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Kim H, Shim WS, Oh U. Anoctamin 1, a multi-modal player in pain and itch. Cell Calcium 2024; 123:102924. [PMID: 38964236 DOI: 10.1016/j.ceca.2024.102924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 06/05/2024] [Accepted: 06/13/2024] [Indexed: 07/06/2024]
Abstract
Anoctamin 1 (ANO1/TMEM16A) encodes a Ca2+-activated Cl- channel. Among ANO1's many physiological functions, it plays a significant role in mediating nociception and itch. ANO1 is activated by intracellular Ca2+ and depolarization. Additionally, ANO1 is activated by heat above 44 °C, suggesting heat as another activation stimulus. ANO1 is highly expressed in nociceptors, indicating a role in nociception. Conditional Ano1 ablation in dorsal root ganglion (DRG) neurons results in a reduction in acute thermal pain, as well as thermal and mechanical allodynia or hyperalgesia evoked by inflammation or nerve injury. Pharmacological interventions also lead to a reduction in nocifensive behaviors. ANO1 is functionally linked to the bradykinin receptor and TRPV1. Bradykinin stimulates ANO1 via IP3-mediated Ca2+ release from intracellular stores, whereas TRPV1 stimulates ANO1 via a combination of Ca2+ influx and release. Nerve injury causes upregulation of ANO1 expression in DRG neurons, which is blocked by ANO1 antagonists. Due to its role in nociception, strong and specific ANO1 antagonists have been developed. ANO1 is also expressed in pruritoceptors, mediating Mas-related G protein-coupled receptors (Mrgprs)-dependent itch. The activation of ANO1 leads to chloride efflux and depolarization due to high intracellular chloride concentrations, causing pain and itch. Thus, ANO1 could be a potential target for the development of new drugs treating pain and itch.
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Affiliation(s)
- Hyungsup Kim
- Department of Biotechnology, College of Engineering, The University of Suwon, Hwaseong, 18323, Republic of Korea
| | - Won-Sik Shim
- College of Pharmacy, Gachon University, Incheon 21936, Republic of Korea
| | - Uhtaek Oh
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Republic of Korea.
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2
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O'Brien MS, McDougall JJ. Comparison of nociceptor properties using electrophysiology in preclinical models of osteoarthritis. Neurosci Lett 2024; 840:137950. [PMID: 39182667 DOI: 10.1016/j.neulet.2024.137950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 08/20/2024] [Accepted: 08/22/2024] [Indexed: 08/27/2024]
Abstract
Osteoarthritis (OA) pain originates in the joint by sensitization of articular nociceptors. While behavioural assessments provide valuable information regarding pain symptoms, the techniques are subjective and open to interpretation by the experimenter. This study used in vivo electrophysiological approaches to measure objectively joint nociceptor properties in three rodent models of OA. Single unit extracellular recordings of joint mechanosensitive afferents were carried out in male and female rats following either (1) transection of the medial meniscus (MMT: post-traumatic OA), (2) intra-articular injection of sodium monoiodoacetate (MIA: chemically-induced OA), or (3) intra-articular injection of lysophosphatidic acid (LPA: neuropathic OA). In naïve male control rats, the mechanical threshold of joint mechanonociceptors (23.5 ± 1.8 mNm) was significantly reduced with MMT (9.4 ± 1.1 mNm) and MIA (15.1 ± 1.6 mNm). In females, the mechanical threshold of naïve rats (23.2 ± 3.1 mNm) was reduced following induction of MMT (8.3 ± 1.0 mNm) and LPA (10.6 ± 2.2 mNm). Afferent firing frequency increased in male MMT (∼275 %), LPA (∼175 %), MIA (225 %), and female MMT (∼146 %), LPA (∼200 %), and MIA (∼192 %). Mechanical threshold and evoked firing were negatively correlated in all models for both sexes except LPA rats (male + female) and female MMT. These data indicate that MMT, MIA, and LPA induce peripheral sensitization of joint afferents thereby validating their use in OA pain studies.
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Affiliation(s)
- Melissa S O'Brien
- Departments of Pharmacology and Anaesthesia, Pain Management & Perioperative Medicine, Dalhousie University, 5850 College Street, Halifax, Nova Scotia, B3H 4R2, Canada.
| | - Jason J McDougall
- Departments of Pharmacology and Anaesthesia, Pain Management & Perioperative Medicine, Dalhousie University, 5850 College Street, Halifax, Nova Scotia, B3H 4R2, Canada.
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Calvillo-Montoya DL, Martínez-Magaña CJ, Oviedo N, Murbartián J. The Estrogen Receptor Alpha Regulates the Sex-dependent Expression and Pronociceptive Role of Bestrophin-1 in Neuropathic Rats. THE JOURNAL OF PAIN 2024; 25:104513. [PMID: 38521145 DOI: 10.1016/j.jpain.2024.03.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/21/2024] [Accepted: 03/14/2024] [Indexed: 03/25/2024]
Abstract
Bestrophin-1, a calcium-activated chloride channel (CaCC), is involved in neuropathic pain; however, it is unclear whether it has a dimorphic role in female and male neuropathic rats. This study investigated if 17β-estradiol and estrogen receptor alpha (ERα) activation regulate bestrophin-1 activity and expression in neuropathic rats. Neuropathic pain was induced by L5-spinal nerve transection (SNT). Intrathecal administration of CaCCinh-A01 (.1-1 µg), a CaCC blocker, reversed tactile allodynia induced by SNT in female but not male rats. In contrast, T16Ainh-A01, a selective anoctamin-1 blocker, had an equal antiallodynic effect in both sexes. SNT increased bestrophin-1 protein expression in injured L5 dorsal root ganglia (DRG) in female rats but decreased bestrophin-1 protein in L5 DRG in male rats. Ovariectomy prevented the antiallodynic effect of CaCCinh-A01, but 17β-estradiol replacement restored it. The effect of CaCCinh-A01 was prevented by intrathecal administration of MPP, a selective ERα antagonist, in rats with and without prior hormonal manipulation. In female rats with neuropathy, ovariectomy prevented the increase in bestrophin-1 and ERα protein expression, while 17β-estradiol replacement allowed for an increase in both proteins in L5 DRG. Furthermore, ERα antagonism (with MPP) prevented the increase in bestrophin-1 and ERα protein expression. Finally, ERα activation with PPT, an ERα selective activator, induced the antiallodynic effect of CaCCinh-A01 in neuropathic male rats and prevented the reduction in bestrophin-1 protein expression in L5 DRG. In summary, data suggest ERα activation is necessary for bestrophin-1's pronociceptive action to maintain neuropathic pain in female rats. PERSPECTIVE: The mechanisms involved in neuropathic pain differ between male and female animals. Our data suggest that ERα is necessary for expression and function of bestrophin-1 in neuropathic female but not male rats. Data support the idea that a therapeutic approach to relieving neuropathic pain must be based on patient's gender.
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Affiliation(s)
| | | | - Norma Oviedo
- Unidad de Investigación Médica en Inmunología e Infectología, Centro Médico Nacional, La Raza, IMSS, Mexico City, Mexico
| | - Janet Murbartián
- Department of Pharmacobiologý, Cinvestav, South Campus, Mexico City, Mexico.
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Qiao LY. Satellite Glial Cells Bridge Sensory Neuron Crosstalk in Visceral Pain and Cross-Organ Sensitization. J Pharmacol Exp Ther 2024; 390:213-221. [PMID: 38777604 PMCID: PMC11264254 DOI: 10.1124/jpet.123.002061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 05/07/2024] [Accepted: 05/08/2024] [Indexed: 05/25/2024] Open
Abstract
Following colonic inflammation, the uninjured bladder afferent neurons are also activated. The mechanisms and pathways underlying this sensory neuron cross-activation (from injured neurons to uninjured neurons) are not fully understood. Colonic and bladder afferent neurons reside in the same spinal segments and are separated by satellite glial cells (SGCs) and extracellular matrix in dorsal root ganglia (DRG). SGCs communicate with sensory neurons in a bidirectional fashion. This review summarizes the differentially regulated genes/proteins in the injured and uninjured DRG neurons and explores the role of SGCs in regulation of sensory neuron crosstalk in visceral cross-organ sensitization. The review also highlights the paracrine pathways in mediating neuron-SGC and SGC-neuron coupling with an emphasis on the neurotrophins and purinergic systems. Finally, I discuss the results from recent RNAseq profiling of SGCs to reveal useful molecular markers for characterization, functional study, and therapeutic targets of SGCs. SIGNIFICANCE STATEMENT: Satellite glial cells (SGCs) are the largest glial subtypes in sensory ganglia and play a critical role in mediating sensory neuron crosstalk, an underlying mechanism in colon-bladder cross-sensitization. Identification of novel and unique molecular markers of SGCs can advance the discovery of therapeutic targets in treatment of chronic pain including visceral pain comorbidity.
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Affiliation(s)
- Liya Y Qiao
- Department of Physiology and Biophysics, Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, Virginia
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Choi D, Goodwin G, Stevens EB, Soliman N, Namer B, Denk F. Spontaneous activity in peripheral sensory nerves: a systematic review. Pain 2024; 165:983-996. [PMID: 37991272 PMCID: PMC11017746 DOI: 10.1097/j.pain.0000000000003115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 08/29/2023] [Accepted: 09/23/2023] [Indexed: 11/23/2023]
Abstract
ABSTRACT In the peripheral nervous system, spontaneous activity in sensory neurons is considered to be one of the 2 main drivers of chronic pain states, alongside neuronal sensitization. Despite this, the precise nature and timing of this spontaneous activity in neuropathic pain is not well-established. Here, we have performed a systematic search and data extraction of existing electrophysiological literature to shed light on which fibre types have been shown to maintain spontaneous activity and over what time frame. We examined both in vivo recordings of preclinical models of neuropathic pain, as well as microneurography recordings in humans. Our analyses reveal that there is broad agreement on the presence of spontaneous activity in neuropathic pain conditions, even months after injury or years after onset of neuropathic symptoms in humans. However, because of the highly specialised nature of the electrophysiological methods used to measure spontaneous activity, there is also a high degree of variability and uncertainty around these results. Specifically, there are very few directly controlled experiments, with less directly comparable data between human and animals. Given that spontaneous peripheral neuron activity is considered to be a key mechanistic feature of chronic pain conditions, it may be beneficial to conduct further experiments in this space.
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Affiliation(s)
- Dongchan Choi
- Wolfson Centre for Age-Related Diseases, Guy's Campus, King's College London, London, United Kingdom
| | - George Goodwin
- Wolfson Centre for Age-Related Diseases, Guy's Campus, King's College London, London, United Kingdom
| | - Edward B. Stevens
- Metrion Biosciences Ltd, Building 2 Granta Centre, Granta Park, Cambridge, United Kingdom
| | - Nadia Soliman
- Imperial College London, Pain Research Group, Chelsea and Westminster Hospital, London, United Kingdom
| | - Barbara Namer
- Research Group Neuroscience of the Interdisziplinary Center for Clinical Research, University Hospital of the RWTH Aachen, Aachen, Germany
- Institute for Physiology, University Hospital of the RWTH Aachen, Aachen, Germany
| | - Franziska Denk
- Wolfson Centre for Age-Related Diseases, Guy's Campus, King's College London, London, United Kingdom
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Sas D, Gaudel F, Verdier D, Kolta A. Hyperexcitability of muscle spindle afferents in jaw-closing muscles in experimental myalgia: Evidence for large primary afferents involvement in chronic pain. Exp Physiol 2024; 109:100-111. [PMID: 38103003 PMCID: PMC10988680 DOI: 10.1113/ep090769] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023]
Abstract
The goals of this review are to improve understanding of the aetiology of chronic muscle pain and identify new targets for treatments. Muscle pain is usually associated with trigger points in syndromes such as fibromyalgia and myofascial syndrome, and with small spots associated with spontaneous electrical activity that seems to emanate from fibers inside muscle spindles in EMG studies. These observations, added to the reports that large-diameter primary afferents, such as those innervating muscle spindles, become hyperexcitable and develop spontaneous ectopic firing in conditions leading to neuropathic pain, suggest that changes in excitability of these afferents might make an important contribution to the development of pathological pain. Here, we review evidence that the muscle spindle afferents (MSAs) of the jaw-closing muscles become hyperexcitable in a model of chronic orofacial myalgia. In these afferents, as in other large-diameter primary afferents in dorsal root ganglia, firing emerges from fast membrane potential oscillations that are supported by a persistent sodium current (INaP ) mediated by Na+ channels containing the α-subunit NaV 1.6. The current flowing through NaV 1.6 channels increases when the extracellular Ca2+ concentration decreases, and studies have shown that INaP -driven firing is increased by S100β, an astrocytic protein that chelates Ca2+ when released in the extracellular space. We review evidence of how astrocytes, which are known to be activated in pain conditions, might, through their regulation of extracellular Ca2+ , contribute to the generation of ectopic firing in MSAs. To explain how ectopic firing in MSAs might cause pain, we review evidence supporting the hypothesis that cross-talk between proprioceptive and nociceptive pathways might occur in the periphery, within the spindle capsule.
