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Yu QQ, Yuan M, Sun XY, Zhang NN, Wang XY, Su YS, Zhang ZY, Jing XH. Electroacupuncture at different intensities inhibits nociceptive discharges of wide dynamic range neurons in spinal dorsal horn of rats. Zhen Ci Yan Jiu 2024; 49:448-455. [PMID: 38764115 DOI: 10.13702/j.1000-0607.20231020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2024]
Abstract
OBJECTIVES To observe the effect of electroacupuncture (EA) at different intensities on nociceptive discharges of wide dynamic range (WDR) neurons in the spinal dorsal horns (DHs) of rats, so as to explore its regulatory characteristics on nociceptive signals at the spinal level. METHODS A total of 25 male SD rats were used in the present study. A microelectrode array was used to record the discharge activity of WDR neurons in the lumbar spinal DHs of normal rats. After finding the WDR neuron, electrical stimulation (pulse width of 2 ms) was administered to the plantar receptive field (RF) for determining its response component of discharges according to the latency of action potential generation (Aβ [0 to 20 ms], Aδ [20 to 90 ms], C [90 to 500 ms] and post-discharge [500 to 800 ms]). High-intensity electrical stimulation was continuously applied to the RF at the paw's plantar surface to induce DHs neuronal windup response. Subsequently, EA stimulation at different intensities (1 mA and 2 mA) was applied to the left "Zusanli"(ST36) at a frequency of 2 Hz/15 Hz for 10 min. The induction of WDR neuronal windup was then repeated under the same conditions. The quantity of nociceptive discharge components and the windup response of WDR neurons before and after EA stimulations at different intensities were compared. RESULTS Compared to pre-EA, both EA1 mA and EA2 mA significantly reduced the number of Aδ and C component discharges of WDR neurons during stimulation, as well as post-discharge (P<0.01, P<0.001). The inhibitory rate of C component by EA2 mA was significantly higher than that by EA1 mA (P<0.05). Meanwhile, both EA1 mA and EA2 mA attenuated the windup response of WDR neurons (P<0.05, P<0.01), and the effect of EA2 mA was stronger than that of EA1 mA (P<0.05). Further analysis showed that when EA1 mA and EA2 mA respectively applied to both non-receptive field (non-RF) and RF, a significant reduction in the number of Aδ component, C component and post-discharge was observed (P<0.05, P<0.01). EA2 mA at the non-RF and RF demonstrated a significant inhibitory effect on the windup response of WDR neurons (P<0.01, P<0.05), but EA1 mA only at the non-RF showed a significant inhibitory effect on the windup response (P<0.01). CONCLUSIONS EA can suppress nociceptive discharges of spinal DHs WDR neurons in rats. The inhibitory impact of EA is strongly correlated with the location and intensity of EA stimulation, and EA2 mA has a stronger inhibitory effect than EA1 mA.
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Affiliation(s)
- Qing-Quan Yu
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Mi Yuan
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Xiao-Yue Sun
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Ni-Nan Zhang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Xiao-Yu Wang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Yang-Shuai Su
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Zhi-Yun Zhang
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China.
| | - Xiang-Hong Jing
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing 100700, China
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Gradwell MA, Ozeri-Engelhard N, Eisdorfer JT, Laflamme OD, Gonzalez M, Upadhyay A, Medlock L, Shrier T, Patel KR, Aoki A, Gandhi M, Abbas-Zadeh G, Oputa O, Thackray JK, Ricci M, George A, Yusuf N, Keating J, Imtiaz Z, Alomary SA, Bohic M, Haas M, Hernandez Y, Prescott SA, Akay T, Abraira VE. Multimodal sensory control of motor performance by glycinergic interneurons of the mouse spinal cord deep dorsal horn. Neuron 2024; 112:1302-1327.e13. [PMID: 38452762 DOI: 10.1016/j.neuron.2024.01.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 10/31/2023] [Accepted: 01/26/2024] [Indexed: 03/09/2024]
Abstract
Sensory feedback is integral for contextually appropriate motor output, yet the neural circuits responsible remain elusive. Here, we pinpoint the medial deep dorsal horn of the mouse spinal cord as a convergence point for proprioceptive and cutaneous input. Within this region, we identify a population of tonically active glycinergic inhibitory neurons expressing parvalbumin. Using anatomy and electrophysiology, we demonstrate that deep dorsal horn parvalbumin-expressing interneuron (dPV) activity is shaped by convergent proprioceptive, cutaneous, and descending input. Selectively targeting spinal dPVs, we reveal their widespread ipsilateral inhibition onto pre-motor and motor networks and demonstrate their role in gating sensory-evoked muscle activity using electromyography (EMG) recordings. dPV ablation altered limb kinematics and step-cycle timing during treadmill locomotion and reduced the transitions between sub-movements during spontaneous behavior. These findings reveal a circuit basis by which sensory convergence onto dorsal horn inhibitory neurons modulates motor output to facilitate smooth movement and context-appropriate transitions.
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Affiliation(s)
- Mark A Gradwell
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Nofar Ozeri-Engelhard
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Neuroscience PhD program, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - Jaclyn T Eisdorfer
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Olivier D Laflamme
- Dalhousie PhD program, Dalhousie University, Halifax, NS, Canada; Department of Medical Neuroscience, Atlantic Mobility Action Project, Brain Repair Center, Dalhousie University, Halifax, NS, Canada
| | - Melissa Gonzalez
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Department of Biomedical Engineering, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Aman Upadhyay
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Neuroscience PhD program, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - Laura Medlock
- Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Tara Shrier
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Komal R Patel
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Adin Aoki
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Melissa Gandhi
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Gloria Abbas-Zadeh
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Olisemaka Oputa
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Joshua K Thackray
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Human Genetics Institute of New Jersey, Rutgers University, The State University of New Jersey, Piscataway, NJ, USA; Tourette International Collaborative Genetics Study (TIC Genetics)
| | - Matthew Ricci
- School of Computer Science and Engineering, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Arlene George
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Nusrath Yusuf
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; Neuroscience PhD program, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - Jessica Keating
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Zarghona Imtiaz
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Simona A Alomary
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Manon Bohic
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Michael Haas
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Yurdiana Hernandez
- W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA
| | - Steven A Prescott
- Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Turgay Akay
- Department of Medical Neuroscience, Atlantic Mobility Action Project, Brain Repair Center, Dalhousie University, Halifax, NS, Canada
| | - Victoria E Abraira
- Cell Biology and Neuroscience Department, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA; W.M. Keck Center for Collaborative Neuroscience, Rutgers University, The State University of New Jersey, New Brunswick, NJ, USA.
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Ru Q, Magnusson J, Li L. Characterization of synaptic structural plasticity in mouse spinal dorsal horn neurons. STAR Protoc 2023; 4:102752. [PMID: 38041818 PMCID: PMC10701437 DOI: 10.1016/j.xpro.2023.102752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 10/23/2023] [Accepted: 11/14/2023] [Indexed: 12/04/2023] Open
Abstract
Here, we present a pipeline for the characterization of synaptic structural plasticity in mouse spinal dorsal horn (SDH) neurons. We describe steps for the intra-SDH microinjection of the EGFP virus to sparsely label L4 SDH neurons without laminectomy, wide dynamic range neuron imaging, dendritic spine morphometric analysis, and F-actin to G-actin ratio measurement. This protocol can be applied to investigate the synaptic structural plasticity mechanisms in the SDH as well as in the brain. For complete details on the use and execution of this protocol, please refer to Li et al. (2023).1.
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Affiliation(s)
- Qin Ru
- Department of Health and Kinesiology, School of Physical Education, Jianghan University, Wuhan 430056, China; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Jennifer Magnusson
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35025, USA
| | - Lingyong Li
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL 35025, USA.
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Foster VS, Saez N, King GF, Rank MM. Acute inhibition of acid sensing ion channel 1a after spinal cord injury selectively affects excitatory synaptic transmission, but not intrinsic membrane properties, in deep dorsal horn interneurons. PLoS One 2023; 18:e0289053. [PMID: 37939057 PMCID: PMC10631665 DOI: 10.1371/journal.pone.0289053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 07/10/2023] [Indexed: 11/10/2023] Open
Abstract
Following a spinal cord injury (SCI), secondary damage mechanisms are triggered that cause inflammation and cell death. A key component of this secondary damage is a reduction in local blood flow that initiates a well-characterised ischemic cascade. Downstream hypoxia and acidosis activate acid sensing ion channel 1a (ASIC1a) to trigger cell death. We recently showed that administration of a potent venom-derived inhibitor of ASIC1a, Hi1a, leads to tissue sparing and improved functional recovery when delivered up to 8 h after ischemic stroke. Here, we use whole-cell patch-clamp electrophysiology in a spinal cord slice preparation to assess the effect of acute ASIC1a inhibition, via a single dose of Hi1a, on intrinsic membrane properties and excitatory synaptic transmission long-term after a spinal cord hemisection injury. We focus on a population of interneurons (INs) in the deep dorsal horn (DDH) that play a key role in relaying sensory information to downstream motoneurons. DDH INs in mice treated with Hi1a 1 h after a spinal cord hemisection showed no change in active or passive intrinsic membrane properties measured 4 weeks after SCI. DDH INs, however, exhibit significant changes in the kinetics of spontaneous excitatory postsynaptic currents after a single dose of Hi1a, when compared to naive animals (unlike SCI mice). Our data suggest that acute ASIC1a inhibition exerts selective effects on excitatory synaptic transmission in DDH INs after SCI via specific ligand-gated receptor channels, and has no effect on other voltage-activated channels long-term after SCI.
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Affiliation(s)
- Victoria S. Foster
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, Australia
- St George’s, University of London, Medical School, London, England
| | - Natalie Saez
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, St Lucia, Queensland, Australia
| | - Glenn F. King
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, St Lucia, Queensland, Australia
| | - Michelle M. Rank
- Department of Anatomy and Physiology, School of Biomedical Science, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Victoria, Australia
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Gilbert JE, Zhang T, Esteller R, Grill WM. Network model of nociceptive processing in the superficial spinal dorsal horn reveals mechanisms of hyperalgesia, allodynia, and spinal cord stimulation. J Neurophysiol 2023; 130:1103-1117. [PMID: 37727912 DOI: 10.1152/jn.00186.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 09/13/2023] [Accepted: 09/15/2023] [Indexed: 09/21/2023] Open
Abstract
The spinal dorsal horn (DH) processes sensory information and plays a key role in transmitting nociception to supraspinal centers. Loss of DH inhibition during neuropathic pain unmasks a pathway from nonnociceptive Aβ-afferent inputs to superficial dorsal horn (SDH) nociceptive-specific (NS) projection neurons, and this change may contribute to hyperalgesia and allodynia. We developed and validated a computational model of SDH neuronal circuitry that links nonnociceptive Aβ-afferent inputs in lamina II/III to a NS projection neuron in lamina I via a network of excitatory interneurons. The excitatory pathway and the NS projection neuron were in turn gated by inhibitory interneurons with connections based on prior patch-clamp recordings. Changing synaptic weights in the computational model to replicate neuropathic pain states unmasked a low-threshold excitatory pathway to NS neurons similar to experimental recordings. Spinal cord stimulation (SCS) is an effective therapy for neuropathic pain, and accumulating experimental evidence indicates that NS neurons in the SDH also respond to SCS. Accounting for these responses may inform therapeutic improvements, and we quantified responses to SCS in the SDH network model and examined the role of different modes of inhibitory control in modulating NS neuron responses to SCS. We combined the SDH network model with a previously published model of the deep dorsal horn (DDH) and identified optimal stimulation frequencies across different neuropathic pain conditions. Finally, we found that SCS-generated inhibition did not completely suppress model NS activity during simulated pinch inputs, providing an explanation of why SCS does not eliminate acute pain.NEW & NOTEWORTHY Chronic pain is a severe public health problem that reduces the quality of life for those affected and exacts an enormous socio-economic burden worldwide. Spinal cord stimulation (SCS) is an effective treatment for chronic pain, but SCS efficacy has not significantly improved over time, in part because the mechanisms of action remain unclear. Most preclinical studies investigating pain and SCS mechanisms have focused on the responses of deep dorsal horn (DDH) neurons, but neural networks in the superficial dorsal horn (SDH) are also important for processing nociceptive information. This work synthesizes heterogeneous experimental recordings from the SDH into a computational model that replicates experimental responses and that can be used to quantify neuronal responses to SCS under neuropathic pain conditions.
