1
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Safronov BV, Szucs P. Novel aspects of signal processing in lamina I. Neuropharmacology 2024; 247:109858. [PMID: 38286189 DOI: 10.1016/j.neuropharm.2024.109858] [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: 11/24/2023] [Revised: 01/12/2024] [Accepted: 01/25/2024] [Indexed: 01/31/2024]
Abstract
The most superficial layer of the spinal dorsal horn, lamina I, is a key element of the nociceptive processing system. It contains different types of projection neurons (PNs) and local-circuit neurons (LCNs) whose functional roles in the signal processing are poorly understood. This article reviews recent progress in elucidating novel anatomical features and physiological properties of lamina I PNs and LCNs revealed by whole-cell recordings in ex vivo spinal cord. This article is part of the Special Issue on "Ukrainian Neuroscience".
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Affiliation(s)
- Boris V Safronov
- Neuronal Networks Group, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.
| | - Peter Szucs
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; HUN-REN-DE Neuroscience Research Group, Debrecen, Hungary
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2
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Chen H, Bleimeister IH, Nguyen EK, Li J, Cui AY, Stratton HJ, Smith KM, Baccei ML, Ross SE. The functional and anatomical characterization of three spinal output pathways of the anterolateral tract. Cell Rep 2024; 43:113829. [PMID: 38421871 PMCID: PMC11025583 DOI: 10.1016/j.celrep.2024.113829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 10/24/2023] [Accepted: 02/03/2024] [Indexed: 03/02/2024] Open
Abstract
The nature of spinal output pathways that convey nociceptive information to the brain has been the subject of controversy. Here, we provide anatomical, molecular, and functional characterizations of two distinct anterolateral pathways: one, ascending in the lateral spinal cord, triggers nociceptive behaviors, and the other one, ascending in the ventral spinal cord, when inhibited, leads to sensorimotor deficits. Moreover, the lateral pathway consists of at least two subtypes. The first is a contralateral pathway that extends to the periaqueductal gray (PAG) and thalamus; the second is a bilateral pathway that projects to the bilateral parabrachial nucleus (PBN). Finally, we present evidence showing that activation of the contralateral pathway is sufficient for defensive behaviors such as running and freezing, whereas the bilateral pathway is sufficient for attending behaviors such as licking and guarding. This work offers insight into the complex organizational logic of the anterolateral system in the mouse.
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Affiliation(s)
- Haichao Chen
- Tsinghua Medicine, Tsinghua University, Beijing 100084, China; Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Isabel H Bleimeister
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA 15213, USA; Medical Scientist Training Program, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Eileen K Nguyen
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA 15213, USA; Medical Scientist Training Program, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Jie Li
- Department of Anesthesiology, Pain Research Center, University of Cincinnati Medical Center, Cincinnati, OH 45267, USA
| | - Abby Yilin Cui
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Harrison J Stratton
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA 15213, USA; Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Kelly M Smith
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA 15213, USA; Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Mark L Baccei
- Department of Anesthesiology, Pain Research Center, University of Cincinnati Medical Center, Cincinnati, OH 45267, USA
| | - Sarah E Ross
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA 15213, USA; Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15213, USA; Department of Anesthesiology, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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3
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Blomqvist A, Evrard HC, Dostrovsky JO, Strigo IA, Jänig W. A. D. (Bud) Craig, Jr. (1951-2023). Nat Neurosci 2023; 26:1835-1836. [PMID: 37749257 DOI: 10.1038/s41593-023-01463-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Affiliation(s)
- Anders Blomqvist
- Division of Neurobiology, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.
| | - Henry C Evrard
- International Center for Primate Brain Research, Center for Excellence in Brain Science and Intelligence, Institute of Neuroscience, Chinese Academy of Sciences, Shanghai, China.
- Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY, USA.
- Werner Reichardt Center for Integrative Neuroscience, Karl Eberhard University of Tübingen, Tübingen, Germany.
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany.
| | | | - Irina A Strigo
- Emotion and Pain Laboratory, San Francisco Veterans Affairs Health Care Center, San Francisco, CA, USA
- Department of Psychiatry, University of California San Francisco, San Francisco, CA, USA
| | - Wilfrid Jänig
- Institute of Physiology, Christian-Albrechts University of Kiel, Kiel, Germany
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4
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Tan S, Faull RLM, Curtis MA. The tracts, cytoarchitecture, and neurochemistry of the spinal cord. Anat Rec (Hoboken) 2023; 306:777-819. [PMID: 36099279 DOI: 10.1002/ar.25079] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/01/2022] [Accepted: 09/11/2022] [Indexed: 11/06/2022]
Abstract
The human spinal cord can be described using a range of nomenclatures with each providing insight into its structure and function. Here we have comprehensively reviewed the key literature detailing the general structure, configuration of tracts, the cytoarchitecture of Rexed's laminae, and the neurochemistry at the spinal segmental level. The purpose of this review is to detail current anatomical understanding of how the spinal cord is structured and to aid researchers in identifying gaps in the literature that need to be studied to improve our knowledge of the spinal cord which in turn will improve the potential of therapeutic intervention for disorders of the spinal cord.
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Affiliation(s)
- Sheryl Tan
- Centre for Brain Research and Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Richard L M Faull
- Centre for Brain Research and Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
| | - Maurice A Curtis
- Centre for Brain Research and Department of Anatomy and Medical Imaging, University of Auckland, Auckland, New Zealand
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5
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Warwick C, Salsovic J, Hachisuka J, Smith KM, Sheahan TD, Chen H, Ibinson J, Koerber HR, Ross SE. Cell type-specific calcium imaging of central sensitization in mouse dorsal horn. Nat Commun 2022; 13:5199. [PMID: 36057681 PMCID: PMC9440908 DOI: 10.1038/s41467-022-32608-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 08/08/2022] [Indexed: 01/12/2023] Open
Abstract
Allodynia is a state in which pain is elicited by innocuous stimuli. Capsaicin applied to the skin results in an allodynia that extends to a broad region beyond the application site. This sensitization is thought to be mediated by spinal networks; however, we do not have a clear picture of which spinal neurons mediate this phenomenon. To address this gap, we used two-photon calcium imaging of excitatory interneurons and spinal projection neurons in the mouse spinal dorsal horn. To distinguish among neuronal subtypes, we developed CICADA, a cell profiling approach to identify cell types during calcium imaging. We then identified capsaicin-responsive and capsaicin-sensitized neuronal populations. Capsaicin-sensitized neurons showed emergent responses to innocuous input and increased receptive field sizes consistent with psychophysical reports. Finally, we identified spinal output neurons that showed enhanced responses from innocuous input. These experiments provide a population-level view of central sensitization and a framework with which to model somatosensory integration in the dorsal horn.
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Affiliation(s)
- Charles Warwick
- Department of Neurobiology and the Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, USA
| | - Joseph Salsovic
- Department of Neurobiology and the Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, USA
| | - Junichi Hachisuka
- Department of Neurobiology and the Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, USA
- Spinal Cord Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, UK
| | - Kelly M Smith
- Department of Neurobiology and the Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, USA
| | - Tayler D Sheahan
- Department of Neurobiology and the Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, USA
| | - Haichao Chen
- Department of Neurobiology and the Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, USA
- School of Medicine, Tsinghua University, Beijing, China
| | - James Ibinson
- Department of Anesthesiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - H Richard Koerber
- Department of Neurobiology and the Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Sarah E Ross
- Department of Neurobiology and the Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, USA.
- Department of Anesthesiology, University of Pittsburgh, Pittsburgh, PA, USA.
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6
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Teuchmann HL, Hogri R, Heinke B, Sandkühler J. Anti-Nociceptive and Anti-Aversive Drugs Differentially Modulate Distinct Inputs to the Rat Lateral Parabrachial Nucleus. THE JOURNAL OF PAIN 2022; 23:1410-1426. [PMID: 35339662 DOI: 10.1016/j.jpain.2022.03.234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 02/16/2022] [Accepted: 03/08/2022] [Indexed: 06/14/2023]
Abstract
The lateral parabrachial nucleus (LPBN) plays an important role in the processing and establishment of pain aversion. It receives direct input from the superficial dorsal horn and forms reciprocal connections with the periaqueductal grey matter (PAG), which is critical for adaptive behaviour and the modulation of pain processing. Here, using in situ hybridization and optogenetics combined with in vitro electrophysiology, we characterized the spinal- and PAG-LPBN circuits of rats. We found spinoparabrachial projections to be strictly glutamatergic, while PAG neurons send glutamatergic and GABAergic projections to the LPBN. We next investigated the effects of drugs with anti-aversive and/or anti-nociceptive properties on these synapses: The µ-opioid receptor agonist DAMGO (10 µM) reduced spinal and PAG synaptic inputs onto LPBN neurons, and the excitability of LPBN neurons receiving these inputs. The benzodiazepine receptor agonist diazepam (5 µM) strongly enhanced GABAergic action at inhibitory PAG-LPBN synapses. The cannabinoid receptor agonist WIN 55,212-2 (5 µM) led to a reduction in inhibitory and excitatory PAG-LPBN synaptic transmission, without affecting excitatory spinoparabrachial synaptic transmission. Our study reveals that opioid, cannabinoid and benzodiazepine receptor agonists differentially affect distinct LPBN synapses. These findings may support the efforts to develop pinpointed therapies for pain patients. PERSPECTIVE: The LPBN is an important brain region for the control of pain aversion versus recuperation, and as such constitutes a promising target for developing new strategies for pain management. We show that clinically-relevant drugs have complex and pathway-specific effects on LPBN processing of putative nociceptive and aversive inputs.
