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Tu T, Fang Z, Cheng Z, Spasic S, Palepu A, Stankovic KM, Natarajan V, Peltz G. Genetic Discovery Enabled by A Large Language Model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.09.566468. [PMID: 37986848 PMCID: PMC10659415 DOI: 10.1101/2023.11.09.566468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Artificial intelligence (AI) has been used in many areas of medicine, and recently large language models (LLMs) have shown potential utility for clinical applications. However, since we do not know if the use of LLMs can accelerate the pace of genetic discovery, we used data generated from mouse genetic models to investigate this possibility. We examined whether a recently developed specialized LLM (Med-PaLM 2) could analyze sets of candidate genes generated from analysis of murine models of biomedical traits. In response to free-text input, Med-PaLM 2 correctly identified the murine genes that contained experimentally verified causative genetic factors for six biomedical traits, which included susceptibility to diabetes and cataracts. Med-PaLM 2 was also able to analyze a list of genes with high impact alleles, which were identified by comparative analysis of murine genomic sequence data, and it identified a causative murine genetic factor for spontaneous hearing loss. Based upon this Med-PaLM 2 finding, a novel bigenic model for susceptibility to spontaneous hearing loss was developed. These results demonstrate Med-PaLM 2 can analyze gene-phenotype relationships and generate novel hypotheses, which can facilitate genetic discovery.
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Affiliation(s)
- Tao Tu
- Google Research, Mountain View, CA, USA
| | - Zhouqing Fang
- Department of Anesthesiology, Pain and Perioperative Medicine
| | - Zhuanfen Cheng
- Department of Anesthesiology, Pain and Perioperative Medicine
| | - Svetolik Spasic
- Department of Otolaryngology - Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | - Konstantina M Stankovic
- Department of Otolaryngology - Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | - Gary Peltz
- Department of Anesthesiology, Pain and Perioperative Medicine
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Smith PA. Neuropathic pain; what we know and what we should do about it. FRONTIERS IN PAIN RESEARCH 2023; 4:1220034. [PMID: 37810432 PMCID: PMC10559888 DOI: 10.3389/fpain.2023.1220034] [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: 05/09/2023] [Accepted: 09/05/2023] [Indexed: 10/10/2023] Open
Abstract
Neuropathic pain can result from injury to, or disease of the nervous system. It is notoriously difficult to treat. Peripheral nerve injury promotes Schwann cell activation and invasion of immunocompetent cells into the site of injury, spinal cord and higher sensory structures such as thalamus and cingulate and sensory cortices. Various cytokines, chemokines, growth factors, monoamines and neuropeptides effect two-way signalling between neurons, glia and immune cells. This promotes sustained hyperexcitability and spontaneous activity in primary afferents that is crucial for onset and persistence of pain as well as misprocessing of sensory information in the spinal cord and supraspinal structures. Much of the current understanding of pain aetiology and identification of drug targets derives from studies of the consequences of peripheral nerve injury in rodent models. Although a vast amount of information has been forthcoming, the translation of this information into the clinical arena has been minimal. Few, if any, major therapeutic approaches have appeared since the mid 1990's. This may reflect failure to recognise differences in pain processing in males vs. females, differences in cellular responses to different types of injury and differences in pain processing in humans vs. animals. Basic science and clinical approaches which seek to bridge this knowledge gap include better assessment of pain in animal models, use of pain models which better emulate human disease, and stratification of human pain phenotypes according to quantitative assessment of signs and symptoms of disease. This can lead to more personalized and effective treatments for individual patients. Significance statement: There is an urgent need to find new treatments for neuropathic pain. Although classical animal models have revealed essential features of pain aetiology such as peripheral and central sensitization and some of the molecular and cellular mechanisms involved, they do not adequately model the multiplicity of disease states or injuries that may bring forth neuropathic pain in the clinic. This review seeks to integrate information from the multiplicity of disciplines that seek to understand neuropathic pain; including immunology, cell biology, electrophysiology and biophysics, anatomy, cell biology, neurology, molecular biology, pharmacology and behavioral science. Beyond this, it underlines ongoing refinements in basic science and clinical practice that will engender improved approaches to pain management.
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Affiliation(s)
- Peter A. Smith
- Neuroscience and Mental Health Institute and Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
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Zimney K, Van Bogaert W, Louw A. The Biology of Chronic Pain and Its Implications for Pain Neuroscience Education: State of the Art. J Clin Med 2023; 12:4199. [PMID: 37445234 DOI: 10.3390/jcm12134199] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/06/2023] [Accepted: 06/14/2023] [Indexed: 07/15/2023] Open
Abstract
Pain is an individualized experience for the person suffering from chronic pain. Significant strides have been made in the last few decades in understanding various biological changes that coincide with chronic pain. This state-of-the-art overview looks at the current evidence related to the biology of chronic pain and the implications these findings have on the delivery of pain neuroscience education (PNE). The paper summarizes the various (epi)genetic, neural, endocrine, and immune factors discovered and explored in the scientific literature concerning chronic pain. Each of these biological factors has various implications for the content and delivery of PNE. We discuss the future directions these biological factors have for the clinical implementation of PNE by linking the importance of behavior change, optimizing the learning environment, and using an individualized multimodal treatment approach with PNE. In addition, future directions for research of PNE based on these biological factors are provided with importance placed on individualized patient-centered care and how PNE can be used with traditional modes of care and growing trends with other care methods. PNE was originally and continues to be rooted in understanding chronic pain biology and how that understanding can improve patient care and outcomes.
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Affiliation(s)
- Kory Zimney
- Department of Physical Therapy, University of South Dakota, 414 East Clark St., Vermillion, SD 57069, USA
| | - Wouter Van Bogaert
- Pain in Motion Research Group (PAIN), Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education and Physiotherapy, Vrije Universiteit Brussel, Laarbeeklaan 121, 1000 Brussels, Belgium
- Research Foundation-Flanders (FWO), Leuvenseweg 38, 1000 Brussels, Belgium
- Interuniversity Centre for Health Economics Research (I-CHER), Department of Public Health (GEWE), Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, 1000 Brussels, Belgium
- Department of Physical Medicine and Physiotherapy, University Hospital Brussels, Laarbeeklaan 101, 1000 Brussels, Belgium
| | - Adriaan Louw
- Evidence in Motion, 618 Broad Street, Suite B, Story City, IA 50248, USA
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Pathophysiological and Neuroplastic Changes in Postamputation and Neuropathic Pain: Review of the Literature. Plast Reconstr Surg Glob Open 2022; 10:e4549. [PMID: 36187278 PMCID: PMC9521753 DOI: 10.1097/gox.0000000000004549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 08/05/2022] [Indexed: 10/24/2022]
Abstract
Despite advancements in surgical and rehabilitation strategies, extremity amputations are frequently associated with disability, phantom limb sensations, and chronic pain. Investigation into potential treatment modalities has focused on the pathophysiological changes in both the peripheral and central nervous systems to better understand the underlying mechanism in the development of chronic pain in persons with amputations. Methods Presented in this article is a discussion outlining the physiological changes that occur in the peripheral and central nervous systems following amputation. In this review, the authors examine the molecular and neuroplastic changes occurring in the nervous system, as well as the state-of-the-art treatment to help reduce the development of postamputation pain. Results This review summarizes the current literature regarding neurological changes following amputation. Development of both central sensitization and neuronal remodeling in the spinal cord and cerebral cortex allows for the development of neuropathic and phantom limb pain postamputation. Recently developed treatments targeting these pathophysiological changes have enabled a reduction in the severity of pain; however, complete resolution remains elusive. Conclusions Changes in the peripheral and central nervous systems following amputation should not be viewed as separate pathologies, but rather two interdependent mechanisms that underlie the development of pathological pain. A better understanding of the physiological changes following amputation will allow for improvements in therapeutic treatments to minimize pathological pain caused by amputation.
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Felix R, Muñoz-Herrera D, Corzo-López A, Fernández-Gallardo M, Leyva-Leyva M, González-Ramírez R, Sandoval A. Ion channel long non-coding RNAs in neuropathic pain. Pflugers Arch 2022; 474:457-468. [PMID: 35235008 DOI: 10.1007/s00424-022-02675-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 02/17/2022] [Accepted: 02/18/2022] [Indexed: 02/01/2023]
Abstract
Neuropathic pain is one of the primary forms of chronic pain and is the consequence of the somatosensory system's direct injury or disease. It is a relevant public health problem that affects about 10% of the world's general population. In neuropathic pain, alteration in neurotransmission occurs at various levels, including the dorsal root ganglia, the spinal cord, and the brain, resulting from the malfunction of diverse molecules such as receptors, ion channels, and elements of specific intracellular signaling pathways. In this context, there have been exciting advances in elucidating neuropathic pain's cellular and molecular mechanisms in the last decade, including the possible role that long non-coding RNAs (lncRNAs) may play, which open up new alternatives for the development of diagnostic and therapeutic strategies for this condition. This review focuses on recent studies associated with the possible relevance of lncRNAs in the development and maintenance of neuropathic pain through their actions on the functional expression of ion channels. Recognizing the changes in the function and spatio-temporal patterns of expression of these membrane proteins is crucial to understanding the control of neuronal excitability in chronic pain syndromes.