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Affiliation(s)
- Dar'ya Sas
- Département de NeurosciencesUniversité de MontréalMontréalQuébecCanada
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage (CIRCA)MontréalQuébecCanada
| | - Fanny Gaudel
- Département de NeurosciencesUniversité de MontréalMontréalQuébecCanada
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage (CIRCA)MontréalQuébecCanada
| | - Dorly Verdier
- Département de NeurosciencesUniversité de MontréalMontréalQuébecCanada
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage (CIRCA)MontréalQuébecCanada
| | - Arlette Kolta
- Département de NeurosciencesUniversité de MontréalMontréalQuébecCanada
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage (CIRCA)MontréalQuébecCanada
- Faculté de Médecine DentaireUniversité de MontréalMontréalQuébecCanada
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Cho YS, Mah W, Youn DH, Kim YS, Ko HG, Bae JY, Kim YS, Bae YC. Increase of glutamate in satellite glial cells of the trigeminal ganglion in a rat model of craniofacial neuropathic pain. Front Neuroanat 2023; 17:1302373. [PMID: 38164516 PMCID: PMC10758013 DOI: 10.3389/fnana.2023.1302373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 11/27/2023] [Indexed: 01/03/2024] Open
Abstract
Introduction Satellite glial cells (SGCs) that envelop the cell bodies of neurons in sensory ganglia have been shown to both release glutamate, and be activated by glutamate in the context of nociceptive signaling. However, little is known about the subpopulations of SGCs that are activated following nerve injury and whether glutamate mechanisms in the SGCs are involved in the pathologic pain. Methods To address this issue, we used light and electron microscopic immunohistochemistry to examine the change in the glutamate levels in the SGCs and the structural relationship between neighboring neurons in the trigeminal ganglion (TG) in a rat model of craniofacial neuropathic pain, CCI-ION. Results Administration of ionomycin, ATP and Bz-ATP induced an increase of extracellular glutamate concentration in cultured trigeminal SGCs, indicating a release of glutamate from SGCs. The level of glutamate immunostaining in the SGCs that envelop neurons of all sizes in the TG was significantly higher in rats with CCI-ION than in control rats, suggesting that SGCs enveloping nociceptive as well as non-nociceptive mechanosensitive neurons are activated following nerve injury, and that the glutamate release from SGCs increases in pathologic pain state. Close appositions between substance-P (SP)-immunopositive (+) or calcitonin gene-related peptide (CGRP)+, likely nociceptive neurons, between Piezo1+, likely non-nociceptive, mechanosensitive neurons and SP+ or CGRP+ neurons, and between SGCs of neighboring neurons were frequently observed. Discussion These findings suggest that glutamate in the trigeminal SGCs that envelop all types of neurons may play a role in the mechanisms of neuropathic pain, possibly via paracrine signaling.
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Affiliation(s)
- Yi Sul Cho
- Department of Anatomy, Physiology and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - Won Mah
- Department of Anatomy, Physiology and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - Dong Ho Youn
- Department of Anatomy, Physiology and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - Yu Shin Kim
- Department of Oral & Maxillofacial Surgery, School of Dentistry, Programs in Integrated Biomedical Sciences, Translational Sciences, Biomedical Engineering, Radiological Sciences, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Hyoung-Gon Ko
- Department of Anatomy, Physiology and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - Jin Young Bae
- Department of Anatomy, Physiology and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - Yun Sook Kim
- Department of Anatomy, Physiology and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
| | - Yong Chul Bae
- Department of Anatomy, Physiology and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, Republic of Korea
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Song X, Wang Y, Yang W, Wang Y, Yang C, Chen Z. Abnormal Spontaneous Discharges of Primary Sensory Neurons and Pain Behavior in a Rat Model of Vascular Dementia. Int J Mol Sci 2023; 24:10198. [PMID: 37373344 DOI: 10.3390/ijms241210198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/04/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023] Open
Abstract
Patients with vascular dementia experience more pain than healthy elders, potentially due to the presence of central neuropathic pain. However, the mechanisms underlying neuropathic pain in vascular dementia remain poorly understood, and there is currently a lack of effective treatment available. In this study, a rat model of vascular dementia was induced by permanently occluding the common carotid arteries bilaterally (2-VO). The cognitive impairments in the 2-VO rats were evaluated using the Morris Water Maze test, while HE and LBF staining were employed to assess brain tissue lesions in the hippocampal, cerebral cortex, and white matter regions known to be associated with severe memory and learning deficits. Furthermore, pain-related behavioral tests, including mechanical and thermal stimuli assessments, were conducted, and in vivo electrophysiological recordings of primary sensory neurons were performed. Compared to sham-operated and pre-operative rats, rats with vascular dementia exhibited mechanical allodynia and thermal hyperalgesia 30 days after surgery. Furthermore, in vivo electrophysiology revealed a significant increase in the occurrence of spontaneous activity of Aβ- and C-fiber sensory neurons in the rat model of vascular dementia. These results indicate that neuropathic pain behaviors developed in the rat model of vascular dementia, and abnormal spontaneous discharges of primary sensory neurons may play a crucial role in the development of pain after vascular dementia.
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Affiliation(s)
- Xiaodan Song
- Department of Pharmaceutical Analysis and Analytical Chemistry, College of Pharmacy, Harbin Medical University, Harbin 150081, China
| | - Yuchen Wang
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin 150081, China
| | - Wei Yang
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin 150081, China
| | - Yingji Wang
- Department of Inorganic Chemistry and Physics Chemistry, College of Pharmacy, Harbin Medical University, Harbin 150081, China
| | - Chunjuan Yang
- Department of Pharmaceutical Analysis and Analytical Chemistry, College of Pharmacy, Harbin Medical University, Harbin 150081, China
| | - Zhiyong Chen
- Department of Physiology, School of Basic Medical Sciences, Harbin Medical University, Harbin 150081, China
- Department of Anatomy, Histology and Embryology, Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing 100005, China
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Klein HJ, Lomiguen CM, Carter S. Dysesthesia and Depression in Undiagnosed Alzheimer's Disease. Cureus 2023; 15:e40264. [PMID: 37440797 PMCID: PMC10335846 DOI: 10.7759/cureus.40264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 06/09/2023] [Indexed: 07/15/2023] Open
Abstract
Dysesthesia is an abnormal sensation typically described as tingling, burning, or itching. Dysesthesia may occur in the presence or absence of causative dermatologic or medical pathology. Sensory abnormalities have been well documented in patients suffering from Alzheimer's disease (AD), though reported abnormalities typically affect the olfactory, visual, and auditory systems. Research describing dysesthetic symptoms in AD is scarce. Major depressive disorder (MDD) is another phenomenon commonly associated with AD, though depressive symptoms are frequently masked by cognitive deficits. Less attention has been given to the reverse of this relationship, in which MDD masks the symptoms of AD. Here, we present a case of undiagnosed AD in a geriatric patient presenting with primary complaints of depression and dysesthesia. We then discuss the pathophysiology of dysesthesia, MDD, and AD, as well as how these entities may interact in a single patient. Lastly, we emphasize the importance of thorough history-taking and multi-specialty collaboration in the care of older adults.
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Affiliation(s)
- Harrison J Klein
- Medical Education, Lake Erie College of Osteopathic Medicine, Erie, USA
| | - Christine M Lomiguen
- Pathology, Lake Erie College of Osteopathic Medicine, Erie, USA
- Family Medicine, LECOM (Lake Erie College of Osteopathic Medicine) Health Millcreek Community Hospital, Erie, USA
| | - Seth Carter
- Geriatrics, LECOM (Lake Erie College of Osteopathic Medicine) Health Institute for Successful Aging, Erie, USA
- Geriatrics, Lake Erie College of Osteopathic Medicine, Erie, USA
- Geriatrics, LECOM (Lake Erie College of Osteopathic Medicine) Health Millcreek Community Hospital, Erie, USA
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García G, Martínez-Magaña CJ, Oviedo N, Granados-Soto V, Murbartián J. Bestrophin-1 Participates in Neuropathic Pain Induced by Spinal Nerve Transection but not Spinal Nerve Ligation. THE JOURNAL OF PAIN 2022; 24:689-705. [PMID: 36521670 DOI: 10.1016/j.jpain.2022.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 11/21/2022] [Accepted: 12/07/2022] [Indexed: 12/15/2022]
Abstract
Previous studies have reported that L5/L6 spinal nerve ligation (SNL), but not L5 spinal nerve transection (SNT), enhances anoctamin-1 in injured and uninjured dorsal root ganglia (DRG) of rats suggesting some differences in function of the type of nerve injury. The role of bestrophin-1 in these conditions is unknown. The aim of this study was to investigate the role of bestrophin-1 in rats subjected to L5 SNT and L5/L6 SNL. SNT up-regulated bestrophin-1 protein expression in injured L5 and uninjured L4 DRG at day 7, whereas it enhanced GAP43 mainly in injured, but also in uninjured DRG. In contrast, SNL enhanced GAP43 at day 1 and 7, while bestrophin-1 expression increased only at day 1 after nerve injury. Accordingly, intrathecal injection of the bestrophin-1 blocker CaCCinh-A01 (1-10 µg) reverted SNT- or SNL-induced tactile allodynia in a concentration-dependent manner. Intrathecal injection of CaCCinh-A01 (10 µg) prevented SNT-induced upregulation of bestrophin-1 and GAP43 at day 7. In contrast, CaCCinh-A01 did not affect SNL-induced up-regulation of GAP43 nor bestrophin-1. Bestrophin-1 was mainly expressed in small- and medium-size neurons in naïve rats, while SNT increased bestrophin-1 immunoreactivity in CGRP+, but not in IB4+ neuronal cells in DRG. Intrathecal injection of bestrophin-1 plasmid (pCMVBest) induced tactile allodynia and increased bestrophin-1 expression in DRG and spinal cord in naïve rats. CaCCinh-A01 reversed bestrophin-1 overexpression-induced tactile allodynia and restored bestrophin-1 expression. Our data suggest that bestrophin-1 plays a relevant role in neuropathic pain induced by SNT, but not by SNL. PERSPECTIVE: SNT, but not SNL, up-regulates bestrophin-1 and GAP43 protein expression in injured L5 and uninjured L4 DRG. SNT increases bestrophin-1 immunoreactivity in CGRP+ neurons in DRG. Bestrophin-1 overexpression induces allodynia. CaCCinh-A01 reduces allodynia and restores bestrophin-1 expression. Our data suggest bestrophin-1 is differentially regulated depending on the neuropathic pain model.
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Affiliation(s)
| | | | - Norma Oviedo
- Unidad de Investigación Médica en Inmunología e Infectología, Centro Médico Nacional, La Raza, IMSS. Mexico City, Mexico
| | - Vinicio Granados-Soto
- Neurobiology of Pain Laboratory, Departamento de Farmacobiología, Cinvestav, Mexico City, Mexico
| | - Janet Murbartián
- Departamento de Farmacobiología, Cinvestav, Mexico City, Mexico.
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11
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Zhu YF, Kan P, Singh G. Differences and Similarities in Spontaneous Activity Between Animal Models of Cancer-Induced Pain and Neuropathic Pain. J Pain Res 2022; 15:3179-3187. [PMID: 36258759 PMCID: PMC9572504 DOI: 10.2147/jpr.s383373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 09/29/2022] [Indexed: 11/07/2022] Open
Abstract
Background Clinical data on cancer-induced pain (CIP) demonstrate widespread changes in sensory function. It is characterized in humans not only by stimulus-invoked pain, but also by spontaneous pain. In our previous studies in an animal model of CIP, we observed changes in intrinsic membrane properties and excitability of dorsal root ganglion (DRG) sensory neurons corresponding to mechanical allodynia and hyperalgesia, of which abnormal activities of Aβ-fiber sensory neurons are consistent in a rat model of peripheral neuropathic pain (NEP). Objective To investigate whether there are related peripheral neural mechanisms between the CIP and NEP models of spontaneous pain, we compared the electrophysiological properties of DRG sensory neurons at 2–3 weeks after CIP and NEP model induction. Methods CIP models were induced with metastasis tumour-1 rat breast cancer cells implanted into the distal epiphysis of the femur. NEP models were induced with a polyethylene cuff implanted around the sciatic nerve. Spontaneous pain in animals is measured by spontaneous foot lifting (SFL). After measurement of SFL, the animals were prepared for electrophysiological recordings of spontaneous activity (SA) in DRG neurons in vivo. Results Our data showed that SFL and SA occurred in both models. The proportion of SFL and SA of C-fiber sensory neurons in CIP was more significantly increased than in NEP models. There was no difference in duration of SFL and the rate of SA between the two models. The duration of SFL is related to the rate of SA in C-fiber in both models. Conclusion Thus, SFL may result from SA activity in C-fiber neurons in CIP and NEP rats. The differences and similarities in spontaneous pain between CIP and NEP rats is related to the proportion and rate of SA in C-fibers, respectively.
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Affiliation(s)
- Yong Fang Zhu
- Michael G. DeGroote Institute for Pain Research and Care, McMaster University, Hamilton, ON, Canada,Department of Pathology & Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - Peter Kan
- Health Sciences, McMaster University, Hamilton, ON, Canada
| | - Gurmit Singh
- Michael G. DeGroote Institute for Pain Research and Care, McMaster University, Hamilton, ON, Canada,Department of Pathology & Molecular Medicine, McMaster University, Hamilton, ON, Canada,Correspondence: Gurmit Singh, Email
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North RY, Odem MA, Li Y, Tatsui CE, Cassidy RM, Dougherty PM, Walters ET. Electrophysiological Alterations Driving Pain-Associated Spontaneous Activity in Human Sensory Neuron Somata Parallel Alterations Described in Spontaneously Active Rodent Nociceptors. THE JOURNAL OF PAIN 2022; 23:1343-1357. [PMID: 35292377 PMCID: PMC9357108 DOI: 10.1016/j.jpain.2022.02.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 02/21/2022] [Accepted: 02/24/2022] [Indexed: 06/10/2023]
Abstract
Neuropathic pain in rodents can be driven by ectopic spontaneous activity (SA) generated by sensory neurons in dorsal root ganglia (DRG). The recent demonstration that SA in dissociated human DRG neurons is associated with reported neuropathic pain in patients enables a detailed comparison of pain-linked electrophysiological alterations driving SA in human DRG neurons to alterations that distinguish SA in nociceptors from SA in low-threshold mechanoreceptors (LTMRs) in rodent neuropathy models. Analysis of recordings from dissociated somata of patient-derived DRG neurons showed that SA and corresponding pain in both sexes were significantly associated with the three functional electrophysiological alterations sufficient to generate SA in the absence of extrinsic depolarizing inputs. These include enhancement of depolarizing spontaneous fluctuations of membrane potential (DSFs), which were analyzed quantitatively for the first time in human DRG neurons. The functional alterations were indistinguishable from SA-driving alterations reported for nociceptors in rodent chronic pain models. Irregular, low-frequency DSFs in human DRG neurons closely resemble DSFs described in rodent nociceptors while differing substantially from the high-frequency sinusoidal oscillations described in rodent LTMRs. These findings suggest that conserved physiological mechanisms of SA in human nociceptor somata can drive neuropathic pain despite documented cellular differences between human and rodent DRG neurons. PERSPECTIVE: Electrophysiological alterations in human sensory neurons associated with patient-reported neuropathic pain include all three of the functional alterations that logically can promote spontaneous activity. The similarity of distinctively altered spontaneous depolarizations in human DRG neurons and rodent nociceptors suggests that spontaneously active human nociceptors can persistently promote neuropathic pain in patients.