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Affiliation(s)
- John E Gilbert
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
| | - Tianhe Zhang
- Neuromodulation Research and Advanced Concepts, Boston Scientific Neuromodulation, Valencia, California, United States
| | - Rosana Esteller
- Neuromodulation Research and Advanced Concepts, Boston Scientific Neuromodulation, Valencia, California, United States
| | - Warren M Grill
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina, United States
- Department of Neurobiology, Duke University School of Medicine, Durham, North Carolina, United States
- Department of Neurosurgery, Duke University School of Medicine, Durham, North Carolina, United States
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Huang Y, Chen H, Jin D, Chen SR, Pan HL. NMDA Receptors at Primary Afferent-Excitatory Neuron Synapses Differentially Sustain Chemotherapy- and Nerve Trauma-Induced Chronic Pain. J Neurosci 2023; 43:3933-3948. [PMID: 37185237 PMCID: PMC10217996 DOI: 10.1523/jneurosci.0183-23.2023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/30/2023] [Accepted: 04/14/2023] [Indexed: 05/17/2023] Open
Abstract
The spinal dorsal horn contains vesicular glutamate transporter-2 (VGluT2)-expressing excitatory neurons and vesicular GABA transporter (VGAT)-expressing inhibitory neurons, which normally have different roles in nociceptive transmission. Spinal glutamate NMDAR hyperactivity is a crucial mechanism of chronic neuropathic pain. However, it is unclear how NMDARs regulate primary afferent input to spinal excitatory and inhibitory neurons in neuropathic pain. Also, the functional significance of presynaptic NMDARs in neuropathic pain has not been defined explicitly. Here we showed that paclitaxel treatment or spared nerve injury (SNI) similarly increased the NMDAR-mediated mEPSC frequency and dorsal root-evoked EPSCs in VGluT2 dorsal horn neurons in male and female mice. By contrast, neither paclitaxel nor SNI had any effect on mEPSCs or evoked EPSCs in VGAT neurons. In mice with conditional Grin1 (gene encoding GluN1) KO in primary sensory neurons (Grin1-cKO), paclitaxel treatment failed to induce pain hypersensitivity. Unexpectedly, SNI still caused long-lasting pain hypersensitivity in Grin1-cKO mice. SNI increased the amplitude of puff NMDA currents in VGluT2 neurons and caused similar depolarizing shifts in GABA reversal potentials in WT and Grin1-cKO mice. Concordantly, spinal Grin1 knockdown diminished SNI-induced pain hypersensitivity. Thus, presynaptic NMDARs preferentially amplify primary afferent input to spinal excitatory neurons in neuropathic pain. Although presynaptic NMDARs are required for chemotherapy-induced pain hypersensitivity, postsynaptic NMDARs in spinal excitatory neurons play a dominant role in traumatic nerve injury-induced chronic pain. Our findings reveal the divergent synaptic connectivity and functional significance of spinal presynaptic and postsynaptic NMDARs in regulating cell type-specific nociceptive input in neuropathic pain with different etiologies.SIGNIFICANCE STATEMENT Spinal excitatory neurons relay input from nociceptors, whereas inhibitory neurons repress spinal nociceptive transmission. Chronic nerve pain is associated with aberrant NMDAR activity in the spinal dorsal horn. This study demonstrates, for the first time, that chemotherapy and traumatic nerve injury preferentially enhance the NMDAR activity at primary afferent-excitatory neuron synapses but have no effect on primary afferent input to spinal inhibitory neurons. NMDARs in primary sensory neurons are essential for chemotherapy-induced chronic pain, whereas nerve trauma causes pain hypersensitivity predominantly via postsynaptic NMDARs in spinal excitatory neurons. Thus, presynaptic and postsynaptic NMDARs at primary afferent-excitatory neuron synapses are differentially engaged in chemotherapy- and nerve injury-induced chronic pain and could be targeted respectively for treating these painful conditions.
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Affiliation(s)
- Yuying Huang
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Hong Chen
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Daozhong Jin
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Shao-Rui Chen
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Hui-Lin Pan
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
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Frezel N, Ranucci M, Foster E, Wende H, Pelczar P, Mendes R, Ganley RP, Werynska K, d'Aquin S, Beccarini C, Birchmeier C, Zeilhofer HU, Wildner H. c-Maf-positive spinal cord neurons are critical elements of a dorsal horn circuit for mechanical hypersensitivity in neuropathy. Cell Rep 2023; 42:112295. [PMID: 36947543 PMCID: PMC10157139 DOI: 10.1016/j.celrep.2023.112295] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/02/2023] [Accepted: 03/06/2023] [Indexed: 03/23/2023] Open
Abstract
Corticospinal tract (CST) neurons innervate the deep spinal dorsal horn to sustain chronic neuropathic pain. The majority of neurons targeted by the CST are interneurons expressing the transcription factor c-Maf. Here, we used intersectional genetics to decipher the function of these neurons in dorsal horn sensory circuits. We find that excitatory c-Maf (c-MafEX) neurons receive sensory input mainly from myelinated fibers and target deep dorsal horn parabrachial projection neurons and superficial dorsal horn neurons, thereby connecting non-nociceptive input to nociceptive output structures. Silencing c-MafEX neurons has little effect in healthy mice but alleviates mechanical hypersensitivity in neuropathic mice. c-MafEX neurons also receive input from inhibitory c-Maf and parvalbumin neurons, and compromising inhibition by these neurons caused mechanical hypersensitivity and spontaneous aversive behaviors reminiscent of c-MafEX neuron activation. Our study identifies c-MafEX neurons as normally silent second-order nociceptors that become engaged in pathological pain signaling upon loss of inhibitory control.
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Affiliation(s)
- Noémie Frezel
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | - Matteo Ranucci
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | - Edmund Foster
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | | | - Pawel Pelczar
- Center for Transgenic Models (CTM), University of Basel, 4001 Basel, Switzerland
| | - Raquel Mendes
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | - Robert P Ganley
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | - Karolina Werynska
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | - Simon d'Aquin
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | - Camilla Beccarini
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland
| | | | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland; Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, 8092 Zürich, Switzerland.
| | - Hendrik Wildner
- Institute of Pharmacology and Toxicology, University of Zürich, 8057 Zürich, Switzerland.
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Wang Y, Huang R, Chai Z, Wang C, Du X, Hang Y, Xu Y, Li J, Jiang X, Wu X, Qiao Z, Li Y, Liu B, Zhang X, Cao P, Zhu F, Zhou Z. Ca 2+ -independent transmission at the central synapse formed between dorsal root ganglion and dorsal horn neurons. EMBO Rep 2022; 23:e54507. [PMID: 36148511 PMCID: PMC9638852 DOI: 10.15252/embr.202154507] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 08/07/2022] [Accepted: 08/30/2022] [Indexed: 09/25/2023] Open
Abstract
A central principle of synaptic transmission is that action potential-induced presynaptic neurotransmitter release occurs exclusively via Ca2+ -dependent secretion (CDS). The discovery and mechanistic investigations of Ca2+ -independent but voltage-dependent secretion (CiVDS) have demonstrated that the action potential per se is sufficient to trigger neurotransmission in the somata of primary sensory and sympathetic neurons in mammals. One key question remains, however, whether CiVDS contributes to central synaptic transmission. Here, we report, in the central transmission from presynaptic (dorsal root ganglion) to postsynaptic (spinal dorsal horn) neurons in vitro, (i) excitatory postsynaptic currents (EPSCs) are mediated by glutamate transmission through both CiVDS (up to 87%) and CDS; (ii) CiVDS-mediated EPSCs are independent of extracellular and intracellular Ca2+ ; (iii) CiVDS is faster than CDS in vesicle recycling with much less short-term depression; (iv) the fusion machinery of CiVDS includes Cav2.2 (voltage sensor) and SNARE (fusion pore). Together, an essential component of activity-induced EPSCs is mediated by CiVDS in a central synapse.
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Affiliation(s)
- Yuan Wang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Rong Huang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Zuying Chai
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Changhe Wang
- Department of NeurologyThe First Affiliated Hospital of Xi'an Jiaotong UniversityXi'anChina
- Neuroscience Research Center, Institute of Mitochondrial Biology and Medicine, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and TechnologyXi'an Jiaotong UniversityXi'anChina
| | - Xingyu Du
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Yuqi Hang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Yongxin Xu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Jie Li
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Xiaohan Jiang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Xi Wu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Zhongjun Qiao
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Yinglin Li
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Bing Liu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | | | - Peng Cao
- National Institute of Biological SciencesBeijingChina
| | - Feipeng Zhu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
| | - Zhuan Zhou
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular MedicineCollege of Future TechnologyPeking UniversityBeijingChina
- Peking‐Tsinghua Center for Life SciencesPeking UniversityBeijingChina
- PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijingChina
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9
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Kókai É, Alsulaiman WAA, Dickie AC, Bell AM, Goffin L, Watanabe M, Gutierrez-Mecinas M, Todd AJ. Characterisation of deep dorsal horn projection neurons in the spinal cord of the Phox2a::Cre mouse line. Mol Pain 2022; 18:17448069221119614. [PMID: 36000342 PMCID: PMC9445510 DOI: 10.1177/17448069221119614] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/20/2022] [Accepted: 07/27/2022] [Indexed: 11/16/2022] Open
Abstract
Projection neurons belonging to the anterolateral system (ALS) underlie the perception of pain, skin temperature and itch. Many ALS cells are located in laminae III-V of the dorsal horn and the adjacent lateral white matter. However, relatively little is known about the excitatory synaptic input to these deep ALS cells, and therefore about their engagement with the neuronal circuitry of the region. We have used a recently developed mouse line, Phox2a::Cre, to investigate a population of deep dorsal horn ALS neurons known as "antenna cells", which are characterised by dense innervation from peptidergic nociceptors, and to compare these with other ALS cells in the deep dorsal horn and lateral white matter. We show that these two classes differ, both in the density of excitatory synapses, and in the source of input at these synapses. Peptidergic nociceptors account for around two-thirds of the excitatory synapses on the antenna cells, but for only a small proportion of the input to the non-antenna cells. Conversely, boutons with high levels of VGLUT2, which are likely to originate mainly from glutamatergic spinal neurons, account for only ∼5% of the excitatory synapses on antenna cells, but for a much larger proportion of the input to the non-antenna cells. VGLUT1 is expressed by myelinated low-threshold mechanoreceptors and corticospinal axons, and these innervate both antenna and non-antenna cells. However, the density of VGLUT1 input to the non-antenna cells is highly variable, consistent with the view that these neurons are functionally heterogeneous.
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Affiliation(s)
- Éva Kókai
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Wafa AA Alsulaiman
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Allen C Dickie
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Andrew M Bell
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Luca Goffin
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University School of Medicine, Sapporo, Japan
| | - Maria Gutierrez-Mecinas
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Andrew J Todd
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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10
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Gradwell MA, Boyle KA, Browne TJ, Bell AM, Leonardo J, Peralta Reyes FS, Dickie AC, Smith KM, Callister RJ, Dayas CV, Hughes DI, Graham BA. Diversity of inhibitory and excitatory parvalbumin interneuron circuits in the dorsal horn. Pain 2022; 163:e432-e452. [PMID: 34326298 PMCID: PMC8832545 DOI: 10.1097/j.pain.0000000000002422] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 07/13/2021] [Accepted: 07/14/2021] [Indexed: 12/03/2022]
Abstract
ABSTRACT Parvalbumin-expressing interneurons (PVINs) in the spinal dorsal horn are found primarily in laminae II inner and III. Inhibitory PVINs play an important role in segregating innocuous tactile input from pain-processing circuits through presynaptic inhibition of myelinated low-threshold mechanoreceptors and postsynaptic inhibition of distinct spinal circuits. By comparison, relatively little is known of the role of excitatory PVINs (ePVINs) in sensory processing. Here, we use neuroanatomical and optogenetic approaches to show that ePVINs comprise a larger proportion of the PVIN population than previously reported and that both ePVIN and inhibitory PVIN populations form synaptic connections among (and between) themselves. We find that these cells contribute to neuronal networks that influence activity within several functionally distinct circuits and that aberrant activity of ePVINs under pathological conditions is well placed to contribute to the development of mechanical hypersensitivity.
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Affiliation(s)
- Mark A. Gradwell
- Faculty of Health, School of Biomedical Sciences & Pharmacy, University of Newcastle, Callaghan, Australia
- Hunter Medical Research Institute (HMRI), New Lambton Heights, New South Wales, Australia
- 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
| | - Kieran A. Boyle
- Institute of Neuroscience Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Tyler J. Browne
- Faculty of Health, School of Biomedical Sciences & Pharmacy, University of Newcastle, Callaghan, Australia
- Hunter Medical Research Institute (HMRI), New Lambton Heights, New South Wales, Australia
| | - Andrew M. Bell
- Institute of Neuroscience Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Jacklyn Leonardo
- Institute of Neuroscience Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Fernanda S. Peralta Reyes
- Institute of Neuroscience Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Allen C. Dickie
- Institute of Neuroscience Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Kelly M. Smith
- Faculty of Health, School of Biomedical Sciences & Pharmacy, University of Newcastle, Callaghan, Australia
- Hunter Medical Research Institute (HMRI), New Lambton Heights, New South Wales, Australia
- Department of Neurobiology and the Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, United States
| | - Robert J. Callister
- Faculty of Health, School of Biomedical Sciences & Pharmacy, University of Newcastle, Callaghan, Australia
- Hunter Medical Research Institute (HMRI), New Lambton Heights, New South Wales, Australia
| | - Christopher V. Dayas
- Faculty of Health, School of Biomedical Sciences & Pharmacy, University of Newcastle, Callaghan, Australia
- Hunter Medical Research Institute (HMRI), New Lambton Heights, New South Wales, Australia
| | - David I. Hughes
- Institute of Neuroscience Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Brett A. Graham
- Faculty of Health, School of Biomedical Sciences & Pharmacy, University of Newcastle, Callaghan, Australia
- Hunter Medical Research Institute (HMRI), New Lambton Heights, New South Wales, Australia
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11
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Cao DY, Hu B, Xue Y, Hanson S, Dessem D, Dorsey SG, Traub RJ. Differential Activation of Colonic Afferents and Dorsal Horn Neurons Underlie Stress-Induced and Comorbid Visceral Hypersensitivity in Female Rats. J Pain 2021; 22:1283-1293. [PMID: 33887444 PMCID: PMC8500917 DOI: 10.1016/j.jpain.2021.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 03/16/2021] [Accepted: 04/02/2021] [Indexed: 12/19/2022]
Abstract
Chronic Overlapping Pain Conditions, including irritable bowel syndrome (IBS) and temporomandibular disorder (TMD), represent a group of idiopathic pain conditions that likely have peripheral and central mechanisms contributing to their pathology, but are poorly understood. These conditions are exacerbated by stress and have a female predominance. The presence of one condition predicts the presence or development of additional conditions, making this a significant pain management problem. The current study was designed to determine if the duration and magnitude of peripheral sensitization and spinal central sensitization differs between restraint stress-induced visceral hypersensitivity (SIH) and chronic comorbid pain hypersensitivity (CPH; stress during pre-existing orofacial pain). SIH in female rats, as determined by the visceromotor response, persisted at least four but resolved by seven weeks. In contrast, CPH persisted at least seven weeks. Surprisingly, colonic afferents in both SIH and CPH rats were sensitized at seven weeks. CPH rats also had referred pain through seven weeks, but locally anesthetizing the colon only attenuated the referred pain through four weeks, suggesting a transition to colonic afferent independent central sensitization. Different phenotypes of dorsal horn neurons were sensitized in the CPH rats seven weeks post stress compared to four weeks or SIH rats. The current study suggests differential processing of colonic afferent input to the lumbosacral spinal cord contributes to visceral hypersensitivity during comorbid chronic pain conditions. PERSPECTIVE: Chronic Overlapping Pain Conditions represent a unique challenge in pain management. The diverse nature of peripheral organs hinders a clear understanding of underlying mechanisms accounting for the comorbidity. This study highlights a mismatch between the condition-dependent behavior and peripheral and spinal mechanisms that contribute to visceral pain hypersensitivity.