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Affiliation(s)
- Ricardo Felix
- Department of Cell Biology, Centre for Research and Advanced Studies (Cinvestav), 07360, Mexico City, Mexico.
| | - David Muñoz-Herrera
- Department of Cell Biology, Centre for Research and Advanced Studies (Cinvestav), 07360, Mexico City, Mexico
| | - Alejandra Corzo-López
- Department of Cell Biology, Centre for Research and Advanced Studies (Cinvestav), 07360, Mexico City, Mexico
| | | | - Margarita Leyva-Leyva
- Department of Molecular Biology and Histocompatibility, "Dr. Manuel Gea González" General Hospital, Mexico City, Mexico
| | - Ricardo González-Ramírez
- Department of Molecular Biology and Histocompatibility, "Dr. Manuel Gea González" General Hospital, Mexico City, Mexico
| | - Alejandro Sandoval
- School of Medicine FES Iztacala, National Autonomous University of Mexico (UNAM), Tlalnepantla, Mexico
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Wistrom E, Chase R, Smith PR, Campbell ZT. A compendium of validated pain genes. WIREs Mech Dis 2022; 14:e1570. [PMID: 35760453 PMCID: PMC9787016 DOI: 10.1002/wsbm.1570] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/28/2022] [Accepted: 06/06/2022] [Indexed: 12/30/2022]
Abstract
The development of novel pain therapeutics hinges on the identification and rigorous validation of potential targets. Model organisms provide a means to test the involvement of specific genes and regulatory elements in pain. Here we provide a list of genes linked to pain-associated behaviors. We capitalize on results spanning over three decades to identify a set of 242 genes. They support a remarkable diversity of functions spanning action potential propagation, immune response, GPCR signaling, enzymatic catalysis, nucleic acid regulation, and intercellular signaling. Making use of existing tissue and single-cell high-throughput RNA sequencing datasets, we examine their patterns of expression. For each gene class, we discuss archetypal members, with an emphasis on opportunities for additional experimentation. Finally, we discuss how powerful and increasingly ubiquitous forward genetic screening approaches could be used to improve our ability to identify pain genes. This article is categorized under: Neurological Diseases > Genetics/Genomics/Epigenetics Neurological Diseases > Molecular and Cellular Physiology.
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Affiliation(s)
- Eric Wistrom
- Department of Biological SciencesUniversity of Texas at DallasRichardsonTexasUSA
| | - Rebecca Chase
- Department of Biological SciencesUniversity of Texas at DallasRichardsonTexasUSA
| | - Patrick R. Smith
- Department of Biological SciencesUniversity of Texas at DallasRichardsonTexasUSA
| | - Zachary T. Campbell
- Department of Biological SciencesUniversity of Texas at DallasRichardsonTexasUSA,Center for Advanced Pain StudiesUniversity of Texas at DallasRichardsonTexasUSA
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7
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Stucky CL, Mikesell AR. Cutaneous pain in disorders affecting peripheral nerves. Neurosci Lett 2021; 765:136233. [PMID: 34506882 PMCID: PMC8579816 DOI: 10.1016/j.neulet.2021.136233] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 08/16/2021] [Accepted: 09/02/2021] [Indexed: 02/08/2023]
Abstract
Our ability to quickly detect and respond to harmful environmental stimuli is vital for our safety and survival. This inherent acute pain detection is a "gift" because it both protects our body from harm and allows healing of damaged tissues [1]. Damage to tissues from trauma or disease can result in distorted or amplified nociceptor signaling and sensitization of the spinal cord and brain (Central Nervous System; CNS) pathways to normal input from light touch mechanoreceptors. Together, these processes can result in nagging to unbearable chronic pain and extreme sensitivity to light skin touch (allodynia). Unlike acute protective pain, chronic pain and allodynia serve no useful purpose and can severely reduce the quality of life of an affected person. Chronic pain can arise from impairment to peripheral neurons, a phenomenon called "peripheral neuropathic pain." Peripheral neuropathic pain can be caused by many insults that directly affect peripheral sensory neurons, including mechanical trauma, metabolic imbalance (e.g., diabetes), autoimmune diseases, chemotherapeutic agents, viral infections (e.g., shingles). These insults cause "acquired" neuropathies such as small-fiber neuropathies, diabetic neuropathy, chemotherapy-induced peripheral neuropathy, and post herpetic neuralgia. Peripheral neuropathic pain can also be caused by genetic factors and result in hereditary neuropathies that include Charcot-Marie-Tooth disease, rare channelopathies and Fabry disease. Many acquired and hereditary neuropathies affect the skin, our largest organ and protector of nearly our entire body. Here we review how cutaneous nociception (pain perceived from the skin) is altered following diseases that affect peripheral nerves that innervate the skin. We provide an overview of how noxious stimuli are detected and encoded by molecular transducers on subtypes of cutaneous afferent endings and conveyed to the CNS. Next, we discuss several acquired and hereditary diseases and disorders that cause painful or insensate (lack of sensation) cutaneous peripheral neuropathies, the symptoms and percepts patients experience, and how cutaneous afferents and other peripheral cell types are altered in function in these disorders. We highlight exciting new research areas that implicate non-neuronal skin cells, particularly keratinocytes, in cutaneous nociception and peripheral neuropathies. Finally, we conclude with ideas for innovative new directions, areas of unmet need, and potential opportunities for novel cutaneous therapeutics that may avoid CNS side effects, as well as ideas for improved translation of mechanisms identified in preclinical models to patients.
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Affiliation(s)
- Cheryl L Stucky
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, United States.
| | - Alexander R Mikesell
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, United States
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8
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Qaswal AB, Ababneh O, Khreesha L, Al-Ani A, Suleihat A, Abbad M. Mathematical Modeling of Ion Quantum Tunneling Reveals Novel Properties of Voltage-Gated Channels and Quantum Aspects of Their Pathophysiology in Excitability-Related Disorders. PATHOPHYSIOLOGY 2021; 28:116-154. [PMID: 35366274 PMCID: PMC8830480 DOI: 10.3390/pathophysiology28010010] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/03/2021] [Accepted: 03/04/2021] [Indexed: 02/08/2023] Open
Abstract
Voltage-gated channels are crucial in action potential initiation and propagation and there are many diseases and disorders related to them. Additionally, the classical mechanics are the main mechanics used to describe the function of the voltage-gated channels and their related abnormalities. However, the quantum mechanics should be considered to unravel new aspects in the voltage-gated channels and resolve the problems and challenges that classical mechanics cannot solve. In the present study, the aim is to mathematically show that quantum mechanics can exhibit a powerful tendency to unveil novel electrical features in voltage-gated channels and be used as a promising tool to solve the problems and challenges in the pathophysiology of excitability-related diseases. The model of quantum tunneling of ions through the intracellular hydrophobic gate is used to evaluate the influence of membrane potential and gating free energy on the tunneling probability, single channel conductance, and quantum membrane conductance. This evaluation is mainly based on graphing the mathematical relationships between these variables. The obtained mathematical graphs showed that ions can achieve significant quantum membrane conductance, which can affect the resting membrane potential and the excitability of cells. In the present work, quantum mechanics reveals original electrical properties associated with voltage-gated channels and introduces new insights and implications into the pathophysiology of excitability- related disorders. In addition, the present work sets a mathematical and theoretical framework that can be utilized to conduct experimental studies in order to explore the quantum aspects of voltage-gated channels and the quantum bioelectrical property of biological membranes.
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Affiliation(s)
- Abdallah Barjas Qaswal
- Department of Internship Program, Jordan University Hospital, The University of Jordan, Amman 11942, Jordan
- Correspondence:
| | - Omar Ababneh
- Department of Anesthesia and Intensive Care, School of Medicine, The University of Jordan, Amman 11942, Jordan;
| | - Lubna Khreesha
- Department of Special Surgery, School of Medicine, The University of Jordan, Amman 11942, Jordan;
| | - Abdallah Al-Ani
- School of Medicine, The University of Jordan, Amman 11942, Jordan;
| | - Ahmad Suleihat
- Department of General Surgery, School of Medicine, The University of Jordan, Amman 11942, Jordan; (A.S.); (M.A.)
| | - Mutaz Abbad
- Department of General Surgery, School of Medicine, The University of Jordan, Amman 11942, Jordan; (A.S.); (M.A.)
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9
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Abstract
A fundamental mechanism that drives the propagation of electrical signals in the nervous system is the activation of voltage-gated sodium channels. The sodium channel subtype Nav1.7 is critical for the transmission of pain-related signaling, with gain-of-function mutations in Nav1.7 resulting in various painful pathologies. Loss-of-function mutations cause complete insensitivity to pain and anosmia in humans that otherwise have normal nervous system function, rendering Nav1.7 an attractive target for the treatment of pain. Despite this, no Nav1.7 selective therapeutic has been approved for use as an analgesic to date. Here we present a summary of research that has focused on engineering peptides found in spider venoms to produce Nav1.7 selective antagonists. We discuss the progress that has been made on various scaffolds from different venom families and highlight the challenges that remain in the effort to produce a Nav1.7 selective, venom-based analgesic.
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Affiliation(s)
- Robert A Neff
- Neuroscience Discovery, Janssen Research and Development, LLC , San Diego, CA, USA
| | - Alan D Wickenden
- Molecular and Cellular Pharmacology, Janssen Research and Development, LLC , San Diego, CA, USA
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Smith PA. K + Channels in Primary Afferents and Their Role in Nerve Injury-Induced Pain. Front Cell Neurosci 2020; 14:566418. [PMID: 33093824 PMCID: PMC7528628 DOI: 10.3389/fncel.2020.566418] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/21/2020] [Indexed: 12/12/2022] Open
Abstract
Sensory abnormalities generated by nerve injury, peripheral neuropathy or disease are often expressed as neuropathic pain. This type of pain is frequently resistant to therapeutic intervention and may be intractable. Numerous studies have revealed the importance of enduring increases in primary afferent excitability and persistent spontaneous activity in the onset and maintenance of peripherally induced neuropathic pain. Some of this activity results from modulation, increased activity and /or expression of voltage-gated Na+ channels and hyperpolarization-activated cyclic nucleotide–gated (HCN) channels. K+ channels expressed in dorsal root ganglia (DRG) include delayed rectifiers (Kv1.1, 1.2), A-channels (Kv1.4, 3.3, 3.4, 4.1, 4.2, and 4.3), KCNQ or M-channels (Kv7.2, 7.3, 7.4, and 7.5), ATP-sensitive channels (KIR6.2), Ca2+-activated K+ channels (KCa1.1, 2.1, 2.2, 2.3, and 3.1), Na+-activated K+ channels (KCa4.1 and 4.2) and two pore domain leak channels (K2p; TWIK related channels). Function of all K+ channel types is reduced via a multiplicity of processes leading to altered expression and/or post-translational modification. This also increases excitability of DRG cell bodies and nociceptive free nerve endings, alters axonal conduction and increases neurotransmitter release from primary afferent terminals in the spinal dorsal horn. Correlation of these cellular changes with behavioral studies provides almost indisputable evidence for K+ channel dysfunction in the onset and maintenance of neuropathic pain. This idea is underlined by the observation that selective impairment of just one subtype of DRG K+ channel can produce signs of pain in vivo. Whilst it is established that various mediators, including cytokines and growth factors bring about injury-induced changes in DRG function and excitability, evidence presently available points to a seminal role for interleukin 1β (IL-1β) in control of K+ channel function. Despite the current state of knowledge, attempts to target K+ channels for therapeutic pain management have met with limited success. This situation may change with the advent of personalized medicine. Identification of specific sensory abnormalities and genetic profiling of individual patients may predict therapeutic benefit of K+ channel activators.