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Affiliation(s)
- Robert Y North
- Department of Neurosurgery, The University of Texas M.D. Anderson Cancer Center, Houston, Texas
| | - Max A Odem
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, Houston, Texas
| | - Yan Li
- Department of Anesthesia and Pain Medicine, The University of Texas M.D. Anderson Cancer Center, Houston, Texas
| | - Claudio Esteves Tatsui
- Department of Neurosurgery, The University of Texas M.D. Anderson Cancer Center, Houston, Texas
| | - Ryan M Cassidy
- M.D. Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, Texas
| | - Patrick M Dougherty
- Department of Anesthesia and Pain Medicine, The University of Texas M.D. Anderson Cancer Center, Houston, Texas
| | - Edgar T Walters
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, Texas..
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Gangadharan V, Zheng H, Taberner FJ, Landry J, Nees TA, Pistolic J, Agarwal N, Männich D, Benes V, Helmstaedter M, Ommer B, Lechner SG, Kuner T, Kuner R. Neuropathic pain caused by miswiring and abnormal end organ targeting. Nature 2022; 606:137-145. [PMID: 35614217 PMCID: PMC9159955 DOI: 10.1038/s41586-022-04777-z] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 04/20/2022] [Indexed: 12/12/2022]
Abstract
Nerve injury leads to chronic pain and exaggerated sensitivity to gentle touch (allodynia) as well as a loss of sensation in the areas in which injured and non-injured nerves come together1-3. The mechanisms that disambiguate these mixed and paradoxical symptoms are unknown. Here we longitudinally and non-invasively imaged genetically labelled populations of fibres that sense noxious stimuli (nociceptors) and gentle touch (low-threshold afferents) peripherally in the skin for longer than 10 months after nerve injury, while simultaneously tracking pain-related behaviour in the same mice. Fully denervated areas of skin initially lost sensation, gradually recovered normal sensitivity and developed marked allodynia and aversion to gentle touch several months after injury. This reinnervation-induced neuropathic pain involved nociceptors that sprouted into denervated territories precisely reproducing the initial pattern of innervation, were guided by blood vessels and showed irregular terminal connectivity in the skin and lowered activation thresholds mimicking low-threshold afferents. By contrast, low-threshold afferents-which normally mediate touch sensation as well as allodynia in intact nerve territories after injury4-7-did not reinnervate, leading to an aberrant innervation of tactile end organs such as Meissner corpuscles with nociceptors alone. Genetic ablation of nociceptors fully abrogated reinnervation allodynia. Our results thus reveal the emergence of a form of chronic neuropathic pain that is driven by structural plasticity, abnormal terminal connectivity and malfunction of nociceptors during reinnervation, and provide a mechanistic framework for the paradoxical sensory manifestations that are observed clinically and can impose a heavy burden on patients.
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Affiliation(s)
- Vijayan Gangadharan
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany
| | - Hongwei Zheng
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Francisco J Taberner
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Jonathan Landry
- Genomics Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Timo A Nees
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Jelena Pistolic
- Genomics Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Nitin Agarwal
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Deepitha Männich
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Vladimir Benes
- Genomics Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | | | - Björn Ommer
- Interdisciplinary Center for Scientific Computing, Heidelberg University, Heidelberg, Germany
| | - Stefan G Lechner
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Thomas Kuner
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Rohini Kuner
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany.
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14
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Roza C, Bernal L. Electrophysiological characterization of ectopic spontaneous discharge in axotomized and intact fibers upon nerve transection: a role in spontaneous pain? Pflugers Arch 2022; 474:387-396. [PMID: 35088129 DOI: 10.1007/s00424-021-02655-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 12/13/2021] [Accepted: 12/14/2021] [Indexed: 12/14/2022]
Abstract
Many patients experience positive symptoms after traumatic nerve injury. Despite the increasing number of experimental studies in models of peripheral neuropathy and the knowledge acquired, most of these patients lack an effective treatment for their chronic pain. One possible explanation might be that most of the preclinical studies focused on the development of mechanical or thermal allodynia/hyperalgesia, neglecting that most of the patients with peripheral neuropathies complain mostly about spontaneous forms of pains. Here, we summarize the aberrant electrophysiological behavior of peripheral nerve fibers recorded in experimental models, the underlying pathophysiological mechanisms, and their relationship with the symptoms reported by patients. Upon nerve section, axotomized but also intact fibers develop ectopic spontaneous activity. Most interestingly, a proportion of axotomized fibers might present receptive fields in the skin far beyond the site of damage, indicative of a functional cross talk between neuromatose and intact fibers. All these features can be linked with some of the symptoms that neuropathic patients experience. Furthermore, we spotlight the consequence of primary afferents with different patterns of spontaneous discharge on the neural code and its relationship with chronic pain states. With this article, readers will be able to understand the pathophysiological mechanisms that might underlie some of the symptoms that experience neuropathic patients, with a special focus on spontaneous pain.
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Affiliation(s)
- Carolina Roza
- Dpto. Biología de Sistemas, Edificio de Medicina Universidad de Alcalá, 28871, Alcalá de Henares, Madrid, Spain.
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15
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Osumi M, Sumitani M, Nobusako S, Sato G, Morioka S. Pain quality of thermal grill illusion is similar to that of central neuropathic pain rather than peripheral neuropathic pain. Scand J Pain 2022; 22:40-47. [PMID: 34019750 DOI: 10.1515/sjpain-2021-0020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 04/07/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Application of spatially interlaced innocuous warm and cool stimuli to the skin elicits illusory pain, known as the thermal grill illusion (TGI). This study aimed to discriminate the underlying mechanisms of central and peripheral neuropathic pain focusing on pain quality, which is considered to indicate the underlying mechanism(s) of pain. We compared pain qualities in central and peripheral neuropathic pain with reference to pain qualities of TGI-induced pain. METHODS Experiment 1:137 healthy participants placed their hand on eight custom-built copper bars for 60 s and their pain quality was assessed by the McGill Pain Questionnaire. Experiment 2: Pain quality was evaluated in patients suffering from central and peripheral neuropathic pain (42 patients with spinal cord injury, 31 patients with stroke, 83 patients with trigeminal neuralgia and 131 patients with postherpetic neuralgia). RESULTS Experiment 1: Two components of TGI-induced pain were found using principal component analysis: component 1 included aching, throbbing, heavy and burning pain, component 2 included itching, electrical-shock, numbness, and cold-freezing. Experiment 2: Multiple correspondence analysis (MCA) and cross tabulation analysis revealed specific pain qualities including aching, hot-burning, heavy, cold-freezing, numbness, and electrical-shock pain were associated with central neuropathic pain rather than peripheral neuropathic pain. CONCLUSIONS We found similar qualities between TGI-induced pain in healthy participants and central neuropathic pain rather than peripheral neuropathic pain. The mechanism of TGI is more similar to the mechanism of central neuropathic pain than that of neuropathic pain.
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Affiliation(s)
- Michihiro Osumi
- Graduate School of Health Science, Kio University, Nara, Japan
- Neurorehabilitation Research Center, Kio University, Nara, Japan
| | - Masahiko Sumitani
- Department of Pain and Palliative Medicine, The University of Tokyo Hospital, Tokyo, Japan
| | - Satoshi Nobusako
- Graduate School of Health Science, Kio University, Nara, Japan
- Neurorehabilitation Research Center, Kio University, Nara, Japan
| | - Gosuke Sato
- Neurorehabilitation Research Center, Kio University, Nara, Japan
| | - Shu Morioka
- Graduate School of Health Science, Kio University, Nara, Japan
- Neurorehabilitation Research Center, Kio University, Nara, Japan
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16
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Zhang C, Hu MW, Wang XW, Cui X, Liu J, Huang Q, Cao X, Zhou FQ, Qian J, He SQ, Guan Y. scRNA-sequencing reveals subtype-specific transcriptomic perturbations in DRG neurons of PirtEGFPf mice in neuropathic pain condition. eLife 2022; 11:76063. [PMID: 36264609 PMCID: PMC9584610 DOI: 10.7554/elife.76063] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 10/03/2022] [Indexed: 01/22/2023] Open
Abstract
Functionally distinct subtypes/clusters of dorsal root ganglion (DRG) neurons may play different roles in nerve regeneration and pain. However, details about their transcriptomic changes under neuropathic pain conditions remain unclear. Chronic constriction injury (CCI) of the sciatic nerve represents a well-established model of neuropathic pain, and we conducted single-cell RNA-sequencing (scRNA-seq) to characterize subtype-specific perturbations of transcriptomes in lumbar DRG neurons on day 7 post-CCI. By using PirtEGFPf mice that selectively express an enhanced green fluorescent protein in DRG neurons, we established a highly efficient purification process to enrich neurons for scRNA-seq. We observed the emergence of four prominent CCI-induced clusters and a loss of marker genes in injured neurons. Importantly, a portion of injured neurons from several clusters were spared from injury-induced identity loss, suggesting subtype-specific transcriptomic changes in injured neurons. Moreover, uninjured neurons, which are necessary for mediating the evoked pain, also demonstrated cell-type-specific transcriptomic perturbations in these clusters, but not in others. Notably, male and female mice showed differential transcriptomic changes in multiple neuronal clusters after CCI, suggesting transcriptomic sexual dimorphism in DRG neurons after nerve injury. Using Fgf3 as a proof-of-principle, RNAscope study provided further evidence of increased Fgf3 in injured neurons after CCI, supporting scRNA-seq analysis, and calcium imaging study unraveled a functional role of Fgf3 in neuronal excitability. These findings may contribute to the identification of new target genes and the development of DRG neuron cell-type-specific therapies for optimizing neuropathic pain treatment and nerve regeneration.
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Affiliation(s)
- Chi Zhang
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Ming-Wen Hu
- Department of Ophthalmology, The Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Xue-Wei Wang
- Department of Orthopaedic Surgery, The Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Xiang Cui
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Jing Liu
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Qian Huang
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Xu Cao
- Department of Orthopaedic Surgery, The Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Feng-Quan Zhou
- Department of Orthopaedic Surgery, The Johns Hopkins University School of MedicineBaltimoreUnited States,The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Jiang Qian
- Department of Ophthalmology, The Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Shao-Qiu He
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of MedicineBaltimoreUnited States,Department of Neurological Surgery, The Johns Hopkins University School of MedicineBaltimoreUnited States
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17
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Ehsanian R, Koshkin E, Goins AE, Montera MA, Alles S. Pre- and Post-Interventional Changes in Physiological Profiles in a Patient Presenting With Opioid Withdrawal After Intrathecal Drug Delivery System Failure Related to Assumed Catheter Microfracture. Cureus 2021; 13:e14835. [PMID: 34104585 PMCID: PMC8173817 DOI: 10.7759/cureus.14835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The intrathecal drug delivery system (IDDS) is successfully utilized for the treatment of chronic pain conditions; however, they are associated with complications related to human error and system failure. A case report is presented of a patient with opioid withdrawal (OW) secondary to assumed catheter microfracture. Interrogation of the IDDS allowed for the collection of pre- and post-treatment/stabilization cerebrospinal fluid (CSF), which is used to investigate the possible physiological determinants of OW. A 46-year-old female with a history of low back pain after traumatic low back injury status post-IDDS placement for failed back surgery syndrome presented with signs and symptoms concerning for OW. After every other possible explanation was ruled out, it was hypothesized that there may be IDDS catheter microfracture(s), and catheter replacement led to symptom resolution. There were no significant differences in cytokine levels tested in pre-CSF versus post-CSF samples. Whole-cell patch-clamp electrophysiology analysis of human-induced pluripotent stem cell-derived nociceptors after treatment with pre- and post-CSF samples demonstrated modulation of action potential waveform. In patients presenting with acute OW attribution IDDS malfunction, catheter microfracture must be in the differential, and non-conventional interrogation of the IDDS catheter should be considered. The possible differences in pre-CSF and post-CSF may be more complicated than previously postulated, as there were no significant differences in cytokine profiles; however, treatment of in vitro neurons with pre- and post-CSF resulted in differential neuronal excitability, which may account for some of the symptoms of OW.
