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Patel R, Taylor JL, Dickenson AH, McMahon SB, Bannister K. A back-translational study of descending interactions with the induction of hyperalgesia by high-frequency electrical stimulation in rats and humans. Pain 2024; 165:1978-1989. [PMID: 38198231 PMCID: PMC11331830 DOI: 10.1097/j.pain.0000000000003166] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 10/13/2023] [Accepted: 10/29/2023] [Indexed: 01/12/2024]
Abstract
ABSTRACT In humans and animals, high-frequency electrocutaneous stimulation (HFS) induces an "early long-term potentiation-like" sensitisation, where synaptic plasticity is underpinned by an ill-defined interaction between peripheral input and central modulatory processes. The relative contributions of these processes to the initial pain or nociceptive response likely differ from those that underpin development of the heightened response. To investigate the impact of HFS-induced hyperalgesia on pain and nociception in perception and neural terms, respectively, and to explore the impact of descending inhibitory pathway activation on the development of HFS-induced hyperalgesia, we performed parallel studies utilising identical stimuli to apply HFS concurrent to (1) a conditioned pain modulation paradigm during psychophysical testing in healthy humans or (2) a diffuse noxious inhibitory controls paradigm during in vivo electrophysiological recording of spinal neurones in healthy anaesthetised rats. High-frequency electrocutaneous stimulation alone induced enhanced perceptual responses to pinprick stimuli in cutaneous areas secondary to the area of electrical stimulation in humans and increased the excitability of spinal neurones which exhibited stimulus intensity-dependent coded responses to pinprick stimulation in a manner that tracked with human psychophysics, supporting their translational validity. Application of a distant noxious conditioning stimulus during HFS did not alter perceived primary or secondary hyperalgesia in humans or the development of primary or secondary neuronal hyperexcitability in rats compared with HFS alone, suggesting that, upon HFS-response initiation in a healthy nervous system, excitatory signalling escapes inhibitory control. Therefore, in this model, dampening facilitatory mechanisms rather than augmenting top-down inhibitions could prevent pain development.
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Affiliation(s)
- Ryan Patel
- King's College London, Wolfson Centre, Guy's Campus, London, United Kingdom
| | - Joseph L. Taylor
- King's College London, Wolfson Centre, Guy's Campus, London, United Kingdom
| | - Anthony H. Dickenson
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom
| | - Stephen B. McMahon
- King's College London, Wolfson Centre, Guy's Campus, London, United Kingdom
| | - Kirsty Bannister
- King's College London, Wolfson Centre, Guy's Campus, London, United Kingdom
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Meijs S, Andreis FR, Janjua TAM, Graven-Nielsen T, Jensen W. High-frequency electrical stimulation increases cortical excitability and mechanical sensitivity in a chronic large animal model. Pain 2024:00006396-990000000-00682. [PMID: 39133034 DOI: 10.1097/j.pain.0000000000003354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 06/12/2024] [Indexed: 08/13/2024]
Abstract
ABSTRACT Translational models of the sensitized pain system are needed to progress the understanding of involved mechanisms. In this study, long-term potentiation was used to develop a mechanism-based large-animal pain model. Event-related potentials to electrical stimulation of the ulnar nerve were recorded by intracranial recordings in pigs, 3 weeks before, immediately before and after, and 3 weeks after peripheral high-frequency stimulation (HFS) applied to the ulnar nerve in the right forelimb (7 pigs) or in control animals (5 pigs). Event-related potential recordings and peripheral HFS were done during anesthesia. Two weeks before and after the HFS, behavioral responses reflecting mechanical and thermal sensitivity were collected using brush, noxious limb-mounted pressure algometer, and noxious laser stimuli. The HFS intervention limb was progressively sensitized to noxious mechanical stimulation in week 1 and 2 compared with baseline (P = 0.045) and the control group (P < 0.034) but not significantly to laser or brush stimulation. The first negative (N1) peak of the event-related potential was increased 30 minutes after HFS compared with before (P < 0.05). The N1 peak was also larger compared with control pigs 20 to 40 minutes after HFS (P < 0.031) but not significantly increased 3 weeks after. The relative increase in N1 30 minutes after HFS and the degree of mechanical hyperalgesia 2 weeks post-HFS was correlated (P < 0.033). These results show for the first time that the pig HFS model resembles the human HFS model closely where the profile of sensitization is comparable. Interestingly, the degree of sensitization was associated with the cortical signs of hyperexcitability at HFS induction.
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Affiliation(s)
- Suzan Meijs
- Department of Health Science and Technology, Center for Neuroplasticity and Pain (CNAP), Aalborg University, Aalborg, Denmark
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Hodkinson DJ, Drabek MM, Jung J, Lankappa ST, Auer DP. Theta Burst Stimulation of the Human Motor Cortex Modulates Secondary Hyperalgesia to Punctate Mechanical Stimuli. Neuromodulation 2024; 27:812-823. [PMID: 37952136 DOI: 10.1016/j.neurom.2023.10.007] [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: 07/12/2023] [Revised: 09/19/2023] [Accepted: 10/03/2023] [Indexed: 11/14/2023]
Abstract
OBJECTIVES Many chronic pain conditions show evidence of dysregulated synaptic plasticity, including the development and maintenance of central sensitization. This provides a strong rationale for neuromodulation therapies for the relief of chronic pain. However, variability in responses and low fidelity across studies remain an issue for both clinical trials and pain management, demonstrating insufficient mechanistic understanding of effective treatment protocols. MATERIALS AND METHODS In a randomized counterbalanced crossover designed study, we evaluated two forms of patterned repetitive transcranial magnetic stimulation, known as continuous theta burst stimulation (TBS) and intermittent TBS, during normal and central sensitization states. Secondary hyperalgesia (a form of use-dependent central sensitization) was induced using a well-established injury-free pain model and assessed by standardized quantitative sensory testing involving light touch and pinprick pain thresholds in addition to stimulus-response functions. RESULTS We found that continuous TBS of the human motor cortex has a facilitatory (pronociceptive) effect on the magnitude of perceived pain to secondary hyperalgesia, which may rely on induction and expression of neural plasticity through heterosynaptic long-term potentiation-like mechanisms. CONCLUSIONS By defining the underlying mechanisms of TBS-driven synaptic plasticity in the nociceptive system, we offer new insight into disease mechanisms and provide targets for promoting functional recovery and repair in chronic pain. For clinical applications, this knowledge is critical for development of more efficacious and mechanisms-based neuromodulation protocols, which are urgently needed to address the chronic pain and opioid epidemics.
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Affiliation(s)
- Duncan J Hodkinson
- Division of Mental Health and Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, UK; Sir Peter Mansfield Imaging Center, School of Medicine, University of Nottingham, Nottingham, UK; National Institute for Health Research, Nottingham Biomedical Research Center, Queens Medical Center, Nottingham, UK.
| | - Marianne M Drabek
- Division of Mental Health and Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, UK; Sir Peter Mansfield Imaging Center, School of Medicine, University of Nottingham, Nottingham, UK; National Institute for Health Research, Nottingham Biomedical Research Center, Queens Medical Center, Nottingham, UK
| | - JeYoung Jung
- School of Psychology, University of Nottingham, Nottingham, UK
| | - Sudheer T Lankappa
- Nottinghamshire Healthcare National Health Service Foundation Trust, Nottingham, UK
| | - Dorothee P Auer
- Division of Mental Health and Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, UK; Sir Peter Mansfield Imaging Center, School of Medicine, University of Nottingham, Nottingham, UK; National Institute for Health Research, Nottingham Biomedical Research Center, Queens Medical Center, Nottingham, UK
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Luebke L, Lopes CG, Myka Y, Lumma A, Adamczyk WM, Carvalho GF, Scholten-Peeters GGM, Luedtke K, Szikszay TM. Assessing the Influence of Nonischemic A-Fiber Conduction Blockade on Offset Analgesia: An Experimental Study. THE JOURNAL OF PAIN 2024:104611. [PMID: 38908497 DOI: 10.1016/j.jpain.2024.104611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 05/31/2024] [Accepted: 06/14/2024] [Indexed: 06/24/2024]
Abstract
Offset analgesia (OA) is believed to reflect the efficiency of the endogenous pain modulatory system. However, the underlying mechanisms are still being debated. Previous research suggested both, central and peripheral mechanisms, with the latter involving the influence of specific A-delta-fibers. Therefore, this study aimed to investigate the influence of a nonischemic A-fiber conduction blockade on the OA response in healthy participants. A total of 52 participants were recruited for an A-fiber conduction blockade via compression of the superficial radial nerve. To monitor fiber-specific peripheral nerve conduction capacity, quantitative sensory testing was performed continuously. Before, during, and after the A-fiber block, an individualized OA paradigm was applied to the dorsum of both hands (blocked and control sides were randomized). The pain intensity of each heat stimulus was evaluated by an electronic visual analog scale. A successful A-fiber conduction blockade was achieved in thirty participants. OA has been verified within time (before, during, and after blockade) and condition (blocked and control side) (P < .01, d > .5). Repeated measurements analysis of variance showed no significant interaction effects between OA within condition and time (P = .24, η²p = .05). Hence, no significant effect of A-fiber blockade was detected on OA during noxious heat stimulation. The results suggest that peripheral A-fiber afferents may play a minor role in OA compared with alternative central mechanisms or other fibers. However, further studies are needed to substantiate a central rather than peripheral influence on OA. PERSPECTIVE: This article presents the observation of OA before, during, and after a successful A-fiber conduction blockade in healthy volunteers. A better understanding of the mechanisms of OA and endogenous pain modulation, in general, may help to explain the underlying aspects of pain disorders.
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Affiliation(s)
- Luisa Luebke
- Department of Physiotherapy, Pain and Exercise Research Luebeck (P.E.R.L.), Institute of Health Sciences, University of Luebeck, Lübeck, Germany; Center of Brain, Behavior and Metabolism (CBBM), University of Luebeck, Lübeck, Germany.
| | - Clara Gieseke Lopes
- Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Program Musculoskeletal Health, Amsterdam, The Netherlands
| | - Yasmin Myka
- Department of Physiotherapy, Pain and Exercise Research Luebeck (P.E.R.L.), Institute of Health Sciences, University of Luebeck, Lübeck, Germany
| | - Annika Lumma
- Department of Physiotherapy, Pain and Exercise Research Luebeck (P.E.R.L.), Institute of Health Sciences, University of Luebeck, Lübeck, Germany
| | - Wacław M Adamczyk
- Department of Physiotherapy, Pain and Exercise Research Luebeck (P.E.R.L.), Institute of Health Sciences, University of Luebeck, Lübeck, Germany; Center of Brain, Behavior and Metabolism (CBBM), University of Luebeck, Lübeck, Germany; Laboratory of Pain Research, Institute of Physiotherapy and Health Sciences, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Gabriela F Carvalho
- Department of Physiotherapy, Faculty of Health, Safety and Society, Furtwangen University, Furtwangen, Germany
| | - Gwendolyne G M Scholten-Peeters
- Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Program Musculoskeletal Health, Amsterdam, The Netherlands
| | - Kerstin Luedtke
- Department of Physiotherapy, Pain and Exercise Research Luebeck (P.E.R.L.), Institute of Health Sciences, University of Luebeck, Lübeck, Germany; Center of Brain, Behavior and Metabolism (CBBM), University of Luebeck, Lübeck, Germany
| | - Tibor M Szikszay
- Department of Physiotherapy, Pain and Exercise Research Luebeck (P.E.R.L.), Institute of Health Sciences, University of Luebeck, Lübeck, Germany; Center of Brain, Behavior and Metabolism (CBBM), University of Luebeck, Lübeck, Germany
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Rees TA, Tasma Z, Garelja ML, O'Carroll SJ, Walker CS, Hay DL. Calcitonin receptor, calcitonin gene-related peptide and amylin distribution in C1/2 dorsal root ganglia. J Headache Pain 2024; 25:36. [PMID: 38481170 PMCID: PMC10938748 DOI: 10.1186/s10194-024-01744-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 03/05/2024] [Indexed: 03/17/2024] Open
Abstract
BACKGROUND The upper cervical dorsal root ganglia (DRG) are important for the transmission of sensory information associated with the back of the head and neck, contributing to head pain. Calcitonin receptor (CTR)-based receptors, such as the amylin 1 (AMY1) receptor, and ligands, calcitonin gene-related peptide (CGRP) and amylin, have been linked to migraine and pain. However, the contribution of this system to nociception involving the cervical DRG is unclear. Therefore, this study aimed to determine the relative distribution of the CTR, CGRP, and amylin in upper cervical DRG. METHODS CTR, CGRP, and amylin immunofluorescence was examined relative to neural markers in C1/2 DRG from male and female mice, rats, and human cases. Immunofluorescence was supported by RNA-fluorescence in situ hybridization examining amylin mRNA distribution in rat DRG. RESULTS Amylin immunofluorescence was observed in neuronal soma and fibres. Amylin mRNA (Iapp) was also detected. Amylin and CGRP co-expression was observed in 19% (mouse), 17% (rat), and 36% (human) of DRG neurons in distinct vesicle-like neuronal puncta from one another. CTR immunoreactivity was present in DRG neurons, and both peptides produced receptor signalling in primary DRG cell cultures. CTR-positive neurons frequently co-expressed amylin and/or CGRP (66% rat; 84% human), with some sex differences. CONCLUSIONS Amylin and CGRP could both be local peptide agonists for CTR-based receptors in upper cervical DRG, potentially acting through autocrine and/or paracrine signalling mechanisms to modulate neuron function. Amylin and its receptors could represent novel pain targets.
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Affiliation(s)
- Tayla A Rees
- School of Biological Sciences, University of Auckland, Auckland, 1010, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, 1010, New Zealand
| | - Zoe Tasma
- School of Biological Sciences, University of Auckland, Auckland, 1010, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, 1010, New Zealand
| | - Michael L Garelja
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, 1010, New Zealand
- Department of Pharmacology and Toxicology, University of Otago, Dunedin, 9016, New Zealand
| | - Simon J O'Carroll
- Department of Anatomy and Medical Imaging, Centre for Brain Research, Faculty of Medical and Health Science, University of Auckland, Auckland, 1023, New Zealand
| | - Christopher S Walker
- School of Biological Sciences, University of Auckland, Auckland, 1010, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, 1010, New Zealand
| | - Debbie L Hay
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, 1010, New Zealand.
- Department of Pharmacology and Toxicology, University of Otago, Dunedin, 9016, New Zealand.
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Martel RD, Papafragou G, Weigand S, Rolke R, Prawitt D, Birklein F, Treede RD, Magerl W. Interindividual variability in cold-pressor pain sensitivity is not explained by peripheral vascular responding and generalizes to a C-nociceptor-specific pain phenotype. Pain 2024; 165:e1-e14. [PMID: 38284423 DOI: 10.1097/j.pain.0000000000003049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 07/07/2023] [Indexed: 01/30/2024]
Abstract
ABSTRACT Pain sensitivity of healthy subjects in the cold-pressor (CP) test was proposed to be dichotomously distributed and to represent a pain sensitivity trait. Still, it has not been systematically explored which factors influence this pain sensitivity readout. The aim of this study was to distinguish potential contributions of local tissue-related factors such as perfusion and thermoregulation or gain settings in nociceptive systems. Cold-pressor-sensitive and CP-insensitive students screened from a medical student laboratory course were recruited for a CP retest with additional cardiovascular and bilateral local vascular monitoring. In addition, comprehensive quantitative sensory testing according to Deutscher Forschungsverbund Neuropathischer Schmerz standards and a sustained pinch test were performed. Cold pressor was reproducible across sessions (Cohen kappa 0.61 ± 0.14, P < 0.005). At 30 seconds in ice water, CP-sensitive subjects exhibited not only more pain (78.6 ± 26.3 vs 29.5 ± 17.5, P < 0.0001) but also significantly stronger increases in mean arterial blood pressure (12.6 ± 9.3 vs 5.6 ± 8.1 mm Hg, P < 0.05) and heart rate (15.0 ± 8.2 vs 7.1 ± 6.2 bpm, P < 0.005), and lower baroreflex sensitivity, but not local or vasoconstrictor reflex-mediated microcirculatory responses. Cold-pressor-sensitive subjects exhibited significantly lower pain thresholds also for cold, heat, and blunt pressure, and enhanced pain summation, but no significant differences in Aδ-nociceptor-mediated punctate mechanical pain. In conclusion, differences in nociceptive signal processing drove systemic cardiovascular responses. Baroreceptor activation suppressed pain and cardiovascular responses more efficiently in CP-insensitive subjects. Cold-pressor sensitivity generalized to a pain trait of C-fiber-mediated nociceptive channels, which was independent of local thermal and vascular changes in the ice-water-exposed hand. Thus, the C-fiber pain trait reflects gain setting of the nociceptive system.