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Affiliation(s)
- Peter A Smith
- Department of Pharmacology and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
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11
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Mechanisms of small nerve fiber pathology. Neurosci Lett 2020; 737:135316. [PMID: 32828814 DOI: 10.1016/j.neulet.2020.135316] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/16/2020] [Accepted: 08/18/2020] [Indexed: 12/14/2022]
Abstract
Small fiber pathology is increasingly recognized as a potential contributor to neuropathic pain in different clinical syndromes, however, the underlying mechanisms leading to nociceptor sensitization and degeneration are unclear. With the diversity in clinical pain phenotypes and etiology of small fiber pathology, individual mechanisms are assumed, but are not yet fully understood. The thinly-myelinated Aδ- and unmyelinated C-nerve fibers are mainly affected and clinically require special small fiber test methods to capture functional, morphological, and electrophysiological alterations. Several methods have been established and implemented in clinical practice in the last years. In parallel, experimental and in vitro test systems have been developed allowing important insights into the molecular mechanisms underlying nociceptor sensitization and degeneration as main hallmarks of small fiber pathology. In our narrative review, we focus on these methods and current knowledge, and provide a synopsis of the achievements made so far in this exciting field.
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Alieva AK, Rudenok MM, Novosadova EV, Vlasov IN, Arsenyeva EL, Rosinskaya AV, Grivennikov IA, Slominsky PA, Shadrina MI. Whole-Transcriptome Analysis of Dermal Fibroblasts, Derived from Three Pairs of Monozygotic Twins, Discordant for Parkinson's Disease. J Mol Neurosci 2020; 70:284-293. [PMID: 31823283 PMCID: PMC7222158 DOI: 10.1007/s12031-019-01452-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 11/17/2019] [Indexed: 01/24/2023]
Abstract
Parkinson's disease (PD) is one of the most common neurodegenerative diseases. In most cases, the development of the disease is sporadic and is not associated with any currently known mutations associated with PD. It is believed that changes associated with the epigenetic regulation of gene expression may play an important role in the pathogenesis of this disease. The study of individuals with an almost identical genetic background, such as monozygotic twins, is one of the best approaches to the analysis of such changes. A whole-transcriptome analysis of dermal fibroblasts obtained from three pairs of monozygotic twins discordant for PD was carried out in this work. Twenty-nine differentially expressed genes were identified in the three pairs of twins. These genes were included in seven processes within two clusters, according to the results of an enrichment analysis. The cluster with the greatest statistical significance included processes associated with the regulation of the differentiation of fat cells, the action potential, and the regulation of glutamatergic synaptic transmission. The most significant genes, which occupied a central position in this cluster, were PTGS2, SCN9A, and GRIK2. These genes can be considered as potential candidate genes for PD.
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Affiliation(s)
- Anelya Kh. Alieva
- Institute of Molecular Genetics of Russian Academy of Sciences, 2 Kurchatova sq, Moscow, 123182 Russia
| | - Margarita M. Rudenok
- Institute of Molecular Genetics of Russian Academy of Sciences, 2 Kurchatova sq, Moscow, 123182 Russia
| | - Ekaterina V. Novosadova
- Institute of Molecular Genetics of Russian Academy of Sciences, 2 Kurchatova sq, Moscow, 123182 Russia
| | - Ivan N. Vlasov
- Institute of Molecular Genetics of Russian Academy of Sciences, 2 Kurchatova sq, Moscow, 123182 Russia
| | - Elena L. Arsenyeva
- Institute of Molecular Genetics of Russian Academy of Sciences, 2 Kurchatova sq, Moscow, 123182 Russia
| | - Anna V. Rosinskaya
- State Public Health Institution Primorsk Regional Clinical Hospital No. 1, 57 Aleutskaya St, Vladivostok, 690091 Russia
| | - Igor A. Grivennikov
- Institute of Molecular Genetics of Russian Academy of Sciences, 2 Kurchatova sq, Moscow, 123182 Russia
| | - Petr A. Slominsky
- Institute of Molecular Genetics of Russian Academy of Sciences, 2 Kurchatova sq, Moscow, 123182 Russia
| | - Maria I. Shadrina
- Institute of Molecular Genetics of Russian Academy of Sciences, 2 Kurchatova sq, Moscow, 123182 Russia
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13
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Saro G, Lia AS, Thapliyal S, Marques F, Busch KE, Glauser DA. Specific Ion Channels Control Sensory Gain, Sensitivity, and Kinetics in a Tonic Thermonociceptor. Cell Rep 2020; 30:397-408.e4. [DOI: 10.1016/j.celrep.2019.12.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 10/17/2019] [Accepted: 12/06/2019] [Indexed: 10/25/2022] Open
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14
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Huygen FJPM, Kallewaard JW, Nijhuis H, Liem L, Vesper J, Fahey ME, Blomme B, Morgalla MH, Deer TR, Capobianco RA. Effectiveness and Safety of Dorsal Root Ganglion Stimulation for the Treatment of Chronic Pain: A Pooled Analysis. Neuromodulation 2019; 23:213-221. [PMID: 31730273 PMCID: PMC7079258 DOI: 10.1111/ner.13074] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 10/14/2019] [Accepted: 10/18/2019] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Since it became available in the mid-2010s, dorsal root ganglion (DRG) stimulation has become part of the armamentarium to treat chronic pain. To date, one randomized controlled trial, and several studies of moderate sample size and various etiologies have been published on this topic. We conducted a pooled analysis to investigate the generalizability of individual studies and to identify differences in outcome between chronic pain etiologic subgroups and/or pain location. MATERIALS AND METHODS One prospective, randomized comparative trial and six prospective, single-arm, observational studies were identified that met pre-defined acceptance criteria. Pain scores and patient-reported outcome (PRO) measures were weighted by study sample sizes and pooled. Safety data are reported in aggregate form. RESULTS Our analysis included 217 patients with a permanent implant at 12-month follow-up. Analysis of pooled data showed an overall weighted mean pain score of 3.4, with 63% of patients reporting ≥50% pain relief. Effectiveness sub-analyses in CRPS-I, causalgia, and back pain resulted in a mean reduction in pain intensity of 4.9, 4.6, and 3.9 points, respectively. Our pooled analysis showed a pain score for primary affected region ranging from 1.7 (groin) to 3.0 (buttocks) and responder rates of 80% for foot and groin, 75% for leg, and 70% for back. A substantial improvement in all PROs was observed at 12 months. The most commonly reported procedural or device complications were pain at the IPG pocket site, lead fracture, lead migration, and infection. CONCLUSIONS DRG stimulation is an effective and safe therapy for various etiologies of chronic pain.
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Affiliation(s)
- Frank J P M Huygen
- Department of Anesthesiology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Jan Willem Kallewaard
- Department of Anesthesiology and Pain Management Arnhem, Rijnstate Hospital, Velp, The Netherlands
| | | | - Liong Liem
- Maastricht University Medical Center, Maastricht, The Netherlands
| | - Jan Vesper
- Department of Functional Neurosurgery and Stereotaxy, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | | | - Bram Blomme
- Neuromodulation Division, Abbott, Austin, TX, USA
| | | | - Timothy R Deer
- The Spine and Nerve Center of the Virginias, Charleston, WV, USA
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15
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Sutherland HG, Albury CL, Griffiths LR. Advances in genetics of migraine. J Headache Pain 2019; 20:72. [PMID: 31226929 PMCID: PMC6734342 DOI: 10.1186/s10194-019-1017-9] [Citation(s) in RCA: 105] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 05/24/2019] [Indexed: 02/06/2023] Open
Abstract
Background Migraine is a complex neurovascular disorder with a strong genetic component. There are rare monogenic forms of migraine, as well as more common polygenic forms; research into the genes involved in both types has provided insights into the many contributing genetic factors. This review summarises advances that have been made in the knowledge and understanding of the genes and genetic variations implicated in migraine etiology. Findings Migraine is characterised into two main types, migraine without aura (MO) and migraine with aura (MA). Hemiplegic migraine is a rare monogenic MA subtype caused by mutations in three main genes - CACNA1A, ATP1A2 and SCN1A - which encode ion channel and transport proteins. Functional studies in cellular and animal models show that, in general, mutations result in impaired glutamatergic neurotransmission and cortical hyperexcitability, which make the brain more susceptible to cortical spreading depression, a phenomenon thought to coincide with aura symptoms. Variants in other genes encoding ion channels and solute carriers, or with roles in regulating neurotransmitters at neuronal synapses, or in vascular function, can also cause monogenic migraine, hemiplegic migraine and related disorders with overlapping symptoms. Next-generation sequencing will accelerate the finding of new potentially causal variants and genes, with high-throughput bioinformatics analysis methods and functional analysis pipelines important in prioritising, confirming and understanding the mechanisms of disease-causing variants. With respect to common migraine forms, large genome-wide association studies (GWAS) have greatly expanded our knowledge of the genes involved, emphasizing the role of both neuronal and vascular pathways. Dissecting the genetic architecture of migraine leads to greater understanding of what underpins relationships between subtypes and comorbid disorders, and may have utility in diagnosis or tailoring treatments. Further work is required to identify causal polymorphisms and the mechanism of their effect, and studies of gene expression and epigenetic factors will help bridge the genetics with migraine pathophysiology. Conclusions The complexity of migraine disorders is mirrored by their genetic complexity. A comprehensive knowledge of the genetic factors underpinning migraine will lead to improved understanding of molecular mechanisms and pathogenesis, to enable better diagnosis and treatments for migraine sufferers.