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Affiliation(s)
- Hannah Luise Teuchmann
- Department of Neurophysiology, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Roni Hogri
- Department of Neurophysiology, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Bernhard Heinke
- Department of Neurophysiology, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Jürgen Sandkühler
- Department of Neurophysiology, Center for Brain Research, Medical University of Vienna, Vienna, Austria.
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7
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Wang H, Chen W, Dong Z, Xing G, Cui W, Yao L, Zou WJ, Robinson HL, Bian Y, Liu Z, Zhao K, Luo B, Gao N, Zhang H, Ren X, Yu Z, Meixiong J, Xiong WC, Mei L. A novel spinal neuron connection for heat sensation. Neuron 2022; 110:2315-2333.e6. [PMID: 35561677 DOI: 10.1016/j.neuron.2022.04.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 03/14/2022] [Accepted: 04/19/2022] [Indexed: 12/30/2022]
Abstract
Heat perception enables acute avoidance responses to prevent tissue damage and maintain body thermal homeostasis. Unlike other modalities, how heat signals are processed in the spinal cord remains unclear. By single-cell gene profiling, we identified ErbB4, a transmembrane tyrosine kinase, as a novel marker of heat-sensitive spinal neurons in mice. Ablating spinal ErbB4+ neurons attenuates heat sensation. These neurons receive monosynaptic inputs from TRPV1+ nociceptors and form excitatory synapses onto target neurons. Activation of ErbB4+ neurons enhances the heat response, while inhibition reduces the heat response. We showed that heat sensation is regulated by NRG1, an activator of ErbB4, and it involves dynamic activity of the tyrosine kinase that promotes glutamatergic transmission. Evidence indicates that the NRG1-ErbB4 signaling is also engaged in hypersensitivity of pathological pain. Together, these results identify a spinal neuron connection consisting of ErbB4+ neurons for heat sensation and reveal a regulatory mechanism by the NRG1-ErbB4 signaling.
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Affiliation(s)
- Hongsheng Wang
- Department of Neurosciences, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Wenbing Chen
- Department of Neurosciences, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Zhaoqi Dong
- Department of Neurosciences, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Guanglin Xing
- Department of Neurosciences, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Wanpeng Cui
- Department of Neurosciences, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Lingling Yao
- Department of Neurosciences, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Wen-Jun Zou
- Department of Neurosciences, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Heath L Robinson
- Department of Neurosciences, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Yaoyao Bian
- Department of Neurosciences, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Zhipeng Liu
- Department of Neurosciences, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Kai Zhao
- Department of Neurosciences, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Bin Luo
- Department of Neurosciences, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Nannan Gao
- Department of Neurosciences, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Hongsheng Zhang
- Department of Neurosciences, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Xiao Ren
- Department of Neurosciences, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Zheng Yu
- Department of Neurosciences, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - James Meixiong
- Solomon H. Snyder Department of Neuroscience and Medical Scientist Training Program, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Wen-Cheng Xiong
- Department of Neurosciences, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA
| | - Lin Mei
- Department of Neurosciences, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
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Spinal integration of hot and cold nociceptive stimuli by wide-dynamic-range neurons in anesthetized adult rats. Pain Rep 2021; 6:e983. [PMID: 34938936 PMCID: PMC8687733 DOI: 10.1097/pr9.0000000000000983] [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: 07/15/2021] [Revised: 10/07/2021] [Accepted: 11/02/2021] [Indexed: 12/28/2022] Open
Abstract
Introduction Early neuronal processing of thermal noxious information relies mostly on molecular detectors of the transient receptor potential family expressed by specific subpopulation of sensory neurons. This information may converge to second-order wide-dynamic-range (WDR) neurons located in the deep layer of the dorsal horn of the spinal cord. Method Using a micro-Peltier thermode thermal contact stimulator II delivering various cold and hot noxious stimulations, we have characterized the extracellular electrophysiological responses of mechanosensitive WDR neurons in anesthetized adult male and female Wistar rats. Results Most of the WDR neurons were activated after hot and cold noxious stimulations, at mean temperature thresholds corresponding to 43 and 20°C, respectively. If the production of action potential was not different in frequency between the 2 thermal modalities, the latency to observe the first action potential was significantly different (cold: 212 ms; hot: 490 ms, unpaired Student t-test: t = 8.041; df = 32; P < 0.0001), suggesting that different fiber types and circuits were involved. The temporal summation was also different because no facilitation was seen for cold noxious stimulations contrary to hot noxious ones. Conclusion Altogether, this study helps better understand how short-lasting and long-lasting hot or cold noxious stimuli are integrated by mechanosensitive WDR neurons. In our experimental conditions, we found WDR neurons to be nociceptive specific for C-fiber-mediated hot stimuli. We also found that cold nonnoxious and noxious information, triggered at glabrous skin areas, are likely taken in charge by A-type sensory neurons. This study will be helpful to establish working hypothesis explaining the thermal pain symptoms displayed by animal models and patients in a translational extent.
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Brewer R, Murphy J, Bird G. Atypical interoception as a common risk factor for psychopathology: A review. Neurosci Biobehav Rev 2021; 130:470-508. [PMID: 34358578 PMCID: PMC8522807 DOI: 10.1016/j.neubiorev.2021.07.036] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 07/09/2021] [Accepted: 07/31/2021] [Indexed: 02/06/2023]
Abstract
The inadequacy of a categorial approach to mental health diagnosis is now well-recognised, with many authors, diagnostic manuals and funding bodies advocating a dimensional, trans-diagnostic approach to mental health research. Variance in interoception, the ability to perceive one's internal bodily state, is reported across diagnostic boundaries, and is associated with atypical functioning across symptom categories. Drawing on behavioural and neuroscientific evidence, we outline current research on the contribution of interoception to numerous cognitive and affective abilities (in both typical and clinical populations), and describe the interoceptive atypicalities seen in a range of psychiatric conditions. We discuss the role that interoception may play in the development and maintenance of psychopathology, as well as the ways in which interoception may differ across clinical presentations. A number of important areas for further research on the role of interoception in psychopathology are highlighted.
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Affiliation(s)
- Rebecca Brewer
- Department of Psychology, Royal Holloway, University of London, United Kingdom
| | - Jennifer Murphy
- Department of Psychology, Royal Holloway, University of London, United Kingdom.
| | - Geoffrey Bird
- Department of Experimental Psychology, University of Oxford, United Kingdom; Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, United Kingdom
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10
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Characterisation of lamina I anterolateral system neurons that express Cre in a Phox2a-Cre mouse line. Sci Rep 2021; 11:17912. [PMID: 34504158 PMCID: PMC8429737 DOI: 10.1038/s41598-021-97105-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 08/10/2021] [Indexed: 11/13/2022] Open
Abstract
A recently developed Phox2a::Cre mouse line has been shown to capture anterolateral system (ALS) projection neurons. Here, we used this line to test whether Phox2a-positive cells represent a distinct subpopulation among lamina I ALS neurons. We show that virtually all lamina I Phox2a cells can be retrogradely labelled from injections targeted on the lateral parabrachial area (LPb), and that most of those in the cervical cord also belong to the spinothalamic tract. Phox2a cells accounted for ~ 50–60% of the lamina I cells retrogradely labelled from LPb or thalamus. Phox2a was preferentially associated with smaller ALS neurons, and with those showing relatively weak neurokinin 1 receptor expression. The Phox2a cells were also less likely to project to the ipsilateral LPb. Although most Phox2a cells phosphorylated extracellular signal-regulated kinases following noxious heat stimulation, ~ 20% did not, and these were significantly smaller than the activated cells. This suggests that those ALS neurons that respond selectively to skin cooling, which have small cell bodies, may be included among the Phox2a population. Previous studies have defined neurochemical populations among the ALS cells, based on expression of Tac1 or Gpr83. However, we found that the proportions of Phox2a cells that expressed these genes were similar to the proportions reported for all lamina I ALS neurons, suggesting that Phox2a is not differentially expressed among cells belonging to these populations. Finally, we used a mouse line that resulted in membrane labelling of the Phox2a cells and showed that they all possess dendritic spines, although at a relatively low density. However, the distribution of the postsynaptic protein Homer revealed that dendritic spines accounted for a minority of the excitatory synapses on these cells. Our results confirm that Phox2a-positive cells in lamina I are ALS neurons, but show that the Phox2a::Cre line preferentially captures specific types of ALS cells.
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11
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Chisholm KI, Lo Re L, Polgár E, Gutierrez-Mecinas M, Todd AJ, McMahon SB. Encoding of cutaneous stimuli by lamina I projection neurons. Pain 2021; 162:2405-2417. [PMID: 33769365 PMCID: PMC8374708 DOI: 10.1097/j.pain.0000000000002226] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 12/11/2020] [Accepted: 01/04/2021] [Indexed: 11/26/2022]
Abstract
ABSTRACT Lamina I of the dorsal horn, together with its main output pathway, lamina I projection neurons, has long been implicated in the processing of nociceptive stimuli, as well as the development of chronic pain conditions. However, the study of lamina I projection neurons is hampered by technical challenges, including the low throughput and selection biases of traditional electrophysiological techniques. Here we report on a technique that uses anatomical labelling strategies and in vivo imaging to simultaneously study a network of lamina I projection neurons in response to electrical and natural stimuli. Although we were able to confirm the nociceptive involvement of this group of cells, we also describe an unexpected preference for innocuous cooling stimuli. We were able to characterize the thermal responsiveness of these cells in detail and found cooling responses decline when exposed to stable cold temperatures maintained for more than a few seconds, as well as to encode the intensity of the end temperature, while heating responses showed an unexpected reliance on adaptation temperatures.