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Affiliation(s)
- Richard D Martel
- Department of Neurophysiology, Mannheim Center for Translational Neurosciences (MCTN), Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany. Martel is now with the Department of Pediatric Surgery, University Medical Center Mannheim, Heidelberg University, Heidelberg, Germany. Papafragou is now with the Vitos Orthopädische Klinik Kassel, Kassel, Germany. Weigand is now with the Department of Internal Medicine I, University of Regensburg, Regensburg, Germany. Rolke is now with the Department of Palliative Care, RWTH Aachen, Aachen, Germany
| | - Georgios Papafragou
- Department of Neurophysiology, Mannheim Center for Translational Neurosciences (MCTN), Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany. Martel is now with the Department of Pediatric Surgery, University Medical Center Mannheim, Heidelberg University, Heidelberg, Germany. Papafragou is now with the Vitos Orthopädische Klinik Kassel, Kassel, Germany. Weigand is now with the Department of Internal Medicine I, University of Regensburg, Regensburg, Germany. Rolke is now with the Department of Palliative Care, RWTH Aachen, Aachen, Germany
| | - Sylvia Weigand
- Department of Neurophysiology, Mannheim Center for Translational Neurosciences (MCTN), Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany. Martel is now with the Department of Pediatric Surgery, University Medical Center Mannheim, Heidelberg University, Heidelberg, Germany. Papafragou is now with the Vitos Orthopädische Klinik Kassel, Kassel, Germany. Weigand is now with the Department of Internal Medicine I, University of Regensburg, Regensburg, Germany. Rolke is now with the Department of Palliative Care, RWTH Aachen, Aachen, Germany
| | | | - Dirk Prawitt
- Pediatric Medicine, Medical Center, Johannes Gutenberg University, Mainz, Germany
| | | | - Rolf-Detlef Treede
- Department of Neurophysiology, Mannheim Center for Translational Neurosciences (MCTN), Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany. Martel is now with the Department of Pediatric Surgery, University Medical Center Mannheim, Heidelberg University, Heidelberg, Germany. Papafragou is now with the Vitos Orthopädische Klinik Kassel, Kassel, Germany. Weigand is now with the Department of Internal Medicine I, University of Regensburg, Regensburg, Germany. Rolke is now with the Department of Palliative Care, RWTH Aachen, Aachen, Germany
| | - Walter Magerl
- Department of Neurophysiology, Mannheim Center for Translational Neurosciences (MCTN), Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany. Martel is now with the Department of Pediatric Surgery, University Medical Center Mannheim, Heidelberg University, Heidelberg, Germany. Papafragou is now with the Vitos Orthopädische Klinik Kassel, Kassel, Germany. Weigand is now with the Department of Internal Medicine I, University of Regensburg, Regensburg, Germany. Rolke is now with the Department of Palliative Care, RWTH Aachen, Aachen, Germany
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Escobar-Sánchez I, Ríos-León M, Taylor J. Long-term bilateral change in pain and sensitivity to high-frequency cutaneous electrical stimulation in healthy subjects depends on stimulus modality: a dermatomal examination. Front Med (Lausanne) 2024; 10:1337711. [PMID: 38293302 PMCID: PMC10825033 DOI: 10.3389/fmed.2023.1337711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 12/30/2023] [Indexed: 02/01/2024] Open
Abstract
Introduction Contradictory changes in pain and sensitivity at long-term following cutaneous 100 Hz high frequency stimulation (HFS) have been previously observed. Thus, we aimed to document long-lasting changes in multimodal sensitivity following HFS, and factors influencing them. Methods Long-lasting changes were assessed with mechanical [brush, von Frey filament (588.2 mN)] and thermal [heat (40°C)/cold (25°C)] bedside sensory testing, and electrical TS (0.2 ms single electrical stimuli), at the homotopic (ipsilateral C6 dermatome), adjacent heterotopic (ipsilateral C5 and C7 dermatomes) and contralateral (contralateral C6 dermatomes) dermatomal sites in a single testing session. TS were applied before and after application of 100 Hz HFS at the ipsilateral C6 dermatome. Subjects rated their sensation and pain intensity to TS, and completed questionnaires related to pain descriptors and quality of life. Results Long-lasting changes in mechanical and cold sensitivity was detected up to 45 min after HFS at homotopic C6 dermatome, and a temporary increase in cold sensitivity at 20 min in the contralateral C6 dermatome (p < 0.05). A slow development of bilateral depotentiation to electrical pain TS was also detected from 40 min after HFS (p < 0.05). Higher HFS-induced mechanical and cold sensitivity was identified in women (p < 0.05). Age and quality of life were associated with pain intensity (p < 0.05). Conclusion Long-term unilateral and bilateral changes in sensation and pain following electrical HFS have been found. These findings may suggest a new insight into the development of persistent pain mechanisms. Further studies are now needed.
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Affiliation(s)
- Isabel Escobar-Sánchez
- Sensorimotor Function Group, Hospital Nacional de Parapléjicos (SESCAM), Toledo, Spain
- Alumna de Doctorado (Ciencias de la Salud), Escuela Internacional de Doctorado, Universidad de Castilla-La Mancha, Ciudad Real, Spain
| | - Marta Ríos-León
- Sensorimotor Function Group, Hospital Nacional de Parapléjicos (SESCAM), Toledo, Spain
- Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Toledo, Spain
| | - Julian Taylor
- Sensorimotor Function Group, Hospital Nacional de Parapléjicos (SESCAM), Toledo, Spain
- Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Toledo, Spain
- Harris Manchester College, University of Oxford, Oxford, United Kingdom
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Wittkopf PG, Boye Larsen D, Gregoret L, Graven-Nielsen T. Disrupted Cortical Homeostatic Plasticity Due to Prolonged Capsaicin-induced Pain. Neuroscience 2023; 533:1-9. [PMID: 37774909 DOI: 10.1016/j.neuroscience.2023.09.011] [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: 06/29/2023] [Revised: 09/08/2023] [Accepted: 09/20/2023] [Indexed: 10/01/2023]
Abstract
Homeostatic plasticity (HP) regulates cortical excitability (CE) stability but is disrupted in persistent pain conditions. This study investigated how prolonged experimental pain affects HP and if pain relief modulates disrupted HP. Twenty-four healthy participants were randomised into a PainRelief or NoPainRelief group and attended four sessions; two sessions on consecutive days, separated by two weeks. Transcranial magnetic stimulation motor-evoked potentials reflecting CE and quantitative sensory testing (QST) measures were recorded. A capsaicin (pain condition) or placebo (control condition) patch was applied to the hand. HP was induced by cathodal-cathodal transcranial direct current stimulation (HP1) with CE assessment before and after. The PainRelief group had ice applied to the patch, while the NoPainRelief group waited for five minutes; subsequently another HP induction (HP2) and CE assessment were performed. After 24 h with the patch on, HP induction (HP3), QST, and CE recordings were repeated. Capsaicin reduced CE and the pain condition showed disrupted homeostatic responses at all time points (HP1: showed CE inhibition instead of facilitation; HP2 & HP3: lack of CE facilitation). Conversely, homeostatic responses were induced at all time points for the placebo condition. Capsaicin pain disrupts HP which is not restored by ice-induced pain relief. Future research may explore the prevention of HP disruption by targeting capsaicin-induced nociception but not pain perception.
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Affiliation(s)
- Priscilla Geraldine Wittkopf
- Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Selma Lagerløfs Vej 249, 9260 Gistrup, Aalborg, Denmark
| | - Dennis Boye Larsen
- Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Selma Lagerløfs Vej 249, 9260 Gistrup, Aalborg, Denmark
| | - Luisina Gregoret
- Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Selma Lagerløfs Vej 249, 9260 Gistrup, Aalborg, Denmark
| | - Thomas Graven-Nielsen
- Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Selma Lagerløfs Vej 249, 9260 Gistrup, Aalborg, Denmark.
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Guiloff RJ, Campero M, Barraza GR, Treede RD, Matamala JM, Castillo JL. Pain-Related Vertex Evoked Potentials. Comparison of Surface Electrical to Heat Stimulation. J Clin Neurophysiol 2023; 40:616-624. [PMID: 37931163 DOI: 10.1097/wnp.0000000000000929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
INTRODUCTION Demonstration of nociceptive fiber abnormality is important for diagnosing neuropathic pain and small fiber neuropathies. This is usually assessed by brief heat pulses using lasers, contact heat, or special electrodes. We hypothesized that pain-related evoked potentials to conventional surface electrical stimulation (PREPse) can index Aδ afferences despite tactile Aß fibers coactivation. PREPse may be more readily used clinically than contact heat evoked potentials (CHEPS). METHODS Twenty-eight healthy subjects. Vertex (Cz-A1/A2) recordings. Electrical stimulation of middle finger and second toe with conventional ring, and forearm/leg skin with cup, electrodes. Contact heat stimulation to forearm and leg. Compression ischemic nerve blockade. RESULTS PREPse peripheral velocities were within the midrange of Aδ fibers. N1-P1 amplitude increased with pain numerical rating scale graded (0-10) electrical stimulation (n = 25) and decreased with increasing stimulation frequency. Amplitudes were unchanged by different presentation orders of four stimulation intensities. PREPse N1 (∼130 milliseconds) and N2 (∼345 milliseconds) peaks were approximately 40 milliseconds earlier than that with CHEPS. PREPse and CHEPS N1-N2 interpeak latency (∼207 milliseconds) were similar. PREPse became unrecordable with nerve blockade of Aδ fibers. CONCLUSIONS PREPse earlier N1 and N2 peaks, and similar interpeak N1-N2 latencies and central conduction velocities, or synaptic delays, to CHEPS are consistent with direct stimulation of Aδ fibers. The relation of vertex PREPse amplitude and pain, or the differential effects of frequency stimulation, is similar to pain-related evoked potential to laser, special electrodes, or contact heat stimulation. The relationship to Aδ was validated by conduction velocity and nerve block. Clinical utility of PREPse compared with CHEPS needs validation in somatosensory pathways lesions.
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Affiliation(s)
- Roberto J Guiloff
- Faculty of Medicine University of Chile, Santiago, Chile
- Imperial College, London, United Kingdom
- Neuromuscular Unit, Department of Neurology and Neurosurgery, Hospital Clinico Universidad de Chile, Santiago, Chile
| | - Mario Campero
- Faculty of Medicine University of Chile, Santiago, Chile
- Neuromuscular Unit, Department of Neurology and Neurosurgery, Hospital Clinico Universidad de Chile, Santiago, Chile
| | - Gonzalo R Barraza
- Neuromuscular Unit, Department of Neurology and Neurosurgery, Hospital Clinico Universidad de Chile, Santiago, Chile
| | | | - Jose M Matamala
- Faculty of Medicine University of Chile, Santiago, Chile
- Department of Neurological Science, Hospital El Salvador, Santiago, Chile
| | - Jose L Castillo
- Department of Neurological Science, Hospital El Salvador, Santiago, Chile
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Bedwell GJ, Chikezie PC, Siboza FT, Mqadi L, Rice ASC, Kamerman PR, Parker R, Madden VJ. A Systematic Review and Meta-analysis of Non-pharmacological Methods to Manipulate Experimentally Induced Secondary Hypersensitivity. THE JOURNAL OF PAIN 2023; 24:1759-1797. [PMID: 37356604 DOI: 10.1016/j.jpain.2023.06.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 06/13/2023] [Accepted: 06/18/2023] [Indexed: 06/27/2023]
Abstract
This systematic review and meta-analysis investigated the effects of non-pharmacological manipulations on experimentally induced secondary hypersensitivity in pain-free humans. We investigated the magnitude (change/difference in follow-up ratings from pre-manipulation ratings) of secondary hypersensitivity (primary outcome), and surface area of secondary hypersensitivity (secondary outcome), in 27 studies representing 847 participants. Risk of bias assessment concluded most studies (23 of 27) had an unclear or high risk of performance and detection bias. Further, 2 (of 27) studies had a high risk of measurement bias. Datasets were pooled by the method of manipulation and outcome. The magnitude of secondary hypersensitivity was decreased by diverting attention, anodal transcranial direct current stimulation, or emotional disclosure; increased by directing attention toward the induction site, nicotine deprivation, or negative suggestion; and unaffected by cathodal transcranial direct current stimulation or thermal change. Area of secondary hypersensitivity was decreased by anodal transcranial direct current stimulation, emotional disclosure, cognitive behavioral therapy, hyperbaric oxygen therapy, placebo analgesia, or spinal manipulation; increased by directing attention to the induction site, nicotine deprivation, or sleep disruption (in males only); and unaffected by cathodal transcranial direct current stimulation, thermal change, acupuncture, or electroacupuncture. Meta-analytical pooling was only appropriate for studies that used transcranial direct current stimulation or hyperbaric oxygen therapy, given the high clinical heterogeneity among the studies and unavailability of data. The evidence base for this question remains small. We discuss opportunities to improve methodological rigor including manipulation checks, structured blinding strategies, control conditions or time points, and public sharing of raw data. PERSPECTIVE: We described the effects of several non-pharmacological manipulations on experimentally induced secondary hypersensitivity in humans. By shedding light on the potential for non-pharmacological therapies to influence secondary hypersensitivity, it provides a foundation for the development and testing of targeted therapies for secondary hypersensitivity.
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Affiliation(s)
- Gillian J Bedwell
- Department of Health and Rehabilitation Sciences, University of Cape Town, Cape Town, South Africa; Department of Anaesthesia and Perioperative Medicine, University of Cape Town, Cape Town, South Africa
| | - Prince C Chikezie
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Felicia T Siboza
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Luyanduthando Mqadi
- Department of Anaesthesia and Perioperative Medicine, University of Cape Town, Cape Town, South Africa; HIV Mental Health Research Unit, Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
| | - Andrew S C Rice
- Pain Research Group, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, UK
| | - Peter R Kamerman
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Romy Parker
- Department of Anaesthesia and Perioperative Medicine, University of Cape Town, Cape Town, South Africa
| | - Victoria J Madden
- Department of Anaesthesia and Perioperative Medicine, University of Cape Town, Cape Town, South Africa; HIV Mental Health Research Unit, Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
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11
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Glaros AK, Callaghan MU, Smith WR, Zaidi AU. Targeting TRPV1 activity via high‐dose capsaicin in patients with sickle cell disease. EJHAEM 2022; 3:653-659. [PMID: 36051054 PMCID: PMC9421981 DOI: 10.1002/jha2.528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 06/27/2022] [Indexed: 11/09/2022]
Abstract
Evidence suggests neuropathic pain (NP) develops over time in sickle cell disease (SCD), contributing to a complex, difficult‐to‐treat phenotype, with management based on scant evidence. One characteristic of NP found is hyperalgesia caused by nervous system sensitization, but risk factors for this have not been identified within the SCD population, as exact mechanisms leading to its development are not well defined. The SPICE (Sickle cell Pain: Intervention with Capsaicin Exposure) trial was a pilot safety and feasibility trial of high‐dose (8%) topical capsaicin for patients with SCD and recurrent/chronic pain with neuropathic features, aimed at exploring capsaicin's utility as a mechanistic probe and adjunctive pain treatment for this population. Ten participants identifying “target” sites of pain with NP‐type qualities consented to treatment. The primary endpoint was safety/tolerability. The novel Localized Peripheral Hypersensitivity Relief score (LPHR) was developed to determine improvement in sensitivity attributable to TRPV1 neutralization. There were no severe treatment‐related adverse events. Higher baseline pain sensitivity at a given body site was associated with self‐reported history of more frequent localized vaso‐occlusive pain episodes at that site. There was a statistically significant improvement in the mean LPHR, evidencing TRPV1's importance to the development of hypersensitivity and a potential therapeutic benefit of capsaicin for SCD.