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Affiliation(s)
- Heidi G Sutherland
- Genomics Research Centre, Institute of Health and Biomedical Innovation. School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Cassie L Albury
- Genomics Research Centre, Institute of Health and Biomedical Innovation. School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Lyn R Griffiths
- Genomics Research Centre, Institute of Health and Biomedical Innovation. School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD, Australia.
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16
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Lawson K. Kv7 channels a potential therapeutic target in fibromyalgia: A hypothesis. World J Pharmacol 2018; 7:1-9. [DOI: 10.5497/wjp.v7.i1.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/05/2018] [Accepted: 10/13/2018] [Indexed: 02/06/2023] Open
Abstract
Fibromyalgia is characterized by the primary symptoms of persistent diffuse pain, fatigue, sleep disturbance and cognitive dysfunction. Persistent pain conditions, such as fibromyalgia, are often refractory to current available therapies. An involvement of K+ channels in the pathophysiology of fibromyalgia is emerging and supported by drug treatments for this condition exhibiting action at these molecular processes. K+ channels constitute potential novel target candidates for pain therapy offering peripheral and/or central actions. The Kv7 channel activators, flupirtine and retigabine, have exhibited pharmacological profiles compatible to the requirements needed for use as a therapeutic approach to fibromyalgia. Clinical trials to address the multidimensional challenges of fibromyalgia with flupirtine and retigabine will provide important insight to the role of K+ channels in this condition.
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Affiliation(s)
- Kim Lawson
- Department of Biosciences and Chemistry, Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield S1 1WB, United Kingdom
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17
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Zemel BM, Ritter DM, Covarrubias M, Muqeem T. A-Type K V Channels in Dorsal Root Ganglion Neurons: Diversity, Function, and Dysfunction. Front Mol Neurosci 2018; 11:253. [PMID: 30127716 PMCID: PMC6088260 DOI: 10.3389/fnmol.2018.00253] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/04/2018] [Indexed: 12/13/2022] Open
Abstract
A-type voltage-gated potassium (Kv) channels are major regulators of neuronal excitability that have been mainly characterized in the central nervous system. By contrast, there is a paucity of knowledge about the molecular physiology of these Kv channels in the peripheral nervous system, including highly specialized and heterogenous dorsal root ganglion (DRG) neurons. Although all A-type Kv channels display pore-forming subunits with similar structural properties and fast inactivation, their voltage-, and time-dependent properties and modulation are significantly different. These differences ultimately determine distinct physiological roles of diverse A-type Kv channels, and how their dysfunction might contribute to neurological disorders. The importance of A-type Kv channels in DRG neurons is highlighted by recent studies that have linked their dysfunction to persistent pain sensitization. Here, we review the molecular neurophysiology of A-type Kv channels with an emphasis on those that have been identified and investigated in DRG nociceptors (Kv1.4, Kv3.4, and Kv4s). Also, we discuss evidence implicating these Kv channels in neuropathic pain resulting from injury, and present a perspective of outstanding challenges that must be tackled in order to discover novel treatments for intractable pain disorders.
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Affiliation(s)
- Benjamin M. Zemel
- Vollum Institute, Oregon Health and Science University, Portland, OR, United States
| | - David M. Ritter
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Manuel Covarrubias
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College and Jefferson College of Life Sciences at Thomas Jefferson University, Philadelphia, PA, United States
| | - Tanziyah Muqeem
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College and Jefferson College of Life Sciences at Thomas Jefferson University, Philadelphia, PA, United States
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18
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Haehner A, Hummel T, Heinritz W, Krueger S, Meinhardt M, Whitcroft KL, Sabatowski R, Gossrau G. Mutation in Nav
1.7 causes high olfactory sensitivity. Eur J Pain 2018; 22:1767-1773. [DOI: 10.1002/ejp.1272] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2018] [Indexed: 12/11/2022]
Affiliation(s)
- A. Haehner
- Smell & Taste Clinic; Department of Otorhinolaryngology; TU Dresden; Germany
| | - T. Hummel
- Smell & Taste Clinic; Department of Otorhinolaryngology; TU Dresden; Germany
| | - W. Heinritz
- ÜBAG for Human Genetics Oberelbe/Spree; Cottbus/Dresden Germany
| | - S. Krueger
- ÜBAG for Human Genetics Oberelbe/Spree; Cottbus/Dresden Germany
| | | | - K. L. Whitcroft
- Smell & Taste Clinic; Department of Otorhinolaryngology; TU Dresden; Germany
- UCL Ear Institute; University College London; UK
- Centre for the Study of the Senses; School of Advanced Study; London UK
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19
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Ye H, Du X, Hua Q. Effects of voluntary exercise on antiretroviral therapy-induced neuropathic pain in mice. J Physiol Sci 2018; 68:521-530. [PMID: 28975573 PMCID: PMC10717227 DOI: 10.1007/s12576-017-0570-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 09/19/2017] [Indexed: 12/12/2022]
Abstract
Antiretroviral therapy (ART) often results in painful peripheral neuropathy. Given that voluntary exercise has been shown to be beneficial in terms of modulating pain-like behaviors in various animal models of peripheral neuropathy, we have investigated the effects of voluntary wheel running on neuropathic pain induced by chronic ART. We first established an animal model of peripheral neuropathy induced by chronic 2',3'-dideoxycytidine (ddC) treatment. We showed that mice receiving ddC (3 mg/kg/day) had increased mechanical and thermal sensitivity at 9 weeks after the onset of the treatment. We also found that voluntary wheel running attenuated or delayed the onset of ddC-induced peripheral neuropathy. This phenomenon was associated with the attenuation of dorsal root ganglion nociceptive neuron membrane excitability and reduction in the expression of the transient receptor potential cation channel subfamily V member 1 (TRPV1). Taken together, these results suggest that voluntary exercise is an effective strategy by which ART-induced peripheral neuropathy can be alleviated.
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Affiliation(s)
- Hong Ye
- Department of Anesthesiology, Daqing Oil Field General Hospital, No. 9 Saertu District, Daqing, 163000, Heilongjiang, China
| | - Xingguang Du
- Department of Anesthesiology, Daqing Oil Field General Hospital, No. 9 Saertu District, Daqing, 163000, Heilongjiang, China
| | - Qingli Hua
- Department of Anesthesiology, Daqing Longnan Hospital, No. 35 Patriotic Road, Ranghulu District, Daqing, 163000, Heilongjiang, China.
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20
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Tian D, Tian M, Zhang L, Zhao P, Cui Y, Li J. High fat diet sensitizes fibromyalgia-like pain behaviors in mice via tumor necrosis factor alpha. PLoS One 2018; 13:e0190861. [PMID: 29444083 PMCID: PMC5812560 DOI: 10.1371/journal.pone.0190861] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 12/21/2017] [Indexed: 12/21/2022] Open
Abstract
Fibromyalgia (FM) and obesity are closely related. However, little is known about how obesity contributes to FM. Importantly, adequate evidence has shown that tumor necrosis factor alpha (TNF-α) plays a critical role in obesity. Thus, we hypothesized that obesity-induced TNF-α release may potentiate FM-associated pain. To test this hypothesis, we investigated the role of TNF-α in the development of FM-like pain in a mouse model of acid saline injection-induced FM. Consistent with previous reports, we showed that repeated acid saline injections induced bilateral mechanical hyperalgesia, and this effect lasted for at least 4 days after acid saline injections. This phenomenon was associated with increased levels of TNF-α in plasma, muscles, and spinal cord. Furthermore, we found that 24 weeks of high fat diet treatment significantly potentiated acid saline-induced bilateral mechanical hyperalgesia. High fat diet-treated mice exhibited robustly increased levels of TNF-α in plasma, muscles, and spinal cord after acid saline injections compared with low fat diet-treated mice. Additionally, using immunofluorescence staining, we found that the number of TNF-α positive cells in dorsal root ganglion (DRG) was increased after acid saline injections, and high fat diet treatment further sensitized this increase. Finally, we reported that acid saline-induced FM-like pain behaviors were abolished in TNFRp55-/- mice, confirming the critical role of TNF-α in the development of FM-like pain. Taken together, our results suggested that high fat diet treatment may sensitize acid saline-induced FM-like pain via increasing TNF-α levels in plasma, muscles, and DRG.
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Affiliation(s)
- Dan Tian
- Department of Anesthesiology, Second hospital of Jilin University, Changchun, China
| | - Miao Tian
- Department of Gynecology, Second hospital of Jilin University, Changchun, China
| | - Leilei Zhang
- Department of Anesthesiology, Second hospital of Jilin University, Changchun, China
| | - Peng Zhao
- Department of Anesthesiology, Second hospital of Jilin University, Changchun, China
| | - Yunfeng Cui
- Department of Anesthesiology, Second hospital of Jilin University, Changchun, China
| | - Jinlong Li
- Department of Gastrointestinal Surgery, Second hospital of Jilin University, Changchun, China
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21
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Zeng X, Li P, Chen B, Huang J, Lai R, Liu J, Rong M. Selective Closed-State Nav1.7 Blocker JZTX-34 Exhibits Analgesic Effects against Pain. Toxins (Basel) 2018; 10:toxins10020064. [PMID: 29393892 PMCID: PMC5848165 DOI: 10.3390/toxins10020064] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 01/26/2018] [Accepted: 01/31/2018] [Indexed: 12/11/2022] Open
Abstract
Jingzhaotoxin-34 (JZTX-34) is a selective inhibitor of tetrodotoxin-sensitive (TTX-S) sodium channels. In this study, we found that JZTX-34 selectively acted on Nav1.7 with little effect on other sodium channel subtypes including Nav1.5. If the DIIS3-S4 linker of Nav1.5 is substituted by the correspond linker of Nav1.7, the sensitivity of Nav1.5 to JZTX-34 extremely increases to 1.05 µM. Meanwhile, a mutant D816R in the DIIS3-S4 linker of Nav1.7 decreases binding affinity of Nav1.7 to JZTX-34 about 32-fold. The reverse mutant R800D at the corresponding position in Nav1.5 greatly increased its binding affinity to JZTX-34. This implies that JZTX-34 binds to DIIS3-S4 linker of Nav1.7 and the critical residue of Nav1.7 is D816. Unlike β-scorpion toxin trapping sodium channel in an open state, activity of JZTX-34 requires the sodium channel to be in a resting state. JZTX-34 exhibits an obvious analgesic effect in a rodent pain model. Especially, it shows a longer duration and is more effective than morphine in hot pain models. In a formalin-induced pain model, JZTX-34 at dose of 2 mg/kg is equipotent with morphine (5 mg/kg) in the first phase and several-fold more effective than morphine in second phase. Taken together, our data indicate that JZTX-34 releases pain by selectively binding to the domain II voltage sensor of Nav1.7 in a closed configuration.
