afferents. Eur J Pain 2007; 12:686-95. [PMID: 18078769 DOI: 10.1016/j.ejpain.2007.10.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2007] [Revised: 10/22/2007] [Accepted: 10/24/2007] [Indexed: 11/16/2022]
Abstract
A recent study of our group has shown that in the segments L4 and L5 of the rat, the synaptic field potentials (SFPs) evoked by tetrodotoxin-resistant (TTX-r, presumably nociceptive) muscle afferents differ in size and peak location from those of cutaneous afferents from the same body region [Lambertz D, Hoheisel U, Mense S. Distribution of synaptic field potentials induced by TTX-resistant skin and muscle afferents in rat segment L4 and L5. Neurosci Lett 2006;409:14-8]. Here, we investigated the influence of a muscle inflammation on the distribution of SFPs of TTX-r afferent fibres from muscle and skin in the thoracic and lumbar spinal cord. During a TTX block of the dorsal roots L3-L6, a skin nerve (sural, SU) or a muscle nerve (gastrocnemius-soleus, GS) were electrically stimulated at an intensity supramaximal for unmyelinated afferents and the SFPs recorded with tungsten microelectrodes. In control (non-inflamed) rats, the largest SFPs evoked by TTX-r GS afferents were recorded in laminae IV-VI with a maximum in segment L4, whereas the largest SU-induced SFPs were more superficially located with a maximum in L3. In chronic myositis animals, SFPs induced by GS TTX-r fibres exhibited significant decreases in lamina IV-VI of Th 12 and L5 as well as in lamina VII of L5. In contrast, SFPs evoked by SU TTX-r afferents showed significant increases in lamina IV-VI in L1 and in lamina VII in L4. The results demonstrate that a chronic myositis has a strong influence also on the synaptic effects of nociceptive afferents from the skin, which may explain the subjective cutaneous sensations during a pathological alteration of muscle.
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Affiliation(s)
- D Lambertz
- Institute of Anatomy and Cell Biology, University of Heidelberg, Im Neuenheimer Feld 307, D-69120 Heidelberg, Germany.
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30
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Fukui T, Dai Y, Iwata K, Kamo H, Yamanaka H, Obata K, Kobayashi K, Wang S, Cui X, Yoshiya S, Noguchi K. Frequency-dependent ERK phosphorylation in spinal neurons by electric stimulation of the sciatic nerve and the role in electrophysiological activity. Mol Pain 2007; 3:18. [PMID: 17631690 PMCID: PMC1941723 DOI: 10.1186/1744-8069-3-18] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2007] [Accepted: 07/16/2007] [Indexed: 01/08/2023] Open
Abstract
The phosphorylation of extracellular signal-regulated kinase (pERK) in DRG and dorsal horn neurons is induced by the C-fiber electrical stimulation to the peripheral nerve. The present study was designed to investigate the expression and modulation of pERK in the rat dorsal horn neurons produced by repetitive electrical stimulation, and its involvement in the electrophysiological activity of dorsal horn neurons. Electrical stimulation of C-fiber intensity at different frequencies was applied to the sciatic nerve; the stimuli-induced pERK expression and the activity in dorsal horn neurons were studied by immunohistochemistry and extracellular recording, respectively. Electrical stimulation of C-fibers (3 mA) induced pERK expression in dorsal horn neurons in a frequency-dependent manner, indicating that the frequency of electrical stimulation is an important factor which activates the intracellular signal pathway in the spinal cord. To demonstrate the underlying mechanism of this frequency-dependent pERK expression, an NMDA receptor antagonist, MK-801, and a voltage sensitive calcium channel antagonist, nifedipine, were administrated intrathecally before the stimulation. We found that high frequency (0.5 Hz and 10 Hz) but not low frequent (0.05 Hz) stimulus-evoked pERK was partially inhibited by MK-801. Both high and low frequency stimulus-evoked pERK were inhibited by the nifedipine treatment. The extracellular single unit activities were recorded from the laminae I-II and V of the L4-5 dorsal horn, and we found that blockage of the intracellular ERK signal suppressed the wind-up responses in a dose-dependent manner. In contrast, any change in the mechanically evoked responses was not observed following the administration of ERK inhibitor. These observations indicate that ERK activation plays an important role in the induction of the wind-up responses in dorsal horn nociceptive neurons.