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Affiliation(s)
- Dong-Yuan Cao
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, Maryland; Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, Research Center of Stomatology, Xi'an Jiaotong University College of Stomatology, Xi'an, Shaanxi, P. R. China
| | - Bo Hu
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, Maryland; Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, Research Center of Stomatology, Xi'an Jiaotong University College of Stomatology, Xi'an, Shaanxi, P. R. China
| | - Yang Xue
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, Maryland; Department of Prosthodontics, Peking University School and Hospital of Stomatology, Haidian District, Beijing, P. R. China
| | - Shelby Hanson
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, Maryland
| | - Dean Dessem
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, Maryland; UM Center to Advance Chronic Pain Research, University of Maryland, Baltimore, Baltimore, Maryland
| | - Susan G Dorsey
- Department of Pain and Translational Symptom Science, University of Maryland School of Nursing, Baltimore, Maryland; UM Center to Advance Chronic Pain Research, University of Maryland, Baltimore, Baltimore, Maryland
| | - Richard J Traub
- Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore, Maryland; UM Center to Advance Chronic Pain Research, University of Maryland, Baltimore, Baltimore, Maryland.
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12
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Acton D, Ren X, Di Costanzo S, Dalet A, Bourane S, Bertocchi I, Eva C, Goulding M. Spinal Neuropeptide Y1 Receptor-Expressing Neurons Form an Essential Excitatory Pathway for Mechanical Itch. Cell Rep 2020; 28:625-639.e6. [PMID: 31315043 PMCID: PMC6709688 DOI: 10.1016/j.celrep.2019.06.033] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 05/20/2019] [Accepted: 06/06/2019] [Indexed: 01/08/2023] Open
Abstract
Acute itch can be generated by either chemical or mechanical stimuli,
which activate separate pathways in the periphery and spinal cord. While
substantial progress has been made in mapping the transmission pathway for
chemical itch, the central pathway for mechanical itch remains obscure. Using
complementary genetic and pharmacological manipulations, we show that excitatory
neurons marked by the expression of the neuropeptide Y1 receptor
(Y1Cre neurons) form an essential pathway in the dorsal spinal
cord for the transmission of mechanical but not chemical itch. Ablating or
silencing the Y1Cre neurons abrogates mechanical itch, while
chemogenetic activation induces scratching. Moreover, using Y1
conditional knockout mice, we demonstrate that endogenous neuropeptide Y (NPY)
acts via dorsal horn Y1-expressing neurons to suppress light punctate touch and
mechanical itch stimuli. NPY-Y1 signaling thus regulates the transmission of
innocuous tactile information by establishing biologically relevant thresholds
for touch discrimination and mechanical itch reflexes. Acton et al. identify the excitatory neurons in the dorsal spinal cord
that drive mechanical itch. These cells mediate responses to light punctate
touch and are inhibited by neuropeptide Y (NPY)::Cre interneurons. Light touch
sensitivity and mechanical itch responses are gated by NPY signaling mediated by
Y1-expressing neurons in the dorsal horn.
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Affiliation(s)
- David Acton
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Xiangyu Ren
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA; Biology Graduate Program, Division of Biological Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Stefania Di Costanzo
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA; Biology Graduate Program, Division of Biological Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Antoine Dalet
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Steeve Bourane
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Ilaria Bertocchi
- Department of Neuroscience, University of Torino, Neuroscience Institute of the Cavalieri-Ottolenghi Foundation, Regione Gonzole 1, 10043 Orbassano, Italy
| | - Carola Eva
- Department of Neuroscience, University of Torino, Neuroscience Institute of the Cavalieri-Ottolenghi Foundation, Regione Gonzole 1, 10043 Orbassano, Italy
| | - Martyn Goulding
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
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13
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Ferrini F, Perez-Sanchez J, Ferland S, Lorenzo LE, Godin AG, Plasencia-Fernandez I, Cottet M, Castonguay A, Wang F, Salio C, Doyon N, Merighi A, De Koninck Y. Differential chloride homeostasis in the spinal dorsal horn locally shapes synaptic metaplasticity and modality-specific sensitization. Nat Commun 2020; 11:3935. [PMID: 32769979 PMCID: PMC7414850 DOI: 10.1038/s41467-020-17824-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 07/22/2020] [Indexed: 02/06/2023] Open
Abstract
GABAA/glycine-mediated neuronal inhibition critically depends on intracellular chloride (Cl-) concentration which is mainly regulated by the K+-Cl- co-transporter 2 (KCC2) in the adult central nervous system (CNS). KCC2 heterogeneity thus affects information processing across CNS areas. Here, we uncover a gradient in Cl- extrusion capacity across the superficial dorsal horn (SDH) of the spinal cord (laminae I-II: LI-LII), which remains concealed under low Cl- load. Under high Cl- load or heightened synaptic drive, lower Cl- extrusion is unveiled in LI, as expected from the gradient in KCC2 expression found across the SDH. Blocking TrkB receptors increases KCC2 in LI, pointing to differential constitutive TrkB activation across laminae. Higher Cl- lability in LI results in rapidly collapsing inhibition, and a form of activity-dependent synaptic plasticity expressed as a continuous facilitation of excitatory responses. The higher metaplasticity in LI as compared to LII differentially affects sensitization to thermal and mechanical input. Thus, inconspicuous heterogeneity of Cl- extrusion across laminae critically shapes plasticity for selective nociceptive modalities.
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Affiliation(s)
- Francesco Ferrini
- Department of Veterinary Sciences, University of Turin, Turin, Italy.
- CERVO Brain Research Centre, Québec, QC, Canada.
- Department of Psychiatry and Neuroscience, Université Laval, Québec, QC, Canada.
- Graduate program in Neuroscience, Université Laval, Québec, QC, Canada.
| | - Jimena Perez-Sanchez
- CERVO Brain Research Centre, Québec, QC, Canada
- Graduate program in Neuroscience, Université Laval, Québec, QC, Canada
| | - Samuel Ferland
- CERVO Brain Research Centre, Québec, QC, Canada
- Graduate program in Neuroscience, Université Laval, Québec, QC, Canada
| | | | - Antoine G Godin
- CERVO Brain Research Centre, Québec, QC, Canada
- Department of Psychiatry and Neuroscience, Université Laval, Québec, QC, Canada
- Graduate program in Neuroscience, Université Laval, Québec, QC, Canada
| | - Isabel Plasencia-Fernandez
- CERVO Brain Research Centre, Québec, QC, Canada
- Graduate program in Neuroscience, Université Laval, Québec, QC, Canada
| | | | | | - Feng Wang
- CERVO Brain Research Centre, Québec, QC, Canada
| | - Chiara Salio
- Department of Veterinary Sciences, University of Turin, Turin, Italy
| | - Nicolas Doyon
- CERVO Brain Research Centre, Québec, QC, Canada
- Department of Mathematics and Statistics, Université Laval, Québec, QC, Canada
| | - Adalberto Merighi
- Department of Veterinary Sciences, University of Turin, Turin, Italy
| | - Yves De Koninck
- CERVO Brain Research Centre, Québec, QC, Canada
- Department of Psychiatry and Neuroscience, Université Laval, Québec, QC, Canada
- Graduate program in Neuroscience, Université Laval, Québec, QC, Canada
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14
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Alles SRA, Nascimento F, Luján R, Luiz AP, Millet Q, Bangash MA, Santana-Varela S, Zhou X, Cox JJ, Okorokov AL, Beato M, Zhao J, Wood JN. Sensory neuron-derived Na V1.7 contributes to dorsal horn neuron excitability. Sci Adv 2020; 6:eaax4568. [PMID: 32128393 PMCID: PMC7030926 DOI: 10.1126/sciadv.aax4568] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 12/04/2019] [Indexed: 05/08/2023]
Abstract
Expression of the voltage-gated sodium channel NaV1.7 in sensory neurons is required for pain sensation. We examined the role of NaV1.7 in the dorsal horn of the spinal cord using an epitope-tagged NaV1.7 knock-in mouse. Immuno-electron microscopy showed the presence of NaV1.7 in dendrites of superficial dorsal horn neurons, despite the absence of mRNA. Rhizotomy of L5 afferent nerves lowered the levels of NaV1.7 in the dorsal horn. Peripheral nervous system-specific NaV1.7 null mutant mice showed central deficits, with lamina II dorsal horn tonic firing neurons more than halved and single spiking neurons more than doubled. NaV1.7 blocker PF05089771 diminished excitability in dorsal horn neurons but had no effect on NaV1.7 null mutant mice. These data demonstrate an unsuspected functional role of primary afferent neuron-generated NaV1.7 in dorsal horn neurons and an expression pattern that would not be predicted by transcriptomic analysis.
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Affiliation(s)
- Sascha R. A. Alles
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
| | - Filipe Nascimento
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Rafael Luján
- Synaptic Structure Laboratory, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Department Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Campus Biosanitario, C/Almansa 14, 02008 Albacete, Spain
| | - Ana P. Luiz
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
| | - Queensta Millet
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
| | - M. Ali Bangash
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
| | - Sonia Santana-Varela
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
| | - Xuelong Zhou
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
- Department of Anesthesiology, The First Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - James J. Cox
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
| | - Andrei L. Okorokov
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
| | - Marco Beato
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
- Corresponding author. (M.B.); (J.Z.); (J.N.W.)
| | - Jing Zhao
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
- Corresponding author. (M.B.); (J.Z.); (J.N.W.)
| | - John N. Wood
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, UK
- Corresponding author. (M.B.); (J.Z.); (J.N.W.)
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15
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Mapplebeck JCS, Lorenzo LE, Lee KY, Gauthier C, Muley MM, De Koninck Y, Prescott SA, Salter MW. Chloride Dysregulation through Downregulation of KCC2 Mediates Neuropathic Pain in Both Sexes. Cell Rep 2019; 28:590-596.e4. [PMID: 31315039 DOI: 10.1016/j.celrep.2019.06.059] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 05/09/2019] [Accepted: 06/14/2019] [Indexed: 02/08/2023] Open
Abstract
The behavioral features of neuropathic pain are not sexually dimorphic despite sex differences in the underlying neuroimmune signaling. This raises questions about whether neural processing is comparably altered. Here, we test whether the K+-Cl- co-transporter KCC2, which regulates synaptic inhibition, plays an equally important role in development of neuropathic pain in male and female rodents. Past studies on KCC2 tested only males. We find that inhibiting KCC2 in uninjured animals reproduces behavioral and electrophysiological features of neuropathic pain in both sexes and, consistent with equivalent injury-induced downregulation of KCC2, that counteracting chloride dysregulation reverses injury-induced behavioral and electrophysiological changes in both sexes. These findings demonstrate that KCC2 downregulation contributes equally to pain hypersensitivity in males and females. Whereas diverse (and sexually dimorphic) mechanisms regulate KCC2, regulation of intracellular chloride relies almost exclusively on KCC2. Directly targeting KCC2 thus remains a promising strategy for treatment of neuropathic pain in both sexes.
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Affiliation(s)
- Josiane C S Mapplebeck
- Program in Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada; University of Toronto Centre for the Study of Pain, Toronto, ON, Canada
| | | | - Kwan Yeop Lee
- Program in Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
| | - Cédric Gauthier
- CERVO Brain Research Centre, Quebec Mental Health Institute, Quebec, QC, Canada
| | - Milind M Muley
- Program in Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada; University of Toronto Centre for the Study of Pain, Toronto, ON, Canada
| | - Yves De Koninck
- CERVO Brain Research Centre, Quebec Mental Health Institute, Quebec, QC, Canada; Department of Psychiatry and Neuroscience, Université Laval, Quebec, QC, Canada
| | - Steven A Prescott
- Program in Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada; University of Toronto Centre for the Study of Pain, Toronto, ON, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON Canada
| | - Michael W Salter
- Program in Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada; University of Toronto Centre for the Study of Pain, Toronto, ON, Canada.
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16
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Wang X, Yvone GM, Cilluffo M, Kim AS, Basbaum AI, Phelps PE. Mispositioned Neurokinin-1 Receptor-Expressing Neurons Underlie Heat Hyperalgesia in Disabled-1 Mutant Mice. eNeuro 2019; 6:ENEURO.0131-19.2019. [PMID: 31122949 PMCID: PMC6584071 DOI: 10.1523/eneuro.0131-19.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 05/11/2019] [Accepted: 05/15/2019] [Indexed: 11/30/2022] Open
Abstract
Reelin (Reln) and Disabled-1 (Dab1) participate in the Reln-signaling pathway and when either is deleted, mutant mice have the same spinally mediated behavioral abnormalities, increased sensitivity to noxious heat and a profound loss in mechanical sensitivity. Both Reln and Dab1 are highly expressed in dorsal horn areas that receive and convey nociceptive information, Laminae I-II, lateral Lamina V, and the lateral spinal nucleus (LSN). Lamina I contains both projection neurons and interneurons that express Neurokinin-1 receptors (NK1Rs) and they transmit information about noxious heat both within the dorsal horn and to the brain. Here, we ask whether the increased heat nociception in Reln and dab1 mutants is due to incorrectly positioned dorsal horn neurons that express NK1Rs. We found more NK1R-expressing neurons in Reln-/- and dab1-/- Laminae I-II than in their respective wild-type mice, and some NK1R neurons co-expressed Dab1 and the transcription factor Lmx1b, confirming their excitatory phenotype. Importantly, heat stimulation in dab1-/- mice induced Fos in incorrectly positioned NK1R neurons in Laminae I-II. Next, we asked whether these ectopically placed and noxious-heat responsive NK1R neurons participated in pain behavior. Ablation of the superficial NK1Rs with an intrathecal injection of a substance P analog conjugated to the toxin saporin (SSP-SAP) eliminated the thermal hypersensitivity of dab1-/- mice, without altering their mechanical insensitivity. These results suggest that ectopically positioned NK1R-expressing neurons underlie the heat hyperalgesia of Reelin-signaling pathway mutants, but do not contribute to their profound mechanical insensitivity.