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Affiliation(s)
- Xiongzhi Zeng
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China.
- The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China.
| | - Pengpeng Li
- Life Sciences College of Nanjing Agricultural University, 210095, Jiangsu, China.
| | - Bo Chen
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China.
- The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China.
| | - Juan Huang
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China.
- The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China.
| | - Ren Lai
- Life Sciences College of Nanjing Agricultural University, 210095, Jiangsu, China.
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming 650223, Yunnan, China.
| | - Jingze Liu
- Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University, Shijiazhuang 050024, Hebei, China.
| | - Mingqiang Rong
- The National & Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China.
- The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China.
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22
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23
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Wang J, Ou SW, Wang YJ. Distribution and function of voltage-gated sodium channels in the nervous system. Channels (Austin) 2017; 11:534-554. [PMID: 28922053 DOI: 10.1080/19336950.2017.1380758] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Voltage-gated sodium channels (VGSCs) are the basic ion channels for neuronal excitability, which are crucial for the resting potential and the generation and propagation of action potentials in neurons. To date, at least nine distinct sodium channel isoforms have been detected in the nervous system. Recent studies have identified that voltage-gated sodium channels not only play an essential role in the normal electrophysiological activities of neurons but also have a close relationship with neurological diseases. In this study, the latest research findings regarding the structure, type, distribution, and function of VGSCs in the nervous system and their relationship to neurological diseases, such as epilepsy, neuropathic pain, brain tumors, neural trauma, and multiple sclerosis, are reviewed in detail.
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Affiliation(s)
- Jun Wang
- a Department of Neurosurgery , The First Hospital of China Medical University , Shenyang , P.R. China
| | - Shao-Wu Ou
- a Department of Neurosurgery , The First Hospital of China Medical University , Shenyang , P.R. China
| | - Yun-Jie Wang
- a Department of Neurosurgery , The First Hospital of China Medical University , Shenyang , P.R. China
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24
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Loewendorf AI, Matynia A, Saribekyan H, Gross N, Csete M, Harrington M. Roads Less Traveled: Sexual Dimorphism and Mast Cell Contributions to Migraine Pathology. Front Immunol 2016; 7:140. [PMID: 27148260 PMCID: PMC4836167 DOI: 10.3389/fimmu.2016.00140] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 03/31/2016] [Indexed: 12/30/2022] Open
Abstract
Migraine is a common, little understood, and debilitating disease. It is much more prominent in women than in men (~2/3 are women) but the reasons for female preponderance are not clear. Migraineurs frequently experience severe comorbidities, such as allergies, depression, irritable bowel syndrome, and others; many of the comorbidities are more common in females. Current treatments for migraine are not gender specific, and rarely are migraine and its comorbidities considered and treated by the same specialist. Thus, migraine treatments represent a huge unmet medical need, which will only be addressed with greater understanding of its underlying pathophysiology. We discuss the current knowledge about sex differences in migraine and its comorbidities, and focus on the potential role of mast cells (MCs) in both. Sex-based differences in pain recognition and drug responses, fluid balance, and the blood–brain barrier are recognized but their impact on migraine is not well studied. Furthermore, MCs are well recognized for their prominent role in allergies but much less is known about their contributions to pain pathways in general and migraine specifically. MC-neuron bidirectional communication uniquely positions these cells as potential initiators and/or perpetuators of pain. MCs can secrete nociceptor sensitizing and activating agents, such as serotonin, prostaglandins, histamine, and proteolytic enzymes that can also activate the pain-mediating transient receptor potential vanilloid channels. MCs express receptors for both estrogen and progesterone that induce degranulation upon binding. Furthermore, environmental estrogens, such as Bisphenol A, activate MCs in preclinical models but their impact on pain pathways or migraine is understudied. We hope that this discussion will encourage scientists and physicians alike to bridge the knowledge gaps linking sex, MCs, and migraine to develop better, more comprehensive treatments for migraine patients.
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Affiliation(s)
| | - Anna Matynia
- Department of Ophthalmology, Jules Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA; Brain Research Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
| | | | - Noah Gross
- Huntington Medical Research Institutes , Pasadena, CA , USA
| | - Marie Csete
- Huntington Medical Research Institutes , Pasadena, CA , USA
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25
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Pogoda JM, Gross NB, Arakaki X, Fonteh AN, Cowan RP, Harrington MG. Severe Headache or Migraine History is Inversely Correlated With Dietary Sodium Intake: NHANES 1999-2004. Headache 2016; 56:688-98. [PMID: 27016121 PMCID: PMC4836999 DOI: 10.1111/head.12792] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Objective We investigated whether dietary sodium intake from respondents of a national cross‐sectional nutritional study differed by history of migraine or severe headaches. Background Several lines of evidence support a disruption of sodium homeostasis in migraine. Design Our analysis population was 8819 adults in the 1999–2004 National Health and Nutrition Examination Survey (NHANES) with reliable data on diet and headache history. We classified respondents who reported a history of migraine or severe headaches as having probable history of migraine. To reduce the diagnostic conflict from medication overuse headache, we excluded respondents who reported taking analgesic medications. Dietary sodium intake was measured using validated estimates of self‐reported total grams of daily sodium consumption and was analyzed as the residual value from the linear regression of total grams of sodium on total calories. Multivariable logistic regression that accounted for the stratified, multistage probability cluster sampling design of NHANES was used to analyze the relationship between migraine and dietary sodium. Results Odds of probable migraine history decreased with increasing dietary sodium intake (odds ratio = 0.93, 95% confidence interval = 0.87, 1.00, P = .0455). This relationship was maintained after adjusting for age, sex, and body mass index (BMI) with slightly reduced significance (P = .0505). In women, this inverse relationship was limited to those with lower BMI (P = .007), while in men the relationship did not differ by BMI. We likely excluded some migraineurs by omitting frequent analgesic users; however, a sensitivity analysis suggested little effect from this exclusion. Conclusions This study is the first evidence of an inverse relationship between migraine and dietary sodium intake. These results are consistent with altered sodium homeostasis in migraine and our hypothesis that dietary sodium may affect brain extracellular fluid sodium concentrations and neuronal excitability.
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Affiliation(s)
- Janice M Pogoda
- Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
| | - Noah B Gross
- Molecular Neurology Program, Huntington Medical Research Institutes, Pasadena, CA, USA
| | - Xianghong Arakaki
- Molecular Neurology Program, Huntington Medical Research Institutes, Pasadena, CA, USA
| | - Alfred N Fonteh
- Molecular Neurology Program, Huntington Medical Research Institutes, Pasadena, CA, USA
| | - Robert P Cowan
- Department of Neurology, Stanford University School of Medicine, Stanford, CA, USA
| | - Michael G Harrington
- Molecular Neurology Program, Huntington Medical Research Institutes, Pasadena, CA, USA
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26
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Boadas-Vaello P, Castany S, Homs J, Álvarez-Pérez B, Deulofeu M, Verdú E. Neuroplasticity of ascending and descending pathways after somatosensory system injury: reviewing knowledge to identify neuropathic pain therapeutic targets. Spinal Cord 2016; 54:330-40. [DOI: 10.1038/sc.2015.225] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 11/25/2015] [Accepted: 11/28/2015] [Indexed: 12/16/2022]
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27
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Spencer NJ. Switching off pain at the source: is this the end for opioid pain relief? Pain Manag 2015; 6:39-47. [PMID: 26678066 DOI: 10.2217/pmt.15.52] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Opiates, like morphine or codeine, are used to suppress nociceptive pain in humans. While these drugs can provide effective pain relief, they also cause an extensive array of undesirable side effects, including central depression, sedation and addiction. Relatively recently, the sodium channel Nav1.7 was shown to be essential for pain perception in humans. Based on this, we describe a new technical approach that may be useful for the prolonged suppression of nociceptive pain. The technique uses a harmless adeno-associated virus carrying a short hairpin RNA to silence Nav1.7 ion channels only in sensory neurons underlying pain perception. The major advantage is that pain may be suppressed at the source for many months, without the side effects of opiates.
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Affiliation(s)
- Nick J Spencer
- Department of Human Physiology & Centre for Neuroscience, Flinders University of South Australia, Adelaide, Australia
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28
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An Introduction to Pain Pathways and Pain “Targets”. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 131:1-30. [DOI: 10.1016/bs.pmbts.2015.01.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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29
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Boukalova S, Touska F, Marsakova L, Hynkova A, Sura L, Chvojka S, Dittert I, Vlachova V. Gain-of-function mutations in the transient receptor potential channels TRPV1 and TRPA1: how painful? Physiol Res 2014; 63:S205-13. [PMID: 24564660 DOI: 10.33549/physiolres.932658] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Gain-of-function (GOF) mutations in ion channels are rare events, which lead to increased agonist sensitivity or altered gating properties, and may render the channel constitutively active. Uncovering and following characterization of such mutants contribute substantially to the understanding of the molecular basis of ion channel functioning. Here we give an overview of some GOF mutants in polymodal ion channels specifically involved in transduction of painful stimuli--TRPV1 and TRPA1, which are scrutinized by scientists due to their important role in development of some pathological pain states. Remarkably, a substitution of single amino acid in the S4-S5 region of TRPA1 (N855S) has been recently associated with familial episodic pain syndrome. This mutation increases chemical sensitivity of TRPA1, but leaves the voltage sensitivity unchanged. On the other hand, mutations in the analogous region of TRPV1 (R557K and G563S) severely affect all aspects of channel activation and lead to spontaneous activity. Comparison of the effects induced by mutations in homologous positions in different TRP receptors (or more generally in other distantly related ion channels) may elucidate the gating mechanisms conserved during evolution.