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Affiliation(s)
- Reza Ehsanian
- Orthopaedics and Rehabilitation, University of New Mexico School of Medicine, Albuquerque, USA
| | - Eugene Koshkin
- Anesthesiology and Critical Care Medicine, University of New Mexico School of Medicine, Albuquerque, USA
| | - Aleyah E Goins
- Anesthesiology and Critical Care Medicine, University of New Mexico School of Medicine, Albuquerque, USA
| | - Marena A Montera
- Anesthesiology and Critical Care Medicine, University of New Mexico School of Medicine, Albuquerque, USA
| | - Sascha Alles
- Anesthesiology and Critical Care Medicine, University of New Mexico School of Medicine, Albuquerque, USA
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18
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Raja SN, Ringkamp M, Guan Y, Campbell JN. John J. Bonica Award Lecture: Peripheral neuronal hyperexcitability: the "low-hanging" target for safe therapeutic strategies in neuropathic pain. Pain 2021; 161 Suppl 1:S14-S26. [PMID: 33090736 DOI: 10.1097/j.pain.0000000000001838] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
| | - Matthias Ringkamp
- Neurological Surgery, Department of Neurosurgery, Johns Hopkins University, School of Medicine, Baltimore, MD, United States
| | - Yun Guan
- Departments of Anesthesiology and Critical Care Medicine and.,Neurological Surgery, Department of Neurosurgery, Johns Hopkins University, School of Medicine, Baltimore, MD, United States
| | - James N Campbell
- Neurological Surgery, Department of Neurosurgery, Johns Hopkins University, School of Medicine, Baltimore, MD, United States
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19
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Peripheral nerve injury and sensitization underlie pain associated with oral cancer perineural invasion. Pain 2021; 161:2592-2602. [PMID: 32658150 DOI: 10.1097/j.pain.0000000000001986] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cancer invading into nerves, termed perineural invasion (PNI), is associated with pain. Here, we show that oral cancer patients with PNI report greater spontaneous pain and mechanical allodynia compared with patients without PNI, suggesting that unique mechanisms drive PNI-induced pain. We studied the impact of PNI on peripheral nerve physiology and anatomy using a murine sciatic nerve PNI model. Mice with PNI exhibited spontaneous nociception and mechanical allodynia. Perineural invasion induced afterdischarge in A high-threshold mechanoreceptors (HTMRs), mechanical sensitization (ie, decreased mechanical thresholds) in both A and C HTMRs, and mechanical desensitization in low-threshold mechanoreceptors. Perineural invasion resulted in nerve damage, including axon loss, myelin damage, and axon degeneration. Electrophysiological evidence of nerve injury included decreased conduction velocity, and increased percentage of both mechanically insensitive and electrically unexcitable neurons. We conclude that PNI-induced pain is driven by nerve injury and peripheral sensitization in HTMRs.
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20
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Tran EL, Crawford LK. Revisiting PNS Plasticity: How Uninjured Sensory Afferents Promote Neuropathic Pain. Front Cell Neurosci 2020; 14:612982. [PMID: 33362476 PMCID: PMC7759741 DOI: 10.3389/fncel.2020.612982] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 11/12/2020] [Indexed: 11/13/2022] Open
Abstract
Despite the widespread study of how injured nerves contribute to chronic pain, there are still major gaps in our understanding of pain mechanisms. This is particularly true of pain resulting from nerve injury, or neuropathic pain, wherein tactile or thermal stimuli cause painful responses that are particularly difficult to treat with existing therapies. Curiously, this stimulus-driven pain relies upon intact, uninjured sensory neurons that transmit the signals that are ultimately sensed as painful. Studies that interrogate uninjured neurons in search of cell-specific mechanisms have shown that nerve injury alters intact, uninjured neurons resulting in an activity that drives stimulus-evoked pain. This review of neuropathic pain mechanisms summarizes cell-type-specific pathology of uninjured sensory neurons and the sensory ganglia that house their cell bodies. Uninjured neurons have demonstrated a wide range of molecular and neurophysiologic changes, many of which are distinct from those detected in injured neurons. These intriguing findings include expression of pain-associated molecules, neurophysiological changes that underlie increased excitability, and evidence that intercellular signaling within sensory ganglia alters uninjured neurons. In addition to well-supported findings, this review also discusses potential mechanisms that remain poorly understood in the context of nerve injury. This review highlights key questions that will advance our understanding of the plasticity of sensory neuron subpopulations and clarify the role of uninjured neurons in developing anti-pain therapies.
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Affiliation(s)
- Emily L Tran
- Department of Pathobiological Sciences, University of Wisconsin-Madison School of Veterinary Medicine, Madison, WI, United States
| | - LaTasha K Crawford
- Department of Pathobiological Sciences, University of Wisconsin-Madison School of Veterinary Medicine, Madison, WI, United States
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21
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Richard SA, Kampo S, Sackey M, Hechavarria ME, Buunaaim ADB. The Pivotal Potentials of Scorpion Buthus Martensii Karsch-Analgesic-Antitumor Peptide in Pain Management and Cancer. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2020; 2020:4234273. [PMID: 33178316 PMCID: PMC7647755 DOI: 10.1155/2020/4234273] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 09/13/2020] [Accepted: 10/20/2020] [Indexed: 01/26/2023]
Abstract
Scorpion Buthus martensii Karsch -analgesic-antitumor peptide (BmK AGAP) has been used to treat diseases like tetanus, tuberculosis, apoplexy, epilepsy, spasm, migraine headaches, rheumatic pain, and cancer in China. AGAP is a distinctive long-chain scorpion toxin with a molecular mass of 7142 Da and composed of 66 amino acids cross-linked by four disulfide bridges. Voltage-gated sodium channels (VGSCs) are present in excitable membranes and partakes in essential roles in action potentials generation as compared to the significant function of voltage-gated calcium channels (VGCCs). A total of nine genes (Nav1.1-Nav1.9) have been recognized to encode practical sodium channel isoforms. Nav1.3, Nav1.7, Nav1.8, and Nav1.9 have been recognized as potential targets for analgesics. Nav1.8 and Nav1.9 are associated with nociception initiated by inflammation signals in the neuronal pain pathway, while Nav1.8 is fundamental for neuropathic pain at low temperatures. AGAP has a sturdy inhibitory influence on both viscera and soma pain. AGAP potentiates the effects of MAPK inhibitors on neuropathic as well as inflammation-associated pain. AGAP downregulates the secretion of phosphorylated p38, phosphorylated JNK, and phosphorylated ERK 1/2 in vitro. AGAP has an analgesic activity which may be an effective therapeutic agent for pain management because of its downregulation of PTX3 via NF-κB and Wnt/beta-catenin signaling pathway. In cancers like colon cancer, breast cancer, lymphoma, and glioma, rAGAP was capable of blocking the proliferation. Thus, AGAP is a promising therapy for these tumors. Nevertheless, research is needed with other tumors.
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Affiliation(s)
- Seidu A. Richard
- Department of Medicine, Princefield University, P.O. Box MA128, Ho, Ghana
| | - Sylvanus Kampo
- Department of Anesthesia and Critical Care, School of Medicine, University of Health and Allied Sciences, Ho, Ghana
| | - Marian Sackey
- Department of Pharmacy, Ho Teaching Hospital, P.O. Box MA-374, Ho, Ghana
| | | | - Alexis D. B. Buunaaim
- Department of Surgery, School of Medicine and Health Science, University for Development Studies, Tamale, Ghana
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22
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Djouhri L, Zeidan A, Alzoghaibi M, Al Otaibi MF, Abd El-Aleem SA. L5 Spinal Nerve Axotomy Induces Distinct Electrophysiological Changes in Axotomized L5- and Adjacent L4-Dorsal Root Ganglion Neurons in Rats In Vivo. J Neurotrauma 2020; 38:330-341. [PMID: 32993425 DOI: 10.1089/neu.2020.7264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Peripheral neuropathic pain (PNP) is a major health problem for which effective drug treatment is lacking. Its underlying neuronal mechanisms are still illusive, but pre-clinical studies using animal models of PNP including the L5-spinal nerve axotomy (L5-SNA) model, suggest that it is partly caused by excitability changes in dorsal root ganglion (DRG) neurons. L5-SNA results in two DRG neuronal groups: (1) axotomized/damaged neurons in L5- plus some in L4-DRGs, and (2) ipsilateral L4-neurons with intact/uninjured fibers intermingling with degenerating L5-fibers. The axotomized neurons are deprived of peripherally derived trophic factors and degenerate causing neuroinflammation, whereas the uninjured L4-neuorns are subject to increased trophic factors and neuroinflammation associated with Wallerian degeneration of axotomized L5-nerve fibers. Whether these two groups of DRG neurons exhibit similar or distinct electrophysiological changes after L5-SNA remains unresolved. Conflicting evidence for this may result from some studies assuming that all L4-fibers are undamaged. Here, we recorded somatic action potentials (APs) intracellularly from C- and A-fiber L4/L5 DRG neurons in vivo, to examine our hypothesis that L5-SNA would induce distinct electrophysiological changes in the two populations of DRG neurons. Consistent with this hypothesis, we found (7 days post-SNA), in SNA rats with established pain hypersensitivity, slower AP kinetics in axotomized L5-neurons and faster AP kinetics in L4-nociceptive neurons including decreased rise time in Aδ-and Aβ-fiber nociceptors, and after-hyperpolarization duration in Aβ-fiber nociceptors. We also found several changes in axotomized L5-neurons but not in L4-nociceptive neurons, and some changes in L4-nociceptive but not L5-neurons. The faster AP kinetics (decreased refractory period) in L4-nociceptive neurons that are consistent with their reported hyperexcitability may lead to repetitive firing and thus provide enhanced afferent input necessary for initiating and/or maintaining PNP development. The changes in axotomized L5-neurons may contribute to the central mechanisms of PNP via enhanced neurotransmitter release in the central nervous system (CNS).
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Affiliation(s)
- Laiche Djouhri
- Department of Basic Medical Sciences, College of Medicine (QU Health), Qatar University, Doha, Qatar
| | - Asad Zeidan
- Department of Basic Medical Sciences, College of Medicine (QU Health), Qatar University, Doha, Qatar
| | - Mohammad Alzoghaibi
- Department of Physiology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Mohammad F Al Otaibi
- Department of Physiology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Seham A Abd El-Aleem
- Department of Histology and Cell Biology, University of Manchester, Manchester, United Kingdom.,Department of Pathology, Faculty of Medicine, Minia University, Minia, Egypt
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23
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Djouhri L, Zeidan A, Abd El-Aleem SA, Smith T. Cutaneous Aβ-Non-nociceptive, but Not C-Nociceptive, Dorsal Root Ganglion Neurons Exhibit Spontaneous Activity in the Streptozotocin Rat Model of Painful Diabetic Neuropathy in vivo. Front Neurosci 2020; 14:530. [PMID: 32528247 PMCID: PMC7263321 DOI: 10.3389/fnins.2020.00530] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/29/2020] [Indexed: 12/30/2022] Open
Abstract
Diabetic peripheral neuropathic pain (DPNP) is the most devastating complication of diabetes mellitus. Unfortunately, successful therapy for DPNP remains a challenge because its pathogenesis is still elusive. However, DPNP is believed to be due partly to abnormal hyperexcitability of dorsal root ganglion (DRG) neurons, but the relative contributions of specific functional subtypes remain largely unknown. Here, using the strepotozotocin (STZ) rat model of DPNP induced by a STZ injection (60 mg/kg, i.p), and intracellular recordings of action potentials (APs) from DRG neurons in anesthetized rats, we examined electrophysiological changes in C-and Aβ-nociceptive and Aβ-low threshold mechanoreceptive (LTM) neurons that may contribute to DPNP. Compared with control, we found in STZ-rats with established pain hypersensitivity (5 weeks post-STZ) several significant changes including: (a) A 23% increase in the incidence of spontaneous activity (SA) in Aβ-LTMs (but not C-mechanosensitive nociceptors) that may cause dysesthesias/paresthesia suffered by DPNP patients, (b) membrane hyperpolarization and a ∼85% reduction in SA rate in Aβ-LTMs by Kv7 channel activation with retigabine (6 mg/kg, i.v.) suggesting that Kv7/M channels may be involved in mechanisms of SA generation in Aβ-LTMs, (c) decreases in AP duration and in duration and amplitude of afterhyperpolarization (AHP) in C-and/or Aβ-nociceptors. These faster AP and AHP kinetics may lead to repetitive firing and an increase in afferent input to the CNS and thereby contribute to DPNP development, and (d) a decrease in the electrical thresholds of Aβ-nociceptors that may contribute to their sensitization, and thus to the resulting hypersensitivity associated with DPNP.
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Affiliation(s)
- Laiche Djouhri
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Asad Zeidan
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Seham A. Abd El-Aleem
- Department of Histology and Cell Biology, University of Manchester, Manchester, United Kingdom
- Department of Pathology, Faculty of Medicine, Minia University, Minya, Egypt
| | - Trevor Smith
- Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
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Boada MD, Martin TJ, Parker R, Houle TT, Eisenach JC, Ririe DG. Recovery from nerve injury induced behavioral hypersensitivity in rats parallels resolution of abnormal primary sensory afferent signaling. Pain 2020; 161:949-959. [PMID: 32040074 PMCID: PMC7166146 DOI: 10.1097/j.pain.0000000000001781] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Pain and hypersensitivity months after peripheral injury reflect abnormal input from peripheral afferents likely in conjunction with central sensitization. We hypothesize that peripheral changes occur in defined sensory afferents and resolve as behavioral response to injury resolves. Male Sprague-Dawley rats underwent sham or partial L5 spinal nerve ligation, and paw withdrawal threshold (PWT) was sequentially measured during recovery. At 2, 4, 8, and 12 weeks after injury, randomized animals underwent electrophysiologic assessment of L4 fast-conducting high- and low-threshold mechanoreceptors, and individual neuronal mechanical thresholds (MTs) were contrasted with PWTs in the same animals. Paw withdrawal thresholds decreased after injury and resolved over time (P < 0.001). Similarly, MTs of fast-conducting high-threshold mechanoreceptors decreased after injury and resolved over time (P < 0.001). By contrast, MTs of low-threshold mechanoreceptors increased after injury and resolved over time (P < 0.001). Distributions of recordings from each afferent subtype were perturbed after injury, and this too resolved over time. After resolution of behavioral changes, several electrical abnormalities persisted in both neuronal subtypes. These data extend previous findings that mechanically sensitive nociceptors are sensitized, whereas tactile, largely Aβ afferents are desensitized after nerve injury by showing that the time course of resolution of these changes mirrors that of behavioral hypersensitivity in a surgical injury including neural damage. These data support a role of abnormal peripheral input, from both nociceptor and tactile afferents, during recovery from peripheral injury and underscore the potential importance of both classes of afferents as potential targets for pain treatment.