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Affiliation(s)
- Alexander K. Glaros
- Central Michigan University College of Medicine Mount Pleasant Michigan USA
- Division of Pediatric Hematology‐Oncology Children's Hospital of Michigan Detroit Michigan USA
| | - Michael U. Callaghan
- Central Michigan University College of Medicine Mount Pleasant Michigan USA
- Division of Pediatric Hematology‐Oncology Children's Hospital of Michigan Detroit Michigan USA
| | - Wally R. Smith
- Division of General Internal Medicine Virginia Commonwealth University Richmond Virginia USA
| | - Ahmar U. Zaidi
- Central Michigan University College of Medicine Mount Pleasant Michigan USA
- Division of Pediatric Hematology‐Oncology Children's Hospital of Michigan Detroit Michigan USA
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12
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Jubileum E, Binzen U, Treede RD, Greffrath W. Temporal and spatial summation of laser heat stimuli in cultured nociceptive neurons of the rat. Pflugers Arch 2022; 474:1003-1019. [PMID: 35867188 PMCID: PMC9393153 DOI: 10.1007/s00424-022-02728-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 12/04/2022]
Abstract
We studied the efficacy of a near-infrared laser (1475 nm) to activate rat dorsal root ganglion (DRG) neurons with short punctate radiant heat pulses (55 µm diameter) and investigated temporal and spatial summation properties for the transduction process for noxious heat at a subcellular level. Strength-duration curves (10–80 ms range) indicated a minimum power of 30.2mW for the induction of laser-induced calcium transients and a chronaxia of 13.9 ms. However, threshold energy increased with increasing stimulus duration suggesting substantial radial cooling of the laser spot. Increasing stimulus duration demonstrated suprathreshold intensity coding of calcium transients with less than linear gains (Stevens exponents 0.29/35mW, 0.38/60mW, 0.46/70mW). The competitive TRPV1 antagonist capsazepine blocked responses to short near-threshold stimuli and significantly reduced responses to longer duration suprathreshold heat. Heating 1/3 of the soma of a neuron was sufficient to induce calcium transients significantly above baseline (p < 0.05), but maximum amplitude was only achieved by centering the laser over the entire neuron. Heat-induced calcium increase was highest in heated cell parts but rapidly reached unstimulated areas reminiscent of spreading depolarization and opening of voltage-gated calcium channels. Full intracellular equilibrium took about 3 s, consistent with a diffusion process. In summary, we investigated transduction mechanisms for noxious laser heat pulses in native sensory neurons at milliseconds temporal and subcellular spatial resolution and characterized strength duration properties, intensity coding, and spatial summation within single neurons. Thermal excitation of parts of a nociceptor spread via both membrane depolarization and intracellular calcium diffusion.
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Affiliation(s)
- Elisabeth Jubileum
- Department of Neurophysiology, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Str. 13-17, 68167, Mannheim, Germany.,Department of Child and Adolescent Psychiatry, Psychotherapy and Psychosomatics, Rheinhessen Clinics, Hartmühlenweg 2-4, 55122, Mainz, Germany.,Department of Child and Adolescent Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg University, Langenbeckstraße 1, 55131, Mainz, Germany
| | - Uta Binzen
- Department of Neurophysiology, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Str. 13-17, 68167, Mannheim, Germany.,Department of Cardiovascular Physiology, European Center for Angioscience (ECAS), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Rolf-Detlef Treede
- Department of Neurophysiology, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Str. 13-17, 68167, Mannheim, Germany
| | - Wolfgang Greffrath
- Department of Neurophysiology, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Str. 13-17, 68167, Mannheim, Germany.
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13
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Central sensitization: clinical utility of a physiological concept for the International Statistical Classification of Diseases and Related Health Problems and for nociplastic pain. Pain 2022; 163:S99-S107. [PMID: 36099342 DOI: 10.1097/j.pain.0000000000002740] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 07/14/2022] [Indexed: 01/14/2023]
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14
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Bedwell GJ, Louw C, Parker R, van den Broeke E, Vlaeyen JW, Moseley GL, Madden VJ. The influence of a manipulation of threat on experimentally-induced secondary hyperalgesia. PeerJ 2022; 10:e13512. [PMID: 35757170 PMCID: PMC9220919 DOI: 10.7717/peerj.13512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 05/07/2022] [Indexed: 01/17/2023] Open
Abstract
Pain is thought to be influenced by the threat value of the particular context in which it occurs. However, the mechanisms by which a threat achieves this influence on pain are unclear. Here, we explore how threat influences experimentally-induced secondary hyperalgesia, which is thought to be a manifestation of central sensitization. We developed an experimental study to investigate the effect of a manipulation of threat on experimentally-induced secondary hyperalgesia in 26 healthy human adults (16 identifying as female; 10 as male). We induced secondary hyperalgesia at both forearms using high-frequency electrical stimulation. Prior to the induction, we used a previously successful method to manipulate threat of tissue damage at one forearm (threat site). The effect of the threat manipulation was determined by comparing participant-rated anxiety, perceived threat, and pain during the experimental induction of secondary hyperalgesia, between the threat and control sites. We hypothesized that the threat site would show greater secondary hyperalgesia (primary outcome) and greater surface area (secondary outcome) of induced secondary hyperalgesia than the control site. Despite a thorough piloting procedure to test the threat manipulation, our data showed no main effect of site on pain, anxiety, or threat ratings during high-frequency electrical stimulation. In the light of no difference in threat between sites, the primary and secondary hypotheses cannot be tested. We discuss reasons why we were unable to replicate the efficacy of this established threat manipulation in our sample, including: (1) competition between threats, (2) generalization of learned threat value, (3) safety cues, (4) trust, and requirements for participant safety, (5) sampling bias, (6) sample-specific habituation to threat, and (7) implausibility of (sham) skin examination and report. Better strategies to manipulate threat are required for further research on the mechanisms by which threat influences pain.
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Affiliation(s)
- Gillian J. Bedwell
- Department of Health and Rehabilitation Sciences, University of Cape Town, Cape Town, Western Cape, South Africa,Pain Unit, Department of Anaesthesia and Perioperative Medicine, Neuroscience Institute, University of Cape Town, Cape Town, Western Cape, South Africa
| | - Caron Louw
- Pain Unit, Department of Anaesthesia and Perioperative Medicine, Neuroscience Institute, University of Cape Town, Cape Town, Western Cape, South Africa
| | - Romy Parker
- Pain Unit, Department of Anaesthesia and Perioperative Medicine, Neuroscience Institute, University of Cape Town, Cape Town, Western Cape, South Africa
| | - Emanuel van den Broeke
- Institute of Neuroscience, Division Cognitive and Systems, UC Louvain, Brussels, Belgium
| | - Johan W. Vlaeyen
- Research Group Health Psychology, KU Leuven, Leuven, Belgium,Experimental Health Psychology, University of Maastricht, Maastricht, Netherlands
| | | | - Victoria J. Madden
- Pain Unit, Department of Anaesthesia and Perioperative Medicine, Neuroscience Institute, University of Cape Town, Cape Town, Western Cape, South Africa,Research Group Health Psychology, KU Leuven, Leuven, Belgium,IIMPACT in Health, University of South Australia, Adelaide, Australia,Department of Psychiatry and Mental Health, Neuroscience Institute, University of Cape Town, Cape Town, Western Cape, South Africa
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15
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Madden VJ, Msolo N, Mqadi L, Lesosky M, Bedwell GJ, Hutchinson MR, Peter JG, Parker R, Schrepf A, Edwards RR, Joska JA. Study protocol: an observational study of distress, immune function and persistent pain in HIV. BMJ Open 2022; 12:e059723. [PMID: 36691234 PMCID: PMC9171212 DOI: 10.1136/bmjopen-2021-059723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 04/28/2022] [Indexed: 01/27/2023] Open
Abstract
INTRODUCTION Many people with HIV report both distress and pain. The relationship between distress and pain is bidirectional, but the mechanisms by which distress exacerbates pain are unclear. The inflammatory response to challenge (inflammatory reactivity, IR) may be a partial mediator, given that neuroimmune interactions provide a substrate for IR to also influence neurological reactivity and, thus, pain-related neural signalling. This prospective, observational, case-control study will characterise the relationships between distress, IR, pain-related signalling as captured by induced secondary hyperalgesia (SH), and pain, in people with HIV who report persistent pain (PP) (cases) or no pain (controls). METHODS AND ANALYSIS One hundred people with suppressed HIV, reporting either PP or no pain, will be assessed two or four times over 6 months. The primary outcomes are distress (Hopkins 25-item symptom checklist), IR (multiplex assay after LPS challenge), and PP (Brief Pain Inventory), assessed at the baseline timepoint, although each will also be assessed at follow-up time points. Induced SH will be assessed in a subsample of 60 participants (baseline timepoint only). To test the hypothesis that IR partly mediates the relationship between distress and pain, mediation analysis will use the baseline data from the PP group to estimate direct and indirect contributions of distress and IR to pain. To test the hypothesis that IR is positively associated with SH, data from the subsample will be analysed with generalised mixed effects models to estimate the association between IR and group membership, with SH as the dependent variable. ETHICS AND DISSEMINATION Information obtained from this study will be published in peer-reviewed journals and presented at scientific meetings. The study has been approved by the Human Research Ethics Committee of the University of Cape Town (approval number: 764/2019) and the City of Cape Town (ref: 24699). TRIAL REGISTRATION NUMBER NCT04757987.
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Affiliation(s)
- Victoria J Madden
- Pain Research Team, Department of Anaesthesia and Perioperative Medicine, Neuroscience Institute, University of Cape Town, Cape Town, South Africa
- HIV Mental Health Research Unit, Department of Psychiatry and Mental Health, Neuroscience Institute, University of Cape Town, Cape Town, South Africa
| | - Ncumisa Msolo
- Pain Research Team, Department of Anaesthesia and Perioperative Medicine, Neuroscience Institute, University of Cape Town, Cape Town, South Africa
| | - Luyanduthando Mqadi
- Pain Research Team, Department of Anaesthesia and Perioperative Medicine, Neuroscience Institute, University of Cape Town, Cape Town, South Africa
- HIV Mental Health Research Unit, Department of Psychiatry and Mental Health, Neuroscience Institute, University of Cape Town, Cape Town, South Africa
| | - Maia Lesosky
- Division of Epidemiology & Biostatistics, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
| | - Gillian J Bedwell
- Pain Research Team, Department of Anaesthesia and Perioperative Medicine, Neuroscience Institute, University of Cape Town, Cape Town, South Africa
| | - Mark R Hutchinson
- Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
| | - Jonathan Grant Peter
- Division of Allergy and Clinical Immunology, Department of Medicine, Groote Schuur Hospital, University of Cape Town, Rondebosch, South Africa
- Allergy and Immunology Unit, University of Cape Town Lung Institute, University of Cape Town, Cape Town, South Africa
| | - Romy Parker
- Pain Research Team, Department of Anaesthesia and Perioperative Medicine, Neuroscience Institute, University of Cape Town, Cape Town, South Africa
| | - Andrew Schrepf
- Chronic Pain and Fatigue Research Center, Department of Anesthesiology, Michigan Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Robert R Edwards
- Department of Anesthesiology, Perioperative, and Pain Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - John A Joska
- HIV Mental Health Research Unit, Department of Psychiatry and Mental Health, Neuroscience Institute, University of Cape Town, Cape Town, South Africa
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16
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Rees TA, Russo AF, O’Carroll SJ, Hay DL, Walker CS. CGRP and the Calcitonin Receptor are Co-Expressed in Mouse, Rat and Human Trigeminal Ganglia Neurons. Front Physiol 2022; 13:860037. [PMID: 35620595 PMCID: PMC9128745 DOI: 10.3389/fphys.2022.860037] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 04/12/2022] [Indexed: 11/23/2022] Open
Abstract
The neuropeptide calcitonin gene-related peptide (CGRP) is expressed in the trigeminal ganglia, a key site in craniofacial pain and migraine. CGRP potently activates two receptors: the CGRP receptor and the AMY1 receptor. These receptors are heterodimers consisting of receptor activity-modifying protein 1 (RAMP1) with either the calcitonin receptor-like receptor (CLR) to form the CGRP receptor or the calcitonin receptor (CTR) to form the AMY1 receptor. The expression of the CGRP receptor in trigeminal ganglia has been described in several studies; however, there is comparatively limited data available describing AMY1 receptor expression and in which cellular subtypes it is found. This research aimed to determine the relative distributions of the AMY1 receptor subunit, CTR, and CGRP in neurons or glia in rat, mouse and human trigeminal ganglia. Antibodies against CTR, CGRP and neuronal/glial cell markers were applied to trigeminal ganglia sections to investigate their distribution. CTR-like and CGRP-like immunoreactivity were observed in both discrete and overlapping populations of neurons. In rats and mice, 30–40% of trigeminal ganglia neurons displayed CTR-like immunoreactivity in their cell bodies, with approximately 78–80% of these also containing CGRP-like immunoreactivity. Although human cases were more variable, a similar overall pattern of CTR-like immunoreactivity to rodents was observed in the human trigeminal ganglia. CTR and CGRP appeared to be primarily colocalized in small to medium sized neurons, suggesting that colocalization of CTR and CGRP may occur in C-fiber neurons. CGRP-like or CTR-like immunoreactivity were not typically observed in glial cells. Western blotting confirmed that CTR was expressed in the trigeminal ganglia of all three species. These results confirm that CTR is expressed in trigeminal ganglia neurons. The identification of populations of neurons that express both CGRP and CTR suggests that CGRP could act in an autocrine manner through a CTR-based receptor, such as the AMY1 receptor. Overall, this suggests that a trigeminal ganglia CTR-based receptor may be activated during migraine and could therefore represent a potential target to develop treatments for craniofacial pain and migraine.
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Affiliation(s)
- Tayla A. Rees
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - Andrew F. Russo
- Department of Molecular Physiology and Biophysics, Center for the Prevention and Treatment of Visual Loss, Veterans Administration Health Center, Department of Neurology, University of Iowa, Iowa City, IA, United States
| | - Simon J. O’Carroll
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Science, University of Auckland, Auckland, New Zealand
| | - Debbie L. Hay
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
- Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand
- *Correspondence: Debbie L. Hay, ; Christopher S. Walker,
| | - Christopher S. Walker
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
- *Correspondence: Debbie L. Hay, ; Christopher S. Walker,
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17
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Pan LLH, Wang YF, Ling YH, Lai KL, Chen SP, Chen WT, Treede RD, Wang SJ. Pain sensitivities predict prophylactic treatment outcomes of flunarizine in chronic migraine patients: A prospective study. Cephalalgia 2022; 42:899-909. [PMID: 35400174 DOI: 10.1177/03331024221080572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND We aimed to assess the differences in quantitative sensory testing between chronic migraine and healthy controls and to explore the association between pain sensitivities and outcomes in chronic migraine following preventive treatment. METHODS In this prospective open-label study, preventive-naïve chronic migraine and healthy controls were recruited, and cold, heat, mechanical punctate, and pressure pain thresholds over the dermatomes of first branch of trigeminal nerve and first thoracic nerve were measured by quantitative sensory testing at baseline. Chronic migraines were treated with flunarizine and treatment response was defined as ≥50% reduction in the number of monthly headache days over the 12-week treatment period. RESULTS Eighty-four chronic migraines and fifty age-and-sex-matched healthy controls were included in the analysis. The chronic migraine had higher cold pain thresholds over the dermatomes of the first branch of trigeminal nerve and the first thoracic nerve (p < 0.001 and < 0.001), lower pressure pain thresholds over the dermatomes of the first thoracic nerve (p = 0.003), heat pain thresholds over the dermatomes of the first branch of the trigeminal nerve and the first thoracic nerve (p < 0.001 and p = 0.015) than healthy controls. After treatment, 24/84 chronic migraine had treatment response. The responders with relatively normal pain sensitivity had higher heat pain thresholds over the dermatome of the first branch of the trigeminal nerve (p = 0.002), mechanical punctate pain thresholds over the dermatomes of the first branch of the trigeminal nerve (p = 0.023), and pressure pain thresholds over the dermatomes of the first branch of the trigeminal nerve (p = 0.026) than the hypersensitive non-responders. Decision tree analysis showed that patients with mechanical punctate pain threshold over the dermatomes of the first branch of the trigeminal nerve > 158 g (p = 0.020) or heat pain threshold over the dermatome of the first branch of the trigeminal nerve > 44.9°C (p = 0.002) were more likely to be responders. CONCLUSIONS Chronic migraine were generally more sensitive compared to healthy controls. Preventive treatment with flunarizine should be recommended particularly for chronic migraine who have relatively normal sensitivity to mechanical punctate or heat pain.Trial registration: This study was registered on ClinicalTrials.gov (Identifier: NCT02747940).