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Affiliation(s)
- Tomokazu Fukui
- Department of Anatomy and Neuroscience, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
- Department of Orthopaedic Surgery, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
| | - Yi Dai
- Department of Anatomy and Neuroscience, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
| | - Koichi Iwata
- Department of Physiology, School of Dentistry, Nihon University, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
| | - Hiroshi Kamo
- Department of Physiology, School of Dentistry, Nihon University, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
| | - Hiroki Yamanaka
- Department of Anatomy and Neuroscience, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
| | - Koichi Obata
- Department of Anatomy and Neuroscience, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
| | - Kimiko Kobayashi
- Department of Anatomy and Neuroscience, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
| | - Shenglan Wang
- Department of Anatomy and Neuroscience, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
| | - Xiuyu Cui
- Department of Anatomy and Neuroscience, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
- Institute for Biomedical Sciences of Pain, Capital Medical University, Beijing 100069, P.R. China
| | - Shinichi Yoshiya
- Department of Orthopaedic Surgery, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
| | - Koichi Noguchi
- Department of Anatomy and Neuroscience, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
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31
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Abstract
Long-term potentiation (LTP) at synapses of nociceptive nerve fibres is a proposed cellular mechanism underlying some forms of hyperalgesia. In this review fundamental properties of LTP in nociceptive pathways are described. The following topics are specifically addressed: A concise definition of LTP is given and a differentiation is made between LTP and "central sensitisation". How to (and how not to) measure and how to induce LTP in pain pathways is specified. The signal transduction pathways leading to LTP at C-fibre synapses are highlighted and means of how to pre-empt and how to reverse LTP are delineated. The potential functional roles of LTP are evaluated at the cellular level and at the behavioural level in experimental animals. Finally, the impact of LTP on the perception of pain in human subjects is discussed.
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Affiliation(s)
- Jürgen Sandkühler
- Department of Neurophysiology, Center for Brain Research, Medical University of Vienna, Vienna, Austria.
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32
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Andersen OK. Studies of the organization of the human nociceptive withdrawal reflex. Focus on sensory convergence and stimulation site dependency. Acta Physiol (Oxf) 2007; 189 Suppl 654:1-35. [PMID: 17439638 DOI: 10.1111/j.1748-1716.2007.01706.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- O K Andersen
- Department of Health Science and Technology, Center for Sensory-Motor Interaction (SMI), Aalborg University, Denmark
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33
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Lambertz D, Hoheisel U, Mense S. Distribution of synaptic field potentials induced by TTX-resistant skin and muscle afferents in rat spinal segments L4 and L5. Neurosci Lett 2006; 409:14-8. [PMID: 17045398 DOI: 10.1016/j.neulet.2006.09.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2006] [Revised: 09/01/2006] [Accepted: 09/03/2006] [Indexed: 10/24/2022]
Abstract
Previous results from our group and others showed that skin and muscle afferents are equipped with tetrodotoxin-resistant (TTX-r) channels. The great majority of the TTX-r fibres are unmyelinated (C or group IV) and are assumed to have nociceptive functions. Therefore, a block of the TTX-sensitive (TTX-s) fibres offers the possibility to study reactions of central nervous neurones to a purely nociceptive input. The present study compared spinal synaptic field potentials (SFPs) evoked by electrical stimulation of TTX-r afferent fibres from skin and muscle at various depths of the spinal segments L4 and L5 in the rat. Cutaneous input was produced by stimulation of the sural nerve (SU), input from muscle by stimulation of the gastrocnemius-soleus nerves (GS). To block the (non-nociceptive) TTX-s afferents, a pool containing TTX (concentration 1microM) was built around the dorsal roots L3-L6. As a measure of synaptic activity, the area of averaged SFPs was determined. After TTX application, the SFPs of fast conducting myelinated afferent fibres vanished completely. Simultaneously, the size of the potentials evoked by electrical stimulation of slowly conducting TTX-r skin and muscle afferents increased significantly. The field potentials of TTX-r GS afferents had a maximum in laminae IV-VI of the dorsal horn, whereas the SFPs induced by SU stimulation were more evenly distributed over all laminae. The results are a further indication that nociceptive input from skin and muscle is differently processed at the spinal level.
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Affiliation(s)
- D Lambertz
- Institute of Anatomy and Cell Biology, University Heidelberg, Im Neuenheimer Feld 307, D-69120 Heidelberg, Germany.