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Affiliation(s)
- Xidao Wang
- Departments of Anatomy and Physiology and W. M. Keck Foundation Center for Integrative Neuroscience, University of California, San Francisco, CA 94158
| | - Griselda M Yvone
- Department of Integrative Biology and Physiology UCLA, Los Angeles, Los Angeles, CA 90095
| | - Marianne Cilluffo
- Department of Integrative Biology and Physiology UCLA, Los Angeles, Los Angeles, CA 90095
| | - Ashley S Kim
- Department of Integrative Biology and Physiology UCLA, Los Angeles, Los Angeles, CA 90095
| | - Allan I Basbaum
- Departments of Anatomy and Physiology and W. M. Keck Foundation Center for Integrative Neuroscience, University of California, San Francisco, CA 94158
| | - Patricia E Phelps
- Department of Integrative Biology and Physiology UCLA, Los Angeles, Los Angeles, CA 90095
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17
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Albisetti GW, Pagani M, Platonova E, Hösli L, Johannssen HC, Fritschy JM, Wildner H, Zeilhofer HU. Dorsal Horn Gastrin-Releasing Peptide Expressing Neurons Transmit Spinal Itch But Not Pain Signals. J Neurosci 2019; 39:2238-2250. [PMID: 30655357 PMCID: PMC6433763 DOI: 10.1523/jneurosci.2559-18.2019] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 01/10/2019] [Accepted: 01/10/2019] [Indexed: 02/07/2023] Open
Abstract
Gastrin-releasing peptide (GRP) is a spinal itch transmitter expressed by a small population of dorsal horn interneurons (GRP neurons). The contribution of these neurons to spinal itch relay is still only incompletely understood, and their potential contribution to pain-related behaviors remains controversial. Here, we have addressed this question in a series of experiments performed in GRP::cre and GRP::eGFP transgenic male mice. We combined behavioral tests with neuronal circuit tracing, morphology, chemogenetics, optogenetics, and electrophysiology to obtain a more comprehensive picture. We found that GRP neurons form a rather homogeneous population of central cell-like excitatory neurons located in lamina II of the superficial dorsal horn. Multicolor high-resolution confocal microscopy and optogenetic experiments demonstrated that GRP neurons receive direct input from MrgprA3-positive pruritoceptors. Anterograde HSV-based neuronal tracing initiated from GRP neurons revealed ascending polysynaptic projections to distinct areas and nuclei in the brainstem, midbrain, thalamus, and the somatosensory cortex. Spinally restricted ablation of GRP neurons reduced itch-related behaviors to different pruritogens, whereas their chemogenetic excitation elicited itch-like behaviors and facilitated responses to several pruritogens. By contrast, responses to painful stimuli remained unaltered. These data confirm a critical role of dorsal horn GRP neurons in spinal itch transmission but do not support a role in pain.SIGNIFICANCE STATEMENT Dorsal horn gastrin-releasing peptide neurons serve a well-established function in the spinal transmission of pruritic (itch) signals. A potential role in the transmission of nociceptive (pain) signals has remained controversial. Our results provide further support for a critical role of dorsal horn gastrin-releasing peptide neurons in itch circuits, but we failed to find evidence supporting a role in pain.
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Affiliation(s)
- Gioele W Albisetti
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
- Neuroscience Center Zurich, CH-8057 Zurich, Switzerland
| | - Martina Pagani
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
- Neuroscience Center Zurich, CH-8057 Zurich, Switzerland
| | - Evgenia Platonova
- Center for Microscopy and Image Analysis, University of Zurich, CH-8057 Zurich, Switzerland
| | - Ladina Hösli
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
- Neuroscience Center Zurich, CH-8057 Zurich, Switzerland
| | - Helge C Johannssen
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
| | - Jean-Marc Fritschy
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
- Neuroscience Center Zurich, CH-8057 Zurich, Switzerland
| | - Hendrik Wildner
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
| | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland,
- Neuroscience Center Zurich, CH-8057 Zurich, Switzerland
- Drug Discovery Network Zurich, CH-8057 Zurich, Switzerland, and
- Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology Zurich, CH-8090 Zurich, Switzerland
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18
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Contreras‐Hernández E, Chávez D, Hernández E, Velázquez E, Reyes P, Béjar J, Martín M, Cortés U, Glusman S, Rudomin P. Supraspinal modulation of neuronal synchronization by nociceptive stimulation induces an enduring reorganization of dorsal horn neuronal connectivity. J Physiol 2018; 596:1747-1776. [PMID: 29451306 PMCID: PMC5924834 DOI: 10.1113/jp275228] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 02/12/2018] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS The state of central sensitization induced by the intradermic injection of capsaicin leads to structured (non-random) changes in functional connectivity between dorsal horn neuronal populations distributed along the spinal lumbar segments in anaesthetized cats. The capsaicin-induced changes in neuronal connectivity and the concurrent increase in secondary hyperalgesia are transiently reversed by the systemic administration of small doses of lidocaine, a clinically effective procedure to treat neuropathic pain. The effects of both capsaicin and lidocaine are greatly attenuated in spinalized preparations, showing that supraspinal influences play a significant role in the shaping of nociceptive-induced changes in dorsal horn functional neuronal connectivity. We conclude that changes in functional connectivity between segmental populations of dorsal horn neurones induced by capsaicin and lidocaine result from a cooperative adaptive interaction between supraspinal and spinal neuronal networks, a process that may have a relevant role in the pathogenesis of chronic pain and analgesia. ABSTRACT Despite a profusion of information on the molecular and cellular mechanisms involved in the central sensitization produced by intense nociceptive stimulation, the changes in the patterns of functional connectivity between spinal neurones associated with the development of secondary hyperalgesia and allodynia remain largely unknown. Here we show that the state of central sensitization produced by the intradermal injection of capsaicin is associated with structured transformations in neuronal synchronization that lead to an enduring reorganization of the functional connectivity within a segmentally distributed ensemble of dorsal horn neurones. These changes are transiently reversed by the systemic administration of small doses of lidocaine, a clinically effective procedure to treat neuropathic pain. Lidocaine also reduces the capsaicin-induced facilitation of the spinal responses evoked by weak mechanical stimulation of the skin in the region of secondary but not primary hyperalgesia. The effects of both intradermic capsaicin and systemic lidocaine on the segmental correlation and coherence between ongoing cord dorsum potentials and on the responses evoked by tactile stimulation in the region of secondary hyperalgesia are greatly attenuated in spinalized preparations, showing that supraspinal influences are involved in the reorganization of the nociceptive-induced structured patterns of dorsal horn neuronal connectivity. We conclude that the structured reorganization of the functional connectivity between the dorsal horn neurones induced by capsaicin nociceptive stimulation results from cooperative interactions between supraspinal and spinal networks, a process that may have a relevant role in the shaping of the spinal state in the pathogenesis of chronic pain and analgesia.
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Affiliation(s)
- E. Contreras‐Hernández
- Department of PhysiologyCentro de Investigación y de Estudios Avanzados del Instituto Politécnico NacionalMéxico
| | - D. Chávez
- Department of PhysiologyCentro de Investigación y de Estudios Avanzados del Instituto Politécnico NacionalMéxico
| | - E. Hernández
- Department of PhysiologyCentro de Investigación y de Estudios Avanzados del Instituto Politécnico NacionalMéxico
| | - E. Velázquez
- Department of PhysiologyCentro de Investigación y de Estudios Avanzados del Instituto Politécnico NacionalMéxico
| | - P. Reyes
- Department of PhysiologyCentro de Investigación y de Estudios Avanzados del Instituto Politécnico NacionalMéxico
| | - J. Béjar
- Universidad Politécnica de CatalunyaBarcelonaTechCataloniaSpain
| | - M. Martín
- Universidad Politécnica de CatalunyaBarcelonaTechCataloniaSpain
| | - U. Cortés
- Universidad Politécnica de CatalunyaBarcelonaTechCataloniaSpain
- Barcelona Supercomputing CenterCataloniaSpain
| | - S. Glusman
- Department of PhysiologyCentro de Investigación y de Estudios Avanzados del Instituto Politécnico NacionalMéxico
- Stroger Cook County HospitalChicagoIllinoisUSA
| | - P. Rudomin
- Department of PhysiologyCentro de Investigación y de Estudios Avanzados del Instituto Politécnico NacionalMéxico
- El Colegio NacionalMéxico
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19
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Balachandar A, Prescott SA. Origin of heterogeneous spiking patterns from continuously distributed ion channel densities: a computational study in spinal dorsal horn neurons. J Physiol 2018; 596:1681-1697. [PMID: 29352464 PMCID: PMC5924839 DOI: 10.1113/jp275240] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 01/11/2018] [Indexed: 12/31/2022] Open
Abstract
KEY POINTS Distinct spiking patterns may arise from qualitative differences in ion channel expression (i.e. when different neurons express distinct ion channels) and/or when quantitative differences in expression levels qualitatively alter the spike generation process. We hypothesized that spiking patterns in neurons of the superficial dorsal horn (SDH) of spinal cord reflect both mechanisms. We reproduced SDH neuron spiking patterns by varying densities of KV 1- and A-type potassium conductances. Plotting the spiking patterns that emerge from different density combinations revealed spiking-pattern regions separated by boundaries (bifurcations). This map suggests that certain spiking pattern combinations occur when the distribution of potassium channel densities straddle boundaries, whereas other spiking patterns reflect distinct patterns of ion channel expression. The former mechanism may explain why certain spiking patterns co-occur in genetically identified neuron types. We also present algorithms to predict spiking pattern proportions from ion channel density distributions, and vice versa. ABSTRACT Neurons are often classified by spiking pattern. Yet, some neurons exhibit distinct patterns under subtly different test conditions, which suggests that they operate near an abrupt transition, or bifurcation. A set of such neurons may exhibit heterogeneous spiking patterns not because of qualitative differences in which ion channels they express, but rather because quantitative differences in expression levels cause neurons to operate on opposite sides of a bifurcation. Neurons in the spinal dorsal horn, for example, respond to somatic current injection with patterns that include tonic, single, gap, delayed and reluctant spiking. It is unclear whether these patterns reflect five cell populations (defined by distinct ion channel expression patterns), heterogeneity within a single population, or some combination thereof. We reproduced all five spiking patterns in a computational model by varying the densities of a low-threshold (KV 1-type) potassium conductance and an inactivating (A-type) potassium conductance and found that single, gap, delayed and reluctant spiking arise when the joint probability distribution of those channel densities spans two intersecting bifurcations that divide the parameter space into quadrants, each associated with a different spiking pattern. Tonic spiking likely arises from a separate distribution of potassium channel densities. These results argue in favour of two cell populations, one characterized by tonic spiking and the other by heterogeneous spiking patterns. We present algorithms to predict spiking pattern proportions based on ion channel density distributions and, conversely, to estimate ion channel density distributions based on spiking pattern proportions. The implications for classifying cells based on spiking pattern are discussed.
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Affiliation(s)
- Arjun Balachandar
- Neurosciences and Mental HealthThe Hospital for Sick ChildrenTorontoCanada
| | - Steven A. Prescott
- Neurosciences and Mental HealthThe Hospital for Sick ChildrenTorontoCanada
- Department of Physiology and the Institute of Biomaterials and Biomedical EngineeringUniversity of TorontoTorontoCanada
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20
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Yu F, Zhao ZY, He T, Yu YQ, Li Z, Chen J. Temporal and spatial dynamics of peripheral afferent-evoked activity in the dorsal horn recorded in rat spinal cord slices. Brain Res Bull 2017; 131:183-191. [PMID: 28458040 DOI: 10.1016/j.brainresbull.2017.04.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 02/13/2017] [Accepted: 04/21/2017] [Indexed: 01/07/2023]
Abstract
In the present study, multi-electrode array recording was used to examine dorsal horn activity following stimulation of primary afferents in a rat dorsal root attached-spinal cord slice preparation. The multi-electrode array probe was placed under the dorsal horn slice and local field potentials evoked by stimulation on the dorsal root were analyzed. Three kinds of dorsal root-evoked responses were identified. In lamina IIo, local field potentials exhibited P1 (peak latency 1.46±0.08ms), N1 (2.77±0.18ms, n=12), N2 (7.31±0.48ms), N3 (12.12±0.73ms) and P2(18.30±0.80ms) waves. In lamina IIi local field potentials exhibited P (1.99±0.10ms), N1 (3.35±0.17ms) and N2 (8.58±0.44ms) waves. In laminae III-VI, local field potentials exhibited P1 (3.01±0.07ms), P2 (7.02±0.21ms) and N waves (22.57±0.79ms). Sweep spread was calculated by two dimensional current source density (2D-CSD) analysis. Both α-amino-3-hydroxy-5-methylisoxazole-4-propionic a/kainate and N-methyl-d-aspartate-type glutamate receptors participated in this neuronal circuitry. Morphine diminished local field potentials. Gabapentin diminished the negative components in lamina II and P2 component in lamina IIo, but increased the positive components in lamina IIi and laminae III-VI. The present study revealed that functional dorsal horn activity was preserved in the spinal cord slice preparation. Glutamatergic synapses were crucially involved in information processing. Opioid interneurons and gabapentin may play a modulatory role in regulating signal flows in the dorsal horn. Taken together, these results identify a spatio-temporal profile of dorsal horn activity evoked by dorsal root stimulation, and implicate glutamatergic and opioidergic receptors and gabapentin in this activity.
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Affiliation(s)
- Fang Yu
- State Key Laboratory of Cancer Biology & Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, Shaanxi Province, 710038, PR China; Jinan Military General Hospital, Jinan, Shandong Province, 250031, PR China
| | - Zhen-Yu Zhao
- Institute for Biomedical Sciences of Pain and Institute for Functional Brain Disorders, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi Province, 710038, PR China; Jinan Military General Hospital, Jinan, Shandong Province, 250031, PR China
| | - Ting He
- Institute for Biomedical Sciences of Pain and Institute for Functional Brain Disorders, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi Province, 710038, PR China
| | - Yao-Qing Yu
- Institute for Biomedical Sciences of Pain and Institute for Functional Brain Disorders, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi Province, 710038, PR China
| | - Zhen Li
- Institute for Biomedical Sciences of Pain and Institute for Functional Brain Disorders, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi Province, 710038, PR China
| | - Jun Chen
- Institute for Biomedical Sciences of Pain and Institute for Functional Brain Disorders, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi Province, 710038, PR China.