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Affiliation(s)
- Kim I. Chisholm
- Neurorestoration Group, Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | - Laure Lo Re
- Neurorestoration Group, Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | - Erika Polgár
- Spinal Cord Group, Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Maria Gutierrez-Mecinas
- Spinal Cord Group, Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Andrew J. Todd
- Spinal Cord Group, Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Stephen B. McMahon
- Neurorestoration Group, Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
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12
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Veshchitskii AA, Musienko PE, Merkulyeva NS. Distribution of Calretinin-Immunopositive Neurons in the Cat Lumbar Spinal Cord. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021040074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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13
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Wercberger R, Braz JM, Weinrich JA, Basbaum AI. Pain and itch processing by subpopulations of molecularly diverse spinal and trigeminal projection neurons. Proc Natl Acad Sci U S A 2021; 118:e2105732118. [PMID: 34234018 PMCID: PMC8285968 DOI: 10.1073/pnas.2105732118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
A remarkable molecular and functional heterogeneity of the primary sensory neurons and dorsal horn interneurons transmits pain- and or itch-relevant information, but the molecular signature of the projection neurons that convey the messages to the brain is unclear. Here, using retro-TRAP (translating ribosome affinity purification) and RNA sequencing, we reveal extensive molecular diversity of spino- and trigeminoparabrachial projection neurons. Among the many genes identified, we highlight distinct subsets of Cck+ -, Nptx2+ -, Nmb+ -, and Crh+ -expressing projection neurons. By combining in situ hybridization of retrogradely labeled neurons with Fos-based assays, we also demonstrate significant functional heterogeneity, including both convergence and segregation of pain- and itch-provoking inputs into molecularly diverse subsets of NK1R- and non-NK1R-expressing projection neurons.
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Affiliation(s)
- Racheli Wercberger
- Department of Anatomy, University of California, San Francisco, CA 94158
| | - Joao M Braz
- Department of Anatomy, University of California, San Francisco, CA 94158
| | - Jarret A Weinrich
- Department of Anatomy, University of California, San Francisco, CA 94158
| | - Allan I Basbaum
- Department of Anatomy, University of California, San Francisco, CA 94158
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14
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Browne TJ, Smith KM, Gradwell MA, Iredale JA, Dayas CV, Callister RJ, Hughes DI, Graham BA. Spinoparabrachial projection neurons form distinct classes in the mouse dorsal horn. Pain 2021; 162:1977-1994. [PMID: 33779126 PMCID: PMC8208100 DOI: 10.1097/j.pain.0000000000002194] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 12/16/2020] [Accepted: 12/21/2020] [Indexed: 11/29/2022]
Abstract
ABSTRACT Projection neurons in the spinal dorsal horn relay sensory information to higher brain centres. The activation of these populations is shaped by afferent input from the periphery, descending input from the brain, and input from local interneuron circuits. Much of our recent understanding of dorsal horn circuitry comes from studies in transgenic mice; however, information on projection neurons is still based largely on studies in monkey, cat, and rat. We used viral labelling to identify and record from mouse parabrachial nucleus (PBN) projecting neurons located in the dorsal horn of spinal cord slices. Overall, mouse lamina I spinoparabrachial projection neurons (SPBNs) exhibit many electrophysiological and morphological features that overlap with rat. Unbiased cluster analysis distinguished 4 distinct subpopulations of lamina I SPBNs, based on their electrophysiological properties that may underlie different sensory signalling features in each group. We also provide novel information on SPBNs in the deeper lamina (III-V), which have not been previously studied by patch clamp analysis. These neurons exhibited higher action potential discharge frequencies and received weaker excitatory synaptic input than lamina I SPBNs, suggesting this deeper population produces different sensory codes destined for the PBN. Mouse SPBNs from both regions (laminae I and III-V) were often seen to give off local axon collaterals, and we provide neuroanatomical evidence they contribute to excitatory input to dorsal horn circuits. These data provide novel information to implicate excitatory input from parabrachial projection neuron in dorsal horn circuit activity during processing of nociceptive information, as well as defining deep dorsal horn projection neurons that provide an alternative route by which sensory information can reach the PBN.
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Affiliation(s)
- Tyler J. Browne
- School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle, Callaghan, New South Wales, Australia
- Hunter Medical Research Institute (HMRI), New Lambton Heights, New South Wales, Australia
| | - Kelly M. Smith
- Department of Neurobiology and the Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, United States
| | - Mark A. Gradwell
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, United States
- W.M. Keck Center for Collaborative Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, United States
| | - Jacqueline A. Iredale
- School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle, Callaghan, New South Wales, Australia
- Hunter Medical Research Institute (HMRI), New Lambton Heights, New South Wales, Australia
| | - Christopher V. Dayas
- School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle, Callaghan, New South Wales, Australia
- Hunter Medical Research Institute (HMRI), New Lambton Heights, New South Wales, Australia
| | - Robert J. Callister
- School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle, Callaghan, New South Wales, Australia
- Hunter Medical Research Institute (HMRI), New Lambton Heights, New South Wales, Australia
| | - David I. Hughes
- Institute of Neuroscience Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Brett A. Graham
- School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle, Callaghan, New South Wales, Australia
- Hunter Medical Research Institute (HMRI), New Lambton Heights, New South Wales, Australia
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15
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Xiao R, Xu XZS. Temperature Sensation: From Molecular Thermosensors to Neural Circuits and Coding Principles. Annu Rev Physiol 2020; 83:205-230. [PMID: 33085927 DOI: 10.1146/annurev-physiol-031220-095215] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Temperature is a universal cue and regulates many essential processes ranging from enzymatic reactions to species migration. Due to the profound impact of temperature on physiology and behavior, animals and humans have evolved sophisticated mechanisms to detect temperature changes. Studies from animal models, such as mouse, Drosophila, and C. elegans, have revealed many exciting principles of thermosensation. For example, conserved molecular thermosensors, including thermosensitive channels and receptors, act as the initial detectors of temperature changes across taxa. Additionally, thermosensory neurons and circuits in different species appear to adopt similar logic to transduce and process temperature information. Here, we present the current understanding of thermosensation at the molecular and cellular levels. We also discuss the fundamental coding strategies of thermosensation at the circuit level. A thorough understanding of thermosensation not only provides key insights into sensory biology but also builds a foundation for developing better treatments for various sensory disorders.
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Affiliation(s)
- Rui Xiao
- Department of Aging and Geriatric Research, Institute on Aging and Center for Smell and Taste, University of Florida, Gainesville, Florida 32610, USA;
| | - X Z Shawn Xu
- Life Sciences Institute and Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA;
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16
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Wang R, Qiu Z, Wang G, Hu Q, Shi N, Zhang Z, Wu Y, Zhou C. Quercetin attenuates diabetic neuropathic pain by inhibiting mTOR/p70S6K pathway-mediated changes of synaptic morphology and synaptic protein levels in spinal dorsal horn of db/db mice. Eur J Pharmacol 2020; 882:173266. [PMID: 32553736 DOI: 10.1016/j.ejphar.2020.173266] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 06/04/2020] [Accepted: 06/08/2020] [Indexed: 01/27/2023]
Abstract
Numerous studies indicate that the changes of synaptic morphology and synaptic protein levels in spinal dorsal horn neurons contributes to the development and maintenance of neuropathic pain. Quercetin, a bioflavonoid compound, has been shown to have analgesic effect in several pain models. However, the underlying mechanism for quercetin to allieviate pain is unclear. Therefore, in this study, we observed the effect of quercetin on diabetic neuropathic pain in db/db mice and explored the underlying mechanisms. Our results showed that chronic quercetin treatment alleviated thermal hyperalgesia in db/db mice. Moreover, quercetin administration significantly reduced the total dendritic length, the number of dendritic branches, and the dendritic spine density in the spinal dorsal horn neurons of db/db mice. Meanwhile, the up-regulated expressions of synaptic plasticity-associated proteins postsynaptic density protein 95 (PSD-95) and synaptophysin in spinal dorsal horn of db/db mice were decreased by quercetin treatment. In addition, quercetin treatment reduced the phosphorylated levels of mammalian target of rapamycin (mTOR) and p70 ribosomal S6 kinase (p70S6K) in spinal dorsal horn of db/db mice. These results demonstrate that quercetin may alleviate diabetic neuropathic pain by inhibiting mTOR/p70S6K pathway-mediated changes of synaptic morphology and synaptic protein levels in spinal dorsal horn neurons of db/db mice. These findings suggest that quercetin may be a promising therapeutic drug in neuropathic pain.
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Affiliation(s)
- Ruiyao Wang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Zhuang Qiu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Guizhi Wang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Qian Hu
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China
| | - Naihao Shi
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Zongqin Zhang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Yuqing Wu
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, China.
| | - Chenghua Zhou
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China.
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17
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Abstract
Lidocaine, as the only local anesthetic approved for intravenous administration in the clinic, can relieve neuropathic pain, hyperalgesia, and complex regional pain syndrome. Intravenous injection of lidocaine during surgery is considered as an effective strategy to control postoperative pain, but the mechanism of its analgesic effect has not been fully elucidated. This paper intends to review recent studies on the mechanism of the analgesic effect of lidocaine. To the end, we conducted an electronic search of the PubMed database. The search period was from 5 years before June 2019. Lidocaine was used as the search term. A total of 659 documents were obtained, we included 17 articles. These articles combined with the 34 articles found by hand searching made up the 51 articles that were ultimately included. We reviewed the analgesic mechanism of lidocaine in the central nervous system.
