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Nahman-Averbuch H, Piché M, Bannister K, Coghill RC. Involvement of propriospinal processes in conditioned pain modulation. Pain 2024; 165:1907-1913. [PMID: 38537057 PMCID: PMC11333191 DOI: 10.1097/j.pain.0000000000003217] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 02/05/2024] [Indexed: 08/21/2024]
Affiliation(s)
- Hadas Nahman-Averbuch
- Washington University Pain Center and Division of Clinical and Translational Research, Department of Anesthesiology, Washington University in St Louis School of Medicine, St Louis, MO, USA
| | - Mathieu Piché
- Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, Quebec, Canada. CogNAC Research Group, Université du Québec à Trois-Rivières, Trois-Rivières, Quebec, Canada
| | - Kirsty Bannister
- Central Modulation of Pain, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE1 1UL, UK
| | - Robert C Coghill
- Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA; Pediatric Pain Research Center, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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2
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Hewitt D, Byrne A, Henderson J, Newton-Fenner A, Tyson-Carr J, Fallon N, Brown C, Stancak A. Inhibition of cortical somatosensory processing during and after low frequency peripheral nerve stimulation in humans. Clin Neurophysiol 2021; 132:1481-1495. [PMID: 34023628 DOI: 10.1016/j.clinph.2021.03.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 02/25/2021] [Accepted: 03/04/2021] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Transcutaneous low-frequency stimulation (LFS) elicits long-term depression-like effects on human pain perception. However, the neural mechanisms underlying LFS are poorly understood. We investigated cortical activation changes occurring during LFS and if changes were associated with reduced nociceptive processing and increased amplitude of spontaneous cortical oscillations post-treatment. METHODS LFS was applied to the radial nerve of 25 healthy volunteers over two sessions using active (1 Hz) or sham (0.02 Hz) frequencies. Changes in resting electroencephalography (EEG) and laser-evoked potentials (LEPs) were investigated before and after LFS. Somatosensory-evoked potentials were recorded during LFS and source analysis was carried out. RESULTS Ipsilateral midcingulate and operculo-insular cortex source activity declined linearly during LFS. Active LFS was associated with attenuated long-latency LEP amplitude in ipsilateral frontocentral electrodes and increased resting alpha (8-12 Hz) and beta (16-24 Hz) band power in electrodes overlying operculo-insular, sensorimotor and frontal cortical regions. Reduced ipsilateral operculo-insular cortex source activity during LFS correlated with a smaller post-treatment alpha-band power increase. CONCLUSIONS LFS attenuated somatosensory processing both during and after stimulation. SIGNIFICANCE Results further our understanding of the attenuation of somatosensory processing both during and after LFS.
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Affiliation(s)
- Danielle Hewitt
- Department of Psychological Sciences, University of Liverpool, Liverpool, UK.