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34
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Guan Y, Borzan J, Meyer RA, Raja SN. Windup in dorsal horn neurons is modulated by endogenous spinal mu-opioid mechanisms. J Neurosci 2006; 26:4298-307. [PMID: 16624950 PMCID: PMC6674017 DOI: 10.1523/jneurosci.0960-06.2006] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The mu-opioid receptor (MOR) plays a critical role in morphine analgesia and nociceptive transmission. However, the physiological roles for endogenous MOR mechanisms in modulating spinal nociceptive transmission, and particularly in the enhanced excitability of spinal nociceptive neurons after repeated noxious inputs, are less well understood. Using a MOR gene knock-out (-/-) approach and an MOR-preferring antagonist, we investigated the roles of endogenous MOR mechanisms in processing of acute noxious input and in neuronal sensitization during windup-inducing stimuli in wide dynamic range (WDR) neurons. Extracellular single-unit activity of WDR neurons was recorded in isoflurane-anesthetized MOR(-/-) and wild-type C57BL/6 mice. There were no significant differences between the genotypes in the responses of deep WDR cells to acute mechanical stimuli, graded electrical stimuli, and noxious chemical stimuli applied to the receptive field. Intracutaneous electrical stimulation at 1.0 Hz produced similar levels of windup in both genotypes. In contrast, 0.2 Hz stimulation induced significantly higher levels of windup in MOR(-/-) mice compared with the wild-type group. In wild-type mice, spinal superfusion with naloxone hydrochloride (10 mM, 30 microl) significantly enhanced windup to 0.2 Hz stimulation in both deep and superficial WDR cells. A trend toward facilitation of windup was also observed during 1.0 Hz stimulation after naloxone treatment. These results suggest that endogenous MOR mechanisms are not essential in the processing of acute noxious mechanical and electrical stimuli by WDR neurons. However, MORs may play an important role in endogenous inhibitory mechanisms that regulate the development of spinal neuronal sensitization.
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MESH Headings
- Animals
- Electric Stimulation
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Naloxone/pharmacology
- Narcotic Antagonists/pharmacology
- Physical Stimulation
- Posterior Horn Cells/drug effects
- Posterior Horn Cells/physiology
- Receptors, Opioid, mu/antagonists & inhibitors
- Receptors, Opioid, mu/deficiency
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/physiology
- Stimulation, Chemical
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35
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Buesa I, Ortiz V, Aguilera L, Torre F, Zimmermann M, Azkue JJ. Disinhibition of spinal responses to primary afferent input by antagonism at GABA receptors in urethane-anaesthetised rats is dependent on NMDA and metabotropic glutamate receptors. Neuropharmacology 2006; 50:585-94. [PMID: 16412481 DOI: 10.1016/j.neuropharm.2005.11.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2005] [Revised: 08/18/2005] [Accepted: 11/09/2005] [Indexed: 11/21/2022]
Abstract
Disruption of spinal GABAergic circuits, which regulate the conveyance of sensory information to spinal cord neurones from the primary afferent system, leads to miscoding of afferent input and often results in hyperresponsiveness states. In the present work, extracellular field potentials elicited by electrical peripheral nerve activation were recorded in the urethane-anaesthetised rat following spinal administration of GABA(A) or GABA(B) receptor-antagonists, and the involvement of glutamate receptors of the NMDA and metabotropic types in changes induced by altered GABAergic function was examined by pre-treating the spinal dorsal horn with appropriate antagonist drugs. Spinal administration of the GABA(A) receptor antagonist bicuculline (BIC) dose-dependently augmented poly- but not monosynaptic field potentials elicited by activation of A fibres or potentials elicited by activation of C fibres, whereas application of the GABA(B) receptor antagonist CGP35348 significantly increased the amplitudes of C- but not A fibre-evoked potentials. BIC-induced augmentation was blocked by pre-treatment with the NMDA receptor antagonist D-(-)-2-amino-5-phosphonopentanoic acid (D-AP5) or the group I or II metabotropic glutamate receptor (mGluR)-antagonists (RS)-1-aminoindan-1,5-dicarboxylic acid (AIDA) or (2S)-alpha-ethylglutamic acid (EGLU), respectively, but not by the group III mGluR-antagonist (RS)-alpha-methylserine-O-phosphate (MSOP). Augmentation of spinal field potentials induced by CGP35348 was prevented by pre-treatment with D-AP5 but not with mGluR-antagonists. The present findings provide novel evidence that disparate synaptic mechanisms subserved by metabotropic and NMDA glutamate receptors may be involved in spinal hyperresponsiveness states secondary to decreased GABA(A) or GABA(B) receptor activity.