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Affiliation(s)
- M Danilo Boada
- Pain Mechanisms Lab, Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Thomas J Martin
- Pain Mechanisms Lab, Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Renee Parker
- Pain Mechanisms Lab, Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Timothy T Houle
- Department of Anesthesiology and Perioperative Medicine, Harvard Medical School, Massachusetts General Hospital, Boston, MA, United States
| | - James C Eisenach
- Pain Mechanisms Lab, Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Douglas G Ririe
- Pain Mechanisms Lab, Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC, United States
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Boada MD, Ririe DG, Martin CW, Martin SJ, Kim SA, Eisenach JC, Martin TJ. Nociceptive input after peripheral nerve injury results in cognitive impairment and alterations in primary afferent physiology in rats. Pain 2020; 161:960-969. [PMID: 32040075 PMCID: PMC7166154 DOI: 10.1097/j.pain.0000000000001782] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Pain alters cognitive performance through centrally mediated effects in the brain. In this study, we hypothesized that persistent activation of peripheral nociceptors after injury would lead to the development of a chronic pain state that impairs attention-related behavior and results in changes in peripheral neuron phenotypes. Attentional performance was measured in rats using the 5-choice serial reaction time titration variant to determine the initial impact of partial L5 spinal nerve ligation and the effect of persistent nociceptor activation on the resolution of injury. The changes in peripheral neuronal sensibilities and phenotypes were determined in sensory afferents using electrophysiologic signatures and receptive field properties from dorsal root ganglion recordings. Partial spinal nerve injury impaired attentional performance, and this was further impaired in a graded fashion by nociceptive input through an engineered surface. Impairment in attention persisted for only up to 4 days initially, followed by a second phase 7 to 10 weeks after injury in animals exposed to nociceptive input. In animals with prolonged impairment in behavior, the mechanonociceptors displayed a persistent hypersensitivity marked by decreased threshold, increased activity to a given stimulus, and spontaneous activity. Nerve injury disrupts attentional performance acutely and is worsened with peripheral mechanonociceptor activation. Acute impairment resolves, but persistent nociceptive activation produces re-emergence of impairment in the attention-related task associated with electrophysiological abnormalities in peripheral nociceptors. This is consistent with the development of a chronic pain state marked by cognitive impairment and related to persistently abnormal peripheral input.
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Affiliation(s)
- M Danilo Boada
- Pain Mechanisms Lab, Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC, United States
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26
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García G, Noriega-Navarro R, Martínez-Rojas VA, Gutiérrez-Lara EJ, Oviedo N, Murbartián J. Spinal TASK-1 and TASK-3 modulate inflammatory and neuropathic pain. Eur J Pharmacol 2019; 862:172631. [DOI: 10.1016/j.ejphar.2019.172631] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 08/09/2019] [Accepted: 08/27/2019] [Indexed: 12/13/2022]
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27
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Crawford LK, Caterina MJ. Functional Anatomy of the Sensory Nervous System: Updates From the Neuroscience Bench. Toxicol Pathol 2019; 48:174-189. [PMID: 31554486 DOI: 10.1177/0192623319869011] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The simple tripartite classification of sensory neurons as A-beta, A-delta, and C fibers fails to convey the complexity of the neurons that encode stimuli as diverse as the texture of a surface, the location of a pinprick, or the direction of hair movement as a breeze moves across the skin. It has also proven to be inadequate when investigating the molecular mechanisms underlying pain, which can encompass any combination of chemical, tactile, and thermal modalities. Beginning with a brief overview of visceral and sensory neuroanatomy, this review expands upon sensory innervation of the skin as a prime example of the heterogeneity and complexity of the somatosensory nervous system. Neuroscientists have characterized defining features of over 15 subtypes of sensory neurons that innervate the skin of the mouse. This has enabled the study of cell-specific mechanisms of pain, which suggests that diverse sensory neuron subtypes may have distinct susceptibilities to toxic injury and different roles in pathologic mechanisms underlying altered sensation. Leveraging this growing body of knowledge for preclinical trials and models of neurotoxicity can vastly improve our understanding of peripheral nervous system dysfunction, advancing the fields of toxicologic pathology and neuropathology alike.
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Affiliation(s)
- LaTasha K Crawford
- Department of Pathobiological Sciences, University of Wisconsin-Madison School of Veterinary Medicine, Madison, WI, USA, Madison, WI, USA
| | - Michael J Caterina
- Neurosurgery Pain Research Institute, Johns Hopkins School of Medicine, Baltimore, MD, USA
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Walters ET. Adaptive mechanisms driving maladaptive pain: how chronic ongoing activity in primary nociceptors can enhance evolutionary fitness after severe injury. Philos Trans R Soc Lond B Biol Sci 2019; 374:20190277. [PMID: 31544606 DOI: 10.1098/rstb.2019.0277] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Chronic pain is considered maladaptive by clinicians because it provides no apparent protective or recuperative benefits. Similarly, evolutionary speculations have assumed that chronic pain represents maladaptive or evolutionarily neutral dysregulation of acute pain mechanisms. By contrast, the present hypothesis proposes that chronic pain can be driven by mechanisms that evolved to reduce increased vulnerability to attack from predators and aggressive conspecifics, which often target prey showing physical impairment after severe injury. Ongoing pain and anxiety persisting long after severe injury continue to enhance vigilance and behavioural caution, decreasing the heightened vulnerability to attack that results from motor impairment and disfigurement, thereby increasing survival and reproduction (fitness). This hypothesis is supported by evidence of animals surviving and reproducing after traumatic amputations, and by complex specializations that enable primary nociceptors to detect local and systemic signs of injury and inflammation, and to maintain low-frequency discharge that can promote ongoing pain indefinitely. Ongoing activity in nociceptors involves intricate electrophysiological and anatomical specializations, including inducible alterations in the expression of ion channels and receptors that produce persistent hyperexcitability and hypersensitivity to chemical signals of injury. Clinically maladaptive chronic pain may sometimes result from the recruitment of this powerful evolutionary adaptation to severe bodily injury. This article is part of the Theo Murphy meeting issue 'Evolution of mechanisms and behaviour important for pain'.
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Affiliation(s)
- Edgar T Walters
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, 6431 Fannin Street, Houston, TX 77030, USA
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Benitez SG, Seltzer AM, Messina DN, Foscolo MR, Patterson SI, Acosta CG. Cutaneous inflammation differentially regulates the expression and function of Angiotensin-II types 1 and 2 receptors in rat primary sensory neurons. J Neurochem 2019; 152:675-696. [PMID: 31386177 DOI: 10.1111/jnc.14848] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 06/25/2019] [Accepted: 07/31/2019] [Indexed: 12/14/2022]
Abstract
Neuropathic and inflammatory pain results from cellular and molecular changes in dorsal root ganglion (DRG) neurons. The type-2 receptor for Angiotensin-II (AT2R) has been involved in this type of pain. However, the underlying mechanisms are poorly understood, including the role of the type-1 receptor for Angiotensin-II (AT1R). Here, we used a combination of immunohistochemistry and immunocytochemistry, RT-PCR and in vitro and in vivo pharmacological manipulation to examine how cutaneous inflammation affected the expression of AT1R and AT2R in subpopulations of rat DRG neurons and studied their impact on inflammation-induced neuritogenesis. We demonstrated that AT2R-neurons express C- or A-neuron markers, primarily IB4, trkA, and substance-P. AT1R expression was highest in small neurons and co-localized significantly with AT2R. In vitro, an inflammatory soup caused significant elevation of AT2R mRNA, whereas AT1R mRNA levels remained unchanged. In vivo, we found a unique pattern of change in the expression of AT1R and AT2R after cutaneous inflammation. AT2R increased in small neurons at 1 day and in medium size neurons at 4 days. Interestingly, cutaneous inflammation increased AT1R levels only in large neurons at 4 days. We found that in vitro and in vivo AT1R and AT2R acted co-operatively to regulate DRG neurite outgrowth. In vivo, AT2R inhibition impacted more on non-peptidergic C-neurons neuritogenesis, whereas AT1R blockade affected primarily peptidergic nerve terminals. Thus, cutaneous-induced inflammation regulated AT1R and AT2R expression and function in different DRG neuronal subpopulations at different times. These findings must be considered when targeting AT1R and AT2R to treat chronic inflammatory pain. Cover Image for this issue: doi: 10.1111/jnc.14737.
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Affiliation(s)
- Sergio G Benitez
- Laboratorio de Neurobiología del Dolor, Instituto de Histología y Embriología de Mendoza (IHEM-CONICET), Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Alicia M Seltzer
- Laboratorio de Neurobiología, Instituto de Embriología e Histología (IHEM-CONICET), Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Diego N Messina
- Laboratorio de Neurobiología del Dolor, Instituto de Histología y Embriología de Mendoza (IHEM-CONICET), Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Mabel R Foscolo
- Laboratorio de Neurobiología del Dolor, Instituto de Histología y Embriología de Mendoza (IHEM-CONICET), Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Sean I Patterson
- Departamento de Morfofisiología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina.,Instituto de Histología y Embriología - CONICET, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Cristian G Acosta
- Laboratorio de Neurobiología del Dolor, Instituto de Histología y Embriología de Mendoza (IHEM-CONICET), Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina
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Overexpression of µ-Opioid Receptors in Peripheral Afferents, but Not in Combination with Enkephalin, Decreases Neuropathic Pain Behavior and Enhances Opioid Analgesia in Mouse. Anesthesiology 2019; 128:967-983. [PMID: 29334500 DOI: 10.1097/aln.0000000000002063] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND The current study used recombinant herpes simplex virus type I to increase expression of µ-opiate receptors and the opioid ligand preproenkephalin in peripheral nerve fibers in a mouse model of neuropathic pain. It was predicted that viral vector delivery of a combination of genes encoding the µ-opioid receptor and preproenkephalin would attenuate neuropathic pain and enhance opioid analgesia. The behavioral effects would be paralleled by changes in response properties of primary afferent neurons. METHODS Recombinant herpes simplex virus type 1 containing cDNA sequences of the µ-opioid receptor, human preproenkephalin, a combination, or Escherichia coli lacZ gene marker (as a control) was used to investigate the role of peripheral opioids in neuropathic pain behaviors. RESULTS Inoculation with the µ-opioid receptor viral vector (n = 13) reversed mechanical allodynia and thermal hyperalgesia and produced leftward shifts in loperamide (ED50 = 0.6 ± 0.2 mg/kg vs. ED50 = 0.9 ± 0.2 mg/kg for control group, n = 8, means ± SD) and morphine dose-response curves (ED50 = 0.3 ± 0.5 mg/kg vs. ED50 = 1.1 ± 0.1 mg/kg for control group). In µ-opioid receptor viral vector inoculated C-fibers, heat-evoked responses (n = 12) and ongoing spontaneous activity (n = 18) were decreased after morphine application. Inoculation with both µ-opioid receptor and preproenkephalin viral vectors did not alter mechanical and thermal responses. CONCLUSIONS Increasing primary afferent expression of opioid receptors can decrease neuropathic pain-associated behaviors and increase systemic opioid analgesia through inhibition of peripheral afferent fiber activity.
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Djouhri L, Malki MI, Zeidan A, Nagi K, Smith T. Activation of Kv7 channels with the anticonvulsant retigabine alleviates neuropathic pain behaviour in the streptozotocin rat model of diabetic neuropathy. J Drug Target 2019; 27:1118-1126. [DOI: 10.1080/1061186x.2019.1608552] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Laiche Djouhri
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Mohammed Imad Malki
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Asad Zeidan
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Karim Nagi
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Trevor Smith
- Department of Medical Physics & Biomedical Engineering, University College London, London, UK
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32
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Jeub M, Taha O, Opitz T, Racz I, Pitsch J, Becker A, Beck H. Partial sciatic nerve ligation leads to an upregulation of Ni 2+-resistant T-type Ca 2+ currents in capsaicin-responsive nociceptive dorsal root ganglion neurons. J Pain Res 2019; 12:635-647. [PMID: 30804682 PMCID: PMC6375107 DOI: 10.2147/jpr.s138708] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Background Neuropathic pain resulting from peripheral nerve lesions is a common medical condition, but current analgesics are often insufficient. The identification of key molecules involved in pathological pain processing is a prerequisite for the development of new analgesic drugs. Hyperexcitability of nociceptive DRG-neurons due to regulation of voltage-gated ion-channels is generally assumed to contribute strongly to neuropathic pain. There is increasing evidence, that T-type Ca2+-currents and in particular the Cav3.2 T-type-channel isoform play an important role in neuropathic pain, but experimental results are contradicting. Purpose To clarify the role of T-type Ca2+-channels and in particular the Cav3.2 T-type-channel isoform in neuropathic pain. Methods The effect of partial sciatic nerve ligation (PNL) on pain behavior and the properties of T-type-currents in nociceptive DRG-neurons was tested in wild-type and Cav3.2-deficient mice. Results In wild-type mice, PNL of the sciatic nerve caused neuropathic pain and an increase of T-type Ca2+-currents in capsaicin-responsive neurons, while capsaicin-unresponsive neurons were unaffected. Pharmacological experiments revealed that this upregulation was due to an increase of a Ni2+-resistant Ca2+-current component, inconsistent with Cav3.2 up-regulation. Moreover, following PNL Cav3.2-deficient mice showed neuropathic pain behavior and an increase of T-Type Ca2+-currents indistinguishable to that of PNL treated wild-type mice. Conclusion These data suggest that PNL induces an upregulation of T-Type Ca2+-currents in capsaicin-responsive DRG-neurons mediated by an increase of a Ni2+-insensitive current component (possibly Cav3.1 or Cav3.3). These findings provide relevance for the development of target specific analgesic drugs.