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Affiliation(s)
- Li-Ling Hope Pan
- Brain Research Center, 34914National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yen-Feng Wang
- College of Medicine, 34914National Yang Ming Chiao Tung University, Taipei, Taiwan.,Department of Neurology, Neurological Institute, 46615Taipei Veterans General Hospital, Taipei, Taiwan
| | - Yu-Hsiang Ling
- College of Medicine, 34914National Yang Ming Chiao Tung University, Taipei, Taiwan.,Department of Neurology, Neurological Institute, 46615Taipei Veterans General Hospital, Taipei, Taiwan
| | - Kuan-Lin Lai
- College of Medicine, 34914National Yang Ming Chiao Tung University, Taipei, Taiwan.,Department of Neurology, Neurological Institute, 46615Taipei Veterans General Hospital, Taipei, Taiwan
| | - Shih-Pin Chen
- Brain Research Center, 34914National Yang Ming Chiao Tung University, Taipei, Taiwan.,College of Medicine, 34914National Yang Ming Chiao Tung University, Taipei, Taiwan.,Department of Neurology, Neurological Institute, 46615Taipei Veterans General Hospital, Taipei, Taiwan.,Institute of Clinical Medicine, 34914National Yang Ming Chiao Tung University, Taipei, Taiwan.,Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Wei-Ta Chen
- Brain Research Center, 34914National Yang Ming Chiao Tung University, Taipei, Taiwan.,College of Medicine, 34914National Yang Ming Chiao Tung University, Taipei, Taiwan.,Department of Neurology, Neurological Institute, 46615Taipei Veterans General Hospital, Taipei, Taiwan.,Department of Neurology, 38004Keelung Hospital, Ministry of Health and Welfare, Keelung, Taiwan
| | - Rolf-Detlef Treede
- Chair of Neurophysiology, Mannheim Center for Translational Neurosciences, Medical Faculty Mannheim, Heidelberg University, Germany
| | - Shuu-Jiun Wang
- Brain Research Center, 34914National Yang Ming Chiao Tung University, Taipei, Taiwan.,College of Medicine, 34914National Yang Ming Chiao Tung University, Taipei, Taiwan.,Department of Neurology, Neurological Institute, 46615Taipei Veterans General Hospital, Taipei, Taiwan
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18
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Xue S, Yang WJ, Cao ZX, Sun T. Comparing the efficacy and safety of short-term spinal cord stimulation and pulsed radiofrequency for zoster-related pain: A systematic review and meta-analysis. Medicine (Baltimore) 2022; 101:e29073. [PMID: 35356934 PMCID: PMC10684147 DOI: 10.1097/md.0000000000029073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Accepted: 02/24/2022] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Pulsed radiofrequency (PRF) is a commonly used method for the treatment of zoster-related pain in the clinic. However, PRF therapy has a high recurrence rate and many adverse reactions. Recent studies have shown that short-term spinal cord stimulation (stSCS) can effectively alleviate zoster-related pain. Due to the lack of evidence, it is unclear whether stSCS is superior to PRF in the efficacy of treating zoster-related pain. OBJECTIVE This study aimed to compare the efficacy and safety of stSCS and PRF for zoster-related pain. METHODS We searched seven electronic databases from the establishment of the database to January 2021. Related randomized controlled trials were included in this meta-analysis. After extracting the data and evaluating the methodological quality of the included trials, the outcome indicators were statistically analyzed by using RevManV.5.3. RESULTS This meta-analysis included 6 trials with a total of 509 patients. Compared with PRF group, stSCS group showed lower pain intensity (standardized mean difference=-0.83, 95%CI [-1.37, -0.30], P=.002), better sleep quality (mean difference=-1.43, 95%CI [-2.29, -0.57], P=.001), lower pain rating index scores, and less incidence of adverse events (RR=0.32, 95%CI [0.12, 0.83], P<.05). However, the efficacies of PRF and stSCS for treating postherpetic neuralgia were consistent in the response rate (RR= 1.10, 95% CI [0.82, 1.48], P=.51) and the complete remission rate (RR=1.05, 95% CI [0.66, 1.68], P=.84). CONCLUSIONS In this study, stSCS showed a better analgesic effect and higher safety than PRF. Our meta-analysis results suggested that stSCS may be a feasible and safe invasive treatment for zoster-related pain. However, high-quality, randomized controlled trials with large sample sizes are needed to further verify our conclusions.
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Affiliation(s)
| | | | | | - Tao Sun
- Correspondence: Tao Sun, Department of Pain Management, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, 324 Jingwu Road, Jinan, 250021, China (e-mail: ).
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19
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Hugosdottir R, Kasting M, Mørch CD, Kæseler Andersen O, Arendt-Nielsen L. Priming of central- and peripheral mechanisms with heat and cutaneous capsaicin facilitates secondary hyperalgesia to high frequency electrical stimulation. J Neurophysiol 2022; 127:651-659. [PMID: 35020531 DOI: 10.1152/jn.00154.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Heat/capsaicin sensitization and electrical high frequency stimulation (HFS) are well known model of secondary hyperalgesia, a phenomenon related to chronic pain conditions. This study investigated whether priming with heat/capsaicin would facilitate hyperalgesia to HFS in healthy subjects. Heat/capsaicin priming consisted of a 45 °C heat stimulation for 5 min followed by a topical capsaicin patch (4x4 cm) for 30 minutes on the volar forearm of 20 subjects. HFS (100 Hz, 5 times 1s, minimum 1.5 mA) was subsequently delivered through a transcutaneous pin electrode approximately 1.5 cm proximal to the heat/capsaicin application. Two sessions were applied in a crossover design; traditional HFS (HFS) and heat/capsaicin sensitization followed by HFS (HFS+HEAT/CAPS). Heat pain threshold (HPT), mechanical pain sensitivity (MPS) and superficial blood perfusion were assessed at baseline, after capsaicin removal, and up to 40 min after HFS. MPS was assessed with pinprick stimulation (128 mN and 256 mN) in the area adjacent to both HFS and heat/capsaicin, distal but adjacent to heat/capsaicin and in a distal control area. HPT was assessed in the area of heat/capsaicin. Higher sensitivity to 128 mN pinprick stimulation (difference from baseline and control area) was observed in the HFS+HEAT/CAPS session than in the HFS session 20 and 30 minutes after HFS. Furthermore, sensitivity was increased after HFS+HEAT/CAPS compared to after heat/capsaicin in the area adjacent to both paradigms, but not in the area distal to heat/capsaicin. Results indicate that heat/capsaicin causes priming of the central- and peripheral nervous system, which facilitates secondary mechanical hyperalgesia to HFS.
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Affiliation(s)
- Rosa Hugosdottir
- Center of Neuroplasticity and Pain, SMI, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Mindy Kasting
- Biomechatronics and Human-Machine Control, Department of Biomechanical Engineering, Faculty of Mechanical Engineering, Delft University of Technology, The Netherlands
| | - Carsten Dahl Mørch
- Center of Neuroplasticity and Pain, SMI, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Ole Kæseler Andersen
- Center of Neuroplasticity and Pain, SMI, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Lars Arendt-Nielsen
- Center of Neuroplasticity and Pain, SMI, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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20
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Verdugo RJ, Matamala JM, Inui K, Kakigi R, Valls-Solé J, Hansson P, Bernhard Nilsen K, Lombardi R, Lauria G, Petropoulos IN, Malik RA, Treede RD, Baumgärtner U, Jara PA, Campero M. Review of techniques useful for the assessment of sensory small fiber neuropathies: Report from an IFCN expert group. Clin Neurophysiol 2022; 136:13-38. [DOI: 10.1016/j.clinph.2022.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/04/2022] [Accepted: 01/06/2022] [Indexed: 02/09/2023]
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21
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Johnson S, Marshall A, Hughes D, Holmes E, Henrich F, Nurmikko T, Sharma M, Frank B, Bassett P, Marshall A, Magerl W, Goebel A. Mechanistically informed non-invasive peripheral nerve stimulation for peripheral neuropathic pain: a randomised double-blind sham-controlled trial. J Transl Med 2021; 19:458. [PMID: 34742297 PMCID: PMC8572078 DOI: 10.1186/s12967-021-03128-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 10/23/2021] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Induction of long-term synaptic depression (LTD) is proposed as a treatment mechanism for chronic pain but remains untested in clinical populations. Two interlinked studies; (1) A patient-assessor blinded, randomised, sham-controlled clinical trial and (2) an open-label mechanistic study, sought to examine therapeutic LTD for persons with chronic peripheral nerve injury pain. METHODS (1) Patients were randomised using a concealed, computer-generated schedule to either active or sham non-invasive low-frequency nerve stimulation (LFS), for 3 months (minimum 10 min/day). The primary outcome was average pain intensity (0-10 Likert scale) recorded over 1 week, at 3 months, compared between study groups. (2) On trial completion, consenting subjects entered a mechanistic study assessing somatosensory changes in response to LFS. RESULTS (1) 76 patients were randomised (38 per group), with 65 (31 active, 34 sham) included in the intention to treat analysis. The primary outcome was not significant, pain scores were 0.3 units lower in active group (95% CI - 1.0, 0.3; p = 0.30) giving an effect size of 0.19 (Cohen's D). Two non-device related serious adverse events were reported. (2) In the mechanistic study (n = 19) primary outcomes of mechanical pain sensitivity (p = 0.006) and dynamic mechanical allodynia (p = 0.043) significantly improved indicating reduced mechanical hyperalgesia. CONCLUSIONS Results from the RCT failed to reach significance. Results from the mechanistic study provide new evidence for effective induction of LTD in a clinical population. Taken together results add to mechanistic understanding of LTD and help inform future study design and approaches to treatment. Trial registration ISRCTN53432663.
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Affiliation(s)
- Selina Johnson
- The Pain Management Programme, Walton Centre NHS Foundation Trust, Lower Lane, Liverpool, L9 7LJ, UK. .,Pain Research Institute, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK.
| | - Anne Marshall
- Pain Research Institute, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
| | - Dyfrig Hughes
- Centre for Health Economics and Medicines Evaluation (CHEME) Department, Bangor University, Bangor, Wales, UK
| | - Emily Holmes
- Centre for Health Economics and Medicines Evaluation (CHEME) Department, Bangor University, Bangor, Wales, UK
| | - Florian Henrich
- Department of Neurophysiology, Mannheim Centre for Translational Neurosciences, Medical Faculty Mannheim, Ruprecht Karls-University Heidelberg, Heidelberg, Germany
| | - Turo Nurmikko
- The Pain Management Programme, Walton Centre NHS Foundation Trust, Lower Lane, Liverpool, L9 7LJ, UK
| | - Manohar Sharma
- The Pain Management Programme, Walton Centre NHS Foundation Trust, Lower Lane, Liverpool, L9 7LJ, UK
| | - Bernhard Frank
- The Pain Management Programme, Walton Centre NHS Foundation Trust, Lower Lane, Liverpool, L9 7LJ, UK.,Pain Research Institute, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
| | | | - Andrew Marshall
- The Pain Management Programme, Walton Centre NHS Foundation Trust, Lower Lane, Liverpool, L9 7LJ, UK.,Pain Research Institute, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
| | - Walter Magerl
- Department of Neurophysiology, Mannheim Centre for Translational Neurosciences, Medical Faculty Mannheim, Ruprecht Karls-University Heidelberg, Heidelberg, Germany
| | - Andreas Goebel
- The Pain Management Programme, Walton Centre NHS Foundation Trust, Lower Lane, Liverpool, L9 7LJ, UK.,Pain Research Institute, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
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22
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Leone C, Di Lionardo A, Di Pietro G, Di Stefano G, Falco P, Blockeel AJ, Caspani O, Garcia-Larrea L, Mouraux A, Phillips KG, Treede RD, Truini A. How different experimental models of secondary hyperalgesia change the nociceptive flexion reflex. Clin Neurophysiol 2021; 132:2989-2995. [PMID: 34715423 DOI: 10.1016/j.clinph.2021.08.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 08/05/2021] [Accepted: 08/29/2021] [Indexed: 10/20/2022]
Abstract
OBJECTIVE In this neurophysiological study in healthy humans, we assessed how central sensitization induced by either high-frequency stimulation (HFS) or topical capsaicin application modulates features of the RIII reflex response. The ability of these stimuli to engage the endogenous pain modulatory system was also tested. METHODS In 26 healthy participants we elicited an RIII reflex using suprathreshold stimulation of the sural nerve. Subsequently HFS or capsaicin were applied to the foot and the RIII reflex repeated after 15 minutes. Contact heating of the volar forearm served as the heterotopic test stimulus to probe activation of the endogenous pain modulatory system. RESULTS HFS significantly reduced the pain threshold by 29% and the RIII reflex threshold by 20%. Capsaicin significantly reduced the pain threshold by 17% and the RIII reflex threshold by 18%. Both HFS and capsaicin left RIII reflex size unaffected. Numerical Rating Scale (NRS) pain scores elicited by the heterotopic noxious heat stimulus were unaffected by capsaicin and slightly increased by HFS. CONCLUSIONS HFS and capsaicin similarly modulated the pain threshold and RIII reflex threshold, without a concomitant inhibitory effect of the endogenous pain modulatory system. SIGNIFICANCE Our neurophysiological study supports the use of the RIII reflex in investigating central sensitization in humans.
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Affiliation(s)
- C Leone
- Department of Human Neuroscience, Sapienza University, Rome, Italy
| | - A Di Lionardo
- Department of Human Neuroscience, Sapienza University, Rome, Italy
| | - G Di Pietro
- Department of Human Neuroscience, Sapienza University, Rome, Italy
| | - G Di Stefano
- Department of Human Neuroscience, Sapienza University, Rome, Italy
| | - P Falco
- Department of Human Neuroscience, Sapienza University, Rome, Italy
| | - A J Blockeel
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK
| | - O Caspani
- Department of Neurophysiology, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim of Heidelberg University, Mannheim, Germany
| | - L Garcia-Larrea
- Lyon Neurosciences Center Research Unit Inserm U 1028, Pierre Wertheimer Hospital, Hospices Civils de Lyon, Lyon 1 University, Lyon, France; Pain Center, Pierre Wertheimer Hospital, Hospices Civils de Lyon, Lyon 1 University, Lyon, France
| | - A Mouraux
- Université Catholique de Louvain, Institute of Neuroscience (IoNS), Faculty of Medicine, Bruxelles, Belgium
| | - K G Phillips
- Lilly United Kingdom Erl Wood Manor Windlesham, Surrey, United Kingdom
| | - R D Treede
- Department of Neurophysiology, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim of Heidelberg University, Mannheim, Germany
| | - A Truini
- Department of Human Neuroscience, Sapienza University, Rome, Italy.
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23
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A systematic review of porcine models in translational pain research. Lab Anim (NY) 2021; 50:313-326. [PMID: 34650279 DOI: 10.1038/s41684-021-00862-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 08/27/2021] [Indexed: 11/09/2022]
Abstract
Translating basic pain research from rodents to humans has proven to be a challenging task. Efforts have been made to develop preclinical large animal models of pain, such as the pig. However, no consistent overview and comparison of pig models of pain are currently available. Therefore, in this review, our primary aim was to identify the available pig models in pain research and compare these models in terms of intensity and duration. First, we systematically searched Proquest, Scopus and Web of Science and compared the duration for which the pigs were significantly sensitized as well as the intensity of mechanical sensitization. We searched models within the specific field of pain and adjacent fields in which pain induction or assessment is relevant, such as pig production. Second, we compared assessment methodologies in surrogate pain models in humans and pigs to identify areas of overlap and possible improvement. Based on the literature search, 23 types of porcine pain models were identified; 13 of which could be compared quantitatively. The induced sensitization lasted from hours to months and intensities ranged from insignificant to the maximum attainable. We also found a near to complete overlap of assessment methodologies between human and pig models within the area of peripheral neurophysiology, which allows for direct comparison of results obtained in the two species. In spite of this overlap, further development of pain assessment methodologies is still needed. We suggest that central nervous system electrophysiology, such as electroencephalography, electrocorticography or intracortical recordings, may pave the way for future objective pain assessment.