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Affiliation(s)
- Itsaso Buesa
- Department of Neurosciences, School of Medicine and Dentistry, Basque Country University, Barrio Sarriena s/n, 48940 Leioa, Spain
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36
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Bolton S, O'Shaughnessy CT, Goadsby PJ. Properties of neurons in the trigeminal nucleus caudalis responding to noxious dural and facial stimulation. Brain Res 2005; 1046:122-9. [PMID: 15885666 DOI: 10.1016/j.brainres.2005.03.044] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2004] [Revised: 03/18/2005] [Accepted: 03/29/2005] [Indexed: 10/25/2022]
Abstract
Extracellular single unit recordings were made in the rat trigeminal nucleus caudalis (Vc) from cells with Adelta and C-fibre latency responding to electrical stimulation of the thinned cranium overlying the middle meningeal artery (MMA). The neurons had an ipsilateral facial receptive field (FRF) that mainly extended over areas innervated by the first and second division of the trigeminal nerve but in some cases also included areas innervated by the third division of the trigeminal nerve. No wind-up of either long latency C-fibre or short latency Adelta responses was seen during trains of electrical stimulation. Sensitisation of mechanical stimulation of the FRF could also not be observed at any time during dural stimulation. In contrast, extracellular single unit recordings in the Vc activated by electrical stimulation of the facial skin resulted in a significant wind-up response of long latency response in six of ten cells studied. The facial-elicited wind-up response was significantly enhanced, 18 min after the electrical stimulation protocol was started, indicating that the process of wind-up had generated central excitability. The findings in this study demonstrate a clear difference between the effects of electrical stimulation of cutaneous and non-cutaneous inputs. In the trigeminal system, this has implications for the study of pathways such as those involved in headache, where it is believed that an enhanced dural input to the Vc may generate central sensitisation and partly explain the hyperalgesia and allodynia reported by patients.
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Affiliation(s)
- S Bolton
- Headache Group, Institute of Neurology, London, UK
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37
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Moffitt MA, Grill WM. Electrical localization of neural activity in the dorsal horn of the spinal cord: a modeling study. Ann Biomed Eng 2005; 32:1694-709. [PMID: 15675681 DOI: 10.1007/s10439-004-7822-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Intraspinal microstimulation is a means of eliciting coordinated motor responses for restoration of function. However, detailed maps of the neuroanatomy of the human spinal cord are lacking, and it is not clear where electrodes should be implanted. We developed an electrical approach to localize active neurons in the spinal cord using potentials recorded from the surface of the spinal cord. We evaluated this localization method using an analytical model of the spinal cord and two previously developed inverse algorithms (standardized low resolution brain electromagnetic tomography (sLORETA) and a locally optimal source (LOS) method). The results support electrical source localization as a feasible imaging approach for localizing (within 300 microm) active neurons in the spinal cord. The LOS method could localize the source when 16 recording electrodes were placed on the dorsolateral aspect of the cord and the noise level was 2%. When recording electrodes were positioned around the entire circumference of the spinal cord, either localization method could localize the source, even at 15% noise. Finally, localization error was not sensitive to inaccuracies in the expected electrode positions or the electrical parameters of the forward model, but was sensitive to a geometrical modification of the forward model in one case.
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Affiliation(s)
- Michael A Moffitt
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
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38
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Kimura S, Tanabe M, Honda M, Ono H. Enhanced Wind-Up of the C-Fiber-Mediated Nociceptive Flexor Reflex Movement Following Painful Diabetic Neuropathy in Mice. J Pharmacol Sci 2005; 97:195-202. [PMID: 15684569 DOI: 10.1254/jphs.fp0040785] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
We examined wind-up of the nociceptive flexor withdrawal responses in diabetic mice that had developed tactile allodynia after treatment with streptozotocin (STZ). In control and STZ-treated mice, simultaneous activation of Adelta- and C-fibers by electrical stimuli at C-fiber intensity delivered to the ventral aspect of the toe elicited a biphasic withdrawal reflex composed of short- and long-latency movements of the ipsilateral hind paw that were respectively mediated by activation of Adelta- and C-fibers. There were no significant differences between control and diabetic mice in the activation threshold of each reflex movement or the amplitude of reflexes elicited by various stimulus intensities. However, a repetitive conditioning stimulus (CS) elicited significantly greater wind-up of the C-fiber-mediated movement and early saturation of wind-up in diabetic mice. In both control and diabetic mice, the CS elicited no or occasionally slight wind-up of the A delta-fiber-mediated movement. Moreover, post-CS facilitation, which reflects the prolonged excitability increase, was observed in both Adelta-fiber- and C-fiber-mediated movements of control mice, whereas significant post-CS facilitation was only obtained in the C-fiber-mediated movement of diabetic mice, which may reflect supraspinal descending influences. Such changes in the excitability of spinal neurons in diabetic mice may represent some aspect of painful diabetic neuropathy.