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Affiliation(s)
- Monika Jeub
- Department of Neurology, University of Bonn Medical Center, Bonn, Germany, .,Department of Epileptology, University of Bonn Medical Center, Bonn, Germany,
| | - Omneya Taha
- Department of Neurology, University of Bonn Medical Center, Bonn, Germany, .,Department of Epileptology, University of Bonn Medical Center, Bonn, Germany,
| | - Thoralf Opitz
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany,
| | - Ildiko Racz
- Institute of Molecular Psychiatry, University of Bonn Medical Center, Bonn, Germany.,Department of Neurodegenerative Diseases and Gerontopsychiatry, University of Bonn Medical Center, Bonn, Germany
| | - Julika Pitsch
- Department of Neuropathology, University of Bonn Medical Center, Bonn, Germany
| | - Albert Becker
- Department of Neuropathology, University of Bonn Medical Center, Bonn, Germany
| | - Heinz Beck
- Department of Epileptology, University of Bonn Medical Center, Bonn, Germany,
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Yang XD, Fang PF, Xiang DX, Yang YY. Topical treatments for diabetic neuropathic pain. Exp Ther Med 2019; 17:1963-1976. [PMID: 30783472 PMCID: PMC6364237 DOI: 10.3892/etm.2019.7173] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 11/22/2018] [Indexed: 12/14/2022] Open
Abstract
Diabetic neuropathic pain (DNP) has a huge impact on quality of life and can be difficult to treat. Oral treatment is the most frequently used method for DNP, but its use is often limited by systemic side effects. Topical use of drugs as an alternative option for DNP treatment is currently gaining interest. In the present review, a summary is provided of the available agents for topical use in patients with DNP, including lidocaine plasters or patches, capsaicin cream, gel or patches, amitriptyline cream, clonidine gel, ketamine cream, extracts from medicinal plants including nutmeg extracts and Citrullus colocynthis extract oil, and certain compounded topical analgesics. Furthermore, the potential efficacy of these treatments is addressed according to the available clinical research literature. It has been indicated that these topical drugs have the potential to be valuable additional options for the management of DNP, with adequate safety and continuous long-term treatment efficacy. Compounded topical agents are also effective and safe for patients with DNP and could be another area worthy of further investigation based on the strategy of using low-dose, complementary therapies for DNP. The findings indicate that developing topical drugs acting on different targets in the process of DNP is a valuable area of future research.
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Affiliation(s)
- Xi-Ding Yang
- Department of Pharmacy, The Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, P.R. China.,Phase I Clinical Trial Center, The Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, P.R. China
| | - Ping-Fei Fang
- Department of Pharmacy, The Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, P.R. China.,Phase I Clinical Trial Center, The Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, P.R. China
| | - Da-Xiong Xiang
- Department of Pharmacy, The Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, P.R. China.,Hunan Provincial Engineering Research Center of Translational Medical and Innovative Drug, The Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, P.R. China
| | - Yong-Yu Yang
- Department of Pharmacy, The Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, P.R. China.,Hunan Provincial Engineering Research Center of Translational Medical and Innovative Drug, The Second Xiangya Hospital of Central South University, Changsha, Hunan 410011, P.R. China
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Odem MA, Bavencoffe AG, Cassidy RM, Lopez ER, Tian J, Dessauer CW, Walters ET. Isolated nociceptors reveal multiple specializations for generating irregular ongoing activity associated with ongoing pain. Pain 2018; 159:2347-2362. [PMID: 30015712 PMCID: PMC6193853 DOI: 10.1097/j.pain.0000000000001341] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Ongoing pain has been linked to ongoing activity (OA) in human C-fiber nociceptors, but rodent models of pain-related OA have concentrated on allodynia rather than ongoing pain, and on OA generated in non-nociceptive Aβ fibers rather than C-fiber nociceptors. Little is known about how ongoing pain or nociceptor OA is generated. To define neurophysiological alterations underlying nociceptor OA, we have used isolated dorsal root ganglion neurons that continue to generate OA after removal from animals displaying ongoing pain. We subclassify OA as either spontaneous activity generated solely by alterations intrinsic to the active neuron or as extrinsically driven OA. Both types of OA were implicated previously in nociceptors in vivo and after isolation following spinal cord injury, which produces chronic ongoing pain. Using novel automated algorithms to analyze irregular changes in membrane potential, we have found, in a distinctive, nonaccommodating type of probable nociceptor, induction by spinal cord injury of 3 alterations that promote OA: (1) prolonged depolarization of resting membrane potential, (2) a hyperpolarizing shift in the voltage threshold for action potential generation, and (3) an increase in the incidence of large depolarizing spontaneous fluctuations (DSFs). Can DSFs also be enhanced acutely to promote OA in neurons from uninjured animals? A low dose of serotonin failed to change resting membrane potential but lowered action potential threshold. When combined with artificial depolarization to model inflammation, serotonin also strongly potentiated DSFs and OA. These findings reveal nociceptor specializations for generating OA that may promote ongoing pain in chronic and acute conditions.
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Affiliation(s)
- Max A. Odem
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Alexis G. Bavencoffe
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Ryan M. Cassidy
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Elia R. Lopez
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Jinbin Tian
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Carmen W. Dessauer
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
| | - Edgar T. Walters
- Department of Integrative Biology and Pharmacology, McGovern Medical School at UTHealth, Houston, TX, USA
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35
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Xie MX, Yang J, Pang RP, Zeng WA, Ouyang HD, Liu YQ, Liu XG. Bulleyaconitine A attenuates hyperexcitability of dorsal root ganglion neurons induced by spared nerve injury: The role of preferably blocking Nav1.7 and Nav1.3 channels. Mol Pain 2018; 14:1744806918778491. [PMID: 29783906 PMCID: PMC5967161 DOI: 10.1177/1744806918778491] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Background Oral administration of Bulleyaconitine A, an extracted diterpenoid alkaloid from Aconitum bulleyanum plants, is effective for treating chronic pain in rats and in human patients, but the underlying mechanisms are poorly understood. Results As the hyperexcitability of dorsal root ganglion neurons resulting from the upregulation of voltage-gated sodium (Nav) channels has been proved critical for development of chronic pain, we tested the effects of Bulleyaconitine A on Nav channels in rat spared nerve injury model of neuropathic pain. We found that Bulleyaconitine A at 5 nM increased the threshold of action potentials and reduced the firing rate of dorsal root ganglion neurons in spared nerve injury rats but not in sham rats. Bulleyaconitine A preferably blocked tetrodotoxin-sensitive Nav channels over tetrodotoxin-resistant ones in dorsal root ganglion neurons of spared nerve injury rats. Bulleyaconitine A was more potent for blocking Nav1.3 and Nav1.7 than Nav1.8 in cell lines. The half maximal inhibitory concentration (IC50) values for resting Nav1.3, Nav1.7, and Nav1.8 were 995.6 ± 139.1 nM, 125.7 ± 18.6 nM, and 151.2 ± 15.4 μM, respectively, which were much higher than those for inactivated Nav1.3 (20.3 ± 3.4 pM), Nav1.7 (132.9 ± 25.5 pM), and Nav1.8 (18.0 ± 2.5 μM). The most profound use-dependent blocking effect of Bulleyaconitine A was observed on Nav1.7, less on Nav1.3, and least on Nav1.8 at IC50 concentrations. Bulleyaconitine A facilitated the inactivation of Nav channels in each subtype. Conclusions Preferably blocking tetrodotoxin-sensitive Nav1.7 and Nav1.3 in dorsal root ganglion neurons may contribute to Bulleyaconitine A’s antineuropathic pain effect.
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Affiliation(s)
- Man-Xiu Xie
- 1 Department of Anesthesiology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Jie Yang
- 2 Department of Physiology, Pain Research Center, Zhongshan School of Medicine of Sun Yat-Sen University, Guangzhou, China
| | - Rui-Ping Pang
- 2 Department of Physiology, Pain Research Center, Zhongshan School of Medicine of Sun Yat-Sen University, Guangzhou, China.,3 Guangdong Provincial Key Laboratory of Brain Function and Disease, Guangdong, China
| | - Wei-An Zeng
- 1 Department of Anesthesiology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Han-Dong Ouyang
- 1 Department of Anesthesiology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Yan-Qing Liu
- 4 Department of Pain Medicine, Beijing Tian Tan Hospital, Capital Medical University, Beijing, China
| | - Xian-Guo Liu
- 2 Department of Physiology, Pain Research Center, Zhongshan School of Medicine of Sun Yat-Sen University, Guangzhou, China.,3 Guangdong Provincial Key Laboratory of Brain Function and Disease, Guangdong, China
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García G, Martínez-Rojas VA, Oviedo N, Murbartián J. Blockade of anoctamin-1 in injured and uninjured nerves reduces neuropathic pain. Brain Res 2018; 1696:38-48. [DOI: 10.1016/j.brainres.2018.06.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 04/12/2018] [Accepted: 06/01/2018] [Indexed: 12/28/2022]
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North RY, Lazaro TT, Dougherty PM. Ectopic Spontaneous Afferent Activity and Neuropathic Pain. Neurosurgery 2018; 65:49-54. [PMID: 31076785 DOI: 10.1093/neuros/nyy119] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 04/04/2018] [Indexed: 12/17/2022] Open
Affiliation(s)
- Robert Y North
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas
| | - Tyler T Lazaro
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas
| | - Patrick M Dougherty
- The Departments of Pain Medicine Research, The Division of Anesthesia, Critical Care and Pain Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas
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Djouhri L, Smith T, Ahmeda A, Alotaibi M, Weng X. Hyperpolarization-activated cyclic nucleotide-gated channels contribute to spontaneous activity in L4 C-fiber nociceptors, but not Aβ-non-nociceptors, after axotomy of L5-spinal nerve in the rat in vivo. Pain 2018; 159:1392-1402. [PMID: 29578948 DOI: 10.1097/j.pain.0000000000001224] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Peripheral neuropathic pain associated with partial nerve injury is believed to be driven partly by aberrant spontaneous activity (SA) in both injured and uninjured dorsal root ganglion (DRG) neurons. The underlying ionic mechanisms are not fully understood, but hyperpolarization-activated cyclic nucleotide-gated (HCN) channels which underlie the excitatory Ih current have been implicated in SA generation in axotomized A-fiber neurons after L5-spinal nerve ligation/axotomy (SNL/SNA). Here, using a modified model of SNA (mSNA) which involves, in addition to L5-SNA, loose ligation of the L4-spinal nerve with neuroinflammation-inducing chromic gut, we examined whether HCN channels also contribute to SA in the adjacent L4-neurons. Intracellular recordings from L4-DRG neurons in control rats, and L4-DRG neurons in mSNA rats were made using in vivo voltage- and current-clamp techniques. Compared with control, L4 C-nociceptors and Aβ-low-threshold mechanoreceptors (LTMs) exhibited SA 7 days after mSNA. This was accompanied, in C-nociceptors, by a significant increase in Ih amplitude, the percentage of Ih-expressing neurons, and Ih activation rate. Hyperpolarization-activated cyclic nucleotide-gated channel blockade with ZD7288 (10 mg/kg, intravenously) suppressed SA in C-nociceptors, but not Aβ-LTMs, and caused in C-nociceptors, membrane hyperpolarization and a decrease in Ih activation rate. Furthermore, intraplantar injection of ZD7288 (100 μM) was found to be as effective as gabapentin (positive control) in attenuating cold hypersensitivity in mSNA rats. These findings suggest that HCN channels contribute to nerve injury-induced SA in L4 C-nociceptors, but not Aβ-LTMs, and that ZD7288 exerts its analgesic effects by altering Ih activation properties and/or causing membrane hyperpolarization in L4 C-nociceptors.
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Affiliation(s)
- Laiche Djouhri
- Department of Physiology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
- Department of Clinical and Molecular Pharmacology, Institute of Translational Medicine, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Trevor Smith
- Wolfson CARD, Neurorestoration Group, King's College London, London, United Kingdom
| | - Ahmad Ahmeda
- Department of Physiology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Mohammad Alotaibi
- Department of Physiology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Xiechuan Weng
- State Key Laboratory of Proteomics, Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China
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Djouhri L, Smith T, Alotaibi M, Weng X. Membrane potential oscillations are not essential for spontaneous firing generation in L4 Aβ-afferent neurons after L5 spinal nerve axotomy and are not mediated by HCN channels. Exp Physiol 2018; 103:1145-1156. [PMID: 29860719 DOI: 10.1113/ep087013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 05/23/2018] [Indexed: 01/01/2023]
Abstract
NEW FINDINGS What is the central question of this study? Is spontaneous activity (SA) in L4 dorsal root ganglion (DRG) neurons induced by L5 spinal nerve axotomy associated with membrane potential oscillations in these neurons, and if so, are these membrane oscillations mediated by HCN channels? What is the main finding and its importance? Unlike injured L5 DRG neurons, which have been shown to be incapable of firing spontaneously without membrane potential oscillations, membrane potential oscillations are not essential for SA generation in conducting 'uninjured' L4 neurons, and they are not mediated by HCN channels. These findings suggest that the underlying cellular mechanisms of SA in injured and 'uninjured' DRG neurons induced by spinal nerve injury are distinct. ABSTRACT The underlying cellular and molecular mechanisms of peripheral neuropathic pain are not fully understood. However, preclinical studies using animal models suggest that this debilitating condition is driven partly by aberrant spontaneous activity (SA) in injured and uninjured dorsal root ganglion (DRG) neurons, and that SA in injured DRG neurons is triggered by subthreshold membrane potential oscillations (SMPOs). Here, using in vivo intracellular recording from control L4-DRG neurons, and ipsilateral L4-DRG neurons in female Wistar rats that had previously undergone L5 spinal nerve axotomy (SNA), we examined whether conducting 'uninjured' L4-DRG neurons in SNA rats exhibit SMPOs, and if so, whether such SMPOs are associated with SA in those L4 neurons, and whether they are mediated by hyperpolarization-activated cyclic nucleotide gated (HCN) channels. We found that 7 days after SNA: (a) none of the control A- or C-fibre DRG neurons showed SMPOs or SA, but 50%, 43% and 0% of spontaneously active cutaneous L4 Aβ-low threshold mechanoreceptors, Aβ-nociceptors and C-nociceptors exhibited SMPOs, respectively, in SNA rats with established neuropathic pain behaviors; (b) neither SMPOs nor SA in L4 Aβ-neurons was suppressed by blocking HCN channels with ZD7288 (10 mg kg-1 , i.v.); and (c) there is a tendency for female rats to show greater pain hypersensitivity than male rats. These results suggest that SMPOs are linked to SA only in some of the conducting L4 Aβ-neurons, that such oscillations are not a prerequisite for SA generation in those L4 A- or C-fibre neurons, and that HCN channels are not involved in their electrogenesis.