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Affiliation(s)
- S Boukalova
- Department of Cellular Neurophysiology, Institute of Physiology Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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30
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Weiss J, Pyrski M, Weissgerber P, Zufall F. Altered synaptic transmission at olfactory and vomeronasal nerve terminals in mice lacking N-type calcium channel Cav2.2. Eur J Neurosci 2014; 40:3422-35. [PMID: 25195871 DOI: 10.1111/ejn.12713] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/31/2014] [Accepted: 08/04/2014] [Indexed: 12/19/2022]
Abstract
We investigated the role of voltage-activated calcium (Cav) channels for synaptic transmission at mouse olfactory and vomeronasal nerve terminals at the first synapse of the main and accessory olfactory pathways, respectively. We provided evidence for a central role of the N-type Cav channel subunit Cav2.2 in presynaptic transmitter release at these synapses. Striking Cav2.2 immunoreactivity was localised to the glomerular neuropil of the main olfactory bulb (MOB) and accessory olfactory bulb (AOB), and co-localised with presynaptic molecules such as bassoon. Voltage-clamp recordings of sensory nerve-evoked, excitatory postsynaptic currents (EPSCs) in mitral/tufted (M/T) and superficial tufted cells of the MOB and mitral cells of the AOB, in combination with established subtype-specific Cav channel toxins, indicated a predominant role of N-type channels in transmitter release at these synapses, whereas L-type, P/Q-type, and R-type channels had either no or only relatively minor contributions. In Cacna1b mutant mice lacking the Cav2.2 (α1B) subunit of N-type channels, olfactory nerve-evoked M/T cell EPSCs were not reduced but became blocker-resistant, thus indicating a major reorganisation and compensation of Cav channel subunits as a result of the Cav2.2 deletion at this synapse. Cav2.2-deficient mice also revealed that Cav2.2 was critically required for paired-pulse depression of olfactory nerve-evoked EPSCs in M/T cells of the MOB, and they demonstrated an essential requirement for Cav2.2 in vomeronasal nerve-evoked EPSCs of AOB mitral cells. Thus, Cacna1b loss-of-function mutations are unlikely to cause general anosmia but Cacna1b emerges as a strong candidate in the search for mutations causing altered olfactory perception, such as changes in general olfactory sensitivity and altered social responses to chemostimuli.
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Affiliation(s)
- Jan Weiss
- Department of Physiology, University of Saarland School of Medicine, Kirrbergerstrasse, Building 58, D-66421, Homburg, Germany
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Payandeh J, Minor DL. Bacterial voltage-gated sodium channels (BacNa(V)s) from the soil, sea, and salt lakes enlighten molecular mechanisms of electrical signaling and pharmacology in the brain and heart. J Mol Biol 2014; 427:3-30. [PMID: 25158094 DOI: 10.1016/j.jmb.2014.08.010] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 08/11/2014] [Accepted: 08/18/2014] [Indexed: 12/19/2022]
Abstract
Voltage-gated sodium channels (Na(V)s) provide the initial electrical signal that drives action potential generation in many excitable cells of the brain, heart, and nervous system. For more than 60years, functional studies of Na(V)s have occupied a central place in physiological and biophysical investigation of the molecular basis of excitability. Recently, structural studies of members of a large family of bacterial voltage-gated sodium channels (BacNa(V)s) prevalent in soil, marine, and salt lake environments that bear many of the core features of eukaryotic Na(V)s have reframed ideas for voltage-gated channel function, ion selectivity, and pharmacology. Here, we analyze the recent advances, unanswered questions, and potential of BacNa(V)s as templates for drug development efforts.
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Affiliation(s)
- Jian Payandeh
- Department of Structural Biology, Genentech, Inc., South San Francisco, CA 94080, USA.
| | - Daniel L Minor
- Cardiovascular Research Institute, Departments of Biochemistry and Biophysics and Cellular and Molecular Pharmacology, California Institute for Quantitative Biomedical Research, University of California, San Francisco, CA 93858-2330, USA; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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Duan JH, Hodgdon KE, Hingtgen CM, Nicol GD. N-type calcium current, Cav2.2, is enhanced in small-diameter sensory neurons isolated from Nf1+/- mice. Neuroscience 2014; 270:192-202. [PMID: 24755485 PMCID: PMC4075288 DOI: 10.1016/j.neuroscience.2014.04.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 04/04/2014] [Accepted: 04/09/2014] [Indexed: 02/07/2023]
Abstract
Major aspects of neuronal function are regulated by Ca(2+) including neurotransmitter release, excitability, developmental plasticity, and gene expression. We reported previously that sensory neurons isolated from a mouse model with a heterozygous mutation of the Nf1 gene (Nf1+/-) exhibited both greater excitability and evoked release of neuropeptides compared to wildtype mice. Furthermore, augmented voltage-dependent sodium currents but not potassium currents contribute to the enhanced excitability. To determine the mechanisms giving rise to the enhanced release of substance P and calcitonin gene-related peptide in the Nf1+/- sensory neurons, the potential differences in the total voltage-dependent calcium current (ICa) as well as the contributions of individual Ca(2+) channel subtypes were assessed. Whole-cell patch-clamp recordings from small-diameter capsaicin-sensitive sensory neurons demonstrated that the average peak ICa densities were not different between the two genotypes. However, by using selective blockers of channel subtypes, the current density of N-type (Cav2.2) ICa was significantly larger in Nf1+/- neurons compared to wildtype neurons. In contrast, there were no significant differences in L-, P/Q- and R-type currents between the two genotypes. Quantitative real-time polymerase chain reaction measurements made from the isolated but intact dorsal root ganglia indicated that N-type (Cav2.2) and P/Q-type (Cav2.1) Ca(2+) channels exhibited the highest mRNA expression levels although there were no significant differences in the levels of mRNA expression between the genotypes. These results suggest that the augmented N-type (Cav2.2) ICa observed in the Nf1+/- sensory neurons does not result from genomic differences but may reflect post-translational or some other non-genomic modifications. Thus, our results demonstrate that sensory neurons from Nf1+/- mice, exhibit increased N-type ICa and likely account for the increased release of substance P and calcitonin gene-related peptide that occurs in Nf1+/- sensory neurons.
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Affiliation(s)
- J-H Duan
- Department of Pharmacology & Toxicology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
| | - K E Hodgdon
- Department of Pharmacology & Toxicology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
| | - C M Hingtgen
- Department of Pharmacology & Toxicology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA; Department of Neurology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
| | - G D Nicol
- Department of Pharmacology & Toxicology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA.
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Bladen C, Hamid J, Souza IA, Zamponi GW. Block of T-type calcium channels by protoxins I and II. Mol Brain 2014; 7:36. [PMID: 24886690 PMCID: PMC4030284 DOI: 10.1186/1756-6606-7-36] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 05/05/2014] [Indexed: 01/08/2023] Open
Abstract
Background Low-voltage-activated (T-type) calcium channels play a crucial role in a number of physiological processes, including neuronal and cardiac pacemaker activity and nociception. Therefore, finding specific modulators and/or blockers of T-type channels has become an important field of drug discovery. One characteristic of T-type calcium channels is that they share several structural similarities with voltage-gated sodium channels (VGSCs). We therefore hypothesized that binding sites for certain sodium channel blocking peptide toxins may be present in T-type calcium channels. Findings The sodium channel blocker ProTx I tonically blocked native and transiently expressed T-type channels in the sub- to low micro molar range with at least a ten-fold selectivity for the T-type calcium channel hCav3.1 over hCav3.3, and more than one hundred fold selectivity over hCav3.2. Using chimeras of hCav3.1 and hCav3.3, we determined that the domain IV region of hCav3.1 is a major determinant of toxin affinity, with a minor contribution from domain II. Further analysis revealed several residues in a highly conserved region between T-type and sodium channels that may correspond to toxin binding sites. Mutagenesis of several of these residues on an individual basis, however, did not alter the blocking effects of the toxin. ProTx II on the other hand preferentially blocked hCav3.2 and significantly shifted the steady state inactivation of this channel. Conclusions ProTx I blocks hCav3.1 both selectively and with high affinity. Domain IV appears to play a major role in this selectivity with some contribution from domain II. Given the structural similarities between sodium and T-type calcium channels and the apparent conservation in toxin binding sites, these data could provide insights into the development and synthesis of novel T-type channel antagonists.
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Affiliation(s)
| | | | | | - Gerald W Zamponi
- Department of Physiology & Pharmacology, Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive, Calgary, NW, Canada.
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Langeslag M, Malsch P, Welling A, Kress M. Reduced excitability of gp130-deficient nociceptors is associated with increased voltage-gated potassium currents and Kcna4 channel upregulation. Pflugers Arch 2014; 466:2153-65. [DOI: 10.1007/s00424-014-1443-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 12/18/2013] [Accepted: 01/04/2014] [Indexed: 12/20/2022]
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Blockade of Nav1.8 Currents in Nociceptive Trigeminal Neurons Contributes to Anti-trigeminovascular Nociceptive Effect of Amitriptyline. Neuromolecular Med 2013; 16:308-21. [DOI: 10.1007/s12017-013-8282-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 11/08/2013] [Indexed: 01/22/2023]
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Dunn TW, Sossin WS. Inhibition of the Aplysia sensory neuron calcium current with dopamine and serotonin. J Neurophysiol 2013; 110:2071-81. [DOI: 10.1152/jn.00217.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The inhibition of Aplysia pleural mechanosensory neuron synapses by dopamine and serotonin through activation of endogenous dopaminergic and expressed 5-HT1Apl(a)/b receptors, respectively, involves a reduction in action potential-associated calcium influx. We show that the inhibition of synaptic efficacy is downstream of the readily releasable pool, suggesting that inhibition is at the level of calcium secretion coupling, likely a result of the changes in the calcium current. Indeed, the inhibitory responses directly reduce a CaV2-like calcium current in isolated sensory neurons. The inhibition of the calcium current is voltage independent as it is not affected by a strong depolarizing prepulse, consistent with other invertebrate CaV2 calcium currents. Similar to voltage-independent inhibition of vertebrate nociceptors, inhibition was blocked with Src tyrosine kinase inhibitors. The data suggest a conserved mechanism by which G protein-coupled receptor activation can inhibit the CaV2 calcium current in nociceptive neurons.