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21
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Mrozkova P, Spicarova D, Palecek J. Hypersensitivity Induced by Activation of Spinal Cord PAR2 Receptors Is Partially Mediated by TRPV1 Receptors. PLoS One 2016; 11:e0163991. [PMID: 27755539 PMCID: PMC5068818 DOI: 10.1371/journal.pone.0163991] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 09/19/2016] [Indexed: 12/23/2022] Open
Abstract
Protease-activated receptors 2 (PAR2) and transient receptor potential vanilloid 1 (TRPV1) receptors in the peripheral nerve endings are implicated in the development of increased sensitivity to mechanical and thermal stimuli, especially during inflammatory states. Both PAR2 and TRPV1 receptors are co-expressed in nociceptive dorsal root ganglion (DRG) neurons on their peripheral endings and also on presynaptic endings in the spinal cord dorsal horn. However, the modulation of nociceptive synaptic transmission in the superficial dorsal horn after activation of PAR2 and their functional coupling with TRPV1 is not clear. To investigate the role of spinal PAR2 activation on nociceptive modulation, intrathecal drug application was used in behavioural experiments and patch-clamp recordings of spontaneous, miniature and dorsal root stimulation-evoked excitatory postsynaptic currents (sEPSCs, mEPSCs, eEPSCs) were performed on superficial dorsal horn neurons in acute rat spinal cord slices. Intrathecal application of PAR2 activating peptide SLIGKV-NH2 induced thermal hyperalgesia, which was prevented by pretreatment with TRPV1 antagonist SB 366791 and was reduced by protein kinases inhibitor staurosporine. Patch-clamp experiments revealed robust decrease of mEPSC frequency (62.8 ± 4.9%), increase of sEPSC frequency (127.0 ± 5.9%) and eEPSC amplitude (126.9 ± 12.0%) in dorsal horn neurons after acute SLIGKV-NH2 application. All these EPSC changes, induced by PAR2 activation, were prevented by SB 366791 and staurosporine pretreatment. Our results demonstrate an important role of spinal PAR2 receptors in modulation of nociceptive transmission in the spinal cord dorsal horn at least partially mediated by activation of presynaptic TRPV1 receptors. The functional coupling between the PAR2 and TRPV1 receptors on the central branches of DRG neurons may be important especially during different pathological states when it may enhance pain perception.
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Affiliation(s)
- Petra Mrozkova
- Department of Functional Morphology, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
| | - Diana Spicarova
- Department of Functional Morphology, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
| | - Jiri Palecek
- Department of Functional Morphology, Institute of Physiology, The Czech Academy of Sciences, Prague, Czech Republic
- * E-mail:
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22
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Thaweerattanasinp T, Heckman CJ, Tysseling VM. Firing characteristics of deep dorsal horn neurons after acute spinal transection during administration of agonists for 5-HT1B/1D and NMDA receptors. J Neurophysiol 2016; 116:1644-1653. [PMID: 27486104 PMCID: PMC5144700 DOI: 10.1152/jn.00198.2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 07/07/2016] [Indexed: 11/22/2022] Open
Abstract
Spinal cord injury (SCI) results in a loss of serotonin (5-HT) to the spinal cord and a loss of inhibition to deep dorsal horn (DDH) neurons, which produces an exaggerated excitatory drive to motoneurons. The mechanism of this excitatory drive could involve the DDH neurons triggering long excitatory postsynaptic potentials in motoneurons, which may ultimately drive muscle spasms. Modifying the activity of DDH neurons with drugs such as NMDA or the 5-HT1B/1D receptor agonist zolmitriptan could have a large effect on motoneuron activity and, therefore, on muscle spasms. In this study, we characterize the firing properties of DDH neurons after acute spinal transection in adult mice during administration of zolmitriptan and NMDA, using the in vitro sacral cord preparation and extracellular electrophysiology. DDH neurons can be categorized into three major types with distinct evoked and spontaneous firing characteristics: burst (bursting), simple (single spiking), and tonic (spontaneously tonic firing) neurons. The burst neurons likely contribute to muscle spasm mechanisms because of their bursting behavior. Only the burst neurons show significant changes in their firing characteristics during zolmitriptan and NMDA administration. Zolmitriptan suppresses the burst neurons by reducing their evoked spikes, burst duration, and spontaneous firing rate. Conversely, NMDA facilitates them by enhancing their burst duration and spontaneous firing rate. These results suggest that zolmitriptan may exert its antispastic effect on the burst neurons via activation of 5-HT1B/1D receptors, whereas activation of NMDA receptors may facilitate the burst neurons in contributing to muscle spasm mechanisms following SCI.
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Affiliation(s)
| | - Charles J Heckman
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois; Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, Illinois; and Department of Physical Therapy and Human Movement Science, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Vicki M Tysseling
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois; Department of Physical Therapy and Human Movement Science, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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23
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Abstract
In the somatosensory system, P2X receptors are expressed on both peripheral and central terminals of primary afferent neurons. Those expressed on peripheral terminals are activated in response to both nociceptive and innocuous stimuli, whereas those at central terminals (“central terminal P2X receptors”) play an important role in modulating sensory transmission to the spinal cord dorsal horn. The author reviews recent studies on the central terminal P2X receptors. It is proposed that central terminal P2X receptors, once activated, may be involved in both central sensitization and initiation of pain. Thus, these receptors may repesent a promising target for therapeutic management of pathological pain.
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Affiliation(s)
- Jianguo G Gu
- Department of Oral Surgery, Division of Neuroscience, McKnight Brain Institute and College of Dentistry, University of Florida, Gainesville 32610, USA.
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24
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Abstract
We used optical tweezers, video imaging, immunocytochemistry and a variety of inhibitors to analyze the role of Rac1 in the motility and force generation of lamellipodia and filopodia from developing growth cones of isolated Dorsal Root Ganglia neurons. When the activity of Rac1 was inhibited by the drug EHop-016, the period of lamellipodia protrusion/retraction cycles increased and the lamellipodia retrograde flow rate decreased; moreover, the axial force exerted by lamellipodia was reduced dramatically. Inhibition of Arp2/3 by a moderate amount of the drug CK-548 caused a transient retraction of lamellipodia followed by a complete recovery of their usual motility. This recovery was abolished by the concomitant inhibition of Rac1. The filopodia length increased upon inhibition of both Rac1 and Arp2/3, but the speed of filopodia protrusion increased when Rac1 was inhibited and decreased instead when Arp2/3 was inhibited. These results suggest that Rac1 acts as a switch that activates upon inhibition of Arp2/3. Rac1 also controls the filopodia dynamics necessary to explore the environment.
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Affiliation(s)
- Wasim A. Sayyad
- Neuroscience Area, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Paolo Fabris
- Neuroscience Area, International School for Advanced Studies (SISSA), Trieste, Italy
| | - Vincent Torre
- Neuroscience Area, International School for Advanced Studies (SISSA), Trieste, Italy
- * E-mail:
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25
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Zhang Y, Zhao S, Rodriguez E, Takatoh J, Han BX, Zhou X, Wang F. Identifying local and descending inputs for primary sensory neurons. J Clin Invest 2015; 125:3782-94. [PMID: 26426077 DOI: 10.1172/jci81156] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Accepted: 07/23/2015] [Indexed: 12/25/2022] Open
Abstract
Primary pain and touch sensory neurons not only detect internal and external sensory stimuli, but also receive inputs from other neurons. However, the neuronal derived inputs for primary neurons have not been systematically identified. Using a monosynaptic rabies viruses-based transneuronal tracing method combined with sensory-specific Cre-drivers, we found that sensory neurons receive intraganglion, intraspinal, and supraspinal inputs, the latter of which are mainly derived from the rostroventral medulla (RVM). The viral-traced central neurons were largely inhibitory but also consisted of some glutamatergic neurons in the spinal cord and serotonergic neurons in the RVM. The majority of RVM-derived descending inputs were dual GABAergic and enkephalinergic (opioidergic). These inputs projected through the dorsolateral funiculus and primarily innervated layers I, II, and V of the dorsal horn, where pain-sensory afferents terminate. Silencing or activation of the dual GABA/enkephalinergic RVM neurons in adult animals substantially increased or decreased behavioral sensitivity, respectively, to heat and mechanical stimuli. These results are consistent with the fact that both GABA and enkephalin can exert presynaptic inhibition of the sensory afferents. Taken together, this work provides a systematic view of and a set of tools for examining peri- and extrasynaptic regulations of pain-afferent transmission.
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26
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Sdrulla AD, Xu Q, He SQ, Tiwari V, Yang F, Zhang C, Shu B, Shechter R, Raja SN, Wang Y, Dong X, Guan Y. Electrical stimulation of low-threshold afferent fibers induces a prolonged synaptic depression in lamina II dorsal horn neurons to high-threshold afferent inputs in mice. Pain 2015; 156:1008-1017. [PMID: 25974163 PMCID: PMC4437220 DOI: 10.1097/01.j.pain.0000460353.15460.a3] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Electrical stimulation of low-threshold Aβ-fibers (Aβ-ES) is used clinically to treat neuropathic pain conditions that are refractory to pharmacotherapy. However, it is unclear how Aβ-ES modulates synaptic responses to high-threshold afferent inputs (C-, Aδ-fibers) in superficial dorsal horn. Substantia gelatinosa (SG) (lamina II) neurons are important for relaying and modulating converging spinal nociceptive inputs. We recorded C-fiber-evoked excitatory postsynaptic currents (eEPSCs) in spinal cord slices in response to paired-pulse test stimulation (500 μA, 0.1 millisecond, 400 milliseconds apart). We showed that 50-Hz and 1000-Hz, but not 4-Hz, Aβ-ES (10 μA, 0.1 millisecond, 5 minutes) induced prolonged inhibition of C-fiber eEPSCs in SG neurons in naive mice. Furthermore, 50-Hz Aβ-ES inhibited both monosynaptic and polysynaptic forms of C-fiber eEPSC in naive mice and mice that had undergone spinal nerve ligation (SNL). The paired-pulse ratio (amplitude second eEPSC/first eEPSC) increased only in naive mice after 50-Hz Aβ-ES, suggesting that Aβ-ES may inhibit SG neurons by different mechanisms under naive and nerve-injured conditions. Finally, 50-Hz Aβ-ES inhibited both glutamatergic excitatory and GABAergic inhibitory interneurons, which were identified by fluorescence in vGlut2-Td and glutamic acid decarboxylase-green fluorescent protein transgenic mice after SNL. These findings show that activities in Aβ-fibers lead to frequency-dependent depression of synaptic transmission in SG neurons in response to peripheral noxious inputs. However, 50-Hz Aβ-ES failed to induce cell-type-selective inhibition in SG neurons. The physiologic implication of this novel form of synaptic depression for pain modulation by Aβ-ES warrants further investigation.
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Affiliation(s)
- Andrei D. Sdrulla
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Qian Xu
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
- Howard Hughes Medical Institute, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Shao-Qiu He
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Vinod Tiwari
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Fei Yang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Chen Zhang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
- Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China
| | - Bin Shu
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Ronen Shechter
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Srinivasa N. Raja
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Yun Wang
- Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
- Howard Hughes Medical Institute, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
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Foster E, Wildner H, Tudeau L, Haueter S, Ralvenius WT, Jegen M, Johannssen H, Hösli L, Haenraets K, Ghanem A, Conzelmann KK, Bösl M, Zeilhofer HU. Targeted ablation, silencing, and activation establish glycinergic dorsal horn neurons as key components of a spinal gate for pain and itch. Neuron 2015; 85:1289-304. [PMID: 25789756 PMCID: PMC4372258 DOI: 10.1016/j.neuron.2015.02.028] [Citation(s) in RCA: 249] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 01/26/2015] [Accepted: 02/12/2015] [Indexed: 01/28/2023]
Abstract
The gate control theory of pain proposes that inhibitory neurons of the spinal dorsal horn exert critical control over the relay of nociceptive signals to higher brain areas. Here we investigated how the glycinergic subpopulation of these neurons contributes to modality-specific pain and itch processing. We generated a GlyT2::Cre transgenic mouse line suitable for virus-mediated retrograde tracing studies and for spatially precise ablation, silencing, and activation of glycinergic neurons. We found that these neurons receive sensory input mainly from myelinated primary sensory neurons and that their local toxin-mediated ablation or silencing induces localized mechanical, heat, and cold hyperalgesia; spontaneous flinching behavior; and excessive licking and biting directed toward the corresponding skin territory. Conversely, local pharmacogenetic activation of the same neurons alleviated neuropathic hyperalgesia and chloroquine- and histamine-induced itch. These results establish glycinergic neurons of the spinal dorsal horn as key elements of an inhibitory pain and itch control circuit. Glycinergic dorsal horn neurons exert segmental control over pain and itch Their local inhibition causes hyperalgesia and signs of spontaneous discomfort Local activation reduces acute pain, neuropathic hyperalgesia, and chemical itch
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Affiliation(s)
- Edmund Foster
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Hendrik Wildner
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Laetitia Tudeau
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland; Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Vladimir Prelog Weg 4, 8093 Zürich, Switzerland
| | - Sabine Haueter
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland; Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Vladimir Prelog Weg 4, 8093 Zürich, Switzerland
| | - William T Ralvenius
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Monika Jegen
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland; Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Vladimir Prelog Weg 4, 8093 Zürich, Switzerland
| | - Helge Johannssen
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Ladina Hösli
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Karen Haenraets
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland; Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Vladimir Prelog Weg 4, 8093 Zürich, Switzerland
| | - Alexander Ghanem
- Gene Center, Ludwig Maximilians University Munich, Max von Pettenkofer Institute of Virology, Feodor Lynen Strasse 25, 81377 Munich, Germany
| | - Karl-Klaus Conzelmann
- Gene Center, Ludwig Maximilians University Munich, Max von Pettenkofer Institute of Virology, Feodor Lynen Strasse 25, 81377 Munich, Germany
| | - Michael Bösl
- Experimental Biomedicine, University of Würzburg, Josef Schneider Strasse 2, 97080 Würzburg, Germany
| | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland; Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Vladimir Prelog Weg 4, 8093 Zürich, Switzerland.