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Affiliation(s)
- Satoko Kimura
- Laboratory of CNS Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Japan
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Oda M, Kitagawa N, Yang BX, Totoki T, Morimoto M. Quantitative and fiber-selective evaluation of dose-dependent nerve blockade by intrathecal lidocaine in rats. J Pharmacol Exp Ther 2004; 312:1132-7. [PMID: 15572650 DOI: 10.1124/jpet.104.076893] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We investigated whether cutaneous stimulus threshold (CST), as determined using a Neurometer, could be used for quantitative and differential nerve evaluation of reversible and irreversible nerve block following intrathecal lidocaine administration in rats. Rats with intrathecal catheters were randomly assigned to one of five groups (saline or 2, 5, 10, or 20% lidocaine). Prior to and 4 days after drug administration, CST was determined at 5, 250, and 2000 Hz. In the 2% lidocaine group, CST from end of lidocaine infusion to recovery from anesthesia was also monitored. Skin-clamp testing and gait observation were performed for comparison with CST findings. Behavioral examinations revealed persistent sensory or motor impairment lasting 4 days in groups receiving >/=5% lidocaine but not in the saline and 2% lidocaine groups. With 2% lidocaine, return to baseline CSTs at 5 and 250 Hz was delayed compared with thresholds at 2000 Hz. Although CSTs in the 5% group at 5 and 250 Hz increased significantly, thresholds at 2000 Hz did not differ from those in rats administered saline. CSTs with >/=10% lidocaine displayed no differences between frequencies. At each frequency, CSTs for rats with >/=5% lidocaine increased in a clearly concentration-dependent manner. These results suggest that CST testing enables evaluation of the different nerve functions for Abeta, Adelta, and C fibers in rats for lidocaine concentrations </=5% and allows quantitative assessment of persistent neurological deficit induced by lidocaine in rats.
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Affiliation(s)
- Mayuko Oda
- Center for Laboratory Animals, Saga Medical School, Nabeshima, Saga, 849-8501, Japan.
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Abstract
The nociceptive spinal reflex system performs highly precise sensorimotor transformations that require functionally specified synaptic strengths. The specification is gradually attained during early development and appears to be learning dependent. Here we determine the time course of this specification for heat-nociceptive tail withdrawal reflexes and analyze which types of primary afferents are important for the learning by applying various forms of noninvasive sensory deprivations. The percentage of erroneous heat-nociceptive tail withdrawal reflexes (i.e., movements directed toward the stimulation) decreased gradually from 64.1 +/- 2.5% (mean +/- SEM) to <10% during postnatal days 10-21. This improvement was completely blocked by anesthetizing the tail during the adaptation period, confirming that an experience-dependent mechanism is involved in the specification of synaptic strengths. However, the results show that the adaptation occurs to a significant extent despite local analgesia and protection of the tail from noxious input, provided that tactile sensitivity is preserved. Therefore, it appears that a nociceptive input is not necessary for the adaptation, and that input from tactile receptors can be used to guide the nociceptive synaptic organization during development. Sensory deprivation in the adult rat failed to affect the heat-nociceptive withdrawal reflex system, indicating that the adaptation has a "critical period" during early development. These findings provide a key to the puzzle of how pain-related systems can be functionally adapted through experience despite the rare occurrence of noxious input during early life.
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Waldenström A, Thelin J, Thimansson E, Levinsson A, Schouenborg J. Developmental learning in a pain-related system: evidence for a cross-modality mechanism. J Neurosci 2003; 23:7719-25. [PMID: 12930812 PMCID: PMC6740755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2003] [Revised: 06/27/2003] [Accepted: 06/30/2003] [Indexed: 03/04/2023] Open
Abstract
The nociceptive spinal reflex system performs highly precise sensorimotor transformations that require functionally specified synaptic strengths. The specification is gradually attained during early development and appears to be learning dependent. Here we determine the time course of this specification for heat-nociceptive tail withdrawal reflexes and analyze which types of primary afferents are important for the learning by applying various forms of noninvasive sensory deprivations. The percentage of erroneous heat-nociceptive tail withdrawal reflexes (i.e., movements directed toward the stimulation) decreased gradually from 64.1 +/- 2.5% (mean +/- SEM) to <10% during postnatal days 10-21. This improvement was completely blocked by anesthetizing the tail during the adaptation period, confirming that an experience-dependent mechanism is involved in the specification of synaptic strengths. However, the results show that the adaptation occurs to a significant extent despite local analgesia and protection of the tail from noxious input, provided that tactile sensitivity is preserved. Therefore, it appears that a nociceptive input is not necessary for the adaptation, and that input from tactile receptors can be used to guide the nociceptive synaptic organization during development. Sensory deprivation in the adult rat failed to affect the heat-nociceptive withdrawal reflex system, indicating that the adaptation has a "critical period" during early development. These findings provide a key to the puzzle of how pain-related systems can be functionally adapted through experience despite the rare occurrence of noxious input during early life.