| | - Adam Byrne
- Department of Psychological Sciences, University of Liverpool, Liverpool, UK; Institute for Risk and Uncertainty, University of Liverpool, Liverpool, UK
| | - Jessica Henderson
- Department of Psychological Sciences, University of Liverpool, Liverpool, UK
| | - Alice Newton-Fenner
- Department of Psychological Sciences, University of Liverpool, Liverpool, UK; Institute for Risk and Uncertainty, University of Liverpool, Liverpool, UK
| | - John Tyson-Carr
- Department of Psychological Sciences, University of Liverpool, Liverpool, UK
| | - Nicholas Fallon
- Department of Psychological Sciences, University of Liverpool, Liverpool, UK
| | - Christopher Brown
- Department of Psychological Sciences, University of Liverpool, Liverpool, UK
| | - Andrej Stancak
- Department of Psychological Sciences, University of Liverpool, Liverpool, UK; Institute for Risk and Uncertainty, University of Liverpool, Liverpool, UK
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3
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Sasaki R, Sakamoto J, Kondo Y, Oga S, Takeshita I, Honda Y, Kataoka H, Origuchi T, Okita M. Effects of Cryotherapy Applied at Different Temperatures on Inflammatory Pain During the Acute Phase of Arthritis in Rats. Phys Ther 2021; 101:6039322. [PMID: 33351944 DOI: 10.1093/ptj/pzaa211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 06/21/2020] [Accepted: 11/03/2020] [Indexed: 11/14/2022]
Abstract
OBJECTIVE The biological mechanisms of cryotherapy for managing acute pain remain unclear. Additionally, it is unknown whether the effectiveness of cryotherapy depends on the applied temperature. This study aimed to clarify the biological effects of cryotherapy and to examine the therapeutic effects of cryotherapy applied at different temperatures in rats. METHODS This was an experimental study using a rat knee joint arthritis model. Thirty-five Wistar rats were randomly divided into arthritis (AR), arthritis with 5°C cryotherapy (CR-5), arthritis with 10°C cryotherapy (CR-10), and sham-arthritis control (CON) groups. Arthritis was induced by injecting a mixture of kaolin/carrageenan into the right knee joint. Cryotherapy was applied for 7 days starting the day after injection by immersing the right knee joint in 5°C or 10°C water. Joint transverse diameter, pressure pain threshold, and pain-related behaviors were assessed for 7 days. The number of CD68-positive cells in the knee joint and the expression of calcitonin gene-related peptide in the spinal dorsal horn 8 days after injection were analyzed by immunohistochemical staining. RESULTS Improvements in transverse diameter, pressure pain threshold, and pain-related behaviors were observed in the CR-5 and CR-10 groups on the 3rd day compared with the AR group. The number of CD68-positive cells and the expression of calcitonin gene-related peptide in the CR-5 and CR-10 groups were significantly decreased compared with the AR group. There were no significant differences in all results between the CR-5 and CR-10 groups. CONCLUSIONS Cryotherapy can ameliorate inflammatory pain through reduction of synovium and central sensitization. Additionally, the effects of cryotherapy lower than 10°C are observed independent of applied temperature. IMPACT Cryotherapy may be beneficial as a physical therapy modality for pain and swelling management in the acute phase of inflammation. Translational human study is needed to determine the effective cryotherapy temperature for the inflammatory pain.
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Affiliation(s)
- Ryo Sasaki
- Department of Locomotive Rehabilitation Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.,Department of Rehabilitation, Juzenkai Hospital, Nagasaki, Japan
| | - Junya Sakamoto
- Department of Physical Therapy Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Yasutaka Kondo
- Department of Rehabilitation, Japan Red Cross Nagasaki Genbaku Hospital, Nagasaki, Japan
| | - Satoshi Oga
- Department of Locomotive Rehabilitation Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.,Department of Rehabilitation, Japan Red Cross Nagasaki Genbaku Hospital, Nagasaki, Japan
| | - Idumi Takeshita
- Department of Rehabilitation, Faculty of Medicine, University of Miyazaki Hospital, Miyazaki, Japan
| | - Yuichiro Honda
- Department of Physical Therapy Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Hideki Kataoka
- Department of Locomotive Rehabilitation Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.,Department of Rehabilitation, Nagasaki Memorial Hospital, Nagasaki, Japan
| | - Tomoki Origuchi
- Department of Locomotive Rehabilitation Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Minoru Okita
- Department of Locomotive Rehabilitation Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
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4
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The Distributed Nociceptive System: A Framework for Understanding Pain. Trends Neurosci 2020; 43:780-794. [PMID: 32800534 DOI: 10.1016/j.tins.2020.07.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/30/2020] [Accepted: 07/12/2020] [Indexed: 12/31/2022]
Abstract
Chronic pain remains challenging to both diagnose and treat. These challenges, in part, arise from limited systems-level understanding of the basic mechanisms that process nociceptive information and ultimately instantiate a subjectively available experience of pain. Here, I provide a framework, the distributed nociceptive system, for understanding nociceptive mechanisms at a systems level by integrating the concepts of neural population coding with distributed processing. Within this framework, wide-spread engagement of populations of neurons produces representations of nociceptive information that are highly resilient to disruption. The distributed nociceptive system provides a foundation for understanding complex spatial aspects of chronic pain and provides an impetus for nonpharmacological cognitive and physical therapies that can effectively target the highly distributed system that gives rise to an experience of pain.