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Affiliation(s)
- Tyler W. Dunn
- Department Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Wayne S. Sossin
- Department Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
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Bladen C, Gündüz MG, Şimşek R, Şafak C, Zamponi GW. Synthesis and Evaluation of 1,4-Dihydropyridine Derivatives with Calcium Channel Blocking Activity. Pflugers Arch 2013; 466:1355-63. [DOI: 10.1007/s00424-013-1376-z] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 10/01/2013] [Accepted: 10/01/2013] [Indexed: 01/29/2023]
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Physiological roles and potential therapeutic applications of the P2X7 receptor in inflammation and pain. Molecules 2013; 18:10953-72. [PMID: 24013409 PMCID: PMC6270334 DOI: 10.3390/molecules180910953] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 08/26/2013] [Accepted: 08/27/2013] [Indexed: 12/21/2022] Open
Abstract
The P2X7 receptor (P2X7R) is a nonselective cation channel that is activated by extracellular ATP and triggers the secretion of several proinflammatory substances, such as IL-1β, IL-18, TNF-α, and nitric oxide. Recently, several preclinical studies have demonstrated that this receptor participates in inflammation and pain mechanisms. Taken together, these results indicate that P2X7R is a promising pharmacological target, and compounds that modulate the function of this receptor show potential as new anti-inflammatory medicines. In this review, we discuss aspects of P2X7R pharmacology and the participation of this protein in inflammation and pain and provide an overview of some promising compounds that have been tested as antagonists of P2X7R, with clinical applicability.
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Abstract
A number of agents from diverse pharmacological classes are used to treat neuropathic pain associated with diabetic peripheral neuropathy. Only three of these have regulatory approval for this indication in the U.S. In this focused article, I will discuss selected drugs, newly approved or in development, to treat neuropathic pain in patients with diabetic neuropathy. These will include agonists and antagonists of the transient receptor potential channels, a family of receptor proteins that play a role in the transduction of physical stress; sodium channel isoform specific antagonists; a recently approved dual-action opioid receptor agonist-norepinephrine reuptake inhibitor; gene therapy for neuropathic pain; and anti-nerve growth factor molecules. Mechanisms of action, preclinical supporting data, clinical trial evidence, and adverse effects will be reviewed.
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Affiliation(s)
- Roy Freeman
- Center for Autonomic and Peripheral Nerve Disorders, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
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Heimann D, Lötsch J, Hummel T, Doehring A, Oertel BG. Linkage between increased nociception and olfaction via a SCN9A haplotype. PLoS One 2013; 8:e68654. [PMID: 23874707 PMCID: PMC3707874 DOI: 10.1371/journal.pone.0068654] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 05/30/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND AND AIMS Mutations reducing the function of Nav1.7 sodium channels entail diminished pain perception and olfactory acuity, suggesting a link between nociception and olfaction at ion channel level. We hypothesized that if such link exists, it should work in both directions and gain-of-function Nav1.7 mutations known to be associated with increased pain perception should also increase olfactory acuity. METHODS SCN9A variants were assessed known to enhance pain perception and found more frequently in the average population. Specifically, carriers of SCN9A variants rs41268673C>A (P610T; n = 14) or rs6746030C>T (R1150W; n = 21) were compared with non-carriers (n = 40). Olfactory function was quantified by assessing odor threshold, odor discrimination and odor identification using an established olfactory test. Nociception was assessed by measuring pain thresholds to experimental nociceptive stimuli (punctate and blunt mechanical pressure, heat and electrical stimuli). RESULTS The number of carried alleles of the non-mutated SCN9A haplotype rs41268673C/rs6746030C was significantly associated with the comparatively highest olfactory threshold (0 alleles: threshold at phenylethylethanol dilution step 12 of 16 (n = 1), 1 allele: 10.6±2.6 (n = 34), 2 alleles: 9.5±2.1 (n = 40)). The same SCN9A haplotype determined the pain threshold to blunt pressure stimuli (0 alleles: 21.1 N/m(2), 1 allele: 29.8±10.4 N/m(2), 2 alleles: 33.5±10.2 N/m(2)). CONCLUSIONS The findings established a working link between nociception and olfaction via Nav1.7 in the gain-of-function direction. Hence, together with the known reduced olfaction and pain in loss-of-function mutations, a bidirectional genetic functional association between nociception and olfaction exists at Nav1.7 level.
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Affiliation(s)
- Dirk Heimann
- Institute of Clinical Pharmacology, Goethe - University, Frankfurt am Main, Germany
| | - Jörn Lötsch
- Institute of Clinical Pharmacology, Goethe - University, Frankfurt am Main, Germany
- Fraunhofer Institute of Molecular Biology and Applied Ecology - Project Group Translational Medicine and Pharmacology (IME-TMP), Frankfurt am Main, Germany
| | - Thomas Hummel
- Smell and Taste Clinic, Department of Otorhinolaryngology, University of Dresden Medical School, Dresden, Germany
| | - Alexandra Doehring
- Institute of Clinical Pharmacology, Goethe - University, Frankfurt am Main, Germany
| | - Bruno G. Oertel
- Institute of Clinical Pharmacology, Goethe - University, Frankfurt am Main, Germany
- Fraunhofer Institute of Molecular Biology and Applied Ecology - Project Group Translational Medicine and Pharmacology (IME-TMP), Frankfurt am Main, Germany
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Qu R, Tao J, Wang Y, Zhou Y, Wu G, Xiao Y, Hu CY, Jiang X, Xu GY. Neonatal colonic inflammation sensitizes voltage-gated Na(+) channels via upregulation of cystathionine β-synthetase expression in rat primary sensory neurons. Am J Physiol Gastrointest Liver Physiol 2013; 304:G763-72. [PMID: 23449670 DOI: 10.1152/ajpgi.00466.2012] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The pathogenesis of pain in irritable bowel syndrome (IBS) is poorly understood, and treatment remains difficult. We have previously reported that colon-specific dorsal root ganglion (DRG) neurons were hyperactive in a rat model of IBS induced by neonatal colonic inflammation (NCI). This study was designed to examine plasticity of voltage-gated Na(+) channel activities and roles for the endogenous hydrogen sulfide-producing enzyme cystathionine β-synthetase (CBS) in chronic visceral hyperalgesia. Abdominal withdrawal reflex (AWR) scores were recorded in response to graded colorectal distention in adult male rats as a measure of visceral hypersensitivity. Colon-specific DRG neurons were labeled with 1,1'-dioleyl-3,3,3',3-tetramethylindocarbocyanine methanesulfonate and acutely dissociated for measuring Na(+) channel currents. Western blot analysis was employed to detect changes in expressions of voltage-gated Na(+) (Na(V)) channel subtype 1.7, Na(V)1.8, and CBS. NCI significantly increased AWR scores when compared with age-matched controls. NCI also led to an ~2.5-fold increase in Na(+) current density in colon-specific DRG neurons. Furthermore, NCI dramatically enhanced expression of Na(V)1.7, Na(V)1.8, and CBS in colon-related DRGs. CBS was colocalized with Na(V)1.7 or -1.8 in colon-specific DRG neurons. Administration of O-(carboxymethyl)hydroxylamine hemihydrochloride (AOAA), an inhibitor for CBS, remarkably suppressed Na(+) current density and reduced expression of Na(V)1.7 and Na(V)1.8. More importantly, intraperitoneal or intrathecal application of AOAA attenuated AWR scores in NCI rats in a dose-dependent manner. These data suggest that NCI enhances Na(+) channel activity of colon DRG neurons, which is most likely mediated by upregulation of CBS expression, thus identifying a potential target for treatment for chronic visceral pain in patients with IBS.
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Affiliation(s)
- Ruobing Qu
- Institute of Neuroscience, Laboratory for Translational Pain Medicine, Department of Neurobiology, Soochow University, Suzhou, Peoples Republic of China
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Sensory neuron downregulation of the Kv9.1 potassium channel subunit mediates neuropathic pain following nerve injury. J Neurosci 2013. [PMID: 23197740 DOI: 10.1523/jneurosci.3561-12.2012] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Chronic neuropathic pain affects millions of individuals worldwide, is typically long-lasting, and remains poorly treated with existing therapies. Neuropathic pain arising from peripheral nerve lesions is known to be dependent on the emergence of spontaneous and evoked hyperexcitability in damaged nerves. Here, we report that the potassium channel subunit Kv9.1 is expressed in myelinated sensory neurons, but is absent from small unmyelinated neurons. Kv9.1 expression was strongly and rapidly downregulated following axotomy, with a time course that matches the development of spontaneous activity and pain hypersensitivity in animal models. Interestingly, siRNA-mediated knock-down of Kv9.1 in naive rats led to neuropathic pain behaviors. Diminished Kv9.1 function also augmented myelinated sensory neuron excitability, manifested as spontaneous firing, hyper-responsiveness to stimulation, and persistent after-discharge. Intracellular recordings from ex vivo dorsal root ganglion preparations revealed that Kv9.1 knock-down was linked to lowered firing thresholds and increased firing rates under physiologically relevant conditions of extracellular potassium accumulation during prolonged activity. Similar neurophysiological changes were detected in animals subjected to traumatic nerve injury and provide an explanation for neuropathic pain symptoms, including poorly understood conditions such as hyperpathia and paresthesias. In summary, our results demonstrate that Kv9.1 dysfunction leads to spontaneous and evoked neuronal hyperexcitability in myelinated fibers, coupled with development of neuropathic pain behaviors.