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Affiliation(s)
- Alexandra Waldenström
- Section of Neurophysiology, Department for Physiological Sciences, Lund University, S-221 84 Lund, Sweden.
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Nilsson HJ, Psouni E, Schouenborg J. Long term depression of human nociceptive skin senses induced by thin fibre stimulation. Eur J Pain 2003; 7:225-33. [PMID: 12725845 DOI: 10.1016/s1090-3801(02)00120-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We have recently shown that stimulation, through a multi-electrode array, of thin nerve fibres close to the dermo-epidermal junction in the skin, produces powerful inhibition of itch and, to a lesser degree, cutaneous pain in humans. Here, we have studied the induction time and frequency dependency (range 1-10Hz) of the inhibitory effects of such stimulation on itch, mechanical, and thermal pain, in 20 healthy subjects. Sixteen electrodes applied on the skin were consecutively stimulated using a method termed cutaneous field stimulation (CFS). The results show that different treatment periods with CFS were required for the induction of significant inhibitory effects on different nociceptive qualities: 1st heat pain (1 min), itch (3 min), 2nd heat pain (6 min), pinch evoked pain (8 min). Six to ten minutes stimulation sufficed to induce peak inhibitory effects on all these sensory qualities while longer stimulation (up to 40 min) did not cause significantly stronger inhibition. The effects on itch, 1st and 2nd heat pain lasted over 55 min after termination of CFS. There was no effect on prickle. No significant difference in inhibitory effects of different stimulation frequencies (1, 4 and 10Hz/electrode) was found. The induction time and effective stimulation frequencies may suggest that the underlying mechanisms are similar to those of long term depression (LTD) previously described in the spinal cord in animal experiments.
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Affiliation(s)
- Hans Jörgen Nilsson
- Section for Neurophysiology, Department of Physiological Sciences, University of Lund, BMC-F10, Tornavägen 10, S-221 84 Lund, Sweden
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Kalliomäki J, Granmo M, Schouenborg J. Spinal NMDA-receptor dependent amplification of nociceptive transmission to rat primary somatosensory cortex (SI). Pain 2003; 104:195-200. [PMID: 12855329 DOI: 10.1016/s0304-3959(03)00002-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The role of NMDA mechanisms in spinal pathways mediating acute nociceptive input to the somatosensory cortex is not clear. In this study, the effect of NMDA-antagonists on nociceptive C fibre transmission to the primary somatosensory cortex (SI) was investigated. Cortical field potentials evoked by CO(2)-laser stimulation of the skin were recorded in the halothane/nitrous oxide anaesthetized rat. The SI nociceptive evoked potential (EP) amplitudes were dependent on the frequency of noxious heat stimulation. The amplitudes of SI potentials evoked by CO(2)-laser pulses (duration 15-20 ms, stimulation energy 21-28 mJ/mm(2)) delivered at a frequency of 0.1 Hz were approximately 40% of the amplitudes of potentials evoked by 1.0 Hz stimulation. After intrathecal lumbar application of either of the NMDA-antagonists CPP or MK-801, the amplitudes of nociceptive SI potentials, evoked by 1.0 Hz stimulation of the contralateral hindpaw, were reduced to approximately 40% of controls. By contrast, field potentials evoked by 0.1 Hz stimulation of the hindpaw were unaffected by MK-801. SI potentials evoked by 1.0 Hz stimulation of the contralateral forepaw did not change after lumbar application of CPP or MK-801, indicating that the depression of hindpaw EPs was due to a segmental effect in the spinal cord. It is concluded that spinal NMDA-receptor mechanisms amplify the acute transmission of nociceptive C fiber input to SI in a frequency-dependent way.