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Dieb W, Alvarez P, Hafidi A. PKCγ-positive neurons gate light tactile inputs to pain pathway through pERK1/2 neuronal network in trigeminal neuropathic pain model. J Oral Facial Pain Headache 2015; 29:70-82. [PMID: 25635962 DOI: 10.11607/ofph.1353] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
AIMS To explore the possible relationship between protein kinase C gamma (PKCγ) and phosphorylated forms of extracellular signal-regulated kinases 1/2 (pERK1/2) in the rat medullary dorsal horn and the facial hypersensitivity indicative of dynamic mechanical allodynia (DMA) following chronic constriction of the infraorbital nerve (CCI-IoN). METHODS A well-established rat model of trigeminal neuropathic pain involving CCI-IoN was used. Facial mechanical hypersensitivity was tested with non-noxious dynamic mechanical stimulation (air-puff), and the medullary dorsal horn was examined immunohistochemically using PKCγ and pERK1/2 as pain markers. Statistical analysis was performed using Student t test or one-way analysis of variance (ANOVA). RESULTS Increased PKCγ and pERK1/2 expressions within the medullary dorsal horn were associated with DMA following CCI-IoN. A segmental network composed of PKCγ-positive cells located in medullary dorsal horn laminae II/III, contacting more superficially located pERK1/2-expressing cells, was identified. Ultrastructural analysis confirmed the presence of PKCγ to pERK1/2-positive cells. Moreover, intracisternal administration of the selective PKCγ inhibitor KIG31-I blocked both the DMA and pERK1/2 expression in a dose-dependent manner. Although the number of pERK1/2-positive cells was significantly elevated with air-puff stimulation, DMA rats not receiving air-puff stimulation showed significant pERK1/2 expression, suggesting they were experiencing spontaneous pain. CONCLUSION PKCγ cells in the medullary dorsal horn may be involved in DMA following CCI-IoN through the activation of pERK1/2-expressing cells, which then may relay non-nociceptive information to lamina I cells in the medullary dorsal horn.
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29
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Shelykh TN, Plakhova VB, Podzorova SA, Bagrov AY, Krylov BV. Modulating effect of the cardiotonic steroid marinobufagenin on slow sodium channels. Dokl Biol Sci 2014; 458:278-280. [PMID: 25371252 DOI: 10.1134/s0012496614050111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Indexed: 06/04/2023]
Affiliation(s)
- T N Shelykh
- Pavlov Institute of Physiology, Russian Academy of Sciences, St. Petersburg, Russia
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Spicarova D, Adamek P, Kalynovska N, Mrozkova P, Palecek J. TRPV1 receptor inhibition decreases CCL2-induced hyperalgesia. Neuropharmacology 2014; 81:75-84. [PMID: 24495396 DOI: 10.1016/j.neuropharm.2014.01.041] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Revised: 01/23/2014] [Accepted: 01/24/2014] [Indexed: 01/03/2023]
Abstract
Modulation of nociceptive synaptic transmission in the spinal cord is implicated in the development and maintenance of several pathological pain states. The chemokine CCL2 (C-C motif ligand 2) was shown to be an important factor in the development of neuropathic pain after peripheral nerve injury. In our experiments we have studied the effect of CCL2 application and TRPV1 (transient receptor potential vanilloid 1) receptor activation on nociceptive signaling and the modulation of synaptic transmission. Intrathecal drug application in behavioral experiments and patch-clamp recordings of spontaneous, miniature and dorsal root stimulation-evoked excitatory postsynaptic currents (sEPSCs, mEPSCs, eEPSCs) from superficial dorsal horn neurons in acute rat spinal cord slices were used. The intrathecal application of CCL2 induced thermal hyperalgesia and mechanical allodynia, while pretreatment with the TRPV1 receptor antagonist SB366791 diminished the thermal but not the mechanical hypersensitivity. Patch-clamp experiments showed an increase of sEPSC and mEPSC (124.5 ± 12.8% and 161.2 ± 17.3%, respectively) frequency in dorsal horn neurons after acute CCL2 application. This CCL2-induced increase was prevented by SB366791 pretreatment (89.4 ± 6.0%, 107.5 ± 14.2%). CCL2 application increased the amplitude of eEPSCs (188.1 ± 32.1%); this increase was significantly lower in experiments with SB366791 pretreatment (120.8 ± 17.2%). Our results demonstrate that the activation of spinal TRPV1 receptors plays an important role in the modulation of nociceptive signaling induced by CCL2 application. The mechanisms of cooperation between the CCL2 activated receptors and TRPV1 receptors on the central branches of primary afferent fibers may be especially important during different pathological pain states and need to be further investigated.
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Affiliation(s)
- Diana Spicarova
- Department of Functional Morphology, Institute of Physiology vvi, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic.
| | - Pavel Adamek
- Department of Functional Morphology, Institute of Physiology vvi, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic.
| | - Nataliia Kalynovska
- Department of Functional Morphology, Institute of Physiology vvi, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic.
| | - Petra Mrozkova
- Department of Functional Morphology, Institute of Physiology vvi, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic.
| | - Jiri Palecek
- Department of Functional Morphology, Institute of Physiology vvi, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic.
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31
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Qiao GF, Qian Z, Sun HL, Xu WX, Yan ZY, Liu Y, Zhou JY, Zhang HC, Wang LJ, Pan XD, Fu Y. Remodeling of hyperpolarization-activated current, Ih, in Ah-type visceral ganglion neurons following ovariectomy in adult rats. PLoS One 2013; 8:e71184. [PMID: 23951107 PMCID: PMC3741359 DOI: 10.1371/journal.pone.0071184] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 06/27/2013] [Indexed: 12/21/2022] Open
Abstract
Hyperpolarization-activated currents (Ih) mediated by hyperpolarization-activated cyclic nucleotide-gated (HCN) channels modulate excitability of myelinated A− and Ah-type visceral ganglion neurons (VGN). Whether alterations in Ih underlie the previously reported reduction of excitability of myelinated Ah-type VGNs following ovariectomy (OVX) has remained unclear. Here we used the intact nodose ganglion preparation in conjunction with electrophysiological approaches to examine the role of Ih remodeling in altering Ah-type neuron excitability following ovariectomy in adult rats. Ah-type neurons were identified based on their afferent conduction velocity. Ah-type neurons in nodose ganglia from non-OVX rats exhibited a voltage ‘sag’ as well as ‘rebound’ action potentials immediately following hyperpolarizing current injections, which both were suppressed by the Ih blocker ZD7288. Repetitive spike activity induced afterhyperpolarizations lasting several hundreds of milliseconds (termed post-excitatory membrane hyperpolarizations, PEMHs), which were significantly reduced by ZD7288, suggesting that they resulted from transient deactivation of Ih during the preceding spike trains. Ovariectomy reduced whole-cell Ih density, caused a hyperpolarizing shift of the voltage-dependence of Ih activation, and slowed Ih activation. OVX-induced Ih remodeling was accompanied by a flattening of the stimulus frequency/response curve and loss of PEMHs. Also, HCN1 mRNA levels were reduced by ∼30% in nodose ganglia from OVX rats compared with their non-OVX counterparts. Acute exposure of nodose ganglia to 17beta-estradiol partly restored Ih density and accelerated Ih activation in Ah-type cells. In conclusion, Ih plays a significant role in modulating the excitability of myelinated Ah-type VGNs in adult female rats.
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Affiliation(s)
- Guo-Fen Qiao
- State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin, Heilongjiang, China
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Zhao Qian
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Hong-Li Sun
- Department of Pharmacology, Da-Qing Campus of Harbin Medical University, Da-Qing, Heilongjiang, China
| | - Wen-Xiao Xu
- Department of Orthopedics, the First Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang, China
| | - Zhen-Yu Yan
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Yang Liu
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Jia-Ying Zhou
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Hao-Cheng Zhang
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Li-Juan Wang
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Xiao-Dong Pan
- Department of Pharmacology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Yili Fu
- State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin, Heilongjiang, China
- * E-mail:
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Logan SM, Romero MI, Nguyen DH, Benson MD. Ephrin-B2 expression in the proprioceptive sensory system. Neurosci Lett 2013; 545:69-74. [PMID: 23623938 PMCID: PMC3867235 DOI: 10.1016/j.neulet.2013.04.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 04/04/2013] [Accepted: 04/10/2013] [Indexed: 11/17/2022]
Abstract
Recent studies have shown that ephrin-B2 on sensory afferent fibers from the dorsal root ganglia (DRG) controls transmission of pain sensation to the spinal cord. We examined ephrin-B2 expression in mouse DRG and spinal cord using an ephrin-B2/ß-galactosidase chimeric allele. We found that ephrin-B2 is expressed exclusively in proprioceptive neurons and fibers in neonates, while expression in lamina III and IV of the adult spinal cord was observed in addition to that in the deeper laminae. We confirmed that ephrin-B2 protein causes co-clustering of EphB2 and glutamate receptors in spinal cord neurons. Our data are consistent with a role for ephrin-B2 in transmission of positional information to the CNS, and thus suggest a role in synaptic plasticity of spinal cord locomotor circuits that are known to be sensitive to proprioceptive sensory input after spinal cord injury.
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Affiliation(s)
- Shaun M. Logan
- Department of Biomedical Sciences, Texas A&M Health Science Center Baylor College of Dentistry, 3302 Gaston Ave., Dallas, TX, 75246
| | - Mario I. Romero
- Department of Bioengineering, The University of Texas Arlington, 500 UTA Blvd., Arlington, TX, 76019
| | - Dianna H. Nguyen
- Department of Bioengineering, The University of Texas Arlington, 500 UTA Blvd., Arlington, TX, 76019
| | - M. Douglas Benson
- Department of Biomedical Sciences, Texas A&M Health Science Center Baylor College of Dentistry, 3302 Gaston Ave., Dallas, TX, 75246
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33
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Okubo M, Castro A, Guo W, Zou S, Ren K, Wei F, Keller A, Dubner R. Transition to persistent orofacial pain after nerve injury involves supraspinal serotonin mechanisms. J Neurosci 2013; 33:5152-61. [PMID: 23516281 PMCID: PMC3640487 DOI: 10.1523/jneurosci.3390-12.2013] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The orofacial region is a major focus of chronic neuropathic pain conditions characterized by primary hyperalgesia at the site of injury and secondary hyperalgesia outside the injured zone. We have used a rat model of injury to the maxillary branch (V2) of the trigeminal nerve to produce constant and long-lasting primary hyperalgesia in the V2 territory and secondary hyperalgesia in territories innervated by the mandibular branch (V3). Our findings indicate that the induction of primary and secondary hyperalgesia depended on peripheral input from the injured nerve. In contrast, the maintenance of secondary hyperalgesia depended on central mechanisms. The centralization of the secondary hyperalgesia involved descending 5-HT drive from the rostral ventromedial medulla and the contribution of 5-HT3 receptors in the trigeminal nucleus caudalis (Vc), the homolog of the spinal dorsal horn. Electrophysiological studies further indicate that after nerve injury spontaneous responses and enhanced poststimulus discharges in Vc nociresponsive neurons were time-dependent on descending 5-HT drive and peripheral input. The induction phase of secondary hyperalgesia involved central sensitization mechanisms in Vc neurons that were dependent on peripheral input, whereas the maintenance phase of secondary hyperalgesia involved central sensitization in Vc neurons conducted by a delayed descending 5-HT drive and a persistence of peripheral inputs. Our results are the first to show that the maintenance of secondary hyperalgesia and underlying central sensitization associated with persistent pain depend on a transition to supraspinal mechanisms involving the serotonin system in rostral ventromedial medulla-dorsal horn circuits.
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Affiliation(s)
| | - Alberto Castro
- 2Department of Anatomy and Neurobiology, Medical School; Program in Neuroscience, University of Maryland, Baltimore, Maryland 21201
| | - Wei Guo
- 1Department of Neural and Pain Sciences, Dental School and
| | - Shiping Zou
- 1Department of Neural and Pain Sciences, Dental School and
| | - Ke Ren
- 1Department of Neural and Pain Sciences, Dental School and
| | - Feng Wei
- 1Department of Neural and Pain Sciences, Dental School and
| | - Asaf Keller
- 2Department of Anatomy and Neurobiology, Medical School; Program in Neuroscience, University of Maryland, Baltimore, Maryland 21201
| | - Ronald Dubner
- 1Department of Neural and Pain Sciences, Dental School and
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Vierck CJ, Whitsel BL, Favorov OV, Brown AW, Tommerdahl M. Role of primary somatosensory cortex in the coding of pain. Pain 2013; 154:334-344. [PMID: 23245864 PMCID: PMC4501501 DOI: 10.1016/j.pain.2012.10.021] [Citation(s) in RCA: 137] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 09/15/2012] [Accepted: 10/29/2012] [Indexed: 02/04/2023]
Abstract
The intensity and submodality of pain are widely attributed to stimulus encoding by peripheral and subcortical spinal/trigeminal portions of the somatosensory nervous system. Consistent with this interpretation are studies of surgically anesthetized animals, demonstrating that relationships between nociceptive stimulation and activation of neurons are similar at subcortical levels of somatosensory projection and within the primary somatosensory cortex (in cytoarchitectural areas 3b and 1 of somatosensory cortex, SI). Such findings have led to characterizations of SI as a network that preserves, rather than transforms, the excitatory drive it receives from subcortical levels. Inconsistent with this perspective are images and neurophysiological recordings of SI neurons in lightly anesthetized primates. These studies demonstrate that an extreme anterior position within SI (area 3a) receives input originating predominantly from unmyelinated nociceptors, distinguishing it from posterior SI (areas 3b and 1), long recognized as receiving input predominantly from myelinated afferents, including nociceptors. Of particular importance, interactions between these subregions during maintained nociceptive stimulation are accompanied by an altered SI response to myelinated and unmyelinated nociceptors. A revised view of pain coding within SI cortex is discussed, and potentially significant clinical implications are emphasized.