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Affiliation(s)
- L Djouhri
- Department of Physiology, College of Medicine, Alfaisal University, PO Box 50927, Riyadh, 11533, Saudi Arabia
| | - T Smith
- Wolfson CARD, Neurorestoration Group, Hodgkin Building, King's College London, Guy's Campus, London, SE1 1UL, UK
| | - M Alotaibi
- Department of Physiology, College of Medicine, King Saud University, PO Box 7805, Riyadh, 11472, Saudi Arabia
| | - X Weng
- Department of Neurobiology and State Key Laboratory of Proteomics, Beijing Institute of Basic Medical Sciences, Beijing, 100850, China
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Poli-Neto OB, Campos Martins Chamochumbi C, Toscano P, Pitanguy Julio M, Marques W, Rosa-e-Silva JC, Candido-dos-Reis FJ, Nogueira AA. Electromyographic characterisation of abdominal wall trigger points developed after caesarean section and response to local anaesthesia: an observational study. BJOG 2018; 125:1313-1318. [DOI: 10.1111/1471-0528.15204] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2018] [Indexed: 01/17/2023]
Affiliation(s)
- OB Poli-Neto
- Departamento de Ginecologia e Obstetrícia; Faculdade de Medicina de Ribeirão Preto; Universidade de São Paulo; Ribeirão Preto Brazil
| | - C Campos Martins Chamochumbi
- Departamento de Ginecologia e Obstetrícia; Faculdade de Medicina de Ribeirão Preto; Universidade de São Paulo; Ribeirão Preto Brazil
| | - P Toscano
- Departamento de Neurologia, Psiquiatria e Psicologia Médica; Faculdade de Medicina de Ribeirão Preto; Universidade de São Paulo; Ribeirão Preto Brazil
| | - M Pitanguy Julio
- Departamento de Ginecologia e Obstetrícia; Faculdade de Medicina de Ribeirão Preto; Universidade de São Paulo; Ribeirão Preto Brazil
| | - W Marques
- Departamento de Neurologia, Psiquiatria e Psicologia Médica; Faculdade de Medicina de Ribeirão Preto; Universidade de São Paulo; Ribeirão Preto Brazil
| | - JC Rosa-e-Silva
- Departamento de Ginecologia e Obstetrícia; Faculdade de Medicina de Ribeirão Preto; Universidade de São Paulo; Ribeirão Preto Brazil
| | - FJ Candido-dos-Reis
- Departamento de Ginecologia e Obstetrícia; Faculdade de Medicina de Ribeirão Preto; Universidade de São Paulo; Ribeirão Preto Brazil
| | - AA Nogueira
- Departamento de Ginecologia e Obstetrícia; Faculdade de Medicina de Ribeirão Preto; Universidade de São Paulo; Ribeirão Preto Brazil
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Staunton CA, Barrett-Jolley R, Djouhri L, Thippeswamy T. Inducible nitric oxide synthase inhibition by 1400W limits pain hypersensitivity in a neuropathic pain rat model. Exp Physiol 2018; 103:535-544. [PMID: 29441689 DOI: 10.1113/ep086764] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 02/08/2018] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Can modulation of inducible NO synthase reduce pain behaviour and pro-inflammatory cytokine signalling in a rat model of neuropathic pain? What is the main finding and its importance? Nitric oxide synthase-based therapies could be effective for the treatment of peripheral neuropathic pain. ABSTRACT Peripheral neuropathic pain (PNP), resulting from injury to or dysfunction of a peripheral nerve, is a major health problem that affects 7-8% of the population. It is inadequately controlled by current drugs and is characterized by pain hypersensitivity, which is believed to be attributable to sensitization of peripheral and CNS neurons by various inflammatory mediators. Here we examined, in a rat model of PNP: (i) whether reducing levels of nitric oxide (NO) with 1400W, a highly selective inhibitor of inducible NO synthase (iNOS), would prevent or attenuate pain hypersensitivity; and (ii) the effects of 1400W on plasma concentrations of several cytokines that are secreted after iNOS upregulation during chronic pain states. The L5 spinal nerve axotomy (SNA) model of PNP was used, and 1400W (20 mg kg-1 ) was administered i.p. at 8 h intervals for 3 days starting at 18 h post-SNA. Changes in plasma concentrations of 12 cytokines in SNA rats treated with 1400W were examined using multiplex enzyme-linked immunosorbent assay. The SNA rats developed behavioural signs of mechanical and heat hypersensitivity. Compared with the vehicle/control, 1400W significantly: (i) limited development of mechanical hypersensitivity at 66 h post-SNA and of heat hypersensitivity at 42 h and at several time points tested thereafter; and (ii) increased the plasma concentrations of interleukin (IL)-1α, IL-1β and IL-10 in the SNA rats. The findings suggest that 1400W might exert its analgesic effects by reducing iNOS and altering the balance between the pro-inflammatory (IL-1β and IL-1α) and anti-inflammatory (IL-10) cytokines and that therapies targeting NO or its enzymes might be effective for the treatment of PNP.
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Affiliation(s)
- C A Staunton
- Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - R Barrett-Jolley
- Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
| | - L Djouhri
- Department of Physiology, College of Medicine, King Saud University, Riyadh, Kingdom of Saudi Arabia
| | - T Thippeswamy
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
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Zou Y, Xu F, Tang Z, Zhong T, Cao J, Guo Q, Huang C. Distinct calcitonin gene-related peptide expression pattern in primary afferents contribute to different neuropathic symptoms following chronic constriction or crush injuries to the rat sciatic nerve. Mol Pain 2018; 12:1744806916681566. [PMID: 28256957 PMCID: PMC5521344 DOI: 10.1177/1744806916681566] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Although calcitonin gene-related peptide is a recognized pain transducer, the expression of calcitonin gene-related peptide in primary afferents may be differentially affected following different types of nerve injury. Here, we examined whether different calcitonin gene-related peptide expression patterns in primary afferents contributes to distinct sensory disturbances in three animal models of sciatic nerve injury: chronic constriction injury, mild (100g force) or strong (1000g force) transient crush in rats. Assessments of withdrawal reflexes and spontaneous behavior indicated that chronic constriction injury and mild crush resulted in positive neuropathic symptoms (static/dynamic mechanical allodynia, heat hyperalgesia, cold allodynia, spontaneous pain). However, strong crush led to both positive (dynamic mechanical allodynia, cold allodynia, spontaneous pain) and negative symptoms (static mechanical hypoesthesia, heat hypoalgesia). Calcitonin gene-related peptide immunoreactivity in dorsal root ganglia and corresponding spinal cord segments, and calcitonin gene-related peptide mRNA levels in dorsal root ganglia, indicated that the primary afferent calcitonin gene-related peptide supply was markedly reduced only after strong crush. This reduction paralleled the development of negative symptoms (static mechanical hypoesthesia and heat hypoalgesia). Administration of exogenous calcitonin gene-related peptide intrathecally after strong crush did not alter heat hypoalgesia but ameliorated static mechanical hypoesthesia, an effect blocked by a calcitonin gene-related peptide receptor antagonist. Thus, reducing the primary afferent calcitonin gene-related peptide supply contributed to subsequent negative neuropathic symptoms, especially to static mechanical stimuli. Moreover, nerve injury caused a subcellular redistribution of calcitonin gene-related peptide from small- and medium-size dorsal root ganglia neurons to large-size dorsal root ganglia neurons, which paralleled the development of positive neuropathic symptoms. Intrathecal administration of the calcitonin gene-related peptide receptor antagonist ameliorated these positive symptoms, indicating that the expression of calcitonin gene-related peptide in large-size dorsal root ganglia neurons is important for the positive neuropathic symptoms in all three models. Taken together, these results suggest that distinct calcitonin gene-related peptide expression pattern in primary afferents contribute to different neuropathic symptoms following chronic constriction or crush injuries to the rat sciatic nerve.
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Affiliation(s)
- Yu Zou
- 1 Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
| | - Fangting Xu
- 1 Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
| | - Zhaohui Tang
- 1 Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
| | - Tao Zhong
- 1 Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
| | - Jiawei Cao
- 1 Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
| | - Qulian Guo
- 1 Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
| | - Changsheng Huang
- 1 Department of Anesthesiology, Xiangya Hospital of Central South University, Changsha, China
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Al-Mazidi S, Alotaibi M, Nedjadi T, Chaudhary A, Alzoghaibi M, Djouhri L. Blocking of cytokines signalling attenuates evoked and spontaneous neuropathic pain behaviours in the paclitaxel rat model of chemotherapy-induced neuropathy. Eur J Pain 2017; 22:810-821. [DOI: 10.1002/ejp.1169] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2017] [Indexed: 12/26/2022]
Affiliation(s)
- S. Al-Mazidi
- Department of Physiology; College of Medicine; King Saud University; Riyadh Saudi Arabia
- Rehabilitation Department; College of Health, and Rehabilitation Sciences; Princess Nourah Bint Abdulrahman University; Riyadh Saudi Arabia
| | - M. Alotaibi
- Department of Physiology; College of Medicine; King Saud University; Riyadh Saudi Arabia
| | - T. Nedjadi
- King Abdullah International Medical Research Center (KAIMRC); King Fahd Medical Research Center; King Abdulaziz University; Jeddah Saudi Arabia
| | - A. Chaudhary
- Center of Excellence in Genomic Medicine Research; King Abdulaziz University; Jeddah Saudi Arabia
| | - M. Alzoghaibi
- Department of Physiology; College of Medicine; King Saud University; Riyadh Saudi Arabia
| | - L. Djouhri
- Department of Physiology; College of Medicine; King Saud University; Riyadh Saudi Arabia
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Dorsal root ganglion neurons become hyperexcitable and increase expression of voltage-gated T-type calcium channels (Cav3.2) in paclitaxel-induced peripheral neuropathy. Pain 2017; 158:417-429. [PMID: 27902567 DOI: 10.1097/j.pain.0000000000000774] [Citation(s) in RCA: 133] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Here, it is shown that paclitaxel-induced neuropathy is associated with the development of spontaneous activity (SA) and hyperexcitability in dorsal root ganglion (DRG) neurons that is paralleled by increased expression of low-voltage-activated calcium channels (T-type; Cav3.2). The percentage of DRG neurons showing SA and the overall mean rate of SA were significantly higher at day 7 in rats receiving paclitaxel treatment than in rats receiving vehicle. Cav3.2 expression was increased in L4-L6 DRG and spinal cord segments in paclitaxel-treated rats, localized to small calcitonin gene-related peptide and isolectin B4 expressing DRG neurons and to glial fibrillary acidic protein-positive spinal cord cells. Cav3.2 expression was also co-localized with toll-like receptor 4 (TLR4) in both the DRG and the dorsal horn. T-type current amplitudes and density were increased at day 7 after paclitaxel treatment. Perfusion of the TLR4 agonist lipopolysaccharide directly activated DRG neurons, whereas this was prevented by pretreatment with the specific T-type calcium channel inhibitor ML218 hydrochloride. Paclitaxel-induced behavioral hypersensitivity to mechanical stimuli in rats was prevented but not reversed by spinal administration of ML218 hydrochloride or intravenous injection of the TLR4 antagonist TAK242. Paclitaxel induced inward current and action potential discharges in cultured human DRG neurons, and this was blocked by ML218 hydrochloride pretreatment. Furthermore, ML218 hydrochloride decreased firing frequency in human DRG, where spontaneous action potentials were present. In summary, Cav3.2 in concert with TLR4 in DRG neurons appears to contribute to paclitaxel-induced neuropathy.
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Chen CJ, Liu DZ, Yao WF, Gu Y, Huang F, Hei ZQ, Li X. Identification of key genes and pathways associated with neuropathic pain in uninjured dorsal root ganglion by using bioinformatic analysis. J Pain Res 2017; 10:2665-2674. [PMID: 29180893 PMCID: PMC5694199 DOI: 10.2147/jpr.s143431] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Purpose Neuropathic pain is a complex chronic condition occurring post-nervous system damage. The transcriptional reprogramming of injured dorsal root ganglia (DRGs) drives neuropathic pain. However, few comparative analyses using high-throughput platforms have investigated uninjured DRG in neuropathic pain, and potential interactions among differentially expressed genes (DEGs) and pathways were not taken into consideration. The aim of this study was to identify changes in genes and pathways associated with neuropathic pain in uninjured L4 DRG after L5 spinal nerve ligation (SNL) by using bioinformatic analysis. Materials and methods The microarray profile GSE24982 was downloaded from the Gene Expression Omnibus database to identify DEGs between DRGs in SNL and sham rats. The prioritization for these DEGs was performed using the Toppgene database followed by gene ontology and pathway enrichment analyses. The relationships among DEGs from the protein interactive perspective were analyzed using protein–protein interaction (PPI) network and module analysis. Real-time polymerase chain reaction (PCR) and Western blotting were used to confirm the expression of DEGs in the rodent neuropathic pain model. Results A total of 206 DEGs that might play a role in neuropathic pain were identified in L4 DRG, of which 75 were upregulated and 131 were downregulated. The upregulated DEGs were enriched in biological processes related to transcription regulation and molecular functions such as DNA binding, cell cycle, and the FoxO signaling pathway. Ctnnb1 protein had the highest connectivity degrees in the PPI network. The in vivo studies also validated that mRNA and protein levels of Ctnnb1 were upregulated in both L4 and L5 DRGs. Conclusion This study provides insight into the functional gene sets and pathways associated with neuropathic pain in L4 uninjured DRG after L5 SNL, which might promote our understanding of the molecular mechanisms underlying the development of neuropathic pain.