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Affiliation(s)
- Jarkko Kalliomäki
- Section for Neurophysiology, Department of Physiological Sciences, Lund University, BMC F10, S-221 84 Lund, Sweden
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Laird J, Cervero F. From Acute to Chronic Pain Peripheral and Central Mechanisms. Pain 2003. [DOI: 10.1201/9780203911259.ch3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Thelin J, Waldenström A, Bartsch U, Schachner M, Schouenborg J. Heat nociception is severely reduced in a mutant mouse deficient for the L1 adhesion molecule. Brain Res 2003; 965:75-82. [PMID: 12591122 DOI: 10.1016/s0006-8993(02)04126-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Recent findings indicate that the spatial organization of the spinal nociceptive reflex system is adjusted postnatally through experience-dependent mechanisms. The cellular and molecular mechanisms underlying this tuning are not known. Because the adhesion molecule L1 is known to play an important role in neural development and synaptic plasticity, we studied the nociceptive withdrawal reflexes in awake adult mutant mice deficient in L1. Withdrawal reflexes were elicited by a CO(2) laser (heat stimulation) and von Frey monofilaments (tactile stimulation). L1-deficient mice (n=10) had an abnormally high nociceptive heat-reflex threshold compared with wild-type mice (n=11), except for the nose. Other behavioral signs of heat pain, such as vocalization, were either absent or strongly reduced in L1-deficient mice. Tactile thresholds for withdrawal reflexes were increased in L1-deficient mice when compared with wild-types except for the tail. By contrast, the spatial organization of the withdrawal reflexes appeared normal indicating that the L1 adhesion molecule is not essential for the spatial adjustments of reflex connections during development. The termination patterns of thin primary afferent fibers in the superficial dorsal horn, visualized using intra-plantar injections of WGA-HRP, were normal, suggesting that decreased nociceptive heat sensitivity in L1-deficient mice is mainly due to altered central processing. In view of the known interactions between L1 and some of the NMDA-receptor subtypes, and the prominent role of NMDA receptors in nociception and plasticity, it is conceivable that the hypoalgesia seen in L1 mutants is due, in part, to disturbed NMDA-receptor function.
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Affiliation(s)
- Jonas Thelin
- Section for Neurophysiology, Department of Physiological Sciences, Lund University, BMC F10, S-221 84, Lund, Sweden.
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Glykys J, Guadama M, Marcano L, Ochoa E, Eblen-Zajjur A. Inflammation induced increase of fluoride resistant acid phosphatase (FRAP) activity in the spinal dorsal horn in rats. Neurosci Lett 2003; 337:167-9. [PMID: 12536050 DOI: 10.1016/s0304-3940(02)01323-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fluoride-resistant acid phosphatase (FRAP) has been suggested as an enzymatic marker for nociceptive primary afferent terminals in the spinal dorsal horn, however there has not been demonstrated a direct functional relation between FRAP activity and an increased nociceptive transmission. For this purpose, we quantitated FRAP activity in the spinal dorsal horn of the rat in a heat-induced cutaneous inflammatory model. Male Sprague-Dawley rats anaesthetised with thiopental were separated in two groups where the left hindpaw was submerged during 60 s either in water at room temperature (control group) or in water at 60 degrees C (inflammation group) which induce in this group a progressive hindpaw inflammation. After 8 h, the lumbar enlargement of the spinal cord was extracted, cut in slices and 1 mm micropunch fragments were obtained from the right and left dorsal horn. The activity of FRAP was determined using the Gomori colorimetric method and corrected by the protein concentrations. FRAP activity in the left dorsal horn was statistically higher than right dorsal horn in the inflammation group (3.05+/-0.54 versus 1.91+/-0.23 u/g per l; P<0.05). Also, FRAP activity from the left dorsal horn of the control and inflammation groups show a significant increase in the last group (3.05+/-0.54 versus 2.17+/-0.23 u/g per l; P<0.05). This results demonstrate that FRAP is not only an enzymatic marker for neuronal and fibre integrity of nociceptive primary afferents but also it is associated to the nociceptive afferent activation.
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Affiliation(s)
- J Glykys
- Departamento de Ciencias Fisiológicas, Facultad de Ciencias de la Salud, Universidad de Carabobo, P.O. Box 3798, El Trigal, Valencia, Venezuela
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Crown ED, Ferguson AR, Joynes RL, Grau JW. Instrumental learning within the spinal cord: IV. Induction and retention of the behavioral deficit observed after noncontingent shock. Behav Neurosci 2002; 116:1032-51. [PMID: 12492302 DOI: 10.1037/0735-7044.116.6.1032] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Spinalized rats given shock whenever 1 hind leg is extended learn to maintain that leg in a flexed position, a simple form of instrumental learning. Rats given shock independent of leg position do not exhibit an increase in flexion duration. Experiment 1 showed that 6 min of intermittent legshock can produce this deficit. Intermittent tailshock undermines learning (Experiments 2-3), and this effect lasts at least 2 days (Experiment 4). Exposure to continuous shock did not induce a deficit (Experiment 5) but did induce antinociception (Experiment 6). Intermittent shock did not induce antinociception (Experiment 6). Experiment 7 addressed an alternative interpretation of the results, and Experiment 8 showed that presenting a continuous tailshock while intermittent legshock is applied can prevent the deficit.