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24
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Wilson SH, Hellman KM, James D, Adler AC, Chandrakantan A. Mechanisms, Diagnosis, and Medical Management of Hyperalgesia: an Educational Review. CURRENT ANESTHESIOLOGY REPORTS 2021. [DOI: 10.1007/s40140-021-00485-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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25
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Isensee J, van Cann M, Despang P, Araldi D, Moeller K, Petersen J, Schmidtko A, Matthes J, Levine JD, Hucho T. Depolarization induces nociceptor sensitization by CaV1.2-mediated PKA-II activation. J Cell Biol 2021; 220:212600. [PMID: 34431981 PMCID: PMC8404467 DOI: 10.1083/jcb.202002083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 06/14/2021] [Accepted: 08/05/2021] [Indexed: 01/20/2023] Open
Abstract
Depolarization drives neuronal plasticity. However, whether depolarization drives sensitization of peripheral nociceptive neurons remains elusive. By high-content screening (HCS) microscopy, we revealed that depolarization of cultured sensory neurons rapidly activates protein kinase A type II (PKA-II) in nociceptors by calcium influx through CaV1.2 channels. This effect was modulated by calpains but insensitive to inhibitors of cAMP formation, including opioids. In turn, PKA-II phosphorylated Ser1928 in the distal C terminus of CaV1.2, thereby increasing channel gating, whereas dephosphorylation of Ser1928 involved the phosphatase calcineurin. Patch-clamp and behavioral experiments confirmed that depolarization leads to calcium- and PKA-dependent sensitization of calcium currents ex vivo and local peripheral hyperalgesia in the skin in vivo. Our data suggest a local activity-driven feed-forward mechanism that selectively translates strong depolarization into further activity and thereby facilitates hypersensitivity of nociceptor terminals by a mechanism inaccessible to opioids.
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Affiliation(s)
- Jörg Isensee
- Department of Anesthesiology and Intensive Care Medicine, Translational Pain Research, Faculty of Medicine and University Hospital of Cologne, University of Cologne, Cologne, Germany
| | - Marianne van Cann
- Department of Anesthesiology and Intensive Care Medicine, Translational Pain Research, Faculty of Medicine and University Hospital of Cologne, University of Cologne, Cologne, Germany
| | - Patrick Despang
- Department of Pharmacology, Faculty of Medicine and University Hospital of Cologne, University of Cologne, Cologne, Germany
| | - Dioneia Araldi
- Division of Neuroscience, Departments of Medicine and Oral & Maxillofacial Surgery, University of California, San Francisco, San Francisco, CA
| | - Katharina Moeller
- Department of Anesthesiology and Intensive Care Medicine, Translational Pain Research, Faculty of Medicine and University Hospital of Cologne, University of Cologne, Cologne, Germany
| | - Jonas Petersen
- Institute for Pharmacology and Clinical Pharmacy, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Achim Schmidtko
- Institute for Pharmacology and Clinical Pharmacy, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Jan Matthes
- Department of Pharmacology, Faculty of Medicine and University Hospital of Cologne, University of Cologne, Cologne, Germany
| | - Jon D Levine
- Division of Neuroscience, Departments of Medicine and Oral & Maxillofacial Surgery, University of California, San Francisco, San Francisco, CA
| | - Tim Hucho
- Department of Anesthesiology and Intensive Care Medicine, Translational Pain Research, Faculty of Medicine and University Hospital of Cologne, University of Cologne, Cologne, Germany
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26
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Meeker TJ, Quiton RL, Moulton EA. In memoriam: Joel D. Greenspan 1952 to 2021. Pain 2021; 162:2459-2463. [PMID: 37595319 DOI: 10.1097/j.pain.0000000000002393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Timothy J Meeker
- Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, United States
| | - Raimi L Quiton
- Department of Psychology, University of Maryland, Baltimore, MD, United States
| | - Eric A Moulton
- Brain and Eye Pain Imaging Lab, Pain and Affective Neuroscience Center, Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, United States
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27
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Experimental evidence of a functional relationship within the brainstem trigeminocervical complex in humans. Pain 2021; 163:729-734. [PMID: 34326294 DOI: 10.1097/j.pain.0000000000002417] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 07/19/2021] [Indexed: 11/26/2022]
Abstract
ABSTRACT The existence of a trigeminocervical complex (TCC) has been suggested based on animal data, but only indirect evidence exists in humans. We investigated the functional relationship between the trigeminal and the occipital region by stimulating one region and measuring electrical pain thresholds (EPTs) of the corresponding opposite region. This study consists of two single-blinded, randomized protocols. 40 healthy participants were recruited in the propaedeutic Protocol I. EPTs were measured on the V1 and the greater occipital nerve (GON) dermatome bilaterally as well as on the left forearm longitudinally before and after application of topical capsaicin. Protocol II was then online pre-registered and, additionally, the ipsilateral trigeminal dermatomes V2 and V3 were tested. GON stimulation increased the EPT ipsilateral at V1 after 20 minutes (p=0.006) compared to baseline, whereas trigeminal stimulation increased the EPT at the ipsilateral (p=0.023) as well as the contralateral GON (p=0.001) following capsaicin application. Protocol II confirmed these results and additionally showed that GON stimulation with capsaicin increased EPTs ipsilateral at all three trigeminal dermatomes and that trigeminal stimulation on V1 led to an ipsilateral increase of EPTs at GON, V2 and V3. Our data suggest a strong functional interplay between the trigeminal and occipital system in humans. The fact that stimulation of one of these dermatomes increases the electrical pain threshold of the respective other nerve could be explained by segmental inhibition on brainstem level.
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28
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Sensory defunctionalization induced by 8% topical capsaicin treatment in a model of ultraviolet-B-induced cutaneous hyperalgesia. Exp Brain Res 2021; 239:2873-2886. [PMID: 34302514 DOI: 10.1007/s00221-021-06170-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 07/02/2021] [Indexed: 10/20/2022]
Abstract
Subpopulations of primary nociceptors (C- and Aδ-fibers), express the TRPV1 receptor for heat and capsaicin. During cutaneous inflammation, these afferents may become sensitized, leading to primary hyperalgesia. It is known that TRPV1+ nociceptors are involved in heat hyperalgesia; however, their involvement in mechanical hyperalgesia is unclear. This study explored the contribution of capsaicin-sensitive nociceptors in the development of mechanical and heat hyperalgesia in humans following ultraviolet-B (UVB) irradiation. Skin areas in 18 healthy volunteers were randomized to treatment with 8% capsaicin/vehicle patches for 24 h. After patches removal, one capsaicin-treated area and one vehicle area were irradiated with 2xMED (minimal erythema dose) of UVB. 1, 3 and 7 days post-UVB exposure, tests were performed to evaluate the development of UVB-induced cutaneous hyperalgesia: thermal detection and pain thresholds, pain sensitivity to supra-threshold heat stimuli, mechanical pain threshold and sensitivity, touch pleasantness, trans-epidermal water loss (TEWL), inflammatory response, pigmentation and micro-vascular reactivity. Capsaicin pre-treatment, in the UVB-irradiated area (Capsaicin + UVB area), increased heat pain thresholds (P < 0.05), and decreased supra-threshold heat pain sensitivity (P < 0.05) 1, 3 and 7 days post-UVB irradiation, while mechanical hyperalgesia resulted unchanged (P > 0.2). No effects of capsaicin were reported on touch pleasantness (P = 1), TEWL (P = 0.31), inflammatory response and pigmentation (P > 0.3) or micro-vascular reactivity (P > 0.8) in response to the UVB irradiation. 8% capsaicin ablation predominantly defunctionalizes TRPV1+-expressing cutaneous nociceptors responsible for heat pain transduction, suggesting that sensitization of these fibers is required for development of heat hyperalgesia following cutaneous UVB-induced inflammation but they are likely only partially necessary for the establishment of robust primary mechanical hyperalgesia.
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29
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Christensen JD, Lo Vecchio S, Andersen HH, Elberling J, Arendt-Nielsen L. Effect of Topical Analgesia on Desensitization Following 8% Topical Capsaicin Application. THE JOURNAL OF PAIN 2021; 22:778-788. [PMID: 33524549 DOI: 10.1016/j.jpain.2021.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 11/24/2020] [Accepted: 01/26/2021] [Indexed: 12/12/2022]
Abstract
To prevent pain associated with 8% capsaicin application, pretreatment with local anesthetics, such as EMLA (eutectic mixture of lidocaine 2.5% and prilocaine 2.5%), is considered an option. However, there is contradicting evidence regarding the effects of local analgesia on capsaicin-induced desensitization. In session 1, 2 skin areas in each forearm of 24 healthy volunteers were randomized to 2-hour pretreatment with EMLA/placebo cream. After pretreatment, 8% capsaicin patches were applied for 3 hours in 1 placebo and 1 EMLA pretreated area, obtaining the following four areas: Capsaicin + EMLA, Capsaicin + Placebo, EMLA alone, and Placebo. Pain intensity scores were assessed during the 3-hour application of capsaicin. Warmth detection, heat pain sensitivity, and microvascular reactivity were measured after the removal of capsaicin. After 24 hours, in session 2, all tests were repeated followed by histamine application in each area to examine itch intensity and neurogenic flare. Overall, EMLA caused significant reductions in capsaicin-induced pain compared with placebo (P= .007) and enhanced the capsaicin-induced increase in superficial blood perfusion immediately after the 3-hour capsaicin application (P< .01). Regardless of pretreatment, capsaicin induced heat hyperalgesia immediately after the application (P< .001). Twenty-four hours post application, heat pain sensitivity was normalized. However, WDT increased significantly (P< .001). Capsaicin tended to reduce the itch intensity and significantly reduced the neurogenic flare (P< .05) induced by histamine compared with EMLA alone. The findings suggest that pretreatment with topical analgesic cream reduces application site pain without interfering with the 8% topical capsaicin-induced desensitization. PERSPECTIVE: Pretreatment with local anesthetic EMLA cream might be considered a good therapeutic option to reduce the pain associated with 8% capsaicin application currently used for treatment of neuropathic pain syndromes. This study also suggests the existence of a synergistic effect of capsaicin and EMLA on the process of neurogenic inflammation.
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Affiliation(s)
- Janne D Christensen
- Laboratory for Experimental Cutaneous Pain and Itch Research, SMI, Center for Neuroplasticity and Pain, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Denmark
| | - Silvia Lo Vecchio
- Laboratory for Experimental Cutaneous Pain and Itch Research, SMI, Center for Neuroplasticity and Pain, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Denmark.
| | - Hjalte H Andersen
- Laboratory for Experimental Cutaneous Pain and Itch Research, SMI, Center for Neuroplasticity and Pain, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Denmark
| | - Jesper Elberling
- The Allergy Clinic, Department of Dermato-Allergology, Copenhagen University Hospital, Gentofte, Copenhagen, Denmark
| | - Lars Arendt-Nielsen
- Laboratory for Experimental Cutaneous Pain and Itch Research, SMI, Center for Neuroplasticity and Pain, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Denmark
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Mehesz E, Karoui H, Strutton PH, Hughes SW. Exposure to an Immersive Virtual Reality Environment can Modulate Perceptual Correlates of Endogenous Analgesia and Central Sensitization in Healthy Volunteers. THE JOURNAL OF PAIN 2021; 22:707-714. [PMID: 33465506 DOI: 10.1016/j.jpain.2020.12.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 12/14/2020] [Accepted: 12/29/2020] [Indexed: 11/26/2022]
Abstract
Virtual reality (VR) has been shown to produce analgesic effects during different experimental and clinical pain states. Despite this, the top-down mechanisms are still poorly understood. In this study, we examined the influence of both a real and sham (ie, the same images in 2D) immersive arctic VR environment on conditioned pain modulation (CPM) and in a human surrogate model of central sensitization in 38 healthy volunteers. CPM and acute heat pain thresholds were assessed before and during VR/sham exposure in the absence of any sensitization. In a follow-on study, we used the cutaneous high frequency stimulation model of central sensitization and measured changes in mechanical pain sensitivity in an area of heterotopic sensitization before and during VR/sham exposure. There was an increase in CPM efficiency during the VR condition compared to baseline (P < .01). In the sham condition, there was a decrease in CPM efficiency compared to baseline (P < .01) and the real VR condition (P < .001). Neither real nor sham VR had any effect on pain ratings reported during the conditioning period or on heat pain threshold. There was also an attenuation of mechanical pain sensitivity during the VR condition indicating a lower sensitivity compared to sham (P < .05). We conclude that exposure to an immersive VR environment has no effect over acute pain thresholds but can modulate dynamic CPM responses and mechanical hypersensitivity in healthy volunteers. PERSPECTIVE: This study has demonstrated that exposure to an immersive virtual reality environment can modulate perceptual correlates of endogenous pain modulation and secondary hyperalgesia in a human surrogate pain model. These results suggest that virtual reality could provide a novel mechanism-driven analgesic strategy in patients with altered central pain processing.
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Affiliation(s)
- Erzsebet Mehesz
- The Nick Davey Laboratory, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Hajer Karoui
- The Nick Davey Laboratory, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Paul H Strutton
- The Nick Davey Laboratory, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Sam W Hughes
- The Pain Neuroplasticity and Modulation Laboratory, Brain Research and Imaging Centre (BRIC), School of Psychology, Faculty of Health, University of Plymouth, Plymouth, UK.
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31
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Modality-specific facilitation of noninjurious sharp mechanical pain by topical capsaicin. Pain 2021; 162:275-286. [PMID: 32701656 DOI: 10.1097/j.pain.0000000000002020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We had previously shown that a "blunt blade" stimulator can mimic the noninjurious strain phase of incisional pain, but not its sustained duration. Here, we tested whether acute sensitization of the skin with topical capsaicin can add the sustained phase to this noninvasive surrogate model of intraoperative pain. Altogether, 110 healthy volunteers (55 male and 55 female; 26 ± 5 years) participated in several experiments using the "blunt blade" (0.25 × 4 mm) on normal skin (n = 36) and on skin pretreated by a high-concentration capsaicin patch (8%, Qutenza; n = 36). These data were compared with an experimental incision (n = 40) using quantitative and qualitative pain ratings by numerical rating scale and SES Pain Perception Scale descriptors. Capsaicin sensitization increased blade-induced pain magnitude and duration significantly (both P < 0.05), but it failed to fully match the sustained duration of incisional pain. In normal skin, the SES pattern of pain qualities elicited by the blade matched incision in pain magnitude and pattern of pain descriptors. In capsaicin-treated skin, the blade acquired a significant facilitation only of the perceived heat pain component (P < 0.001), but not of mechanical pain components. Thus, capsaicin morphed the descriptor pattern of the blade to become more capsaicin-like, which is probably explained best by peripheral sensitization of the TRPV1 receptor. Quantitative sensory testing in capsaicin-sensitized skin revealed hyperalgesia to heat and pressure stimuli, and loss of cold and cold pain sensitivity. These findings support our hypothesis that the blade models the early tissue-strain-related mechanical pain phase of surgical incisions.