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Hu S, Xiao Y, Zhu L, Li L, Hu CY, Jiang X, Xu GY. Neonatal maternal deprivation sensitizes voltage-gated sodium channel currents in colon-specific dorsal root ganglion neurons in rats. Am J Physiol Gastrointest Liver Physiol 2013; 304:G311-21. [PMID: 23139220 DOI: 10.1152/ajpgi.00338.2012] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Irritable bowel syndrome (IBS) is a common gastrointestinal disorder characterized by abdominal pain in association with altered bowel movements. The underlying mechanisms of visceral hypersensitivity remain elusive. This study was designed to examine the role for sodium channels in a rat model of chronic visceral hyperalgesia induced by neonatal maternal deprivation (NMD). Abdominal withdrawal reflex (AWR) scores were performed on adult male rats. Colon-specific dorsal root ganglion (DRG) neurons were labeled with DiI and acutely dissociated for measuring excitability and sodium channel current under whole-cell patch-clamp configurations. The expression of Na(V)1.8 was analyzed by Western blot and quantitative real-time PCR. NMD significantly increased AWR scores, which lasted for ~6 wk in an association with hyperexcitability of colon DRG neurons. TTX-resistant but not TTX-sensitive sodium current density was greatly enhanced in colon DRG neurons in NMD rats. Compared with controls, activation curves showed a leftward shift in NMD rats whereas inactivation curves did not differ significantly. NMD markedly accelerated the activation time of peak current amplitude without any changes in inactivation time. Furthermore, NMD remarkably enhanced expression of Na(V)1.8 at protein levels but not at mRNA levels in colon-related DRGs. The expression of Na(V)1.9 was not altered after NMD. These data suggest that NMD enhances TTX-resistant sodium activity of colon DRG neurons, which is most likely mediated by a leftward shift of activation curve and by enhanced expression of Na(V)1.8 at protein levels, thus identifying a specific molecular mechanism underlying chronic visceral pain and sensitization in patients with IBS.
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Affiliation(s)
- Shufen Hu
- Institute of Neuroscience, Laboratory for Translational Pain Medicine, Department of Neurobiology, Soochow University, Suzhou, People's Republic of China
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Sobrido MJ, Cacheiro P, Carracedo A, Bertram L. Databases for neurogenetics: introduction, overview, and challenges. Hum Mutat 2012; 33:1311-4. [PMID: 22890789 DOI: 10.1002/humu.22164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The importance for research and clinical utility of mutation databases, as well as the issues and difficulties entailed in their construction, is discussed within the Human Variome Project. While general principles and standards can apply to most human diseases, some specific questions arise when dealing with the nature of genetic neurological disorders. So far, publically accessible mutation databases exist for only about half of the genes causing neurogenetic disorders; and a considerable work is clearly still needed to optimize their content. The current landscape, main challenges, some potential solutions, and future perspectives on genetic databases for disorders of the nervous system are reviewed in this special issue of Human Mutation on neurogenetics.
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Affiliation(s)
- María-Jesús Sobrido
- Fundación Pública Galega de Medicina Xenómica-SERGAS, Santiago de Compostela, Galicia, Spain.
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Attenuation of TRPV1 and TRPV4 Expression and Function in Mouse Inflammatory Pain Models Using Electroacupuncture. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2012; 2012:636848. [PMID: 23258994 PMCID: PMC3520481 DOI: 10.1155/2012/636848] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 10/15/2012] [Accepted: 10/18/2012] [Indexed: 11/17/2022]
Abstract
Although pain is a major human affliction, our understanding of pain mechanisms is limited. TRPV1 (transient receptor potential vanilloid subtype 1) and TRPV4 are two crucial receptors involved in inflammatory pain, but their roles in EA- (electroacupuncture-) mediated analgesia are unknown. We injected mice with carrageenan (carra) or a complete Freund's adjuvant (CFA) to model inflammatory pain and investigated the analgesic effect of EA using animal behavior tests, immunostaining, Western blotting, and a whole-cell recording technique. The inflammatory pain model mice developed both mechanical and thermal hyperalgesia. Notably, EA at the ST36 acupoint reversed these phenomena, indicating its curative effect in inflammatory pain. The protein levels of TRPV1 and TRPV4 in DRG (dorsal root ganglion) neurons were both increased at day 4 after the initiation of inflammatory pain and were attenuated by EA, as demonstrated by immunostaining and Western blot analysis. We verified DRG electrophysiological properties to confirm that EA ameliorated peripheral nerve hyperexcitation. Our results indicated that the AP (action potential) threshold, rise time, and fall time, and the percentage and amplitude of TRPV1 and TRPV4 were altered by EA, indicating that EA has an antinociceptive role in inflammatory pain. Our results demonstrate a novel role for EA in regulating TRPV1 and TRPV4 protein expression and nerve excitation in mouse inflammatory pain models.
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Abstract
Here we review recent research into the mechanisms of chronic pain that has focused on neuronal sodium channels, a target of classic analgesic agents. We first discuss evidence that specific sodium channel isoforms are essential for the detection and conduction of normal acutely painful stimuli from nociceptors. We then review findings that show changes in sodium channel expression and localization in chronic inflammation and nerve injury in animal and human tissues. We conclude by discussing the role that myelination plays in organizing and maintaining sodium channel clusters at nodes of Ranvier in normal development and how inflammatory processes or nerve injury alter the characteristics of such clusters. Based on these findings, we suggest that chronic pain may in part result from partial demyelination of axons during chronic injury, which creates aberrant sodium channel clusters that serve as sites of ectopic sensitivity or spontaneous activity.
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Affiliation(s)
- Simon R Levinson
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA.
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47
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Bladen C, Zamponi GW. Common Mechanisms of Drug Interactions with Sodium and T-Type Calcium Channels. Mol Pharmacol 2012; 82:481-7. [DOI: 10.1124/mol.112.079715] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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48
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Lei Q, Malykhina AP. Colonic inflammation up-regulates voltage-gated sodium channels in bladder sensory neurons via activation of peripheral transient potential vanilloid 1 receptors. Neurogastroenterol Motil 2012; 24:575-85, e257. [PMID: 22420642 PMCID: PMC3352963 DOI: 10.1111/j.1365-2982.2012.01910.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Primary sensory neurons express several types of ion channels including transient receptor potential vanilloid 1 (TRPV1) and voltage-gated Na(+) channels. Our previous studies showed an increased excitability of bladder primary sensory and spinal neurons triggered by inflammation in the distal colon as a result of pelvic organ cross-sensitization. The goal of this work was to determine the effects of TRPV1 receptor activation by potent agonists and/or colonic inflammation on voltage-gated Na(+) channels expressed in bladder sensory neurons. METHODS Sprague-Dawley rats were treated with intracolonic saline (control), resiniferatoxin (RTX, 10(-7 ) mol L(-1)), TNBS (colonic irritant) or double treatment (RTX followed by TNBS). KEY RESULTS TNBS-induced colitis increased the amplitude of total Na(+) current by two-fold and of tetrodotoxin resistant (TTX-R) Na(+) current by 78% (P ≤ 0.05 to control) in lumbosacral bladder neurons during acute phase (3 days post-TNBS). Instillation of RTX in the distal colon caused an enhancement in the amplitude of total Na(+) current at -20 mV from -112.1 ± 18.7 pA/pF (control) to -183.6 ± 27.8 pA/pF (3 days post-RTX, P ≤ 0.05) without changes in TTX resistant component. The amplitude of net Na(+) current was also increased by 119% at day 3 in the group with double treatment (RTX followed by TNBS, P ≤ 0.05 to control) which was significantly higher than in either group with a single treatment. CONCLUSIONS & INFERENCES These results provide evidence that colonic inflammation activates TRPV1 receptors at the peripheral sensory terminals leading to an up-regulation of voltage gated Na(+) channels on the cell soma of bladder sensory neurons. This mechanism may underlie the occurrence of peripheral cross-sensitization in the pelvis and functional chronic pelvic pain.
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Affiliation(s)
| | - Anna P. Malykhina
- Corresponding Author: Anna P. Malykhina, Ph.D., Division of Urology, Department of Surgery, University of Pennsylvania School of Medicine, 500 S. Ridgeway Ave, #158, Glenolden, PA, 19036-2307, Tel. (office): (267) 350-9606, Fax: (267) 350-9609,
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Hoeijmakers JG, Faber CG, Lauria G, Merkies IS, Waxman SG. Small-fibre neuropathies—advances in diagnosis, pathophysiology and management. Nat Rev Neurol 2012; 8:369-79. [DOI: 10.1038/nrneurol.2012.97] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Cologna CT, Peigneur S, Rustiguel JK, Nonato MC, Tytgat J, Arantes EC. Investigation of the relationship between the structure and function of Ts2, a neurotoxin from Tityus serrulatus venom. FEBS J 2012; 279:1495-504. [PMID: 22356164 DOI: 10.1111/j.1742-4658.2012.08545.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Scorpion toxins targeting voltage-gated sodium (Na(V)) channels are peptides that comprise 60-76 amino acid residues cross-linked by four disulfide bridges. These toxins can be divided in two groups (α and β toxins), according to their binding properties and mode of action. The scorpion α-toxin Ts2, previously described as a β-toxin, was purified from the venom of Tityus serrulatus, the most dangerous Brazilian scorpion. In this study, seven mammalian Na(V) channel isoforms (rNa(V)1.2, rNa(V)1.3, rNa(V)1.4, hNa(V)1.5, mNa(V)1.6, rNa(V)1.7 and rNa(V)1.8) and one insect Na(V) channel isoform (DmNa(V)1) were used to investigate the subtype specificity and selectivity of Ts2. The electrophysiology assays showed that Ts2 inhibits rapid inactivation of Na(V)1.2, Na(V)1.3, Na(V)1.5, Na(V)1.6 and Na(V)1.7, but does not affect Na(V)1.4, Na(V)1.8 or DmNa(V)1. Interestingly, Ts2 significantly shifts the voltage dependence of activation of Na(V)1.3 channels. The 3D structure of this toxin was modeled based on the high sequence identity (72%) shared with Ts1, another T. serrulatus toxin. The overall fold of the Ts2 model consists of three β-strands and one α-helix, and is arranged in a triangular shape forming a cysteine-stabilized α-helix/β-sheet (CSαβ) motif.
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Affiliation(s)
- Camila T Cologna
- Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
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