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Hass RM, Benarroch EE. What Are the Central Mechanisms of Cough and Their Neurologic Implications? Neurology 2024; 103:e210064. [PMID: 39509665 DOI: 10.1212/wnl.0000000000210064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2024] Open
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Lu H, Cao P. Neural Mechanisms Underlying the Coughing Reflex. Neurosci Bull 2023; 39:1823-1839. [PMID: 37606821 PMCID: PMC10661548 DOI: 10.1007/s12264-023-01104-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 05/15/2023] [Indexed: 08/23/2023] Open
Abstract
Breathing is an intrinsic natural behavior and physiological process that maintains life. The rhythmic exchange of gases regulates the delicate balance of chemical constituents within an organism throughout its lifespan. However, chronic airway diseases, including asthma and chronic obstructive pulmonary disease, affect millions of people worldwide. Pathological airway conditions can disrupt respiration, causing asphyxia, cardiac arrest, and potential death. The innervation of the respiratory tract and the action of the immune system confer robust airway surveillance and protection against environmental irritants and pathogens. However, aberrant activation of the immune system or sensitization of the nervous system can contribute to the development of autoimmune airway disorders. Transient receptor potential ion channels and voltage-gated Na+ channels play critical roles in sensing noxious stimuli within the respiratory tract and interacting with the immune system to generate neurogenic inflammation and airway hypersensitivity. Although recent studies have revealed the involvement of nociceptor neurons in airway diseases, the further neural circuitry underlying airway protection remains elusive. Unraveling the mechanism underpinning neural circuit regulation in the airway may provide precise therapeutic strategies and valuable insights into the management of airway diseases.
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Affiliation(s)
- Haicheng Lu
- National Institute of Biological Sciences, Beijing, 102206, China.
- School of Life Sciences, Tsinghua University, Beijing, 100084, China.
| | - Peng Cao
- National Institute of Biological Sciences, Beijing, 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, 102206, China
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Loya-López SI, Duran P, Ran D, Calderon-Rivera A, Gomez K, Moutal A, Khanna R. Cell specific regulation of NaV1.7 activity and trafficking in rat nodose ganglia neurons. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2022; 12:100109. [PMID: 36531612 PMCID: PMC9755031 DOI: 10.1016/j.ynpai.2022.100109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/10/2022] [Accepted: 11/10/2022] [Indexed: 06/17/2023]
Abstract
The voltage-gated sodium NaV1.7 channel sets the threshold for electrogenesis. Mutations in the gene encoding human NaV1.7 (SCN9A) cause painful neuropathies or pain insensitivity. In dorsal root ganglion (DRG) neurons, activity and trafficking of NaV1.7 are regulated by the auxiliary collapsin response mediator protein 2 (CRMP2). Specifically, preventing addition of a small ubiquitin-like modifier (SUMO), by the E2 SUMO-conjugating enzyme Ubc9, at lysine-374 (K374) of CRMP2 reduces NaV1.7 channel trafficking and activity. We previously identified a small molecule, designated 194, that prevented CRMP2 SUMOylation by Ubc9 to reduce NaV1.7 surface expression and currents, leading to a reduction in spinal nociceptive transmission, and culminating in normalization of mechanical allodynia in models of neuropathic pain. In this study, we investigated whether NaV1.7 control via CRMP2-SUMOylation is conserved in nodose ganglion (NG) neurons. This study was motivated by our desire to develop 194 as a safe, non-opioid substitute for persistent pain, which led us to wonder how 194 would impact NaV1.7 in NG neurons, which are responsible for driving the cough reflex. We found functioning NaV1.7 channels in NG neurons; however, they were resistant to downregulation via either CRMP2 knockdown or pharmacological inhibition of CRMP2 SUMOylation by 194. CRMP2 SUMOylation and interaction with NaV1.7 was consered in NG neurons but the endocytic machinery was deficient in the endocytic adaptor protein Numb. Overexpression of Numb rescued CRMP2-dependent regulation on NaV1.7, rendering NG neurons sensitive to 194. Altogether, these data point at the existence of cell-specific mechanisms regulating NaV1.7 trafficking.