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Chapman KB, Groenen PS, Vissers KC, van Helmond N, Stanton-Hicks MD. The Pathways and Processes Underlying Spinal Transmission of Low Back Pain: Observations From Dorsal Root Ganglion Stimulation Treatment. Neuromodulation 2020; 24:610-621. [PMID: 32329155 DOI: 10.1111/ner.13150] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/02/2020] [Indexed: 12/15/2022]
Abstract
BACKGROUND Dorsal root ganglion stimulation (DRG-S) is a novel approach to treat chronic pain. Lead placement at L2 has been reported to be an effective treatment for axial low back pain (LBP) primarily of discogenic etiology. We have recently shown, in a diverse cohort including cases of multilevel instrumentation following extensive prior back surgeries, that DRG-S lead placement at T12 is another promising target. Local effects at the T12 DRG, alone, are insufficient to explain these results. MATERIALS AND METHODS We performed a literature review to explore the mechanisms of LBP relief with T12 DRG-S. FINDINGS Branches of individual spinal nerve roots innervate facet joints and posterior spinal structures, while the discs and anterior vertebrae are carried via L2, and converge in the dorsal horn (DH) of the spinal cord at T8-T9. The T12 nerve root contains cutaneous afferents from the low back and enters the DH of the spinal cord at T10. Low back Aδ and C-fibers then ascend via Lissauer's tract (LT) to T8-T9, converging with other low back afferents. DRG-S at T12, then, results in inhibition of the converged low back fibers via endorphin-mediated and GABAergic frequency-dependent mechanisms. Therefore, T12 lead placement may be the optimal location for DRG-S to treat LBP.
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Affiliation(s)
- Kenneth B Chapman
- The Spine & Pain Institute of New York, New York City, NY, USA.,Department of Anesthesiology, New York University Langone Medical Center, New York City, NY, USA.,Northwell Health Systems, New York City, NY, USA
| | - Pauline S Groenen
- The Spine & Pain Institute of New York, New York City, NY, USA.,College of Medicine, Radboud University, Nijmegen, the Netherlands
| | - Kris C Vissers
- Department of Anesthesiology, Pain, and Palliative Medicine, Radboud University, Nijmegen, the Netherlands
| | - Noud van Helmond
- The Spine & Pain Institute of New York, New York City, NY, USA.,Department of Anesthesiology, Cooper Medical School of Rowan University, Cooper University Hospital, Camden, NJ, USA
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6
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Idlett S, Halder M, Zhang T, Quevedo J, Brill N, Gu W, Moffitt M, Hochman S. Assessment of axonal recruitment using model-guided preclinical spinal cord stimulation in the ex vivo adult mouse spinal cord. J Neurophysiol 2019; 122:1406-1420. [PMID: 31339796 DOI: 10.1152/jn.00538.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Spinal cord stimulation (SCS) is used clinically to limit chronic pain, but fundamental questions remain on the identity of axonal populations recruited. We developed an ex vivo adult mouse spinal cord preparation to assess recruitment following delivery of clinically analogous stimuli determined by downscaling a finite element model of clinical SCS. Analogous electric field distributions were generated with 300-µm × 300-µm electrodes positioned 200 µm above the dorsal column (DC) with stimulation between 50 and 200 µA. We compared axonal recruitment using electrodes of comparable size and stimulus amplitudes when contacting the caudal thoracic DC and at 200 or 600 μm above. Antidromic responses recorded distally from the DC, the adjacent Lissauer tract (LT), and in dorsal roots (DRs) were found to be amplitude and site dependent. Responses in the DC included a unique component not seen in