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Affiliation(s)
- Chao-Jin Chen
- Department of Anesthesiology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, People's Republic of China
| | - De-Zhao Liu
- Department of Anesthesiology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Wei-Feng Yao
- Department of Anesthesiology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Yu Gu
- Department of Anesthesiology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Fei Huang
- Department of Anesthesiology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Zi-Qing Hei
- Department of Anesthesiology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Xiang Li
- Department of Anesthesiology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, People's Republic of China
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Haskins W, Benitez S, Mercado JM, Acosta CG. Cutaneous inflammation regulates THIK1 expression in small C-like nociceptor dorsal root ganglion neurons. Mol Cell Neurosci 2017; 83:13-26. [DOI: 10.1016/j.mcn.2017.06.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 06/29/2017] [Accepted: 06/30/2017] [Indexed: 10/19/2022] Open
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Taha O, Opitz T, Mueller M, Pitsch J, Becker A, Evert BO, Beck H, Jeub M. Neuropathic pain in experimental autoimmune neuritis is associated with altered electrophysiological properties of nociceptive DRG neurons. Exp Neurol 2017; 297:25-35. [PMID: 28734788 DOI: 10.1016/j.expneurol.2017.07.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 07/02/2017] [Accepted: 07/13/2017] [Indexed: 12/30/2022]
Abstract
Guillain-Barré syndrome (GBS) is an acute, immune-mediated polyradiculoneuropathy characterized by rapidly progressive paresis and sensory disturbances. Moderate to severe and often intractable neuropathic pain is a common symptom of GBS, but its underlying mechanisms are unknown. Pathology of GBS is classically attributed to demyelination of large, myelinated peripheral fibers. However, there is increasing evidence that neuropathic pain in GBS is associated with impaired function of small, unmyelinated, nociceptive fibers. We therefore examined the functional properties of small DRG neurons, the somata of nociceptive fibers, in a rat model of GBS (experimental autoimmune neuritis=EAN). EAN rats developed behavioral signs of neuropathic pain. This was accompanied by a significant shortening of action potentials due to a more rapid repolarization and an increase in repetitive firing in a subgroup of capsaicin-responsive DRG neurons. Na+ current measurements revealed a significant increase of the fast TTX-sensitive current and a reduction of the persistent TTX-sensitive current component. These changes of Na+ currents may account for the significant decrease in AP duration leading to an overall increase in excitability and are therefore possibly directly linked to pathological pain behavior. Thus, like in other animal models of neuropathic and inflammatory pain, Na+ channels seem to be crucially involved in the pathology of GBS and may constitute promising targets for pain modulating pharmaceuticals.
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Affiliation(s)
- Omneya Taha
- Department of Neurology, University of Bonn Medical Center, Sigmund Freud Straße 25, 53105 Bonn, Germany; Department of Epileptology, University of Bonn Medical Center, Sigmund Freud Straße 25, 53105 Bonn, Germany
| | - Thoralf Opitz
- Department of Epileptology, University of Bonn Medical Center, Sigmund Freud Straße 25, 53105 Bonn, Germany
| | - Marcus Mueller
- Department of Neurology, University of Bonn Medical Center, Sigmund Freud Straße 25, 53105 Bonn, Germany
| | - Julika Pitsch
- Department of Neuropathology, University of Bonn Medical Center, Sigmund Freud Straße 25, 53105 Bonn, Germany
| | - Albert Becker
- Department of Neuropathology, University of Bonn Medical Center, Sigmund Freud Straße 25, 53105 Bonn, Germany
| | - Bernd Oliver Evert
- Department of Neurology, University of Bonn Medical Center, Sigmund Freud Straße 25, 53105 Bonn, Germany
| | - Heinz Beck
- Department of Epileptology, University of Bonn Medical Center, Sigmund Freud Straße 25, 53105 Bonn, Germany
| | - Monika Jeub
- Department of Neurology, University of Bonn Medical Center, Sigmund Freud Straße 25, 53105 Bonn, Germany; Department of Epileptology, University of Bonn Medical Center, Sigmund Freud Straße 25, 53105 Bonn, Germany.
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Barkai O, Goldstein RH, Caspi Y, Katz B, Lev S, Binshtok AM. The Role of Kv7/M Potassium Channels in Controlling Ectopic Firing in Nociceptors. Front Mol Neurosci 2017; 10:181. [PMID: 28659757 PMCID: PMC5468463 DOI: 10.3389/fnmol.2017.00181] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 05/24/2017] [Indexed: 11/13/2022] Open
Abstract
Peripheral nociceptive neurons encode and convey injury-inducing stimuli toward the central nervous system. In normal conditions, tight control of nociceptive resting potential prevents their spontaneous activation. However, in many pathological conditions the control of membrane potential is disrupted, leading to ectopic, stimulus-unrelated firing of nociceptive neurons, which is correlated to spontaneous pain. We have investigated the role of KV7/M channels in stabilizing membrane potential and impeding spontaneous firing of nociceptive neurons. These channels generate low voltage-activating, noninactivating M-type K+ currents (M-current, IM ), which control neuronal excitability. Using perforated-patch recordings from cultured, rat nociceptor-like dorsal root ganglion neurons, we show that inhibition of M-current leads to depolarization of nociceptive neurons and generation of repetitive firing. To assess to what extent the M-current, acting at the nociceptive terminals, is able to stabilize terminals' membrane potential, thus preventing their ectopic activation, in normal and pathological conditions, we built a multi-compartment computational model of a pseudo-unipolar unmyelinated nociceptive neuron with a realistic terminal tree. The modeled terminal tree was based on the in vivo structure of nociceptive peripheral terminal, which we assessed by in vivo multiphoton imaging of GFP-expressing nociceptive neuronal terminals innervating mice hind paw. By modifying the conductance of the KV7/M channels at the modeled terminal tree (terminal gKV7/M) we have found that 40% of the terminal gKV7/M conductance is sufficient to prevent spontaneous firing, while ~75% of terminal gKV7/M is sufficient to inhibit stimulus induced activation of nociceptive neurons. Moreover, we showed that terminal M-current reduces susceptibility of nociceptive neurons to a small fluctuations of membrane potentials. Furthermore, we simulated how the interaction between terminal persistent sodium current and M-current affects the excitability of the neurons. We demonstrated that terminal M-current in nociceptive neurons impeded spontaneous firing even when terminal Na(V)1.9 channels conductance was substantially increased. On the other hand, when terminal gKV7/M was decreased, nociceptive neurons fire spontaneously after slight increase in terminal Na(V)1.9 conductance. Our results emphasize the pivotal role of M-current in stabilizing membrane potential and hereby in controlling nociceptive spontaneous firing, in normal and pathological conditions.
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Affiliation(s)
- Omer Barkai
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, Hadassah School of Medicine, The Hebrew University-Hadassah School of MedicineJerusalem, Israel.,The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of JerusalemJerusalem, Israel
| | - Robert H Goldstein
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, Hadassah School of Medicine, The Hebrew University-Hadassah School of MedicineJerusalem, Israel.,The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of JerusalemJerusalem, Israel
| | - Yaki Caspi
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, Hadassah School of Medicine, The Hebrew University-Hadassah School of MedicineJerusalem, Israel.,The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of JerusalemJerusalem, Israel
| | - Ben Katz
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, Hadassah School of Medicine, The Hebrew University-Hadassah School of MedicineJerusalem, Israel.,The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of JerusalemJerusalem, Israel
| | - Shaya Lev
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, Hadassah School of Medicine, The Hebrew University-Hadassah School of MedicineJerusalem, Israel.,The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of JerusalemJerusalem, Israel
| | - Alexander M Binshtok
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, Hadassah School of Medicine, The Hebrew University-Hadassah School of MedicineJerusalem, Israel.,The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of JerusalemJerusalem, Israel
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Hirata H, Mizerska K, Dallacasagrande V, Guaiquil VH, Rosenblatt MI. Acute corneal epithelial debridement unmasks the corneal stromal nerve responses to ocular stimulation in rats: implications for abnormal sensations of the eye. J Neurophysiol 2017; 117:1935-1947. [PMID: 28250152 PMCID: PMC5411471 DOI: 10.1152/jn.00925.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 02/27/2017] [Accepted: 02/27/2017] [Indexed: 11/22/2022] Open
Abstract
It is widely accepted that the mechanisms for transducing sensory information reside in the nerve terminals. Occasionally, however, studies have appeared demonstrating that similar mechanisms may exist in the axon to which these terminals are connected. We examined this issue in the cornea, where nerve terminals in the epithelial cell layers are easily accessible for debridement, leaving the underlying stromal (axonal) nerves undisturbed. In isoflurane-anesthetized rats, we recorded extracellularly from single trigeminal ganglion neurons innervating the cornea that are excited by ocular dryness and cooling: low-threshold (<2°C cooling) and high-threshold (>2°C) cold-sensitive plus dry-sensitive neurons playing possible roles in tearing and ocular pain. We found that the responses in both types of neurons to dryness, wetness, and menthol stimuli were effectively abolished by the debridement, indicating that their transduction mechanisms lie in the nerve terminals. However, some responses to the cold, heat, and hyperosmolar stimuli in low-threshold cold-sensitive plus dry-sensitive neurons still remained. Surprisingly, the responses to heat in approximately half of the neurons were augmented after the debridement. We were also able to evoke these residual responses and follow the trajectory of the stromal nerves, which we subsequently confirmed histologically. The residual responses always disappeared when the stromal nerves were cut at the limbus, suggesting that the additional transduction mechanisms for these sensory modalities originated most likely in stromal nerves. The functional significance of these residual and enhanced responses from stromal nerves may be related to the abnormal sensations observed in ocular disease.NEW & NOTEWORTHY In addition to the traditional view that the sensory transduction mechanisms exist in the nerve terminals, we report here that the proximal axons (stromal nerves in the cornea from which these nerve terminals originate) may also be capable of transducing sensory information. We arrived at this conclusion by removing the epithelial cell layers of the cornea in which the nerve terminals reside but leaving the underlying stromal nerves undisturbed.
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Affiliation(s)
- Harumitsu Hirata
- Department of Ophthalmology, Weill Cornell Medical College, New York, New York; and
| | - Kamila Mizerska
- Department of Ophthalmology, Weill Cornell Medical College, New York, New York; and
| | | | - Victor H Guaiquil
- Department of Ophthalmology and Visual Sciences, College of Medicine, University of Illinois-Chicago, Chicago, Illinois
| | - Mark I Rosenblatt
- Department of Ophthalmology and Visual Sciences, College of Medicine, University of Illinois-Chicago, Chicago, Illinois
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50
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Li CL, Liu XF, Li GX, Ban MQ, Chen JZ, Cui Y, Zhang JH, Wu CF. Antinociceptive Effects of AGAP, a Recombinant Neurotoxic Polypeptide: Possible Involvement of the Tetrodotoxin-Resistant Sodium Channels in Small Dorsal Root Ganglia Neurons. Front Pharmacol 2016; 7:496. [PMID: 28066245 PMCID: PMC5168466 DOI: 10.3389/fphar.2016.00496] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 12/02/2016] [Indexed: 11/22/2022] Open
Abstract
Antitumor-analgesic peptide (AGAP) is a novel recombinant polypeptide. The primary study showed that AGAP 1.0 mg/kg exhibited strong analgesic and antitumor effects. The tail vein administration of AGAP potently reduced pain behaviors in mice induced by intraplantar injection of formalin or intraperitoneal injection of acetic acid, without affecting basal pain perception. To further assess the mechanisms of AGAP, the effects of AGAP on sodium channels were assessed using the whole-cell patch clamp recordings in dorsal root ganglia (DRG) neurons. The results showed that AGAP (3–1000 nM) inhibited the sodium currents in small-diameter DRG neurons in a dose-dependent manner. 1000 nM AGAP could inhibit the current density-voltage relationship curve of sodium channels in a voltage-dependent manner and negatively shift the activation curves. 1000 nM AGAP could reduce the tetrodotoxin-resistant (TTX-R) sodium currents by 42.8% in small-diameter DRG neurons. Further analysis revealed that AGAP potently inhibited NaV1.8 currents by 59.4%, and negatively shifted the activation and inactivation kinetics. 1000 nM AGAP also reduced the NaV1.9 currents by 33.7%, but had no significant effect on activation and inactivation kinetics. Thus, our results demonstrated that submicromolar concentrations of AGAP inhibited TTX-R sodium channel in rat small-diameter DRG neurons. It is concluded that these new results may better explain, at least in part, the analgesic properties of this polypeptide.
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Affiliation(s)
- Chun-Li Li
- Department of Pharmacology, Shenyang Pharmaceutical University Shenyang, China
| | - Xi-Fang Liu
- Department of Pharmacology, Shenyang Pharmaceutical University Shenyang, China
| | - Gui-Xia Li
- Department of Pharmacology, Shenyang Pharmaceutical University Shenyang, China
| | - Meng-Qi Ban
- Department of Pharmacology, Shenyang Pharmaceutical University Shenyang, China
| | - Jian-Zhao Chen
- Department of Pharmacology, Shenyang Pharmaceutical University Shenyang, China
| | - Yong Cui
- Department of Biochemistry, Shenyang Pharmaceutical University Shenyang, China
| | - Jing-Hai Zhang
- Department of Biochemistry, Shenyang Pharmaceutical University Shenyang, China
| | - Chun-Fu Wu
- Department of Pharmacology, Shenyang Pharmaceutical University Shenyang, China
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