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Affiliation(s)
- Xi Yang
- Department of Anesthesiology, Translational Neuroscience Center, West China Hospital, Sichuan University
- Department of Anesthesiology, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital
| | - Xinchuan Wei
- Department of Anesthesiology, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital
| | - Yi Mu
- National Office for Maternal and Child Health Surveillance of China, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Qian Li
- Department of Anesthesiology, Translational Neuroscience Center, West China Hospital, Sichuan University
| | - Jin Liu
- Department of Anesthesiology, Translational Neuroscience Center, West China Hospital, Sichuan University
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18
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Hachisuka J, Koerber HR, Ross SE. Selective-cold output through a distinct subset of lamina I spinoparabrachial neurons. Pain 2020; 161:185-194. [PMID: 31577643 PMCID: PMC10461608 DOI: 10.1097/j.pain.0000000000001710] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Spinal projection neurons are a major pathway through which somatic stimuli are conveyed to the brain. However, the manner in which this information is coded is poorly understood. Here, we report the identification of a modality-selective spinoparabrachial (SPB) neuron subtype with unique properties. Specifically, we find that cold-selective SPB neurons are differentiated by selective afferent input, reduced sensitivity to substance P, distinct physiological properties, small soma size, and low basal drive. In addition, optogenetic experiments reveal that cold-selective SPB neurons do not receive input from Nos1 inhibitory interneurons and, compared with other SPB neurons, show significantly smaller inhibitory postsynaptic currents upon activation of Pdyn inhibitory interneurons. Together, these data suggest that cold output from the spinal cord to the parabrachial nucleus is mediated by a specific cell type with distinct properties.
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Affiliation(s)
- Junichi Hachisuka
- Department of Neurobiology and the Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, United States. Dr. Hachisuka is now with the Spinal Cord Group, Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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19
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Wercberger R, Basbaum AI. Spinal cord projection neurons: a superficial, and also deep, analysis. CURRENT OPINION IN PHYSIOLOGY 2019; 11:109-115. [PMID: 32864531 DOI: 10.1016/j.cophys.2019.10.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Today there are extensive maps of the molecular heterogeneity of primary afferents and dorsal horn interneurons, yet there is a dearth of molecular and functional information regarding the projection neurons that transmit pain and itch information to the brain. Additionally, most contemporary research into the spinal cord and medullary projection neurons focuses on neurons in the superficial dorsal horn; the contribution of deep dorsal horn and even ventral horn projection neurons to pain and itch processing is often overlooked. In the present review we integrate conclusions from classical as well as contemporary studies and provide a more balanced view of the diversity of projection neurons. A major question addressed is the extent to which labeled-lines are maintained in these different populations or whether the brain generates distinct pain and itch percepts by decoding complex convergent inputs that engage projection neurons.
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Affiliation(s)
- Racheli Wercberger
- Department of Anatomy and Neuroscience Graduate Program, University California San Francisco, San Francisco, CA 94158
| | - Allan I Basbaum
- Department of Anatomy and Neuroscience Graduate Program, University California San Francisco, San Francisco, CA 94158
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20
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Ho HN, Chow HM, Tsunokake S, Roseboom W. Thermal-Tactile Integration in Object Temperature Perception. IEEE TRANSACTIONS ON HAPTICS 2019; 12:594-603. [PMID: 30835230 DOI: 10.1109/toh.2019.2894153] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The brain consistently faces a challenge of whether and how to combine the available information sources to estimate the properties of an object explored by hand. While object perception is an inference process involving multisensory inputs, thermal referral (TR) is an illusion demonstrating how the interaction between thermal and tactile systems can lead to deviations from physical reality-when observers touch three stimulators simultaneously with the middle three fingers of one hand but only the outer two stimulators are heated (or cooled), thermal uniformity is perceived across three fingers. Here, we used TR of warmth to examine the thermal-tactile interaction in object temperature perception. We show that TR is consistent with precision-weighted averaging of thermal sensation across tactile locations. Furthermore, we show that prolonged contact with TR stimulation results in adaptation to the local variations of veridical temperatures instead of the thermal uniformity perceived across three fingers. Our results illuminate the flexibility of processing that underlies thermal-tactile interactions and serve as a basis for thermal display design.
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21
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Rosner J, Rinert J, Ernst M, Curt A, Hubli M. Cold evoked potentials: Acquisition from cervical dermatomes. Neurophysiol Clin 2019; 49:49-57. [DOI: 10.1016/j.neucli.2018.11.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 11/26/2018] [Accepted: 11/26/2018] [Indexed: 01/06/2023] Open
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22
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Merighi A. The histology, physiology, neurochemistry and circuitry of the substantia gelatinosa Rolandi (lamina II) in mammalian spinal cord. Prog Neurobiol 2018; 169:91-134. [PMID: 29981393 DOI: 10.1016/j.pneurobio.2018.06.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 06/07/2018] [Accepted: 06/30/2018] [Indexed: 02/06/2023]
Abstract
The substantia gelatinosa Rolandi (SGR) was first described about two centuries ago. In the following decades an enormous amount of information has permitted us to understand - at least in part - its role in the initial processing of pain and itch. Here, I will first provide a comprehensive picture of the histology, physiology, and neurochemistry of the normal SGR. Then, I will analytically discuss the SGR circuits that have been directly demonstrated or deductively envisaged in the course of the intensive research on this area of the spinal cord, with particular emphasis on the pathways connecting the primary afferent fibers and the intrinsic neurons. The perspective existence of neurochemically-defined sets of primary afferent neurons giving rise to these circuits will be also discussed, with the proposition that a cross-talk between different subsets of peptidergic fibers may be the structural and functional substrate of additional gating mechanisms in SGR. Finally, I highlight the role played by slow acting high molecular weight modulators in these gating mechanisms.
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Affiliation(s)
- Adalberto Merighi
- Department of Veterinary Sciences, University of Turin, Largo Paolo Braccini 2, I-10095 Grugliasco (TO), Italy.
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23
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Peripheral and central determinants of skin wetness sensing in humans. HANDBOOK OF CLINICAL NEUROLOGY 2018; 156:83-102. [PMID: 30454611 DOI: 10.1016/b978-0-444-63912-7.00005-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Evolutionarily, our ability to sense skin wetness and humidity (i.e., hygroreception) could have developed as a way of helping to maintain thermal homeostasis, as much as it is the case for the role of temperature sensation and thermoreception. Humans are not provided with a specific skin hygroreceptor, and recent studies have indicated that skin wetness is likely to be centrally processed as a result of the multisensory integration of peripheral inputs from skin thermoreceptors and mechanoreceptors coding the biophysical interactions between skin and moisture. The existence of a specific hygrosensation strategy for human wetness perception has been proposed and the first neurophysiologic model of skin wetness sensing has been recently developed. However, while these recent findings have shed light on some of the peripheral and central neural mechanisms underlying wetness sensing, our understanding of how the brain processes the thermal and mechanical inputs that give rise to one of our "most worn" skin sensory experiences is still far from being conclusive. Understanding these neural mechanisms is clinically relevant in the context of those neurologic conditions that are accompanied by somatosensory abnormalities. The present chapter will present the current knowledge on the peripheral and central determinants of skin wetness sensing in humans.
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24
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Abstract
The sensation of pain plays a vital protecting role, alerting organisms about potentially damaging stimuli. Tissue injury is detected by nerve endings of specialized peripheral sensory neurons called nociceptors that are equipped with different ion channels activated by thermal, mechanic, and chemical stimuli. Several transient receptor potential channels have been identified as molecular transducers of thermal stimuli in pain-sensing neurons. Skin injury or inflammation leads to increased sensitivity to thermal and mechanic stimuli, clinically defined as allodynia or hyperalgesia. This hypersensitivity is also characteristic of systemic inflammatory disorders and neuropathic pain conditions. Mechanisms of thermal hyperalgesia include peripheral sensitization of nociceptor afferents and maladaptive changes in pain-encoding neurons within the central nervous system. An important aspect of pain management involves attempts to minimize the development of nociceptor hypersensitivity. However, knowledge about the cellular and molecular mechanisms causing thermal hyperalgesia and allodynia in human subjects is still limited, and such knowledge would be an essential step for the development of more effective therapies.
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Affiliation(s)
- Félix Viana
- Alicante Institute of Neurosciences, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, San Juan de Alicante, Spain.
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25
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Sikandar S, West SJ, McMahon SB, Bennett DL, Dickenson AH. Sensory processing of deep tissue nociception in the rat spinal cord and thalamic ventrobasal complex. Physiol Rep 2017; 5:e13323. [PMID: 28720713 PMCID: PMC5532477 DOI: 10.14814/phy2.13323] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 05/22/2017] [Accepted: 05/24/2017] [Indexed: 11/24/2022] Open
Abstract
Sensory processing of deep somatic tissue constitutes an important component of the nociceptive system, yet associated central processing pathways remain poorly understood. Here, we provide a novel electrophysiological characterization and immunohistochemical analysis of neural activation in the lateral spinal nucleus (LSN). These neurons show evoked activity to deep, but not cutaneous, stimulation. The evoked responses of neurons in the LSN can be sensitized to somatosensory stimulation following intramuscular hypertonic saline, an acute model of muscle pain, suggesting this is an important spinal relay site for the processing of deep tissue nociceptive inputs. Neurons of the thalamic ventrobasal complex (VBC) mediate both cutaneous and deep tissue sensory processing, but in contrast to the lateral spinal nucleus our electrophysiological studies do not suggest the existence of a subgroup of cells that selectively process deep tissue inputs. The sensitization of polymodal and thermospecific VBC neurons to mechanical somatosensory stimulation following acute muscle stimulation with hypertonic saline suggests differential roles of thalamic subpopulations in mediating cutaneous and deep tissue nociception in pathological states. Overall, our studies at both the spinal (lateral spinal nucleus) and supraspinal (thalamic ventrobasal complex) levels suggest a convergence of cutaneous and deep somatosensory inputs onto spinothalamic pathways, which are unmasked by activation of muscle nociceptive afferents to produce consequent phenotypic alterations in spinal and thalamic neural coding of somatosensory stimulation. A better understanding of the sensory pathways involved in deep tissue nociception, as well as the degree of labeled line and convergent pathways for cutaneous and deep somatosensory inputs, is fundamental to developing targeted analgesic therapies for deep pain syndromes.