DRs, having the lowest SCS recruitment amplitude and fastest conduction velocity. At 200 μm above, mean cathodic SCS recruitment threshold for axons in DRs and LT were 2.6 and 4.4 times higher, respectively, than DC threshold. SCS recruited primary afferents in all (up to 8) caudal segments sampled. Whereas A and C fibers could be recruited at nearby segments, only A fiber recruitment and synaptically mediated dorsal root reflexes were observed in more distant (lumbar) segments. In sum, clinically analogous SCS led to multisegmental recruitment of several somatosensory-encoding axonal populations. Most striking is the possibility that the lowest threshold recruitment of a nonprimary afferent population in the DC are postsynaptic dorsal column tract cells (PSDCs) projecting to gracile nuclei.NEW & NOTEWORTHY Spinal cord stimulation (SCS) is used clinically to control pain. To identify axonal populations recruited, finite element modeling identified scaling parameters to deliver clinically analogous SCS in an ex vivo adult mouse spinal cord preparation. Results showed that SCS first recruited an axonal population in the dorsal column at a threshold severalfold lower than primary afferents. These putative postsynaptic dorsal column tract cells may represent a previously unconsidered population responsible for SCS-induced paresthesias necessary for analgesia.
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Affiliation(s)
- Shaquia Idlett
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia.,Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | - Mallika Halder
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | - Tianhe Zhang
- Boston Scientific Neuromodulation, Valencia, California
| | - Jorge Quevedo
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Natalie Brill
- Boston Scientific Neuromodulation, Valencia, California
| | - Wendy Gu
- Boston Scientific Neuromodulation, Valencia, California
| | | | - Shawn Hochman
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
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7
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Van Boxem K, de Meij N, Patijn J, Wilmink J, van Kleef M, Van Zundert J, Kessels A. Predictive Factors for Successful Outcome of Pulsed Radiofrequency Treatment in Patients with Intractable Lumbosacral Radicular Pain. PAIN MEDICINE 2016; 17:1233-1240. [PMID: 26791777 DOI: 10.1093/pm/pnv052] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND In a previous prospective study on pulsed radiofrequency (PRF) treatment adjacent to the lumbar dorsal root ganglion (DRG) for patients with chronic lumbosacral radicular pain, we reported success in 55.4% of the patients at 6 months. Identification of predictors for success after PRF may improve outcome. We assessed the predictors of PRF in patients with chronic intractable lumbosacral radicular pain. METHODS Patients with monosegmental chronic lumbosacral radicular pain of L5 or S1 first received a selective nerve root block at the corresponding level. Independent of the result of this block a PRF treatment at the same level was performed. At 6 weeks, 3 months, and 6 months after the procedure the outcome was evaluated. RESULTS A positive diagnostic nerve root block and age ≥ 55 were predictive factors for successful outcome at 6 months, while disability was a negative predictor.The use of failed back surgery syndrome, gender, duration of pain, Numerical Rating Scale, level and side of treatment, DN4, and RAND-36 as predictors for success was not supported. CONCLUSIONS Successful outcome after PRF adjacent to the DRG, in patients with intractable chronic lumbosacral radicular pain, is more likely in patients ≥ 55 years, with limited disability and after a positive diagnostic nerve root block. A combination of all these factors creates a fair predictive value (AUC: 0.73).