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32
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Quesada C, Kostenko A, Ho I, Leone C, Nochi Z, Stouffs A, Wittayer M, Caspani O, Brix Finnerup N, Mouraux A, Pickering G, Tracey I, Truini A, Treede RD, Garcia-Larrea L. Human surrogate models of central sensitization: A critical review and practical guide. Eur J Pain 2021; 25:1389-1428. [PMID: 33759294 PMCID: PMC8360051 DOI: 10.1002/ejp.1768] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 03/17/2021] [Accepted: 03/21/2021] [Indexed: 12/11/2022]
Abstract
Background As in other fields of medicine, development of new medications for management of neuropathic pain has been difficult since preclinical rodent models do not necessarily translate to the clinics. Aside from ongoing pain with burning or shock‐like qualities, neuropathic pain is often characterized by pain hypersensitivity (hyperalgesia and allodynia), most often towards mechanical stimuli, reflecting sensitization of neural transmission. Data treatment We therefore performed a systematic literature review (PubMed‐Medline, Cochrane, WoS, ClinicalTrials) and semi‐quantitative meta‐analysis of human pain models that aim to induce central sensitization, and generate hyperalgesia surrounding a real or simulated injury. Results From an initial set of 1569 reports, we identified and analysed 269 studies using more than a dozen human models of sensitization. Five of these models (intradermal or topical capsaicin, low‐ or high‐frequency electrical stimulation, thermode‐induced heat‐injury) were found to reliably induce secondary hyperalgesia to pinprick and have been implemented in multiple laboratories. The ability of these models to induce dynamic mechanical allodynia was however substantially lower. The proportion of subjects who developed hypersensitivity was rarely provided, giving rise to significant reporting bias. In four of these models pharmacological profiles allowed to verify similarity to some clinical conditions, and therefore may inform basic research for new drug development. Conclusions While there is no single “optimal” model of central sensitization, the range of validated and easy‐to‐use procedures in humans should be able to inform preclinical researchers on helpful potential biomarkers, thereby narrowing the translation gap between basic and clinical data. Significance Being able to mimic aspects of pathological pain directly in humans has a huge potential to understand pathophysiology and provide animal research with translatable biomarkers for drug development. One group of human surrogate models has proven to have excellent predictive validity: they respond to clinically active medications and do not respond to clinically inactive medications, including some that worked in animals but failed in the clinics. They should therefore inform basic research for new drug development.
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Affiliation(s)
- Charles Quesada
- NeuroPain lab, Lyon Centre for Neuroscience Inserm U1028, Lyon, France.,Pain Center Neurological Hospital (CETD), Hospices Civils de Lyon, Lyon, France
| | - Anna Kostenko
- Department of Neurophysiology, Mannheim center for Translational Neurosciences, Heidelberg University, Heidelberg, Germany
| | - Idy Ho
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Caterina Leone
- Department of Human Neuroscience, Sapienza University, Rome, Italy
| | - Zahra Nochi
- Danish Pain Research Center, Dept of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Alexandre Stouffs
- Institute of Neuroscience (IoNS), Université Catholique de Louvain (UCLouvain), Ottignies-Louvain-la-Neuve, Belgium
| | - Matthias Wittayer
- Department of Neurophysiology, Mannheim center for Translational Neurosciences, Heidelberg University, Heidelberg, Germany
| | - Ombretta Caspani
- Department of Neurophysiology, Mannheim center for Translational Neurosciences, Heidelberg University, Heidelberg, Germany
| | - Nanna Brix Finnerup
- Danish Pain Research Center, Dept of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - André Mouraux
- Institute of Neuroscience (IoNS), Université Catholique de Louvain (UCLouvain), Ottignies-Louvain-la-Neuve, Belgium
| | | | - Irene Tracey
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Andrea Truini
- Department of Human Neuroscience, Sapienza University, Rome, Italy
| | - Rolf-Detlef Treede
- Department of Neurophysiology, Mannheim center for Translational Neurosciences, Heidelberg University, Heidelberg, Germany
| | - Luis Garcia-Larrea
- NeuroPain lab, Lyon Centre for Neuroscience Inserm U1028, Lyon, France.,Pain Center Neurological Hospital (CETD), Hospices Civils de Lyon, Lyon, France
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Magerl W, Thalacker E, Vogel S, Schleip R, Klein T, Treede RD, Schilder A. Tenderness of the Skin after Chemical Stimulation of Underlying Temporal and Thoracolumbar Fasciae Reveals Somatosensory Crosstalk between Superficial and Deep Tissues. Life (Basel) 2021; 11:life11050370. [PMID: 33919303 PMCID: PMC8143345 DOI: 10.3390/life11050370] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/17/2021] [Accepted: 04/17/2021] [Indexed: 01/14/2023] Open
Abstract
Musculoskeletal pain is often associated with pain referred to adjacent areas or skin. So far, no study has analyzed the somatosensory changes of the skin after the stimulation of different underlying fasciae. The current study aimed to investigate heterotopic somatosensory crosstalk between deep tissue (muscle or fascia) and superficial tissue (skin) using two established models of deep tissue pain (namely focal high frequency electrical stimulation (HFS) (100 pulses of constant current electrical stimulation at 10× detection threshold) or the injection of hypertonic saline in stimulus locations as verified using ultrasound). In a methodological pilot experiment in the TLF, different injection volumes of hypertonic saline (50–800 µL) revealed that small injection volumes were most suitable, as they elicited sufficient pain but avoided the complication of the numbing pinprick sensitivity encountered after the injection of a very large volume (800 µL), particularly following muscle injections. The testing of fascia at different body sites revealed that 100 µL of hypertonic saline in the temporal fascia and TLF elicited significant pinprick hyperalgesia in the overlying skin (–26.2% and –23.5% adjusted threshold reduction, p < 0.001 and p < 0.05, respectively), but not the trapezius fascia or iliotibial band. Notably, both estimates of hyperalgesia were significantly correlated (r = 0.61, p < 0.005). Comprehensive somatosensory testing (DFNS standard) revealed that no test parameter was changed significantly following electrical HFS. The experiments demonstrated that fascia stimulation at a sufficient stimulus intensity elicited significant across-tissue facilitation to pinprick stimulation (referred hyperalgesia), a hallmark sign of nociceptive central sensitization.
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Affiliation(s)
- Walter Magerl
- Department of Neurophysiology, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (W.M.); (E.T.); (S.V.); (T.K.); (R.-D.T.)
| | - Emanuela Thalacker
- Department of Neurophysiology, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (W.M.); (E.T.); (S.V.); (T.K.); (R.-D.T.)
| | - Simon Vogel
- Department of Neurophysiology, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (W.M.); (E.T.); (S.V.); (T.K.); (R.-D.T.)
| | - Robert Schleip
- Conservative and Rehabilitative Orthopedics, Department of Sport and Health Sciences, Health Sciences, Technical University of Munich, 80333 Munich, Germany;
- DIPLOMA Hochschule, 37242 Bad Sooden-Allendorf, Germany
| | - Thomas Klein
- Department of Neurophysiology, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (W.M.); (E.T.); (S.V.); (T.K.); (R.-D.T.)
| | - Rolf-Detlef Treede
- Department of Neurophysiology, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (W.M.); (E.T.); (S.V.); (T.K.); (R.-D.T.)
| | - Andreas Schilder
- Department of Neurophysiology, Mannheim Center for Translational Neuroscience (MCTN), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (W.M.); (E.T.); (S.V.); (T.K.); (R.-D.T.)
- Correspondence: ; Tel.: +49-621-383-71400; Fax: +49-621-383-71401
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34
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Kwok CHT, Kohro Y, Mousseau M, O'Brien MS, Matyas JR, McDougall JJ, Trang T. Role of Primary Afferents in Arthritis Induced Spinal Microglial Reactivity. Front Immunol 2021; 12:626884. [PMID: 33897685 PMCID: PMC8058457 DOI: 10.3389/fimmu.2021.626884] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 03/18/2021] [Indexed: 11/18/2022] Open
Abstract
Increased afferent input resulting from painful injury augments the activity of central nociceptive circuits via both neuron-neuron and neuron-glia interactions. Microglia, resident immune cells of the central nervous system (CNS), play a crucial role in the pathogenesis of chronic pain. This study provides a framework for understanding how peripheral joint injury signals the CNS to engage spinal microglial responses. During the first week of monosodium iodoacetate (MIA)-induced knee joint injury in male rats, inflammatory and neuropathic pain were characterized by increased firing of peripheral joint afferents. This increased peripheral afferent activity was accompanied by increased Iba1 immunoreactivity within the spinal dorsal horn indicating microglial activation. Pharmacological silencing of C and A afferents with co-injections of QX-314 and bupivacaine, capsaicin, or flagellin prevented the development of mechanical allodynia and spinal microglial activity after MIA injection. Elevated levels of ATP in the cerebrospinal fluid (CSF) and increased expression of the ATP transporter vesicular nucleotide transporter (VNUT) in the ipsilateral spinal dorsal horn were also observed after MIA injections. Selective silencing of primary joint afferents subsequently inhibited ATP release into the CSF. Furthermore, increased spinal microglial reactivity, and alleviation of MIA-induced arthralgia with co-administration of QX-314 with bupivacaine were recapitulated in female rats. Our results demonstrate that early peripheral joint injury activates joint nociceptors, which triggers a central spinal microglial response. Elevation of ATP in the CSF, and spinal expression of VNUT suggest ATP signaling may modulate communication between sensory neurons and spinal microglia at 2 weeks of joint degeneration.
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Affiliation(s)
- Charlie H T Kwok
- Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada.,Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Yuta Kohro
- Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada.,Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Michael Mousseau
- Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada.,Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Melissa S O'Brien
- Departments of Pharmacology and Anesthesia, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, NS, Canada
| | - John R Matyas
- Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada
| | - Jason J McDougall
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Tuan Trang
- Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada.,Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
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35
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Wang Q, Zhang Y, Liu J, Zhang W. Quaternary Lidocaine Derivatives: Past, Present, and Future. Drug Des Devel Ther 2021; 15:195-207. [PMID: 33469271 PMCID: PMC7813469 DOI: 10.2147/dddt.s291229] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 12/25/2020] [Indexed: 02/05/2023] Open
Abstract
Local anesthetics have the advantage of complete analgesia with fewer side effects compared to systemic analgesics. However, their clinical use is limited due to their short duration of action. Thus, local anesthetics with fast onset, long duration of action, selective nociceptive block, and low local and systemic toxicity are highly desirable. In the past electrophysiological studies, quaternary lidocaine derivatives (QLDs) showed these characteristics. Here, we review electrophysiological properties of QLDs and their pharmacodynamic characteristics to shed light on potential problems.
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Affiliation(s)
- Qi Wang
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Centre, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Yujun Zhang
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Centre, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Jin Liu
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Centre, West China Hospital, Sichuan University, Chengdu, People's Republic of China.,National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Wensheng Zhang
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Centre, West China Hospital, Sichuan University, Chengdu, People's Republic of China.,National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, People's Republic of China
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36
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Basharat S, Gilani SA, Iftikhar F, Murtaza MA, Basharat A, Sattar A, Qamar MM, Ali M. Capsaicin: Plants of the Genus Capsicum and Positive Effect of Oriental Spice on Skin Health. Skin Pharmacol Physiol 2021; 33:331-341. [PMID: 33401283 DOI: 10.1159/000512196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Accepted: 08/28/2020] [Indexed: 11/19/2022]
Abstract
BACKGROUND Capsaicin, the main pungent ingredient in hot chili peppers, causes excitation of small sensory neurons. It also provides the basic pungent flavor in Capsicum fruits. SUMMARY Capsaicin plays a vital role as an agonist for the TRPV1 (transient receptor potential cation channel, subfamily V, member 1) receptor. TRPV1 is essential for the reduction of oxidative stress, pain sensations, and inflammation. Therefore, it has many pros related to health issue. Activation and positive impact of TRPV1 via capsaicin has been studied in various dermatological conditions and in other skin-related issues. Past studies documented that capsaicin plays a vital role in the prevention of atopic dermatitis as well as psoriasis. Moreover, TRPV1 is also very important for skin health because it acts as a capsaicin receptor. It is found in nociceptive nerve fibers and nonneural structures. It prompts the release of a compound that is involved in communicating pain between the spinal cord nerves and other parts of the body. Key Messages: Here, we summarize the growing evidence for the beneficial role of capsaicin and TRPV1 and how they help in the relief of skin diseases such as inflammation, permeation, dysfunction, atopic dermatitis, and psoriasis and in pain amplification syndrome.
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Affiliation(s)
- Shahnai Basharat
- University Institute of Diet & Nutritional Sciences, The University of Lahore, Sargodha, Pakistan,
| | - Syed Amir Gilani
- Dean, Faculty of Allied Health Sciences, The University of Lahore, Lahore, Pakistan
| | - Faiza Iftikhar
- University Institute of Diet & Nutritional Sciences, The University of Lahore, Sargodha, Pakistan
| | | | - Ayesha Basharat
- Sargodha Medical College, University of Sargodha, Sargodha, Pakistan
| | - Ahsan Sattar
- Food Microbiology and Technology, Bahaudin Zikriya University, Multan, Pakistan
| | - Muhammad Mustafa Qamar
- Department of Physical Therapy, Sargodha Medical College, The University of Sargodha, Sargodha, Pakistan
| | - Muhammad Ali
- Institute of Allied Health Sciences, Sargodha Medical College, The University of Sargodha, Sargodha, Pakistan
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37
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van den Broeke EN, Vanmaele T, Mouraux A, Stouffs A, Biurrun-Manresa J, Torta DM. Perceptual correlates of homosynaptic long-term potentiation in human nociceptive pathways: a replication study. ROYAL SOCIETY OPEN SCIENCE 2021; 8:200830. [PMID: 33614062 PMCID: PMC7890496 DOI: 10.1098/rsos.200830] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 12/18/2020] [Indexed: 06/12/2023]
Abstract
Animal studies have shown that high-frequency stimulation (HFS) of peripheral C-fibres induces long-term potentiation (LTP) within spinal nociceptive pathways. The aim of this replication study was to assess if a perceptual correlate of LTP can be observed in humans. In 20 healthy volunteers, we applied HFS to the left or right volar forearm. Before and after applying HFS, we delivered single electrical test stimuli through the HFS electrode while a second electrode at the contra-lateral arm served as a control condition. Moreover, to test the efficacy of the HFS protocol, we quantified changes in mechanical pinprick sensitivity before and after HFS of the skin surrounding both electrodes. The perceived intensity was collected for both electrical and mechanical stimuli. After HFS, the perceived pain intensity elicited by the mechanical pinprick stimuli applied on the skin surrounding the HFS-treated site was significantly higher compared to control site (heterotopic effect). Furthermore, we found a higher perceived pain intensity for single electrical stimuli delivered to the HFS-treated site compared to the control site (homotopic effect). Whether the homotopic effect reflects a perceptual correlate of homosynaptic LTP remains to be elucidated.
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Affiliation(s)
- E. N. van den Broeke
- Institute of Neuroscience, IoNS, Faculty of Medicine, UC Louvain, Avenue Mounier 53, B-1200, Brussels, Belgium
| | - T. Vanmaele
- Health Psychology Research Group, Faculty of Psychology and Educational Sciences, KU Leuven, Tiensestraat 102, B-3000 Leuven, Belgium
| | - A. Mouraux
- Institute of Neuroscience, IoNS, Faculty of Medicine, UC Louvain, Avenue Mounier 53, B-1200, Brussels, Belgium
| | - A. Stouffs
- Institute of Neuroscience, IoNS, Faculty of Medicine, UC Louvain, Avenue Mounier 53, B-1200, Brussels, Belgium
| | - J. Biurrun-Manresa
- Institute for Research and Development in Bioengineering and Bioinformatics (IBB-CONICET-UNER), National University of Entre Rios, Oro Verde, Argentina
| | - D. M. Torta
- Health Psychology Research Group, Faculty of Psychology and Educational Sciences, KU Leuven, Tiensestraat 102, B-3000 Leuven, Belgium
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Sachau J, Bruckmueller H, Gierthmühlen J, Magerl W, May D, Binder A, Forstenpointner J, Koetting J, Maier C, Tölle TR, Treede RD, Berthele A, Caliebe A, Diesch C, Flor H, Huge V, Maihöfner C, Rehm S, Kersebaum D, Fabig SC, Vollert J, Rolke R, Stemmler S, Sommer C, Westermann A, Cascorbi I, Baron R. The serotonin receptor 2A (HTR2A) rs6313 variant is associated with higher ongoing pain and signs of central sensitization in neuropathic pain patients. Eur J Pain 2020; 25:595-611. [PMID: 33171011 DOI: 10.1002/ejp.1696] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 09/08/2020] [Accepted: 11/08/2020] [Indexed: 12/17/2022]
Abstract
BACKGROUND The serotonin receptor 2A (HTR2A) has been described as an important facilitation mediator of spinal nociceptive processing leading to central sensitization (CS) in animal models of chronic pain. However, whether HTR2A single nucleotide variants (SNVs) modulate neuropathic pain states in patients has not been investigated so far. The aim of this study was to elucidate the potential association of HTR2A variants with sensory abnormalities or ongoing pain in neuropathic pain patients. METHODS At total of 240 neuropathic pain patients and 253 healthy volunteers were included. Patients were phenotypically characterized using standardized quantitative sensory testing (QST). Patients and controls were genotyped for HTR2A g.-1438G > A (rs6311) and c.102C > T (rs6313). Genotype-related differences in QST parameters were assessed considering QST profile clusters, principal somatosensory components and sex. RESULTS There was an equal distribution of rs6313 and linked rs6311 between patients and controls. However, the rs6313 variant was significantly associated with a principal component of pinprick hyperalgesia and dynamic mechanical allodynia, indicating enhanced CS in patients with sensory loss (-0.34 ± 0.15 vs. +0.31 ± 0.11 vs., p < .001). In this cluster, the variant allele was also associated with single QST parameters of pinprick hyperalgesia (MPT, +0.64 ± 0.18 vs. -0.34 ± 0.23 p = .002; MPS, +0.66 ± 0.17 vs. -0.09 ± 0.23, p = .009) and ongoing pain was increased by 30%. CONCLUSIONS The specific association of the rs6313 variant with pinprick hyperalgesia and increased levels of ongoing pain suggests that the HTR2A receptor might be an important modulator in the development of CS in neuropathic pain. SIGNIFICANCE This article presents new insights into serotonin receptor 2A-mediating mechanisms of central sensitization in neuropathic pain patients. The rs6313 variant allele was associated with increased mechanical pinprick sensitivity and increased levels of ongoing pain supporting a contribution of central sensitization in the genesis of ongoing pain providing a possible route for mechanism-based therapies.