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Affiliation(s)
- Shafaq Sikandar
- Wolfson Institute of Biomedical Research, University College London, London, United Kingdom
| | - Steven J West
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, United Kingdom
| | - Stephen B McMahon
- Neurorestoration Group, Wolfson Wing Hodgkin Building, King's College London, London, United Kingdom
| | - David L Bennett
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, United Kingdom
| | - Anthony H Dickenson
- Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
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26
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Matsuzaki K, Katakura M, Sugimoto N, Hara T, Hashimoto M, Shido O. Neural progenitor cell proliferation in the hypothalamus is involved in acquired heat tolerance in long-term heat-acclimated rats. PLoS One 2017. [PMID: 28628625 PMCID: PMC5476247 DOI: 10.1371/journal.pone.0178787] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Constant exposure to moderate heat facilitates progenitor cell proliferation and neuronal differentiation in the hypothalamus of heat-acclimated (HA) rats. In this study, we investigated neural phenotype and responsiveness to heat in HA rats’ hypothalamic newborn cells. Additionally, the effect of hypothalamic neurogenesis on heat acclimation in rats was evaluated. Male Wistar rats (5 weeks old) were housed at an ambient temperature (Ta) of 32°C for 6 days (STHA) or 40 days (LTHA), while control (CN) rats were kept at a Ta of 24°C for 6 days (STCN) or 40 days (LTCN). Bromodeoxyuridine (BrdU) was intraperitoneally injected daily for five consecutive days (50 mg/kg/day) after commencing heat exposure. The number of hypothalamic BrdU-immunopositive (BrdU+) cells in STHA and LTHA rats was determined immunohistochemically in brain samples and found to be significantly greater than those in respective CN groups. In LTHA rats, approximately 32.6% of BrdU+ cells in the preoptic area (POA) of the anterior hypothalamus were stained by GAD67, a GABAergic neuron marker, and 15.2% of BrdU+ cells were stained by the glutamate transporter, a glutamatergic neuron marker. In addition, 63.2% of BrdU+ cells in the POA were immunolabeled with c-Fos. Intracerebral administration of the mitosis inhibitor, cytosine arabinoside (AraC), interfered with the proliferation of neural progenitor cells and acquired heat tolerance in LTHA rats, whereas the selected ambient temperature was not changed. These results demonstrate that heat exposure generates heat responsive neurons in the POA, suggesting a pivotal role in autonomic thermoregulation in long-term heat-acclimated rats.
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Affiliation(s)
- Kentaro Matsuzaki
- Department of Environmental Physiology, Faculty of Medicine, Shimane University, Izumo, Japan
- * E-mail:
| | - Masanori Katakura
- Department of Environmental Physiology, Faculty of Medicine, Shimane University, Izumo, Japan
- Department of Nutritional Physiology, Faculty of Pharmaceutical Sciences, Josai University, Sakado, Saitama, Japan
| | - Naotoshi Sugimoto
- Department of Environmental Physiology, Faculty of Medicine, Shimane University, Izumo, Japan
- Department of Physiology, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan
| | - Toshiko Hara
- Department of Environmental Physiology, Faculty of Medicine, Shimane University, Izumo, Japan
| | - Michio Hashimoto
- Department of Environmental Physiology, Faculty of Medicine, Shimane University, Izumo, Japan
| | - Osamu Shido
- Department of Environmental Physiology, Faculty of Medicine, Shimane University, Izumo, Japan
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27
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Duan B, Cheng L, Ma Q. Spinal Circuits Transmitting Mechanical Pain and Itch. Neurosci Bull 2017; 34:186-193. [PMID: 28484964 PMCID: PMC5799122 DOI: 10.1007/s12264-017-0136-z] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 04/01/2017] [Indexed: 12/11/2022] Open
Abstract
In 1905, Henry Head first suggested that transmission of pain-related protopathic information can be negatively modulated by inputs from afferents sensing innocuous touch and temperature. In 1965, Melzak and Wall proposed a more concrete gate control theory of pain that highlights the interaction between unmyelinated C fibers and myelinated A fibers in pain transmission. Here we review the current understanding of the spinal microcircuits transmitting and gating mechanical pain or itch. We also discuss how disruption of the gate control could cause pain or itch evoked by innocuous mechanical stimuli, a hallmark symptom for many chronic pain or itch patients.
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Affiliation(s)
- Bo Duan
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 830 North University Ave, Ann Arbor, MI, 48109, USA.
| | - Longzhen Cheng
- Institute of Brain Science, the State Key Laboratory of Medical Neurobiology and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China.
| | - Qiufu Ma
- Dana-Farber Cancer Institute and Department of Neurobiology, Harvard Medical School, 1 Jimmy Fund Way, Boston, MA, 02115, USA.
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28
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Filingeri D, Ackerley R. The biology of skin wetness perception and its implications in manual function and for reproducing complex somatosensory signals in neuroprosthetics. J Neurophysiol 2017; 117:1761-1775. [PMID: 28123008 DOI: 10.1152/jn.00883.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 01/19/2017] [Accepted: 01/19/2017] [Indexed: 01/11/2023] Open
Abstract
Our perception of skin wetness is generated readily, yet humans have no known receptor (hygroreceptor) to signal this directly. It is easy to imagine the sensation of water running over our hands or the feel of rain on our skin. The synthetic sensation of wetness is thought to be produced from a combination of specific skin thermal and tactile inputs, registered through thermoreceptors and mechanoreceptors, respectively. The present review explores how thermal and tactile afference from the periphery can generate the percept of wetness centrally. We propose that the main signals include information about skin cooling, signaled primarily by thinly myelinated thermoreceptors, and rapid changes in touch, through fast-conducting, myelinated mechanoreceptors. Potential central sites for integration of these signals, and thus the perception of skin wetness, include the primary and secondary somatosensory cortices and the insula cortex. The interactions underlying these processes can also be modeled to aid in understanding and engineering the mechanisms. Furthermore, we discuss the role that sensing wetness could play in precision grip and the dexterous manipulation of objects. We expand on these lines of inquiry to the application of the knowledge in designing and creating skin sensory feedback in prosthetics. The addition of real-time, complex sensory signals would mark a significant advance in the use and incorporation of prosthetic body parts for amputees in everyday life.NEW & NOTEWORTHY Little is known about the underlying mechanisms that generate the perception of skin wetness. Humans have no specific hygroreceptor, and thus temperature and touch information combine to produce wetness sensations. The present review covers the potential mechanisms leading to the perception of wetness, both peripherally and centrally, along with their implications for manual function. These insights are relevant to inform the design of neuroengineering interfaces, such as sensory prostheses for amputees.
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Affiliation(s)
- Davide Filingeri
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, United Kingdom;
| | - Rochelle Ackerley
- Department of Physiology, University of Gothenburg, Göteborg, Sweden; and.,Laboratoire Neurosciences Intégratives et Adaptatives (UMR 7260), Aix Marseille Université-Centre National de la Recherche Scientifique, Marseille, France
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29
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Todd AJ. Identifying functional populations among the interneurons in laminae I-III of the spinal dorsal horn. Mol Pain 2017; 13:1744806917693003. [PMID: 28326935 PMCID: PMC5315367 DOI: 10.1177/1744806917693003] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 12/16/2016] [Indexed: 12/15/2022] Open
Abstract
The spinal dorsal horn receives input from primary afferent axons, which terminate in a modality-specific fashion in different laminae. The incoming somatosensory information is processed through complex synaptic circuits involving excitatory and inhibitory interneurons, before being transmitted to the brain via projection neurons for conscious perception. The dorsal horn is important, firstly because changes in this region contribute to chronic pain states, and secondly because it contains potential targets for the development of new treatments for pain. However, at present, we have only a limited understanding of the neuronal circuitry within this region, and this is largely because of the difficulty in defining functional populations among the excitatory and inhibitory interneurons. The recent discovery of specific neurochemically defined interneuron populations, together with the development of molecular genetic techniques for altering neuronal function in vivo, are resulting in a dramatic improvement in our understanding of somatosensory processing at the spinal level.
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Affiliation(s)
- Andrew J Todd
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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Ezquerra-Romano I, Ezquerra A. Highway to thermosensation: a traced review, from the proteins to the brain. Rev Neurosci 2017; 28:45-57. [PMID: 27754972 DOI: 10.1515/revneuro-2016-0039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 08/07/2016] [Indexed: 01/09/2023]
Abstract
Temperature maintenance and detection are essential for the survival and perpetuation of any species. This review is focused on thermosensation; thus a detailed and traced explanation of the anatomical and physiological characteristics of each component of this sensation is given. First, the proteins that react to temperature changes are identified; next, the nature of the neurons involved in thermosensation is described; and then, the pathways from the skin through the spinal cord to the brain are outlined. Finally, the areas of the brain and their interconnections where thermoperception arises are explained. Transduction of the external and internal temperature information is essentially mediated by the transient receptor potential ion channels (TRPs). These proteins are embedded in the neurons' membrane and they hyper- or de-polarize neurons in function of the intrinsic voltage and the temperature changes. There are distinct TRP sensors for different temperature ranges. Interestingly, the primary afferent neurons have either cold or hot receptors, so they are dedicated separately to cold or hot sensation. The information is transmitted by different pathways from the skin to the brain, where it either remains separated or is integrated to generate a response. It seems that both the determination of how thermoperception is produced and how we interact with the world are dependent on the particular arrangement and nature of the components, the way of transduction of information and the communication between these elements.