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Affiliation(s)
- Koen Van Boxem
- Departments of *Anesthesiology and Pain Management, Department of Anesthesiology, Critical Care and Multidisciplinary Pain Center, Sint-Jozefkliniek, Bornem & Willebroek, Belgium;
| | | | - Jacob Patijn
- Departments of *Anesthesiology and Pain Management
| | | | - Maarten van Kleef
- Departments of *Anesthesiology and Pain Management, Department of Anesthesiology and Pain Management, VUMC Amsterdam, The Netherlands
| | - Jan Van Zundert
- Departments of *Anesthesiology and Pain Management, Department of Anesthesiology, Critical Care and Multidisciplinary Pain Center, ZOL, Genk, Belgium
| | - Alfons Kessels
- Clinical Epidemiology and Medical Technology Assessment, Maastricht University Medical Centre, The Netherlands
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8
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Ulrich A, Min K, Curt A. High sensitivity of contact-heat evoked potentials in “snake-eye” appearance myelopathy. Clin Neurophysiol 2015; 126:1994-2003. [DOI: 10.1016/j.clinph.2014.12.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Revised: 11/30/2014] [Accepted: 12/10/2014] [Indexed: 12/12/2022]
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Pulsed radiofrequency: a review of the basic science as applied to the pathophysiology of radicular pain: a call for clinical translation. Reg Anesth Pain Med 2014; 39:149-59. [PMID: 24553305 DOI: 10.1097/aap.0000000000000063] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Radicular pain is an important health care problem, with only limited evidence-based treatments available. Treatment selection should ideally target documented pathophysiological pathways. In herniated discs, a sequence in the inflammatory cascade can be observed that initiates and maintains increased nociceptive signal input. Inflammatory mediators including tumor necrosis factor α are released from the nucleus pulposus and the degenerating peripheral nerve, which, in turn, induces production of neurotrophins like nerve growth factor and brain-derived neurotrophic factor. Neurotrophins interfere not only with the generation of ectopic firing of nociceptive neurons in the dorsal root ganglion but also with the excitability and sensitization of neuronal transmission in the dorsal spinal horn. Radicular pain is further characterized by the electrophysiological spreading of the afferent nociceptive input over different spinal nerve roots. Both the complex pathophysiological pathways involved and the spreading of the nociceptive signal make radicular pain difficult to treat. Pulsed radiofrequency (PRF) is considered an option in treatment of radicular pain. To understand and increase the efficiency of PRF interventional treatments in radicular pain, both in vitro and in vivo studies aiming at elucidating part of the mechanism of action of PRF are described. Potential factors that may improve the efficacy of PRF treatment in radicular pain are discussed.
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10
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Longitudinal projections of primary afferents from the single dorsal root ganglion of the cervical or lumbosacral enlargements in chickens. Neurosci Lett 2014; 561:118-22. [PMID: 24394912 DOI: 10.1016/j.neulet.2013.12.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 11/13/2013] [Accepted: 12/23/2013] [Indexed: 11/23/2022]
Abstract
Central projections originated from a single dorsal root ganglion (DRG) were studied in the chicken focusing on the rostrocaudal extension of primary afferents in each lamina by using anterograde labeling by lectin-HRP injection into either the 15th or the 24th DRG. In the injection into the 15th DRG, labeled fibers (LFs) were found in a wide rostrocaudal range of laminas IV (the spinal segment (SS) 1-20) and V (SS 4-18) and in a narrow range of other laminas. In the injection into the 24th DRG, LFs were distributed in a similar rostrocaudal range in all laminas except for laminas VIII and IX. LFs in laminas VIII and IX were restricted in the tracer injected segment. LFs in the lateral funiculus derived from both the enlargements projected into the rostral lamina III in addition to the lower medulla oblongata. There was little overlap in the extent of the primary terminal areas from both the enlargements.
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11
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Bordoni B, Zanier E. Anatomic connections of the diaphragm: influence of respiration on the body system. J Multidiscip Healthc 2013; 6:281-91. [PMID: 23940419 PMCID: PMC3731110 DOI: 10.2147/jmdh.s45443] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The article explains the scientific reasons for the diaphragm muscle being an important crossroads for information involving the entire body. The diaphragm muscle extends from the trigeminal system to the pelvic floor, passing from the thoracic diaphragm to the floor of the mouth. Like many structures in the human body, the diaphragm muscle has more than one function, and has links throughout the body, and provides the network necessary for breathing. To assess and treat this muscle effectively, it is necessary to be aware of its anatomic, fascial, and neurologic complexity in the control of breathing. The patient is never a symptom localized, but a system that adapts to a corporeal dysfunction.