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Affiliation(s)
- Juliane Sachau
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Henrike Bruckmueller
- Institute of Experimental and Clinical Pharmacology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany.,Department of Pharmacy, UiT The Arctic University of Norway, Tromsø, Norway
| | - Janne Gierthmühlen
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Walter Magerl
- Chair of Neurophysiology, Mannheim Center for Translational Neuroscience, Ruprecht Karls University Heidelberg, Mannheim, Germany
| | - Denisa May
- Institute of Experimental and Clinical Pharmacology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Andreas Binder
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Julia Forstenpointner
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Judith Koetting
- Department of Human Genetics, Ruhr University Bochum, Bochum, Germany
| | - Christoph Maier
- Department of Pain Management, BG Kliniken Bergmannsheil, Ruhr University Bochum, Bochum, Germany
| | - Thomas R Tölle
- Department of Neurology, Klinikum Rechts der Isar, Technical University Munich, München, Germany
| | - Rolf-Detlef Treede
- Chair of Neurophysiology, Mannheim Center for Translational Neuroscience, Ruprecht Karls University Heidelberg, Mannheim, Germany
| | - Achim Berthele
- Department of Neurology, Klinikum Rechts der Isar, Technical University Munich, München, Germany
| | - Amke Caliebe
- Institute of Medical Informatics and Statistics, Christian-Albrechts-University and University Hospital Schleswig-Holstein, Kiel, Germany
| | - Carolin Diesch
- Institute of Experimental and Clinical Pharmacology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Herta Flor
- Department of Clinical and Cognitive Neuroscience, Central Institute for Mental Health, Medical Faculty Mannheim, Ruprecht Karls University Heidelberg, Mannheim, Germany
| | - Volker Huge
- Department of Anaesthesiology, Ludwig Maximilians University Munich, München, Germany
| | - Christian Maihöfner
- Department of Neurology, General Hospital Fürth, University of Erlangen-Nuremberg, Nuremberg, Germany
| | - Stefanie Rehm
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Dilara Kersebaum
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Sophie-Charlotte Fabig
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Jan Vollert
- Chair of Neurophysiology, Mannheim Center for Translational Neuroscience, Ruprecht Karls University Heidelberg, Mannheim, Germany.,Pain Research, Department of Surgery and Cancer, Imperial College London, London, UK
| | - Roman Rolke
- Department of Palliative Medicine, Medical Faculty RWTH Aachen University, Aachen, Germany
| | - Susanne Stemmler
- Department of Human Genetics, Ruhr University Bochum, Bochum, Germany
| | - Claudia Sommer
- Department of Neurology, University of Würzburg, Würzburg, Germany
| | - Andrea Westermann
- Department of Pain Management, BG Kliniken Bergmannsheil, Ruhr University Bochum, Bochum, Germany
| | - Ingolf Cascorbi
- Institute of Experimental and Clinical Pharmacology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Ralf Baron
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany
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Schnakenberg M, Thomas C, Schmelz M, Rukwied R. Nerve growth factor sensitizes nociceptors to C-fibre selective supra-threshold electrical stimuli in human skin. Eur J Pain 2020; 25:385-397. [PMID: 33064901 DOI: 10.1002/ejp.1678] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 09/01/2020] [Accepted: 10/07/2020] [Indexed: 11/11/2022]
Abstract
BACKGROUND Intradermal injection of 1 µg nerve growth factor (NGF) causes sustained nociceptor sensitization. Slowly depolarizing electrical current preferentially activates C-nociceptors. METHODS We explored the differential contribution of A-delta and C-nociceptors in NGF-sensitized skin using slowly depolarizing transcutaneous electrical current stimuli, CO2 laser heat, mechanical impact, and A-fibre compression block. In 14 healthy volunteers, pain rating was recorded on a numeric scale at days 1-14 after NGF treatment. Ratings during A-fibre conduction block were investigated at days 3 and 7 post-NGF. RESULTS Pain ratings to electrical, CO2 heat and mechanical impact stimuli were enhanced (>30%, p < .0005, ANOVA) at NGF-injection sites. Axon reflex erythema evoked by electrical stimulation was also larger at NGF-injection sites (p < .02, ANOVA). Diminution of pain during continuous (1 min) sinusoidal current stimulation at 4 Hz was less pronounced after NGF (p < .05, ANOVA). Pain ratings to electrical sinusoidal and mechanical impact stimuli during A-fibre conduction block were significantly elevated at the NGF sites compared to NaCl-treated skin (p < .05, ANOVA). CONCLUSIONS NGF-induced sensitization of human skin to electrical and mechanical stimuli is primarily driven by C-nociceptors with little contribution from A-delta fibres. Less-pronounced accommodation during ongoing sinusoidal stimulation suggests that NGF could facilitate axonal spike generation and conduction in primary afferent nociceptors in humans. Further studies using this sinusoidal electrical stimulation profile to investigate patients with chronic inflammatory pain may allow localized assessment of skin C-nociceptors and their putative excitability changes under pathologic conditions. SIGNIFICANCE The application of novel slowly depolarizing electrical stimuli demonstrated a predominant C-nociceptor sensitization in NGF-treated skin. Increased pain ratings, larger axon reflex erythema and less accommodation of C-fibres to ongoing sinusoidal stimulation all indicated an enhanced nociceptor discharge after NGF. A-fibre conduction block had little effect on electrical and mechanical hyperalgesia skin in NGF-treated compared to NaCl-treated skin. This electrical stimulus profile may be applicable for patients with chronic inflammatory pain, allowing localized assessment of skin C-nociceptors and their putative excitability changes under pathologic conditions.
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Affiliation(s)
- Mark Schnakenberg
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Christian Thomas
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Martin Schmelz
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Roman Rukwied
- Department of Experimental Pain Research, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
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Scheuren PS, Rosner J, Curt A, Hubli M. Pain-autonomic interaction: A surrogate marker of central sensitization. Eur J Pain 2020; 24:2015-2026. [PMID: 32794307 DOI: 10.1002/ejp.1645] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 11/07/2022]
Abstract
BACKGROUND Central sensitization represents a key pathophysiological mechanism underlying the development of neuropathic pain, often manifested clinically as mechanical allodynia and hyperalgesia. Adopting a mechanism-based treatment approach relies highly on the ability to assess the presence of central sensitization. The aim of the study was to investigate potential pain-autonomic readouts to operationalize experimentally induced central sensitization in the area of secondary hyperalgesia. METHODS Pinprick evoked potentials (PEPs) and sympathetic skin responses (SSRs) were recorded in 20 healthy individuals. Three blocks of PEP and SSR recordings were performed before and after heat-induced secondary hyperalgesia. All measurements were also performed before and after a control condition. Multivariate analyses were performed using linear mixed-effect regression models to examine the effect of experimentally induced central sensitization on PEP and SSR parameters (i.e. amplitudes, latencies and habituation) and on pinprick pain ratings. RESULTS The noxious heat stimulation induced robust mechanical hyperalgesia with a significant increase in PEP and SSR amplitudes (p < 0.001) in the area of secondary hyperalgesia. Furthermore, PEP and SSR habituation were reduced (p < 0.001) after experimentally induced central sensitization. CONCLUSIONS The findings demonstrate that combined recordings of PEPs and SSRs are sensitive to objectify experimentally induced central sensitization and may have a great potential to reveal its presence in clinical pain conditions. Corroborating current pain phenotyping with pain-autonomic markers has the potential to unravel central sensitization along the nociceptive neuraxis and might provide a framework for mechanistically founded therapies. SIGNIFICANCE Our findings provide evidence that combined recordings of sympathetic skin responses (SSRs) and pinprick evoked potentials (PEPs) might be able to unmask central sensitization induced through a well-established experimental pain model in healthy individuals. As such, these novel readouts of central sensitization might attain new insights towards complementing clinical pain phenotyping.
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Affiliation(s)
- Paulina S Scheuren
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Jan Rosner
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.,Department of Neurology, University Hospital Bern, Inselspital, University of Bern, Bern, Switzerland
| | - Armin Curt
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Michèle Hubli
- Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
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41
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Forstenpointner J, Berry D, Baron R, Borsook D. The cornucopia of central disinhibition pain - An evaluation of past and novel concepts. Neurobiol Dis 2020; 145:105041. [PMID: 32800994 DOI: 10.1016/j.nbd.2020.105041] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 07/18/2020] [Accepted: 08/08/2020] [Indexed: 12/12/2022] Open
Abstract
Central disinhibition (CD), as applied to pain, decreases thresholds of endogenous systems. This provokes onset of spontaneous or evoked pain in an individual beyond the ability of the nervous system to inhibit pain resulting from a disease or tissue damage. The original CD concept as proposed by Craig entails a shift from the lateral pain pathway (i.e. discriminative pain processing) towards the medial pain pathway (i.e. emotional pain processing), within an otherwise neurophysiological intact environment. In this review, the original CD concept as proposed by Craig is extended by the primary "nociceptive pathway damage - CD" concept and the secondary "central pathway set point - CD". Thereby, the original concept may be transferred into anatomical and psychological non-functional conditions. We provide examples for either primary or secondary CD concepts within different clinical etiologies as well as present surrogate models, which directly mimic the underlying pathophysiology (A-fiber block) or modulate the CD pathway excitability (thermal grill). The thermal grill has especially shown promising advancements, which may be useful to examine CD pathway activation in the future. Therefore, within this topical review, a systematic review on the thermal grill illusion is intended to stimulate future research. Finally, the authors review different mechanism-based treatment approaches to combat CD pain.
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Affiliation(s)
- Julia Forstenpointner
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Campus Kiel, Arnold-Heller-Str. 3, 24105 Kiel, Germany; Center for Pain and the Brain, Boston Children's Hospital, Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, MA, USA.
| | - Delany Berry
- Center for Pain and the Brain, Boston Children's Hospital, Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, MA, USA
| | - Ralf Baron
- Division of Neurological Pain Research and Therapy, Department of Neurology, University Hospital Schleswig-Holstein, Campus Kiel, Arnold-Heller-Str. 3, 24105 Kiel, Germany
| | - David Borsook
- Center for Pain and the Brain, Boston Children's Hospital, Department of Anesthesia, Critical Care and Pain Medicine, Harvard Medical School, Boston, MA, USA
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42
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van Neerven SGA, Mouraux A. Capsaicin-Induced Skin Desensitization Differentially Affects A-Delta and C-Fiber-Mediated Heat Sensitivity. Front Pharmacol 2020; 11:615. [PMID: 32508630 PMCID: PMC7248294 DOI: 10.3389/fphar.2020.00615] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 04/20/2020] [Indexed: 12/19/2022] Open
Abstract
Localized neuropathic pain can be relieved following the topical application of high-concentration capsaicin. This clinical effect is thought to be related to the temporary desensitization of capsaicin- and heat-sensitive epidermal nociceptors. The objective of the present study was to examine whether the changes in thermal sensitivity induced by high-concentration topical capsaicin can be explained entirely by desensitization of capsaicin-sensitive afferents. For this purpose, we characterized, in 20 healthy human volunteers, the time course and spatial extent of the changes in sensitivity to thermal stimuli preferentially activating heat-sensitive A-fiber nociceptors, heat-sensitive C-fiber afferents, and cool-sensitive A-fiber afferents. The volar forearm was treated with a high-concentration capsaicin patch for 1 h. Transient heat, warm and cold stimuli designed to activate Aδ- and C-fiber thermonociceptors, C-fiber warm receptors, and Aδ-fiber cold receptors were applied to the skin before and after treatment at days 1, 3, and 7. Reaction times, intensity ratings, and quality descriptors were collected. The stimuli were applied both within the capsaicin-treated skin and around the capsaicin-treated skin to map the changes in thermal sensitivity. We found that topical capsaicin selectively impairs heat sensitivity without any concomitant changes in cold sensitivity. Most interestingly, we observed a differential effect on the sensitivity to thermal inputs conveyed by Aδ- and C-fibers. Reduced sensitivity to Aδ-fiber-mediated heat was restricted to the capsaicin-treated skin, whereas reduced sensitivity to C-fiber-mediated heat extended well beyond the treated skin. Moreover, the time course of the reduced sensitivity to C-fiber-mediated input was more prolonged than the reduced sensitivity to Aδ-fiber-mediated input.
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Affiliation(s)
| | - André Mouraux
- Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
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43
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Hughes SW, Basra M, Chan C, Parr C, Wong F, Gomes S, Strutton PH. Capsaicin-Induced Changes in Electrical Pain Perception Threshold Can Be Used to Assess the Magnitude of Secondary Hyperalgesia in Humans. PAIN MEDICINE 2020; 21:2830-2838. [DOI: 10.1093/pm/pnaa082] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Abstract
Objectives
Areas of secondary hyperalgesia can be assessed using quantitative sensory testing (QST). Delivering noxious electrocutaneous stimulation could provide added benefit by allowing multiple measurements of the magnitude of hyperalgesia. We aimed to characterize the use of electrical pain perception (EPP) thresholds alongside QST as a means by which to measure changes in pain thresholds within an area of secondary mechanical hyperalgesia.
Methods
EPP and heat pain thresholds (HPTs) were measured at five distinct points at baseline and following 1% capsaicin cream application, one within a central zone and four within a secondary zone. Areas of secondary mechanical hyperalgesia were mapped using QST. In a further 14 participants, capsaicin-induced reduction in EPP thresholds was mapped using a radial lines approach across 24 points.
Results
There was a reduction in EPP threshold measured at the four points within the secondary zone, which was within the mapped area of mechanical secondary hyperalgesia. The magnitude of secondary hyperalgesia could be split into a mild (∼4% reduction) and severe (∼21% reduction) area within an individual subject. There was no reduction in HPT within the secondary zone, but there was a reduction in both HPT and EPP threshold within the primary zone. EPP mapping revealed differences in the magnitude and spread of hyperalgesia across all subjects.
Conclusions
Measuring capsaicin-induced reduction in EPP thresholds can be used to map hyperalgesic areas in humans. This semi-automated approach allows rapid assessment of the magnitude of hyperalgesia, both within an individual subject and across a study population.