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Filingeri D, Morris NB, Jay O. Warm hands, cold heart: progressive whole-body cooling increases warm thermosensitivity of human hands and feet in a dose-dependent fashion. Exp Physiol 2016; 102:100-112. [DOI: 10.1113/ep085955] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 10/28/2016] [Indexed: 12/27/2022]
Affiliation(s)
- Davide Filingeri
- Thermal Ergonomics Laboratory, Faculty of Health Sciences; University of Sydney; NSW Australia
- Environmental Ergonomics Research Centre; Loughborough University; Loughborough UK
| | - Nathan B. Morris
- Thermal Ergonomics Laboratory, Faculty of Health Sciences; University of Sydney; NSW Australia
| | - Ollie Jay
- Thermal Ergonomics Laboratory, Faculty of Health Sciences; University of Sydney; NSW Australia
- Charles Perkins Centre; University of Sydney; NSW Australia
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Ford NC, Baccei ML. Inward-rectifying K + (K ir2) leak conductance dampens the excitability of lamina I projection neurons in the neonatal rat. Neuroscience 2016; 339:502-510. [PMID: 27751963 DOI: 10.1016/j.neuroscience.2016.10.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 09/20/2016] [Accepted: 10/07/2016] [Indexed: 01/03/2023]
Abstract
Spinal lamina I projection neurons serve as a major conduit by which noxious stimuli detected in the periphery are transmitted to nociceptive circuits in the brain, including the parabrachial nucleus (PB) and the periaqueductal gray (PAG). While neonatal spino-PB neurons are more than twice as likely to exhibit spontaneous activity compared to spino-PAG neurons, the underlying mechanisms remain unclear since nothing is known about the voltage-independent (i.e. 'leak') ion channels expressed by these distinct populations during early life. To begin identifying these key leak conductances, the present study investigated the role of classical inward-rectifying K+ (Kir2) channels in the regulation of intrinsic excitability in neonatal rat spino-PB and spino-PAG neurons. The data demonstrate that a reduction in Kir2-mediated conductance by external BaCl2 significantly enhanced intrinsic membrane excitability in both groups. Similar results were observed in spino-PB neurons following Kir2 channel block with the selective antagonist ML133. In addition, voltage-clamp experiments showed that spino-PB and spino-PAG neurons express similar amounts of Kir2 current during the early postnatal period, suggesting that the differences in the prevalence of spontaneous activity between the two populations are not explained by differential expression of Kir2 channels. Overall, the results indicate that Kir2-mediated conductance tonically dampens the firing of multiple subpopulations of lamina I projection neurons during early life. Therefore, Kir2 channels are positioned to tightly shape the output of the immature spinal nociceptive circuit and thus regulate the ascending flow of nociceptive information to the developing brain, which has important functional implications for pediatric pain.
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Affiliation(s)
- Neil C Ford
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267, USA; Pain Research Center, Department of Anesthesiology, University of Cincinnati Medical Center, 231 Albert Sabin Way, Cincinnati, OH 45267, USA
| | - Mark L Baccei
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267, USA; Pain Research Center, Department of Anesthesiology, University of Cincinnati Medical Center, 231 Albert Sabin Way, Cincinnati, OH 45267, USA.
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Neuronal networks and nociceptive processing in the dorsal horn of the spinal cord. Neuroscience 2016; 338:230-247. [PMID: 27595888 DOI: 10.1016/j.neuroscience.2016.08.048] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 08/23/2016] [Accepted: 08/28/2016] [Indexed: 12/31/2022]
Abstract
The dorsal horn (DH) of the spinal cord receives a variety of sensory information arising from the inner and outer environment, as well as modulatory inputs from supraspinal centers. This information is integrated by the DH before being forwarded to brain areas where it may lead to pain perception. Spinal integration of this information relies on the interplay between different DH neurons forming complex and plastic neuronal networks. Elements of these networks are therefore potential targets for new analgesics and pain-relieving strategies. The present review aims at providing an overview of the current knowledge on these networks, with a special emphasis on those involving interlaminar communication in both physiological and pathological conditions.
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van den Broeke EN, Lenoir C, Mouraux A. Secondary hyperalgesia is mediated by heat-insensitive A-fibre nociceptors. J Physiol 2016; 594:6767-6776. [PMID: 27377467 DOI: 10.1113/jp272599] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 07/01/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS It is believed that secondary hyperalgesia (the increased sensitivity to mechanical nociceptive stimuli that develops after cutaneous tissue injury in the surrounding uninjured skin) is mediated by a subclass of nociceptors: the slowly adapting A-fibre mechano-heat nociceptors (AMH-type I). Here we tested this hypothesis. By using intense long-lasting heat stimuli, which are known to activate these slowly adapting AMH-type I nociceptors, we show that the perceived intensity elicited by these stimuli is not increased in the area of secondary hyperalgesia. Moreover, we show that during an A-fibre nerve conduction block the perception elicited by the long-lasting heat stimuli is significantly reduced in a time window that matches the response profile of the AMH-type I nociceptors. AMH-type I nociceptors contribute to the perception of sustained heat, but they do not mediate secondary hyperalgesia. Therefore, we propose that secondary hyperalgesia is mediated by high threshold mechanoreceptors. ABSTRACT Secondary hyperalgesia refers to the increase in sensitivity to mechanical nociceptive stimuli delivered outside the area of tissue injury. Previous studies have suggested that secondary hyperalgesia is mediated by a specific class of myelinated nociceptors: slowly adapting A-fibre mechano- and heat-sensitive (AMH) type I nociceptors. Here, we tested this hypothesis by examining whether long-lasting heat stimuli, which are known to activate AMH-type I nociceptors, elicit enhanced responses when delivered to the area of secondary hyperalgesia induced by high frequency electrical stimulation of the skin (HFS). Before and 20 min after HFS, sustained 30 s radiant heat stimuli were delivered to the area of increased mechanical pinprick sensitivity while participants continuously rated intensity of perception using an online visual analog scale (0-100 mm). After HFS, no significant enhancement of heat perception was observed in the area of increased pinprick sensitivity. To establish that myelinated nociceptors actually contribute to the perception of sustained heat, we conducted a second experiment in which sustained heat stimuli were presented before and during an A-fibre nerve conduction block, achieved by applying a rubber band with weights which compresses the superficial radial nerve against the radius. During the block, heat perception was significantly reduced 17-33 s after the onset of the heat stimulus (before: mean = 53 mm, during: mean = 31 mm; P = 0.03), matching the response profile of AMH-type I nociceptors. These results support the notion that AMH-type I nociceptors contribute to the perception of sustained heat, but also show that these afferents do not mediate secondary hyperalgesia.
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Affiliation(s)
| | - Cédric Lenoir
- Institute of Neuroscience, Université catholique de Louvain, B-1200, Brussels, Belgium
| | - André Mouraux
- Institute of Neuroscience, Université catholique de Louvain, B-1200, Brussels, Belgium
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Dougherty PM, Chen J. Relationship of membrane properties, spike burst responses, laminar location, and functional class of dorsal horn neurons recorded in vitro. J Neurophysiol 2016; 116:1137-51. [PMID: 27334950 PMCID: PMC5013171 DOI: 10.1152/jn.00187.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 06/19/2016] [Indexed: 01/08/2023] Open
Abstract
The input-output and discharge properties of neurons are shaped by both passive and active electrophysiological membrane properties. Whole cell patch-clamp recordings in lamina I-III neurons in an isolated preparation of the whole spinal cord of juvenile rats with attached dorsal roots and dorsal root ganglia were used to further define which of these properties provides the most impactful classification strategy. A total of 95 neurons were recorded in segment L5 and were classified based on the responses to L4 dorsal root stimulation. The results showed that high-threshold and silent neurons had higher membrane resistance and more negative resting membrane potential than low-threshold or wide-dynamic-range neurons. Rheobase in low-threshold and wide-dynamic-range neurons was significantly lower than that of high-threshold or silent neurons. Four types of firing patterns were identified in response to depolarizing current injections. Low-threshold cells most frequently showed a phasic firing pattern characterized by a short initial burst of action potentials, single spiking or irregular firing bursts at the onset of a depolarizing pulse. High-threshold and wide-dynamic-range neurons were characterized by tonic firing with trains of spikes occurring at regular intervals throughout the current pulse. The majority of silent neurons displayed a delayed onset of firing in response to current injection. These results indicate that the passive membrane properties of spinal neurons are tuned to optimize the responses to particular subsets of afferent stimuli.