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Affiliation(s)
- Bruno Bordoni
- Rehabilitation Cardiology Institute of Hospitalization and Care with Scientific Address, S Maria Nascente Don Carlo Gnocchi Foundation
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12
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Bareiss SK, Gwaltney M, Hernandez K, Lee T, Brewer KL. Excitotoxic spinal cord injury induced dysesthesias are associated with enhanced intrinsic growth of sensory neurons. Neurosci Lett 2013; 542:113-7. [DOI: 10.1016/j.neulet.2013.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 03/02/2013] [Accepted: 03/07/2013] [Indexed: 11/25/2022]
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13
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Bedi SS, Lago MT, Masha LI, Crook RJ, Grill RJ, Walters ET. Spinal cord injury triggers an intrinsic growth-promoting state in nociceptors. J Neurotrauma 2011; 29:925-35. [PMID: 21939395 DOI: 10.1089/neu.2011.2007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
Although most investigations of the mechanisms underlying chronic pain after spinal cord injury (SCI) have examined the central nervous system (CNS), recent studies have shown that nociceptive primary afferent neurons display persistent hyperexcitability and spontaneous activity in their peripheral branches and somata in dorsal root ganglia (DRG) after SCI. This suggests that SCI-induced alterations of primary nociceptors contribute to central sensitization and chronic pain after SCI. Does SCI also promote growth of these neurons' fibers, as has been suggested in some reports? The present study tests the hypothesis that SCI induces an intrinsic growth-promoting state in DRG neurons. This was tested by dissociating DRG neurons 3 days or 1 month after spinal contusion injury at thoracic level T10 and measuring neuritic growth 1 day later. Neurons cultured 3 days after SCI exhibited longer neurites without increases in branching ("elongating growth"), compared to neurons from sham-treated or untreated (naïve) rats. Robust promotion of elongating growth was found in small and medium-sized neurons (but not large neurons) from lumbar (L3-L5) and thoracic ganglia immediately above (T9) and below (T10-T11) the contusion site, but not from cervical DRG. Elongating growth was also found in neurons immunoreactive to calcitonin gene-related peptide (CGRP), suggesting that some of the neurons exhibiting enhanced neuritic growth were nociceptors. The same measurements made on neurons dissociated 1 month after SCI revealed no evidence of elongating growth, although evidence for accelerated initiation of neurite outgrowth was found. Under certain conditions this transient growth-promoting state in nociceptors might be important for the development of chronic pain and hyperreflexia after SCI.
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Affiliation(s)
- Supinder S Bedi
- Department of Pediatric Surgery, University of Texas Medical School at Houston, Houston, Texas 77030, USA.
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14
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Van Boxem K, van Bilsen J, de Meij N, Herrler A, Kessels F, Van Zundert J, van Kleef M. Pulsed radiofrequency treatment adjacent to the lumbar dorsal root ganglion for the management of lumbosacral radicular syndrome: a clinical audit. PAIN MEDICINE 2011; 12:1322-30. [PMID: 21812907 DOI: 10.1111/j.1526-4637.2011.01202.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Lumbosacral radicular syndrome (LRS) is probably the most frequent neuropathic pain syndrome. Three months to 1 year after onset, 30% of the patients still experience ongoing pain. The management of those patients is complex, and treatment success rates are rather low. The beneficial effect of pulsed radiofrequency (PRF) therapy has been described for the treatment of LRS in case reports and in retrospective and prospective studies. Up until now, no neurological complications have been reported after PRF treatment. The current clinical audit has been performed to assess the amount of pain relief after a single PRF treatment. METHODS Sixty consecutive patients who received a PRF treatment adjacent to the lumbar dorsal root ganglion for the management of LRS in the period 2007-2009 were included. The main study objective was to measure the reduction of pain after the pulsed radiofrequency treatment by using the global perceived effect. The primary end point was defined as at least 50% pain relief for a period of 2 months or longer. RESULTS The primary end point was achieved in 29.5% of all the PRF interventions. After 6 months, 50% pain relief was still present in 22.9% of the cases and after 12 months in 13.1% of the cases. The need for pain medication was significantly lower after pulsed radiofrequency treatment in the success group compared with the nonsuccess group. CONCLUSIONS PRF treatment can be considered for the management of LRS patients. These results need to be confirmed in a randomized clinical trial.