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Affiliation(s)
- Charles J Vierck
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL 32610-0244, USA Department of Physiology, University of North Carolina School of Medicine, Chapel Hill, NC, USA Department of Computer Sciences, University of North Carolina School of Medicine, Chapel Hill, NC, USA Senior School, Shadyside Academy, Pittsburgh, PA, USA
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Cogli L, Progida C, Thomas CL, Spencer-Dene B, Donno C, Schiavo G, Bucci C. Charcot-Marie-Tooth type 2B disease-causing RAB7A mutant proteins show altered interaction with the neuronal intermediate filament peripherin. Acta Neuropathol 2013; 125:257-72. [PMID: 23179371 PMCID: PMC3549248 DOI: 10.1007/s00401-012-1063-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2012] [Revised: 10/29/2012] [Accepted: 10/29/2012] [Indexed: 12/13/2022]
Abstract
Charcot-Marie-Tooth type 2B (CMT2B) is a peripheral ulcero-mutilating neuropathy caused by four missense mutations in the rab7a gene. CMT2B is clinically characterized by prominent sensory loss, distal muscle weakness leading to muscle atrophy, high frequency of foot ulcers and infections that often results in toe amputations. RAB7A is a ubiquitous small GTPase, which controls transport to late endocytic compartments. Although the biochemical and functional properties of disease-causing RAB7A mutant proteins have been investigated, it is not yet clear how the disease originates. To understand how mutations in a ubiquitous protein specifically affect peripheral neurons, we performed a two-hybrid screen using a dorsal root ganglia cDNA library with the purpose of identifying RAB7A interactors specific for these cells. We identified peripherin, an intermediate filament protein expressed primarily in peripheral neurons, as a putative RAB7A interacting protein. The interaction was confirmed by co-immunoprecipitation and pull-down experiments, and established that the interaction is direct using recombinant proteins. Silencing or overexpression of wild type RAB7A changed the soluble/insoluble rate of peripherin indicating that RAB7A is important for peripherin organization and function. In addition, disease-causing RAB7A mutant proteins bind more strongly to peripherin and their expression causes a significant increase in the amount of soluble peripherin. Since peripherin plays a role not only in neurite outgrowth during development but also in axonal regeneration after injury, these data suggest that the altered interaction between disease-causing RAB7A mutants and peripherin could play an important role in CMT2B neuropathy.
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Affiliation(s)
- Laura Cogli
- Department of Biological and Environmental Sciences and Technologies (DiSTeBA), University of Salento, Via Provinciale Monteroni 165, 73100 Lecce, Italy
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Shypshyna MS, Veselovs'kyĭ MS. [Pre- and postsynaptic expression mechanisms of long-term depression in rats glutamatergic primary afferent synapses on dorsal horn spinal cord neurons in co-culture]. Fiziol Zh (1994) 2013; 59:117-123. [PMID: 23713358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In co-culture of dorsal root ganglion (DRG) and dorsal horn (DH) neurons we studied the long-term depression (LTD) caused by 5 sec(-1) low-frequency stimulation (LFS) of DRG neurons. Dual whole-cell patch clamp recording in the pairs of DRG and DH neurons was used. The monosynaptic AMPA-receptor mediated eEPSC initiated in DH neurons by LFS of DRG neurons were analyzed. LFS with durations from 60 to 360 sec affected the LTD magnitude and involved the different LTD expression mechanisms. The amplitude and variability of miniature EPSC were not changed during LTD. LFS during 60 sec did not alter the eEPSC amplitudes, but significantly increased the coefficient of variation (CV; 56.8% +/- 11.5%, n = 5; P < 0.002) and the paired-pulse ratio (PPR; 37.8% +/- 11.4%, n = 5; P < 0.05), and decreased the release probability (p; 21.9% +/- 5.6%, n = 5; P < 0.05) calculated using binomial analysis. LFS for 120 sec led to LTD (eEPSC decreased to 14% +/- 3.3%, n = 13; P < 0.005); no changes in CV, PPR and p were found. LFS for 160, 200, 240 and 360 sec induced robust LTD: eEPSC decreased to 37.3 +/- 4.3 (n = 9); 48.1 +/- 3.5 (n = 7); 58.3 +/- 2.5 (n = 8) and 57.3% +/- 2.8% (n = 8), respectively; P < 0.001. LTD induced by such LFS durations was not accompanied by significant changing in PPR and p, but showed an increase in CV: 24.4 +/- 8.6 (n = 6); 35.1 +/- 11.2 (n = 6); 37.7 +/- 12.8 (n = 7), and 38.1% +/- 9.3% (n = 8), respectively. LTD magnitude was correlated with the enhancement in CV value at different LFS duration (r = 0.96). Our data suggest that the different mechanisms could be involved in LTD expression according to duration of LFS. Thus, 60 sec LFS induces presynaptic changes, but no change in eEPSC, whereas LTD elicited by 120 and 160 sec LFS affected the postsynaptic site. LTD initiated by longer LFS (200 - 360 sec) probably was caused by a silencing of functional synapses without changes in glutamate release probability.
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Zhou T, Wang J, Han CX. [Nonlinear dynamic analysis of electrical signals of wide dynamic range neurons in the spinal dorsal horn evoked by acupuncture manipulation at different frequencies]. Zhongguo Zhong Xi Yi Jie He Za Zhi 2012; 32:1403-1406. [PMID: 23163156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
OBJECTIVE To study the encoding information of electrical signals of wide dynamic range (WDR) neurons in the spinal dorsal horn evoked by acupuncture manipulation at different frequencies using nonlinear dynamics analysis. METHODS Microelectrode extracellular recordings were used to observe the WDR neuron discharge evoked by acupuncture manipulation at Zusanli point (ST36) with different frequencies (0.5, 1, 2, and 3 Hz) in SD rats. The nonlinear dynamics analysis method was used to extract the nonlinear characteristic parameters, such as interspike interval, the Lyapunov exponent, Lempel-Ziv complexity, and the neural coding of the electrical signal evoked by acupuncture manipulations at different frequencies. RESULTS Different characteristics were manifested with acupuncture manipulations at 4 different frequencies. More than a simple linear correlation was shown between the firing rate of the WDR neurons and the frequency of the acupuncture manipulation. The electrical signals evoked by acupuncture manipulation at Zusanli point (ST36) showed distinguished chaotic features. CONCLUSIONS It is applicable and feasible to describe and summarize the rhythm of the acupuncture electrical signal using the concepts and terminology of the nonlinear dynamics. Different acupuncture manipulation methods could interfere the transmission, coding, and processing of electrical signals in the spinal dorsal horn.
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Affiliation(s)
- Tao Zhou
- Department of Physiology, College of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin
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Cao DY, Ji Y, Tang B, Traub RJ. Estrogen receptor β activation is antinociceptive in a model of visceral pain in the rat. J Pain 2012; 13:685-94. [PMID: 22698981 DOI: 10.1016/j.jpain.2012.04.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 04/19/2012] [Accepted: 04/27/2012] [Indexed: 01/31/2023]
Abstract
UNLABELLED The mechanism underlying estrogen modulation of visceral pain remains unclear. Our previous studies indicate that activation of estrogen receptor α (ERα) enhances visceral pain. The purpose of the present study was to investigate the role of estrogen receptor β (ERβ) activation in spinal processing of visceral stimuli. The effects of selective ERβ agonists on the visceromotor response (VMR) and dorsal horn neuronal responses to colorectal distention (CRD) were tested in ovariectomized and intact female rats. The magnitude of the VMR to CRD was significantly attenuated by ERβ agonists diarylpropionitrile (DPN) and WAY-200070 4 hours after subcutaneous injection. Pretreatment with the estrogen receptor antagonist ICI 182,780 obscured the DPN-evoked attenuation. There was no effect of DPN on the VMR at earlier time points. Subcutaneous and spinal administration of DPN attenuated the response of visceroceptive dorsal horn neurons with a comparable time course. DPN attenuated the VMR in intact rats regardless of estrous cycle stage. The time course of effect of ERβ activation on the visceromotor response and neuronal activity is consistent with transcriptional or translational modulation of neuronal activity. PERSPECTIVE Activation of ERβ is antinociceptive in the colorectal distention model of visceral pain, which may provide a therapeutic target to manage irritable bowel syndrome in the clinic.
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Affiliation(s)
- Dong-Yuan Cao
- Department of Neural and Pain Sciences, School of Dentistry, University of Maryland, Baltimore, Maryland 21201, USA
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McCoy ES, Taylor-Blake B, Zylka MJ. CGRPα-expressing sensory neurons respond to stimuli that evoke sensations of pain and itch. PLoS One 2012; 7:e36355. [PMID: 22563493 PMCID: PMC3341357 DOI: 10.1371/journal.pone.0036355] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Accepted: 04/02/2012] [Indexed: 01/09/2023] Open
Abstract
Calcitonin gene-related peptide (CGRPα, encoded by Calca) is a classic marker of nociceptive dorsal root ganglia (DRG) neurons. Despite years of research, it is unclear what stimuli these neurons detect in vitro or in vivo. To facilitate functional studies of these neurons, we genetically targeted an axonal tracer (farnesylated enhanced green fluorescent protein; GFP) and a LoxP-stopped cell ablation construct (human diphtheria toxin receptor; DTR) to the Calca locus. In culture, 10–50% (depending on ligand) of all CGRPα-GFP-positive (+) neurons responded to capsaicin, mustard oil, menthol, acidic pH, ATP, and pruritogens (histamine and chloroquine), suggesting a role for peptidergic neurons in detecting noxious stimuli and itch. In contrast, few (2.2±1.3%) CGRPα-GFP+ neurons responded to the TRPM8-selective cooling agent icilin. In adult mice, CGRPα-GFP+ cell bodies were located in the DRG, spinal cord (motor neurons and dorsal horn neurons), brain and thyroid—reproducibly marking all cell types known to express Calca. Half of all CGRPα-GFP+ DRG neurons expressed TRPV1, ∼25% expressed neurofilament-200, <10% contained nonpeptidergic markers (IB4 and Prostatic acid phosphatase) and almost none (<1%) expressed TRPM8. CGRPα-GFP+ neurons innervated the dorsal spinal cord and innervated cutaneous and visceral tissues. This included nerve endings in the epidermis and on guard hairs. Our study provides direct evidence that CGRPα+ DRG neurons respond to agonists that evoke pain and itch and constitute a sensory circuit that is largely distinct from nonpeptidergic circuits and TRPM8+/cool temperature circuits. In future studies, it should be possible to conditionally ablate CGRPα-expressing neurons to evaluate sensory and non-sensory functions for these neurons.
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Affiliation(s)
- Eric S McCoy
- Department of Cell and Molecular Physiology, UNC Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
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40
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Aicher SA, Hermes SM, Whittier KL, Hegarty DM. Descending projections from the rostral ventromedial medulla (RVM) to trigeminal and spinal dorsal horns are morphologically and neurochemically distinct. J Chem Neuroanat 2012; 43:103-11. [PMID: 22119519 PMCID: PMC3319838 DOI: 10.1016/j.jchemneu.2011.11.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 11/08/2011] [Accepted: 11/09/2011] [Indexed: 01/16/2023]
Abstract
Neurons in the rostral ventromedial medulla (RVM) are thought to modulate nociceptive transmission via projections to spinal and trigeminal dorsal horns. The cellular substrate for this descending modulation has been studied with regard to projections to spinal dorsal horn, but studies of the projections to trigeminal dorsal horn have been less complete. In this study, we combined anterograde tracing from RVM with immunocytochemical detection of the GABAergic synthetic enzyme, GAD67, to determine if the RVM sends inhibitory projections to trigeminal dorsal horn. We also examined the neuronal targets of this projection using immunocytochemical detection of NeuN. Finally, we used electron microscopy to verify cellular targets. We compared projections to both trigeminal and spinal dorsal horns. We found that RVM projections to both trigeminal and spinal dorsal horn were directed to postsynaptic profiles in the dorsal horn, including somata and dendrites, and not to primary afferent terminals. We found that RVM projections to spinal dorsal horn were more likely to contact neuronal somata and were more likely to contain GAD67 than projections from RVM to trigeminal dorsal horn. These findings suggest that RVM neurons send predominantly GABAergic projections to spinal dorsal horn and provide direct input to postsynaptic neurons such as interneurons or ascending projection neurons. The RVM projection to trigeminal dorsal horn is more heavily targeted to dendrites and is only modestly GABAergic in nature. These anatomical features may underlie differences between trigeminal and spinal dorsal horns with regard to the degree of inhibition or facilitation evoked by RVM stimulation.
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Affiliation(s)
- Sue A Aicher
- Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, OR 97239-3098, United States.
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41
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Furutani K, Kohno T. [Local anesthetics inhibit NMDA-mediated glutamatergic transmission in spinal dorsal horn neurons]. Masui 2011; 60 Suppl:S151-S158. [PMID: 22458033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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Qi J, Zhang H, Guo J, Yang L, Wang W, Chen T, Li H, Wu SX, Li YQ. Synaptic connections of the neurokinin 1 receptor-like immunoreactive neurons in the rat medullary dorsal horn. PLoS One 2011; 6:e23275. [PMID: 21858052 PMCID: PMC3157358 DOI: 10.1371/journal.pone.0023275] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Accepted: 07/10/2011] [Indexed: 01/17/2023] Open
Abstract
The synaptic connections between neurokinin 1 (NK1) receptor-like immunoreactive (LI) neurons and γ-aminobutyric acid (GABA)-, glycine (Gly)-, serotonin (5-HT)- or dopamine-β-hydroxylase (DBH, a specific marker for norepinephrinergic neuronal structures)-LI axon terminals in the rat medullary dorsal horn (MDH) were examined under electron microscope by using a pre-embedding immunohistochemical double-staining technique. NK1 receptor-LI neurons were observed principally in laminae I and III, only a few of them were found in lamina II of the MDH. GABA-, Gly-, 5-HT-, or DBH-LI axon terminals were densely encountered in laminae I and II, and sparsely in lamina III of the MDH. Some of these GABA-, Gly-, 5-HT-, or DBH-LI axon terminals were observed to make principally symmetric synapses with NK1 receptor-LI neuronal cell bodies and dendritic processes in laminae I, II and III of the MDH. The present results suggest that neurons expressing NK1 receptor within the MDH might be modulated by GABAergic and glycinergic inhibitory intrinsic neurons located in the MDH and 5-HT- or norepinephrine (NE)-containing descending fibers originated from structures in the brainstem.