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Affiliation(s)
- Patrick M Dougherty
- Division of Anesthesiology and Critical Care Medicine, Department of Pain Medicine, University of Texas M.D. Anderson Cancer Center, Houston, Texas; and
| | - Jinghong Chen
- Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Benarroch EE. Dorsal horn circuitry: Complexity and implications for mechanisms of neuropathic pain. Neurology 2016; 86:1060-9. [PMID: 26888981 DOI: 10.1212/wnl.0000000000002478] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Saeed AW, Pawlowski SA, Ribeiro-da-Silva A. Limited changes in spinal lamina I dorsal horn neurons following the cytotoxic ablation of non-peptidergic C-fibers. Mol Pain 2015; 11:54. [PMID: 26353788 PMCID: PMC4564961 DOI: 10.1186/s12990-015-0060-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 08/31/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Non-peptidergic nociceptive neurons are a sub-population of small diameter primary sensory neurons that comprise approximately 50 % of the C fiber population. Together with the peptidergic sub-population, they transmit nociceptive information from the periphery to the superficial dorsal horn of the spinal cord. Despite the numerous studies investigating the role of the non-peptidergic primary afferents, their role in normal nociception and in pain remains poorly understood. Our lab has previously demonstrated that, in rat models of neuropathic and inflammatory pain, there is a de novo expression of substance P receptors (NK-1r) by lamina I pyramidal projection neurons, a neuronal population that normally does not express these receptors. RESULTS In this study, we used a ribosomal toxin, saporin, conjugated to the lectin IB4 to selectively ablate the non-peptidergic nociceptive C fibers, to investigate if the loss of these fibers was enough to induce a change in NK-1r expression by lamina I projection neurons. IB4-saporin treatment led to the permanent ablation of the IB4-positive afferents but also to a small non-significant reduction in CGRP-positive afferents. An overall increase in immunoreactivity for the NK-1r was observed in lamina I projection neurons, however, the lack of non-peptidergic afferents did not increase the number of lamina I pyramidal projection neurons immunoreactive for the receptor. CONCLUSIONS Our results demonstrate that the deletion of the non-peptidergic afferents, at the L4-L5 spinal levels, is not sufficient to trigger the de novo expression of NK-1r by projection pyramidal neurons but increases the expression of NK-1r in fusiform and multipolar projection neurons. Furthermore, our data suggest that a neuropathic component is essential to trigger the expression of NK-1r by pyramidal neurons.
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Affiliation(s)
- Abeer W Saeed
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, QC, H3G 1Y6, Canada. .,Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, H3A 0G1, Canada.
| | - Sophie A Pawlowski
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, QC, H3G 1Y6, Canada. .,Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, H3A 0G1, Canada.
| | - Alfredo Ribeiro-da-Silva
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, QC, H3G 1Y6, Canada. .,Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, H3A 0G1, Canada. .,Department of Anatomy and Cell Biology, McGill University, Montreal, QC, H3A 0C7, Canada.
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Matsuzaki K, Katakura M, Sugimoto N, Hara T, Hashimoto M, Shido O. β-amyloid infusion into lateral ventricle alters behavioral thermoregulation and attenuates acquired heat tolerance in rats. Temperature (Austin) 2015; 2:418-24. [PMID: 27227055 PMCID: PMC4843902 DOI: 10.1080/23328940.2015.1044635] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 04/19/2015] [Accepted: 04/20/2015] [Indexed: 11/30/2022] Open
Abstract
We investigated behavioral thermoregulatory function and acquired heat tolerance of β-amyloid (Aβ)-infused rats. Male Wistar rats were anesthetized and implanted in the intraperitoneal cavity with a temperature transmitter. Aβ peptide (4.9-5.5 nmol) was dissolved in a solvent of 35% acetonitrile and 0.1% trifluoroacetic acid (pH 2.0). The solvent was used as the vehicle. An osmotic pump contained 234 ± 13.9 μl of Aβ solution was subcutaneously implanted in the back and was cannulated into the left cerebral ventricle. Moreover, 0.5 µg of AlCl3 was injected into the right cerebral ventricle with a micro syringe pump (Aβ-infused rats). The solvent-infused rats were used as control rats (CN rats). After 2 weeks, rats were placed in a thermal gradient and their intra-abdominal temperature (T ab ) and their ambient temperatures (T a ) selected (T s ) were measured for 3 consecutive days. In an additional study, rats were kept at a T a of 32°C for 4 weeks to attain heat acclimation. Then, rats were subjected to a heat tolerance test, i.e. they were exposed to a T a of 36°C for 160 min. Although there were clear day-night variations of T s and T ab in CN rats, patterns were significantly abolished in Aβ-infused rats. Moreover, heat tolerance obtained by heat acclimation was attenuated in Aβ-infused rats. These results suggest that Aβ-infusion in the lateral ventricle modifies behavioral thermoregulation and lowers an ability to acclimate to heat in rats.
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Affiliation(s)
- Kentaro Matsuzaki
- Department of Environmental Physiology; Faculty of Medicine; Shimane University; Izumo, Shimane, Japan
| | - Masanori Katakura
- Department of Environmental Physiology; Faculty of Medicine; Shimane University; Izumo, Shimane, Japan
| | - Naotoshi Sugimoto
- Department of Environmental Physiology; Faculty of Medicine; Shimane University; Izumo, Shimane, Japan
- Department of Physiology; Graduate School of Medical Science; Kanazawa University; Kanazawa, Ishikawa, Japan
| | - Toshiko Hara
- Department of Environmental Physiology; Faculty of Medicine; Shimane University; Izumo, Shimane, Japan
| | - Michio Hashimoto
- Department of Environmental Physiology; Faculty of Medicine; Shimane University; Izumo, Shimane, Japan
| | - Osamu Shido
- Department of Environmental Physiology; Faculty of Medicine; Shimane University; Izumo, Shimane, Japan
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Raison CL, Hale MW, Williams LE, Wager TD, Lowry CA. Somatic influences on subjective well-being and affective disorders: the convergence of thermosensory and central serotonergic systems. Front Psychol 2015; 5:1580. [PMID: 25628593 PMCID: PMC4292224 DOI: 10.3389/fpsyg.2014.01580] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 12/21/2014] [Indexed: 12/20/2022] Open
Abstract
Current theories suggest that the brain is the sole source of mental illness. However, affective disorders, and major depressive disorder (MDD) in particular, may be better conceptualized as brain-body disorders that involve peripheral systems as well. This perspective emphasizes the embodied, multifaceted physiology of well-being, and suggests that afferent signals from the body may contribute to cognitive and emotional states. In this review, we focus on evidence from preclinical and clinical studies suggesting that afferent thermosensory signals contribute to well-being and depression. Although thermoregulatory systems have traditionally been conceptualized as serving primarily homeostatic functions, increasing evidence suggests neural pathways responsible for regulating body temperature may be linked more closely with emotional states than previously recognized, an affective warmth hypothesis. Human studies indicate that increasing physical warmth activates brain circuits associated with cognitive and affective functions, promotes interpersonal warmth and prosocial behavior, and has antidepressant effects. Consistent with these effects, preclinical studies in rodents demonstrate that physical warmth activates brain serotonergic neurons implicated in antidepressant-like effects. Together, these studies suggest that (1) thermosensory pathways interact with brain systems that control affective function, (2) these pathways are dysregulated in affective disorders, and (3) activating warm thermosensory pathways promotes a sense of well-being and has therapeutic potential in the treatment of affective disorders.
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Affiliation(s)
- Charles L. Raison
- Department of Psychiatry, Norton School of Family and Consumer Sciences, College of Medicine, College of Agriculture and Life Sciences, University of ArizonaTucson, AZ, USA
| | - Matthew W. Hale
- Department of Psychology, School of Psychological Science, La Trobe UniversityBundoora, Australia
| | - Lawrence E. Williams
- Marketing Division, Leeds School of Business, University of Colorado BoulderBoulder, CO, USA
| | - Tor D. Wager
- Department of Psychology and Neuroscience, University of Colorado BoulderBoulder, CO, USA
| | - Christopher A. Lowry
- Department of Integrative Physiology, University of Colorado BoulderBoulder, CO, USA
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Identification of spinal circuits transmitting and gating mechanical pain. Cell 2014; 159:1417-1432. [PMID: 25467445 DOI: 10.1016/j.cell.2014.11.003] [Citation(s) in RCA: 394] [Impact Index Per Article: 39.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 10/07/2014] [Accepted: 10/31/2014] [Indexed: 01/16/2023]
Abstract
Pain information processing in the spinal cord has been postulated to rely on nociceptive transmission (T) neurons receiving inputs from nociceptors and Aβ mechanoreceptors, with Aβ inputs gated through feed-forward activation of spinal inhibitory neurons (INs). Here, we used intersectional genetic manipulations to identify these critical components of pain transduction. Marking and ablating six populations of spinal excitatory and inhibitory neurons, coupled with behavioral and electrophysiological analysis, showed that excitatory neurons expressing somatostatin (SOM) include T-type cells, whose ablation causes loss of mechanical pain. Inhibitory neurons marked by the expression of dynorphin (Dyn) represent INs, which are necessary to gate Aβ fibers from activating SOM(+) neurons to evoke pain. Therefore, peripheral mechanical nociceptors and Aβ mechanoreceptors, together with spinal SOM(+) excitatory and Dyn(+) inhibitory neurons, form a microcircuit that transmits and gates mechanical pain. PAPERCLIP:
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Wolff M, Schnöbel-Ehehalt R, Mühling J, Weigand MA, Olschewski A. Mechanisms of Lidocaine’s Action on Subtypes of Spinal Dorsal Horn Neurons Subject to the Diverse Roles of Na+ and K+ Channels in Action Potential Generation. Anesth Analg 2014; 119:463-470. [DOI: 10.1213/ane.0000000000000280] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Hunter J, Dranga R, van Wyk M, Dostrovsky J. Unique influence of stimulus duration and stimulation site (glabrous vs. hairy skin) on the thermal grill-induced percept. Eur J Pain 2014; 19:202-15. [DOI: 10.1002/ejp.538] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2014] [Indexed: 12/17/2022]
Affiliation(s)
- J. Hunter
- Department of Physical Therapy; University of Toronto; Canada
| | - R. Dranga
- The Institute of Biomaterials & Biomedical Engineering (IBBME); University of Toronto; Canada
| | - M. van Wyk
- Department of Physical Therapy; University of Toronto; Canada
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Braz J, Solorzano C, Wang X, Basbaum AI. Transmitting pain and itch messages: a contemporary view of the spinal cord circuits that generate gate control. Neuron 2014; 82:522-36. [PMID: 24811377 DOI: 10.1016/j.neuron.2014.01.018] [Citation(s) in RCA: 296] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The original formulation of Gate Control Theory (GCT) proposed that the perception of pain produced by spinal cord signaling to the brain depends on a balance of activity generated in large (nonnociceptive)- and small (nociceptive)-diameter primary afferent fibers. The theory proposed that activation of the large-diameter afferent "closes" the gate by engaging a superficial dorsal horn interneuron that inhibits the firing of projection neurons. Activation of the nociceptors "opens" the gate through concomitant excitation of projection neurons and inhibition of the inhibitory interneurons. Sixty years after publication of the GCT, we are faced with an ever-growing list of morphologically and neurochemically distinct spinal cord interneurons. The present Review highlights the complexity of superficial dorsal horn circuitry and addresses the question whether the premises outlined in GCT still have relevance today. By examining the dorsal horn circuits that underlie the transmission of "pain" and "itch" messages, we also address the extent to which labeled lines can be incorporated into a contemporary view of GCT.