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Affiliation(s)
- Koen Van Boxem
- Department of Anesthesiology and Pain Management, Maastricht University Medical Centre, Maastricht, The Netherlands.
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15
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Bedi SS, Yang Q, Crook RJ, Du J, Wu Z, Fishman HM, Grill RJ, Carlton SM, Walters ET. Chronic spontaneous activity generated in the somata of primary nociceptors is associated with pain-related behavior after spinal cord injury. J Neurosci 2010; 30:14870-82. [PMID: 21048146 PMCID: PMC3073589 DOI: 10.1523/jneurosci.2428-10.2010] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 08/24/2010] [Accepted: 09/10/2010] [Indexed: 02/08/2023] Open
Abstract
Mechanisms underlying chronic pain that develops after spinal cord injury (SCI) are incompletely understood. Most research on SCI pain mechanisms has focused on neuronal alterations within pain pathways at spinal and supraspinal levels associated with inflammation and glial activation. These events might also impact central processes of primary sensory neurons, triggering in nociceptors a hyperexcitable state and spontaneous activity (SA) that drive behavioral hypersensitivity and pain. SCI can sensitize peripheral fibers of nociceptors and promote peripheral SA, but whether these effects are driven by extrinsic alterations in surrounding tissue or are intrinsic to the nociceptor, and whether similar SA occurs in nociceptors in vivo are unknown. We show that small DRG neurons from rats (Rattus norvegicus) receiving thoracic spinal injury 3 d to 8 months earlier and recorded 1 d after dissociation exhibit an elevated incidence of SA coupled with soma hyperexcitability compared with untreated and sham-treated groups. SA incidence was greatest in lumbar DRG neurons (57%) and least in cervical neurons (28%), and failed to decline over 8 months. Many sampled SA neurons were capsaicin sensitive and/or bound the nociceptive marker, isolectin B4. This intrinsic SA state was correlated with increased behavioral responsiveness to mechanical and thermal stimulation of sites below and above the injury level. Recordings from C- and Aδ-fibers revealed SCI-induced SA generated in or near the somata of the neurons in vivo. SCI promotes the entry of primary nociceptors into a chronic hyperexcitable-SA state that may provide a useful therapeutic target in some forms of persistent pain.
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Affiliation(s)
- Supinder S. Bedi
- Department of Integrative Biology and Pharmacology, University of Texas Medical School at Houston, Houston, Texas 77030, and
| | - Qing Yang
- Department of Integrative Biology and Pharmacology, University of Texas Medical School at Houston, Houston, Texas 77030, and
| | - Robyn J. Crook
- Department of Integrative Biology and Pharmacology, University of Texas Medical School at Houston, Houston, Texas 77030, and
| | - Junhui Du
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555
| | - Zizhen Wu
- Department of Integrative Biology and Pharmacology, University of Texas Medical School at Houston, Houston, Texas 77030, and
| | - Harvey M. Fishman
- Department of Integrative Biology and Pharmacology, University of Texas Medical School at Houston, Houston, Texas 77030, and
| | - Raymond J. Grill
- Department of Integrative Biology and Pharmacology, University of Texas Medical School at Houston, Houston, Texas 77030, and
| | - Susan M. Carlton
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555
| | - Edgar T. Walters
- Department of Integrative Biology and Pharmacology, University of Texas Medical School at Houston, Houston, Texas 77030, and
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Mandadi S, Nakanishi ST, Takashima Y, Dhaka A, Patapoutian A, McKemy DD, Whelan PJ. Locomotor networks are targets of modulation by sensory transient receptor potential vanilloid 1 and transient receptor potential melastatin 8 channels. Neuroscience 2009; 162:1377-97. [PMID: 19482068 DOI: 10.1016/j.neuroscience.2009.05.063] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 05/22/2009] [Accepted: 05/23/2009] [Indexed: 01/17/2023]