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Affiliation(s)
- Jian Qi
- Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Hua Zhang
- Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Jun Guo
- Department of Physiology, The Fourth Military Medical University, Xi'an, China
| | - Le Yang
- Undergraduate Student of the 2007 in Pharmacology, The Fourth Military Medical University, Xi'an, China
| | - Wen Wang
- Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Tao Chen
- Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Hui Li
- Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Sheng-Xi Wu
- Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
| | - Yun-Qing Li
- Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, China
- * E-mail:
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Robbins MT, Deberry J, Randich A, Ness TJ. Footshock stress differentially affects responses of two subpopulations of spinal dorsal horn neurons to urinary bladder distension in rats. Brain Res 2011; 1386:118-26. [PMID: 21376017 PMCID: PMC3086680 DOI: 10.1016/j.brainres.2011.02.081] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 02/23/2011] [Accepted: 02/24/2011] [Indexed: 11/23/2022]
Abstract
This investigation examined the effect of footshock on responses of 283 spinal dorsal horn neurons (DHNs) to urinary bladder distension (UBD). Female rats were treated with seven daily sessions of footshock (chronic footshock, CFS), six accommodation sessions followed by one exposure to footshock (acute footshock, AFS) or handled similarly without receiving any footshock (no footshock, NFS). After the final footshock or NFS session, rats were anesthetized, a laminectomy performed and extracellular single-unit recordings of L6-S1 DHNs obtained in intact or spinalized preparations. Neurons were classified as Type I-inhibited by heterotopic noxious conditioning stimuli (HNCS) or as Type II-not inhibited by HNCS-and characterized for spontaneous activity and for neuronal discharges evoked by graded UBD. A differential effect of footshock-induced stress was noted on neuronal subgroups. In intact preparations, Type I neurons were less responsive to UBD after either chronic or acute stress, while Type II neurons demonstrated significantly augmented responses to UBD. This enhanced neuronal responsiveness to UBD was present in spinalized preparations following exposure to CFS but not AFS. Type I neurons were still less responsive to stress in spinalized preparations following CFS and AFS. This study provides further evidence that (1) at least two populations of spinal neurons exist which encode for visceral stimuli and are likely to have distinct roles in visceral nociception, and that (2) the chronic stress-induced enhancement of DHN responses to UBD involves changes at the spinal level while the acute stress effects are dependent on a supraspinal substrate.
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Affiliation(s)
- Meredith T Robbins
- Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL, USA.
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Abstract
Though exogenous nerve growth factor (NGF) has been implicated in spinal cord plasticity, whether endogenous NGF plays a crucial role has not been established in vivo. This study investigated first the role of endogenous NGF in spinal dorsal horn (DH) plasticity following removal of L1-L5 and L7-S2 dorsal root ganglions (DRGs) in cats. Co-culture of chick embryo DRG with DH condition media, protein band fishing by cells as well as western blot showed that NGF could promote neurite growth in vitro. Immunohistochemistry and in situ hybridization technique revealed an increase in the NGF and NGF mRNA immunoreactive cells in the DH after partial deafferentation. Lastly, after blocking with NGF antibody, choleragen subunit B horseradish peroxidase (CB-HRP) tracing showed a reduction in the neuronal sprouting observed in the DH. Our results demonstrated that in the cat, endogenous NGF plays a crucial role in DH plasticity after partial deafferentation.
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Affiliation(s)
- Jia Liu
- Institute of Neurological Disease, West China Hospital, Sichuan University, Chengdu 610041, P.R. China
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45
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Kawamata M. [Mechanisms of postoperative pain]. Masui 2010; 59 Suppl:S166-S172. [PMID: 21702103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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46
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Biggs JE, Lu VB, Stebbing MJ, Balasubramanyan S, Smith PA. Is BDNF sufficient for information transfer between microglia and dorsal horn neurons during the onset of central sensitization? Mol Pain 2010; 6:44. [PMID: 20653959 PMCID: PMC2918544 DOI: 10.1186/1744-8069-6-44] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Accepted: 07/23/2010] [Indexed: 12/12/2022] Open
Abstract
Peripheral nerve injury activates spinal microglia. This leads to enduring changes in the properties of dorsal horn neurons that initiate central sensitization and the onset of neuropathic pain. Although a variety of neuropeptides, cytokines, chemokines and neurotransmitters have been implicated at various points in this process, it is possible that much of the information transfer between activated microglia and neurons, at least in this context, may be explicable in terms of the actions of brain derived neurotrophic factor (BDNF). Microglial-derived BDNF mediates central sensitization in lamina I by attenuating inhibitory synaptic transmission. This involves an alteration in the chloride equilibrium potential as a result of down regulation of the potassium-chloride exporter, KCC2. In lamina II, BDNF duplicates many aspects of the effects of chronic constriction injury (CCI) of the sciatic nerve on excitatory transmission. It mediates an increase in synaptic drive to putative excitatory neurons whilst reducing that to inhibitory neurons. CCI produces a specific pattern of changes in excitatory synaptic transmission to tonic, delay, phasic, transient and irregular neurons. A very similar 'injury footprint' is seen following long-term exposure to BDNF. This review presents new information on the action of BDNF and CCI on lamina II neurons, including the similarity of their actions on the kinetics and distributions of subpopulations of miniature excitatory postsynaptic currents (mEPSC). These findings raise the possibility that BDNF functions as a final common path for a convergence of perturbations that culminate in the generation of neuropathic pain.
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Affiliation(s)
- James E Biggs
- Department of Pharmacology and Centre for Neuroscience University of Alberta, Edmonton, Alberta, Canada
| | - Van B Lu
- Laboratory of MolecularPhysiology, NIH/NIAAA, Rockville, MD, USA
| | - Martin J Stebbing
- School of Medical Sciences, RMIT University, Bundoora, Victoria, Australia
| | | | - Peter A Smith
- Department of Pharmacology and Centre for Neuroscience University of Alberta, Edmonton, Alberta, Canada
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Leem JW, Kim HK, Hulsebosch CE, Gwak YS. Ionotropic glutamate receptors contribute to maintained neuronal hyperexcitability following spinal cord injury in rats. Exp Neurol 2010; 224:321-4. [PMID: 20211179 PMCID: PMC3008557 DOI: 10.1016/j.expneurol.2010.02.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 02/04/2010] [Accepted: 02/20/2010] [Indexed: 10/19/2022]
Abstract
In this study, we examined whether topical treatment of glutamate receptor antagonists attenuate hyperexcitability of lumbar spinal dorsal horn neurons following low thoracic hemisection spinal cord injury in rats. Four weeks after spinal hemisection, neuronal activity in response to mechanical stimuli applied on the peripheral receptive field was significantly increased in three different phenotypes of lumbar spinal dorsal horn neurons: wide dynamic range (WDR), low threshold (LT) and high threshold (HT). Topical application of MK-801 (NMDA receptor antagonist, 50 microg) significantly attenuated the activity of WDR, but not LT and HT neurons; whereas, NBQX (AMPA receptor antagonist, 0.5 and 1 microg) significantly attenuated neuronal activity in all three phenotypes of neurons (*p<0.05). However, MCPG (group I/II metabotropic glutamate receptor antagonist, 100 microg) had no effect. The present study, in the context of previous work, suggests that ionotropic glutamate receptor activation play critical roles in the maintenance of neuronal hyperexcitability and neuropathic "below-level" pain behavior following spinal hemisection injury.
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Affiliation(s)
- Joong Woo Leem
- Department of Physiology, Brain Research Institute, and BK21 Project for Medical Science, Yonsei University College of Medicine, C.P.O. Box 8044, Seoul, 120-752, Republic of Korea.
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Joseph DJ, Choudhury P, MacDermott AB. An in vitro assay system for studying synapse formation between nociceptive dorsal root ganglion and dorsal horn neurons. J Neurosci Methods 2010; 189:197-204. [PMID: 20385165 PMCID: PMC2880384 DOI: 10.1016/j.jneumeth.2010.04.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 03/25/2010] [Accepted: 04/05/2010] [Indexed: 01/23/2023]
Abstract
Synapses between nociceptive dorsal root ganglion (DRG) neurons and spinal cord dorsal horn neurons represent the first loci for transmission of painful stimuli. Our knowledge of the molecular organization and development of these synapses is sparse due, partly, to a lack of a reliable model system that reconstitutes synaptogenesis between these two neuronal populations. To address this issue, we have established an in vitro assay system consisting of separately purified DRG neurons and dorsal horn neurons on astrocyte microislands. Using immunocytochemistry, we have found that 97%, 93%, 98%, 96%, and 94% of DRG neurons on these microislands express markers often associated with nociceptive neurons including Substance P, TRPV1, calcitonin-gene related peptide (CGRP), TrKA, and peripherin, respectively. Triple labeling with these nociceptive-like markers, synaptic vesicle marker Vglut2 and using MAP2 as a dendritic marker revealed the presence of nociceptive-like markers at synaptic terminals. Using this immunocytochemical approach, we counted contact points as overlapping MAP2/Vglut2 puncta and showed that they increased with time in culture. Single and dual patch-clamp recordings showed that overlapping Vglut2/MAP2 puncta observed after a few days in culture are likely to be functional synapses between DRG and dorsal horn neurons in our in vitro assay system. Taken together, these data suggest our co-culture microisland model system consists of mostly nociceptive-like DRG neurons that express presynaptic markers and form functional synapses with their dorsal horn partners. Thus, this model system may have direct application for studies on factors regulating development of nociceptive DRG/dorsal horn synapses.
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Affiliation(s)
- Donald J. Joseph
- Program in Neurobiology and Behavior-Department of Neuroscience, College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Papiya Choudhury
- Department of Physiology and Biophysics, College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Amy B. MacDermott
- Program in Neurobiology and Behavior-Department of Neuroscience, College of Physicians and Surgeons, Columbia University, New York, NY 10032
- Department of Physiology and Biophysics, College of Physicians and Surgeons, Columbia University, New York, NY 10032
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Shreckengost J, Calvo J, Quevedo J, Hochman S. Bicuculline-sensitive primary afferent depolarization remains after greatly restricting synaptic transmission in the mammalian spinal cord. J Neurosci 2010; 30:5283-8. [PMID: 20392950 PMCID: PMC6632755 DOI: 10.1523/jneurosci.3873-09.2010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 01/15/2010] [Accepted: 03/02/2010] [Indexed: 01/03/2023] Open
Abstract
Primary afferent neurotransmission is the fundamental first step in the central processing of sensory stimuli. A major mechanism producing afferent presynaptic inhibition is via a channel-mediated depolarization of their intraspinal terminals which can be recorded extracellularly as a dorsal root potential (DRP). Based on measures of DRP latency it has been inferred that this primary afferent depolarization (PAD) of low-threshold afferents is mediated by minimally trisynaptic pathways with GABAergic interneurons forming last-order axoaxonic synapses onto afferent terminals. We used an in vitro rat spinal cord preparation under conditions that restrict synaptic transmission to test whether more direct low-threshold pathways can produce PAD. Mephenesin or high divalent cation solutions were used to limit oligosynaptic transmission. Recordings of synaptic currents in dorsal horn neurons and population synaptic potentials in ventral roots provided evidence that conventional transmission was chiefly restricted to monosynaptic actions. Under these conditions, DRP amplitude was largely unchanged but with faster time to peak and reduced duration. Similar results were obtained following stimulation of peripheral nerves. Even following near complete block of transmission with high Mg(2+)/low Ca(2+)-containing solution, the evoked DRP was reduced but not blocked. In comparison, in nominally Ca(2+)-free or EGTA-containing solution, the DRP was completely blocked confirming that Ca(2+) entry mediated synaptic transmission is required for DRP genesis. Overall these results demonstrate that PAD of low-threshold primary afferents can occur by more direct synaptic mechanisms, including the possibility of direct negative-feedback or nonspiking dendroaxonic pathways.
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Affiliation(s)
- Jacob Shreckengost
- Department of Physiology, Emory University School of Medicine, Atlanta Georgia 30322, and
| | - Jorge Calvo
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, C.P. 07300, México City, México
| | - Jorge Quevedo
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, C.P. 07300, México City, México
| | - Shawn Hochman
- Department of Physiology, Emory University School of Medicine, Atlanta Georgia 30322, and
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Vernon H, Sun K, Zhang Y, Yu XM, Sessle BJ. Central sensitization induced in trigeminal and upper cervical dorsal horn neurons by noxious stimulation of deep cervical paraspinal tissues in rats with minimal surgical trauma. J Manipulative Physiol Ther 2010; 32:506-14. [PMID: 19748401 DOI: 10.1016/j.jmpt.2009.08.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 06/22/2009] [Accepted: 06/29/2009] [Indexed: 11/19/2022]
Abstract
OBJECTIVE This study investigated if central sensitization is induced in the trigeminal subnucleus caudalis (also termed the medullary dorsal horn) and C1 and C2 dorsal horns by noxious stimulation of deep upper cervical paraspinal tissues in a preparation relatively free of surgical trauma. METHODS Adult male Sprague-Dawley rats (275-450 g) were anesthetized intraperitoneally. Animals were then placed in a stereotaxic frame; a small cutaneous incision was made 3 to 4 mm near the bregma in the midline, and an opening into the skull was prepared by a 1/32-inch drill, 1 mm to the left from the midline. An epoxylite-coated tungsten microelectrode was introduced at an 18 degrees angle to enter this small opening on the skull and was then carefully advanced about 16 mm through cortex, cerebellum, and brainstem to reach subsequently histologically confirmed sites in the Vc and upper cervical (C1 and C2) dorsal horn region. Thirty-three, 27, and 15 neurons recorded in medullary, C1, and C2 dorsal horns, respectively, of chloralose/urethane-anesthetized rats were activated by noxious stimulation of mechanoreceptive fields involving V1, V2, and/or V3 trigeminal nerve territories. The inflammatory irritant mustard oil was injected into the deep paraspinal tissues at the level of the left C1-C2 joint. Pre and postinjection receptive field (RF) sizes were mapped by nonnoxious mechanical stimuli and noxious mechanical and heat stimuli. RESULTS A 30- to 50-minute increase (mean, 165% +/- 38.1%) in RF size postinjection for 62% of neurons tested was demonstrated, suggesting central sensitization; for most (>70%) neurons, the RF expanded caudally into cervically innervated tissues. CONCLUSIONS These findings provide the first documentation that deep cervical nociceptive inputs can induce central sensitization in medullary and C1/C2 dorsal horns and suggest that these effects may reflect mechanisms contributing to deep cervical pain and its referral.
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Affiliation(s)
- Howard Vernon
- Canadian Memorial Chiropractic College, Toronto, Ontario, Canada.
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