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Affiliation(s)
- João Braz
- Department of Anatomy, University California, San Francisco, San Francisco, CA 94158, USA
| | - Carlos Solorzano
- Department of Anatomy, University California, San Francisco, San Francisco, CA 94158, USA
| | - Xidao Wang
- Department of Anatomy, University California, San Francisco, San Francisco, CA 94158, USA
| | - Allan I Basbaum
- Department of Anatomy, University California, San Francisco, San Francisco, CA 94158, USA.
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Yamashita A, Hamada A, Suhara Y, Kawabe R, Yanase M, Kuzumaki N, Narita M, Matsui R, Okano H, Narita M. Astrocytic activation in the anterior cingulate cortex is critical for sleep disorder under neuropathic pain. Synapse 2014; 68:235-47. [DOI: 10.1002/syn.21733] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 01/09/2014] [Indexed: 01/21/2023]
Affiliation(s)
- Akira Yamashita
- Department of Pharmacology; Hoshi University School of Pharmacy and Pharmaceutical Sciences; 2-4-41 Ebara Shinagawa-ku Tokyo 142-8501 Japan
| | - Asami Hamada
- Department of Pharmacology; Hoshi University School of Pharmacy and Pharmaceutical Sciences; 2-4-41 Ebara Shinagawa-ku Tokyo 142-8501 Japan
| | - Yuki Suhara
- Department of Pharmacology; Hoshi University School of Pharmacy and Pharmaceutical Sciences; 2-4-41 Ebara Shinagawa-ku Tokyo 142-8501 Japan
| | - Rui Kawabe
- Department of Pharmacology; Hoshi University School of Pharmacy and Pharmaceutical Sciences; 2-4-41 Ebara Shinagawa-ku Tokyo 142-8501 Japan
| | - Makoto Yanase
- Department of Pharmacology; Hoshi University School of Pharmacy and Pharmaceutical Sciences; 2-4-41 Ebara Shinagawa-ku Tokyo 142-8501 Japan
| | - Naoko Kuzumaki
- Department of Physiology; Keio University School of Medicine; 35 Shinanomachi Shinjuku-ku Tokyo 160-8582 Japan
| | - Michiko Narita
- Department of Pharmacology; Hoshi University School of Pharmacy and Pharmaceutical Sciences; 2-4-41 Ebara Shinagawa-ku Tokyo 142-8501 Japan
| | - Ryosuke Matsui
- Department of Molecular and Systems Biology; Graduate School of Biostudies, Kyoto University; Yoshida Sakyo-ku Kyoto 606-8501 Japan
| | - Hideyuki Okano
- Department of Physiology; Keio University School of Medicine; 35 Shinanomachi Shinjuku-ku Tokyo 160-8582 Japan
| | - Minoru Narita
- Department of Pharmacology; Hoshi University School of Pharmacy and Pharmaceutical Sciences; 2-4-41 Ebara Shinagawa-ku Tokyo 142-8501 Japan
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Lavertu G, Côté SL, De Koninck Y. Enhancing K–Cl co-transport restores normal spinothalamic sensory coding in a neuropathic pain model. Brain 2013; 137:724-38. [DOI: 10.1093/brain/awt334] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Abstract
Spatial and temporal cues govern the genesis of a diverse array of neurons located in the dorsal spinal cord, including dI1-dI6, dIL(A), and dIL(B) subtypes, but their physiological functions are poorly understood. Here we generated a new line of conditional knock-out (CKO) mice, in which the homeobox gene Tlx3 was removed in dI5 and dIL(B) cells. In these CKO mice, development of a subset of excitatory neurons located in laminae I and II was impaired, including itch-related GRPR-expressing neurons, PKCγ-expressing neurons, and neurons expressing three neuropeptide genes: somatostatin, preprotachykinin 1, and the gastrin-releasing peptide. These CKO mice displayed marked deficits in generating nocifensive motor behaviors evoked by a range of pain-related or itch-related stimuli. The mutants also failed to exhibit escape response evoked by dynamic mechanical stimuli but retained the ability to sense innocuous cooling and/or warm. Thus, our studies provide new insight into the ontogeny of spinal neurons processing distinct sensory modalities.
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Amandusson Å, Blomqvist A. Estrogenic influences in pain processing. Front Neuroendocrinol 2013; 34:329-49. [PMID: 23817054 DOI: 10.1016/j.yfrne.2013.06.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 06/19/2013] [Accepted: 06/20/2013] [Indexed: 12/24/2022]
Abstract
Gonadal hormones not only play a pivotal role in reproductive behavior and sexual differentiation, they also contribute to thermoregulation, feeding, memory, neuronal survival, and the perception of somatosensory stimuli. Numerous studies on both animals and human subjects have also demonstrated the potential effects of gonadal hormones, such as estrogens, on pain transmission. These effects most likely involve multiple neuroanatomical circuits as well as diverse neurochemical systems and they therefore need to be evaluated specifically to determine the localization and intrinsic characteristics of the neurons engaged. The aim of this review is to summarize the morphological as well as biochemical evidence in support for gonadal hormone modulation of nociceptive processing, with particular focus on estrogens and spinal cord mechanisms.
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Affiliation(s)
- Åsa Amandusson
- Department of Clinical Neurophysiology, Uppsala University, 751 85 Uppsala, Sweden.
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Saeed AW, Ribeiro-da-Silva A. De novo expression of neurokinin-1 receptors by spinoparabrachial lamina I pyramidal neurons following a peripheral nerve lesion. J Comp Neurol 2013; 521:1915-28. [PMID: 23172292 DOI: 10.1002/cne.23267] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2012] [Revised: 09/07/2012] [Accepted: 11/09/2012] [Indexed: 01/07/2023]
Abstract
Lamina I of the spinal dorsal horn is a major site of integration and transmission to higher centers of nociceptive information from the periphery. One important primary afferent population that transmits such information to the spinal cord expresses substance P (SP). These fibers terminate in contact with lamina I projection neurons that express the SP receptor, also known as the neurokinin-1 receptor (NK-1r). Three types of lamina I projection neurons have been described: multipolar, fusiform, and pyramidal. Most neurons of the first two types are thought to be nociceptive and express the NK-1r, whereas most pyramidal neurons are nonnociceptive and do not express the NK-1r. In this immunocytochemical and behavioral study, we induced a neuropathic pain-like condition in the rat by means of a polyethylene cuff placed around in the sciatic nerve. We document that this lesion led to a de novo expression of NK-1r on pyramidal neurons as well as a significant increase in SP-immunoreactive innervation onto these neurons. These phenotypic changes were evident at the time of onset of neuropathic pain-related behavior. Additionally, we show that, after a noxious stimulus (intradermal capsaicin injection), these NK-1r on pyramidal neurons were internalized, providing evidence that these neurons become responsive to peripheral noxious stimulation. We suggest that the changes following nerve lesion in the phenotype and innervation pattern of pyramidal neurons are of significance for neuropathic pain and/or limb temperature regulation.
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Affiliation(s)
- Abeer W Saeed
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec H3G 1Y6, Canada
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50
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Prescott SA, Ratté S. Pain processing by spinal microcircuits: afferent combinatorics. Curr Opin Neurobiol 2012; 22:631-9. [PMID: 22409855 DOI: 10.1016/j.conb.2012.02.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 02/08/2012] [Accepted: 02/19/2012] [Indexed: 10/28/2022]
Abstract
Pain, itch, heat, cold, and touch represent different percepts arising from somatosensory input. How stimuli give rise to these percepts has been debated for over a century. Recent work supports the view that primary afferents are highly specialized to transduce and encode specific stimulus modalities. However, cross-modal interactions (e.g. inhibition or exacerbation of pain by touch) support convergence rather than specificity in central circuits. We outline how peripheral specialization together with central convergence could enable spinal microcircuits to combine inputs from distinctly specialized, co-activated afferents and to modulate the output signals thus formed through computations like normalization. These issues will be discussed alongside recent advances in our understanding of microcircuitry in the superficial dorsal horn.
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Affiliation(s)
- Steven A Prescott
- Department of Neurobiology and the Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, United States.
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