Abstract
It is well recognized that proprioceptive afferent inputs can control the timing and pattern of locomotion. C and Adelta afferents can also affect locomotion but an unresolved issue is the identity of the subsets of these afferents that encode defined modalities. Over the last decade, the transient receptor potential (TRP) ion channels have emerged as a family of non-selective cation conductances that can label specific subsets of afferents. We focus on a class of TRPs known as ThermoTRPs which are well known to be sensor receptors that transduce changes in heat and cold. ThermoTRPs are known to help encode somatosensation and painful stimuli, and receptors have been found on C and Adelta afferents with central projections onto dorsal horn laminae. Here we show, using in vitro neonatal mouse spinal cord preparations, that activation of both spinal and peripheral transient receptor potential vanilloid 1 (TRPV1) and transient receptor potential melastatin 8 (TRPM8) afferent terminals modulates central pattern generators (CPGs). Capsaicin or menthol and cooling modulated both sacrocaudal afferent (SCA) evoked and monoaminergic drug-induced rhythmic locomotor-like activity in spinal cords from wild type but not TRPV1-null (trpv1(-/-)) or TRPM8-null (trpm8(-/-)) mice, respectively. Capsaicin induced an initial increase in excitability of the lumbar motor networks, while menthol or cooling caused a decrease in excitability. Capsaicin and menthol actions on CPGs involved excitatory and inhibitory glutamatergic mechanisms, respectively. These results for the first time show that dedicated pathways of somatosensation and pain identified by TRPV1 or TRPM8 can target spinal locomotor CPGs.
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Affiliation(s)
- S Mandadi
- Hotchkiss Brain Institute, 3330 Hospital Drive Northwest, Calgary, AB, T2N 4N1 Canada
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Pinto V, Szûcs P, Derkach VA, Safronov BV. Monosynaptic convergence of C- and Adelta-afferent fibres from different segmental dorsal roots on to single substantia gelatinosa neurones in the rat spinal cord. J Physiol 2008; 586:4165-77. [PMID: 18635648 DOI: 10.1113/jphysiol.2008.154898] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Although it is known that each spinal cord segment receives thin-fibre inputs from several segmental dorsal roots, it remains unclear how these inputs converge at the cellular level. To study whether C- and Adelta-afferents from different roots can converge monosynaptically on to a single substantia gelatinosa (SG) neurone, we performed tight-seal recordings from SG neurones in the entire lumbar enlargement of the rat spinal cord with all six segmental (L1-L6) dorsal roots attached. The neurones in the spinal cord were visualized using our recently developed oblique LED illumination technique. Individual SG neurones from the spinal segment L4 or L3 were voltage clamped to record the monosynaptic EPSCs evoked by stimulating ipsilateral L1-L6 dorsal roots. We found that one-third of the SG neurones receive simultaneous monosynaptic inputs from two to four different segmental dorsal roots. For the SG neurones from segment L4, the major monosynaptic input was from the L4-L6 roots, whereas for those located in segment L3 the input pattern was shifted to the L2-L5 roots. Based on these data, we propose a new model of primary afferent organization where several C- or Adelta-fibres innervating one cutaneous region (peripheral convergence) and ascending together in a common peripheral nerve may first diverge at the level of spinal nerves and enter the spinal cord through different segmental dorsal roots, but finally re-converge monosynaptically on to a single SG neurone. This organization would allow formation of precise and robust neural maps of the body surface at the spinal cord level.
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Affiliation(s)
- Vitor Pinto
- Instituto de Biologia Molecular e Celular, Rua do Campo Alegre 823, 4150-180 Porto, Portugal
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