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Affiliation(s)
- Sam W Hughes
- Division of Surgery, Department of Surgery and Cancer, The Nick Davey Laboratory, Faculty of Medicine, Imperial College London, London, UK
| | - Meirvaan Basra
- Division of Surgery, Department of Surgery and Cancer, The Nick Davey Laboratory, Faculty of Medicine, Imperial College London, London, UK
| | - Calvin Chan
- Division of Surgery, Department of Surgery and Cancer, The Nick Davey Laboratory, Faculty of Medicine, Imperial College London, London, UK
| | - Callum Parr
- Division of Surgery, Department of Surgery and Cancer, The Nick Davey Laboratory, Faculty of Medicine, Imperial College London, London, UK
| | - Felyx Wong
- Division of Surgery, Department of Surgery and Cancer, The Nick Davey Laboratory, Faculty of Medicine, Imperial College London, London, UK
| | - Sofia Gomes
- Division of Surgery, Department of Surgery and Cancer, The Nick Davey Laboratory, Faculty of Medicine, Imperial College London, London, UK
| | - Paul H Strutton
- Division of Surgery, Department of Surgery and Cancer, The Nick Davey Laboratory, Faculty of Medicine, Imperial College London, London, UK
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44
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Hoeger Bement M, Petersen KK, Sørensen LB, Andersen HH, Graven‐Nielsen T. Temporal aspects of endogenous pain modulation during a noxious stimulus prolonged for 1 day. Eur J Pain 2020; 24:752-760. [DOI: 10.1002/ejp.1523] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 12/17/2019] [Accepted: 12/19/2019] [Indexed: 01/29/2023]
Affiliation(s)
- Marie Hoeger Bement
- Center for Neuroplasticity and Pain (CNAP) Aalborg University Aalborg Denmark
- Department of Physical Therapy Marquette University Milwaukee WI USA
| | | | - Line B. Sørensen
- Center for Neuroplasticity and Pain (CNAP) Aalborg University Aalborg Denmark
| | - Hjalte H. Andersen
- Laboratory of Cutaneous Experimental Pain SMIAalborg University Aalborg Denmark
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The capsaicin receptor TRPV1 is the first line defense protecting from acute non damaging heat: a translational approach. J Transl Med 2020; 18:28. [PMID: 31952468 PMCID: PMC6966804 DOI: 10.1186/s12967-019-02200-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 12/26/2019] [Indexed: 02/07/2023] Open
Abstract
Background Pain is the vital sense preventing tissue damage by harmful noxious stimuli. The capsaicin receptor TRPV1 is activated by noxious temperatures, however, acute heat pain is only marginally affected in mice after TRPV1 knockout but completely eliminated in mice lacking TRPV1 positive fibers. Exploring contribution of candidate signal transduction mechanisms to heat pain in humans needs translational models. Methods We used focused, non-damaging, short near-infrared laser heat stimuli (wavelength 1470/1475 nm) to study the involvement of TRPV1-expressing nerve fibers in the encoding of heat pain intensity. Human psychophysics (both sexes) were compared to calcium transients in native rat DRG neurons and heterologously expressing HEK293 cells. Results Heating of dermal and epidermal nerve fibers in humans with laser stimuli of ≥ 2.5 mJ (≥ 25 ms, 100 mW) induced pain that increased linearly as a function of stimulus intensity in double logarithmic space across two orders of magnitude and was completely abolished by desensitization using topical capsaicin. In DRG neurons and TRPV1-expressing HEK cells, heat sensitivity was restricted to capsaicin sensitive cells. Strength duration curves (2–10 ms range) and thresholds (DRGs 0.56 mJ, HEK cells 0.52 mJ) were nearly identical. Tachyphylaxis upon repetitive stimulation occurred in HEK cells (54%), DRGs (59%), and humans (25%). Conclusion TRPV1-expressing nociceptors encode transient non-damaging heat pain in humans, thermal gating of TRPV1 is similar in HEK cells and DRG neurons, and TRPV1 tachyphylaxis is an important modulator of heat pain sensitivity. These findings suggest that TRPV1 expressed in dermal and epidermal populations of nociceptors serves as first line defense against heat injury.
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46
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Filbrich L, van den Broeke EN, Legrain V, Mouraux A. The focus of spatial attention during the induction of central sensitization can modulate the subsequent development of secondary hyperalgesia. Cortex 2020; 124:193-203. [PMID: 31901709 DOI: 10.1016/j.cortex.2019.11.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 10/11/2019] [Accepted: 11/21/2019] [Indexed: 12/18/2022]
Abstract
Intense or sustained activation of peripheral nociceptors can induce central sensitization. This enhanced responsiveness to nociceptive input of the central nervous system primarily manifests as an increased sensitivity to painful mechanical pinprick stimuli extending beyond the site of injury (secondary mechanical hyperalgesia) and is thought to be a key mechanism in the development of chronic pain, such as persistent post-operative pain. It is increasingly recognized that emotional and cognitive factors can strongly influence the pain experience. Furthermore, through their potential effects on pain modulation circuits including descending pathways to the spinal cord, it has been hypothesized that these emotional and cognitive factors could constitute risk factors for the susceptibility to develop chronic pain. Here, we tested whether, in healthy volunteers, the experimental induction of central sensitization by peripheral nociceptive input can be modulated by selective spatial attention. While participants performed a somatosensory detection task that required focusing attention towards one of the forearms, secondary hyperalgesia was induced at both forearms using bilateral and simultaneous high-frequency electrical stimulation (HFS) of the skin. HFS induced an increased sensitivity to mechanical pinprick stimuli at both forearms, directly (T1) and 20 min (T2) after HFS, confirming the successful induction of secondary hyperalgesia at both forearms. Most importantly, at T2, the HFS-induced increase in pinprick sensitivity as well as the area of secondary hyperalgesia was greater at the attended arm as compared to the non-attended arm. This indicates that top-down attentional factors can modulate the development of central sensitization by peripheral nociceptive input, and that the focus of spatial attention, besides its modulatory effects on perception, can affect activity-dependent neuroplasticity.
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Affiliation(s)
- Lieve Filbrich
- Institute of Neuroscience (IONS), UCLouvain, Brussels, Belgium; Psychological Sciences Research Institute (IPSY), UCLouvain, Louvain-la-Neuve, Belgium.
| | | | - Valéry Legrain
- Institute of Neuroscience (IONS), UCLouvain, Brussels, Belgium; Psychological Sciences Research Institute (IPSY), UCLouvain, Louvain-la-Neuve, Belgium
| | - André Mouraux
- Institute of Neuroscience (IONS), UCLouvain, Brussels, Belgium; Psychological Sciences Research Institute (IPSY), UCLouvain, Louvain-la-Neuve, Belgium
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47
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Gousset S, Mouraux A, van den Broeke EN. Burst-like conditioning electrical stimulation is more efficacious than continuous stimulation for inducing secondary hyperalgesia in humans. J Neurophysiol 2020; 123:323-328. [PMID: 31825708 PMCID: PMC6985853 DOI: 10.1152/jn.00675.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/02/2019] [Accepted: 12/03/2019] [Indexed: 11/22/2022] Open
Abstract
The aim of the present study was to compare the efficacy of burst-like conditioning electrical stimulation vs. continuous stimulation of cutaneous nociceptors for inducing increased pinprick sensitivity in the surrounding unstimulated skin (a phenomenon referred to as secondary hyperalgesia). In a first experiment (n = 30), we compared the increase in mechanical pinprick sensitivity induced by 50-Hz burst-like stimulation (n = 15) vs. 5-Hz continuous stimulation (n = 15) while maintaining constant the total number of stimuli and the total duration of stimulation. We found a significantly greater increase in mechanical pinprick sensitivity in the surrounding unstimulated skin after 50-Hz burst-like stimulation compared with 5-Hz continuous stimulation (P = 0.013, Cohen's d = 0.970). Importantly, to control for the different frequency of stimulation, we compared in a second experiment (n = 40) 5-Hz continuous stimulation (n = 20) vs. 5-Hz burst-like stimulation (n = 20), this time while keeping the total number of stimuli as well as the frequency of stimulation identical. Again, we found a significantly greater increase in pinprick sensitivity after 5-Hz burst-like stimulation compared with 5-Hz continuous stimulation (P = 0.009, Cohen's d = 0.868). To conclude, our data indicate that burst-like conditioning electrical stimulation is more efficacious than continuous stimulation for inducing secondary hyperalgesia.NEW & NOTEWORTHY Burst-like electrical conditioning stimulation of cutaneous nociceptors is more efficacious than continuous stimulation for inducing heterosynaptic facilitation of mechanical nociceptive input in humans.
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Affiliation(s)
- S Gousset
- System and Cognition Division, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - A Mouraux
- System and Cognition Division, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - E N van den Broeke
- System and Cognition Division, Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
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48
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Oaklander AL, Nolano M. Scientific Advances in and Clinical Approaches to Small-Fiber Polyneuropathy: A Review. JAMA Neurol 2019; 76:1240-1251. [PMID: 31498378 PMCID: PMC10021074 DOI: 10.1001/jamaneurol.2019.2917] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
IMPORTANCE Small-fiber polyneuropathy involves preferential damage to the thinly myelinated A-delta fibers, unmyelinated C sensory fibers, or autonomic or trophic fibers. Although this condition is common, most patients still remain undiagnosed and untreated because of lagging medical and public awareness of research advances. Chronic bilateral neuropathic pain, fatigue, and nausea are cardinal symptoms that can cause disability and dependence, including pain medication dependence. OBSERVATIONS Biomarker confirmation is recommended, given the nonspecificity of symptoms. The standard test involves measuring epidermal neurite density within a 3-mm protein gene product 9.5 (PGP9.5)-immunolabeled lower-leg skin biopsy. Biopsies and autonomic function testing confirm that small-fiber neuropathy not uncommonly affects otherwise healthy children and young adults, in whom it is often associated with inflammation or dysimmunity. A recent meta-analysis concluded that small-fiber neuropathy underlies 49% of illnesses labeled as fibromyalgia. Initially, patients with idiopathic small-fiber disorders should be screened by medical history and blood tests for potentially treatable causes, which are identifiable in one-third to one-half of patients. Then, secondary genetic testing is particularly important for familial and childhood cases. Treatable genetic causes include Fabry disease, transthyretin and primary systemic amyloidosis, hereditary sensory autonomic neuropathy-1, and ion-channel mutations. Immunohistopathologic evidence suggests that small-fiber dysfunction and denervation, especially of blood vessels, contributes to diverse symptoms, including postexertional malaise, postural orthostatic tachycardia, and functional gastrointestinal distress. Preliminary evidence implicates acute or chronic autoreactivity in some cases, particularly in female patients and otherwise healthy children and young adults. Different temporal patterns akin to Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy have been described; here, corticosteroids and immunoglobulins, which are often efficacious for inflammatory neuropathic conditions, are increasingly considered. CONCLUSIONS AND RELEVANCE Because small fibers normally grow throughout life, improving contributory conditions may permit regrowth, slow progression, and prevent permanent damage. The prognosis is often hopeful for improving quality of life and sometimes for abatement or resolution, particularly in the young and otherwise healthy individuals. Examples include diabetic, infectious, toxic, genetic, and inflammatory causes. The current standard of care requires prompt diagnosis and treatment, particularly in children and young adults, to restore life trajectory. Consensus diagnostic and tracking metrics should be established to facilitate treatment trials.
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Affiliation(s)
- Anne Louise Oaklander
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston.,Department of Pathology (Neuropathology), Massachusetts General Hospital, Boston
| | - Maria Nolano
- Department of Neuroscience, Reproductive Sciences and Odontostomatology, University "Federico II" of Naples, Naples, Italy.,Skin Biopsy Laboratory, Department of Neurology, IRCCS, Istituti Clinici Scientifici Maugeri, SpA SB, Telese Terme, Italy
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van den Broeke EN, Gousset S, Bouvy J, Stouffs A, Lebrun L, van Neerven SGA, Mouraux A. Heterosynaptic facilitation of mechanical nociceptive input is dependent on the frequency of conditioning stimulation. J Neurophysiol 2019; 122:994-1001. [PMID: 31291140 PMCID: PMC6766737 DOI: 10.1152/jn.00274.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 06/10/2019] [Accepted: 07/09/2019] [Indexed: 11/22/2022] Open
Abstract
High-frequency burstlike electrical conditioning stimulation (HFS) applied to human skin induces an increase in mechanical pinprick sensitivity of the surrounding unconditioned skin (a phenomenon known as secondary hyperalgesia). The present study assessed the effect of frequency of conditioning stimulation on the development of this increased pinprick sensitivity in humans. In a first experiment, we compared the increase in pinprick sensitivity induced by HFS, using monophasic non-charge-compensated pulses and biphasic charge-compensated pulses. High-frequency stimulation, traditionally delivered with non-charge-compensated square-wave pulses, may induce a cumulative depolarization of primary afferents and/or changes in pH at the electrode-tissue interface due to the accumulation of a net residue charge after each pulse. Both could contribute to the development of the increased pinprick sensitivity in a frequency-dependent fashion. We found no significant difference in the increase in pinprick sensitivity between HFS delivered with charge-compensated and non-charge-compensated pulses, indicating that the possible contribution of charge accumulation when non-charge-compensated pulses are used is negligible. In a second experiment, we assessed the effect of different frequencies of conditioning stimulation (5, 20, 42, and 100 Hz) using charge-compensated pulses on the development of increased pinprick sensitivity. The maximal increase in pinprick sensitivity was observed at intermediate frequencies of stimulation (20 and 42 Hz). It is hypothesized that the stronger increase in pinprick sensitivity at intermediate frequencies may be related to the stronger release of substance P and/or neurokinin-1 receptor activation expressed at lamina I neurons after C-fiber stimulation.NEW & NOTEWORTHY Burstlike electrical conditioning stimulation applied to human skin induces an increase in pinprick sensitivity in the surrounding unconditioned skin (a phenomenon referred to as secondary hyperalgesia). Here we show that the development of the increase in pinprick sensitivity is dependent on the frequency of the burstlike electrical conditioning stimulation.
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Affiliation(s)
- E N van den Broeke
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - S Gousset
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - J Bouvy
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - A Stouffs
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - L Lebrun
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - S G A van Neerven
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - A Mouraux
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
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50
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Madden VJ, Bedwell GJ, Chikezie PC, Rice ASC, Kamerman PR. A systematic review of experimental methods to manipulate secondary hyperalgesia in humans: protocol. Syst Rev 2019; 8:208. [PMID: 31426841 PMCID: PMC6700765 DOI: 10.1186/s13643-019-1120-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 07/26/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Neuropathic pain affects 7-10% of people, but responds poorly to pharmacotherapy, indicating a need for better treatments. Mechanistic research on neuropathic pain frequently uses human surrogate models of the secondary hyperalgesia that is a common feature of neuropathic pain. Experimentally induced secondary hyperalgesia has been manipulated with pharmacological and non-pharmacological methods to clarify the relative contributions of different mechanisms to secondary hyperalgesia. However, this literature has not been systematically synthesised. The aim of this systematic review is to identify, describe, and compare methods that have been used to manipulate experimentally induced secondary hyperalgesia in healthy humans. METHODS A systematic search strategy will be supplemented by reference list checks and direct contact with identified laboratories to maximise the identification of data reporting the experimental manipulation of experimentally induced secondary hyperalgesia in healthy humans. Duplicated screening, risk of bias assessment, and data extraction procedures will be used. Authors will be asked to provide data as necessary. Data will be pooled and meta-analyses conducted where possible, with subgrouping according to manipulation method. Manipulation methods will be ranked for potency and risk. DISCUSSION The results of this review will provide a useful reference for researchers interested in using experimental methods to manipulate secondary hyperalgesia in humans and will help to clarify the relative contributions of different mechanisms to secondary hyperalgesia. SYSTEMATIC REVIEW REGISTRATION This protocol will be registered on PROSPERO before the review begins. Review records will be updated on PROSPERO once the review is complete. This review is intended for publication in a peer-reviewed journal. Analyses and scripts will be made publicly available.
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Affiliation(s)
- Victoria J. Madden
- Pain Unit, Department of Anaesthesia and Perioperative Medicine, Neuroscience Institute, University of Cape Town, D23.30 Groote Schuur Hospital, Observatory, Cape Town, 7925 South Africa
- Department of Psychiatry and Mental Health, University of Cape Town, Cape Town, South Africa
| | - Gillian J. Bedwell
- Pain Unit, Department of Anaesthesia and Perioperative Medicine, Neuroscience Institute, University of Cape Town, D23.30 Groote Schuur Hospital, Observatory, Cape Town, 7925 South Africa
- Department of Health and Rehabilitation Sciences, University of Cape Town, Cape Town, South Africa
| | - Prince C. Chikezie
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Andrew S. C. Rice
- Pain Research Group, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, UK
| | - Peter R. Kamerman
- School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin University, Perth, Australia
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