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Affiliation(s)
- Eric D Crown
- Department of Psychology, Texas A&M University, USA.
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Abstract
The projection of primary afferents onto spinal interneurons constitutes the first step in sensorimotor transformations performed by spinal reflex systems. Despite extensive studies on spinal somatotopy, uncertainties remain concerning the extent and significance of representational overlap and relation to spinal reflex circuits. To address these issues, the cutaneous projection from the hindpaw and its relation to the topography of lamina V neurons encoding withdrawal reflex strength ("reflex encoders") was studied in rats. Thin and coarse primary afferent terminations in laminas II and III-IV, respectively, were mapped by wheat germ agglutinin-horseradish peroxidase and choleragenoid tracing. The functional weights of these projections were characterized by mapping nociceptive and tactile field potentials and compared with the topography of reflex encoders. Both anatomical and physiological data indicate that thin and coarse skin afferent input is spatially congruent in the horizontal plane. The representation of the hindpaw in the spinal cord was found to be intricate, with a high degree of convergence between the projections from different skin sites. "Somatotopic disruptions" such as the representation of central pads medial to that of the digits were common. The weight distribution of the cutaneous convergence patterns in laminas III-IV was similar to that of lamina V reflex encoders. This suggests that the cutaneous convergence and features such as somatotopic disruptions have specific relations to the sensorimotor transformations performed by reflex interneurons in the deep dorsal horn. Hence, the spinal somatotopic map may be better understood in light of the topography of such reflex systems.
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Schouenborg J. Modular organisation and spinal somatosensory imprinting. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 2002; 40:80-91. [PMID: 12589908 DOI: 10.1016/s0165-0173(02)00191-1] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The withdrawal reflex system has been extensively used as a model system for studies of pain related mechanisms, sensorimotor integration, learning and memory. For a long time, this system was assumed to be organised as a flexion reflex system. However, recent studies indicate that this system has a modular organisation, each module performing a detailed and functionally adapted sensorimotor transformation related to the withdrawal efficacy of its output muscle(s). Each module appears to be a self-organising circuitry that uses sensory feedback on single muscle contractions to adjust its synaptic organisation during development. These findings and their implications for the understanding of higher motor functions as well as clinical aspects will be discussed.
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Affiliation(s)
- Jens Schouenborg
- Department of Physiological Sciences, Lund University, Tornavägen 10, BMC F10, 221 84, Lund, Sweden.
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Levinsson A, Holmberg H, Broman J, Zhang M, Schouenborg J. Spinal sensorimotor transformation: relation between cutaneous somatotopy and a reflex network. J Neurosci 2002; 22:8170-82. [PMID: 12223571 PMCID: PMC6758104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023] Open
Abstract
The projection of primary afferents onto spinal interneurons constitutes the first step in sensorimotor transformations performed by spinal reflex systems. Despite extensive studies on spinal somatotopy, uncertainties remain concerning the extent and significance of representational overlap and relation to spinal reflex circuits. To address these issues, the cutaneous projection from the hindpaw and its relation to the topography of lamina V neurons encoding withdrawal reflex strength ("reflex encoders") was studied in rats. Thin and coarse primary afferent terminations in laminas II and III-IV, respectively, were mapped by wheat germ agglutinin-horseradish peroxidase and choleragenoid tracing. The functional weights of these projections were characterized by mapping nociceptive and tactile field potentials and compared with the topography of reflex encoders. Both anatomical and physiological data indicate that thin and coarse skin afferent input is spatially congruent in the horizontal plane. The representation of the hindpaw in the spinal cord was found to be intricate, with a high degree of convergence between the projections from different skin sites. "Somatotopic disruptions" such as the representation of central pads medial to that of the digits were common. The weight distribution of the cutaneous convergence patterns in laminas III-IV was similar to that of lamina V reflex encoders. This suggests that the cutaneous convergence and features such as somatotopic disruptions have specific relations to the sensorimotor transformations performed by reflex interneurons in the deep dorsal horn. Hence, the spinal somatotopic map may be better understood in light of the topography of such reflex systems.
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Affiliation(s)
- Anders Levinsson
- Section for Neurophysiology, Department of Physiological Sciences, Lund University, S-221 84 Lund, Sweden.
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