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Affiliation(s)
- Santiago I. Loya-López
- Department of Molecular Pathobiology, College of Dentistry, New York University, New York, USA
- NYU Pain Research Center, 433 First Avenue, New York, NY 10010, USA
| | - Paz Duran
- Department of Molecular Pathobiology, College of Dentistry, New York University, New York, USA
- NYU Pain Research Center, 433 First Avenue, New York, NY 10010, USA
| | - Dongzhi Ran
- Department of Pharmacology, College of Medicine, The University of Arizona, Tucson, AZ 85724, USA
| | - Aida Calderon-Rivera
- Department of Molecular Pathobiology, College of Dentistry, New York University, New York, USA
- NYU Pain Research Center, 433 First Avenue, New York, NY 10010, USA
| | - Kimberly Gomez
- Department of Molecular Pathobiology, College of Dentistry, New York University, New York, USA
- NYU Pain Research Center, 433 First Avenue, New York, NY 10010, USA
| | - Aubin Moutal
- School of Medicine, Department of Pharmacology and Physiology, Saint Louis University, Saint Louis, MO 63104, USA
| | - Rajesh Khanna
- Department of Molecular Pathobiology, College of Dentistry, New York University, New York, USA
- NYU Pain Research Center, 433 First Avenue, New York, NY 10010, USA
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Kim SH, Patil MJ, Hadley SH, Bahia PK, Butler SG, Madaram M, Taylor-Clark TE. Mapping of the Sensory Innervation of the Mouse Lung by Specific Vagal and Dorsal Root Ganglion Neuronal Subsets. eNeuro 2022; 9:ENEURO.0026-22.2022. [PMID: 35365503 PMCID: PMC9015009 DOI: 10.1523/eneuro.0026-22.2022] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/10/2022] [Accepted: 03/26/2022] [Indexed: 11/21/2022] Open
Abstract
The airways are densely innervated by sensory afferent nerves, whose activation regulates respiration and triggers defensive reflexes (e.g., cough, bronchospasm). Airway innervation is heterogeneous, and distinct afferent subsets have distinct functional responses. However, little is known of the innervation patterns of subsets within the lung. A neuroanatomical map is critical for understanding afferent activation under physiological and pathophysiological conditions. Here, we quantified the innervation of the mouse lung by vagal and dorsal root ganglion (DRG) sensory subsets defined by the expression of Pirt (all afferents), 5HT3 (vagal nodose afferents), Tac1 (tachykinergic afferents), and transient receptor potential vanilloid 1 channel (TRPV1; defensive/nociceptive afferents) using Cre-mediated reporter expression. We found that vagal afferents innervate almost all conducting airways and project into the alveolar region, whereas DRG afferents only innervate large airways. Of the two vagal ganglia, only nodose afferents project into the alveolar region, but both nodose and jugular afferents innervate conducting airways throughout the lung. Many afferents that project into the alveolar region express TRPV1. Few DRG afferents expressed TRPV1. Approximately 25% of blood vessels were innervated by vagal afferents (many were Tac1+). Approximately 10% of blood vessels had DRG afferents (some were Tac1+), but this was restricted to large vessels. Lastly, innervation of neuroepithelial bodies (NEBs) correlated with the cell number within the bodies. In conclusion, functionally distinct sensory subsets have distinct innervation patterns within the conducting airways, alveoli and blood vessels. Physiologic (e.g., stretch) and pathophysiological (e.g., inflammation, edema) stimuli likely vary throughout these regions. Our data provide a neuroanatomical basis for understanding afferent responses in vivo.
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Affiliation(s)
- Seol-Hee Kim
- Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL 33612
| | - Mayur J Patil
- Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL 33612
| | - Stephen H Hadley
- Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL 33612
| | - Parmvir K Bahia
- Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL 33612
| | - Shane G Butler
- Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL 33612
| | - Meghana Madaram
- Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL 33612
| | - Thomas E Taylor-Clark
- Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL 33612
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Taylor-Clark TE, Undem BJ. Neural control of the lower airways: Role in cough and airway inflammatory disease. HANDBOOK OF CLINICAL NEUROLOGY 2022; 188:373-391. [PMID: 35965034 PMCID: PMC10688079 DOI: 10.1016/b978-0-323-91534-2.00013-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Airway function is under constant neurophysiological control, in order to maximize airflow and gas exchange and to protect the airways from aspiration, damage, and infection. There are multiple sensory nerve subtypes, whose disparate functions provide a wide array of sensory information into the CNS. Activation of these subtypes triggers specific reflexes, including cough and alterations in autonomic efferent control of airway smooth muscle, secretory cells, and vasculature. Importantly, every aspect of these reflex arcs can be impacted and altered by local inflammation caused by chronic lung disease such as asthma, bronchitis, and infections. Excessive and inappropriate activity in sensory and autonomic nerves within the airways is thought to contribute to the morbidity and symptoms associated with lung disease.
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Affiliation(s)
- Thomas E Taylor-Clark
- Department of Molecular Pharmacology & Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Bradley J Undem
- Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, United States.
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Estévez-López F, Salazar-Tortosa DF, Camiletti-Moirón D, Gavilán-Carrera B, Aparicio VA, Acosta-Manzano P, Segura-Jiménez V, Álvarez-Gallardo IC, Carbonell-Baeza A, Munguía-Izquierdo D, Geenen R, Lacerda E, Delgado-Fernández M, Martínez-González LJ, Ruiz JR, Álvarez-Cubero MJ. Fatigue in Women with Fibromyalgia: A Gene-Physical Activity Interaction Study. J Clin Med 2021; 10:jcm10091902. [PMID: 33924903 PMCID: PMC8125111 DOI: 10.3390/jcm10091902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/27/2021] [Accepted: 04/06/2021] [Indexed: 11/16/2022] Open
Abstract
Fatigue is a cardinal symptom in fibromyalgia. Fatigue is assumed to be the result of genetic susceptibility and environmental factors. We aimed at examining the role of genetic susceptibility for fatigue in southern Spanish women with fibromyalgia, by looking at single nucleotide polymorphisms in 34 fibromyalgia candidate-genes, at the interactions between genes, and at the gene-physical activity interactions. We extracted DNA from saliva of 276 fibromyalgia women to analyze gene-polymorphisms. Accelerometers registered physical activity and sedentary behavior. Fatigue was assessed with the Multidimensional Fatigue Inventory. Based on the Bonferroni’s and False Discovery Rate values, we found that the genotype of the rs4453709 polymorphism (sodium channel protein type 9 subunit alpha, SCN9A, gene) was related to reduced motivation (AT carriers showed the highest reduced motivation) and reduced activity (AA carriers showed the lowest reduced activity). Carriers of the heterozygous genotype of the rs1801133 (methylene tetrahydrofolate reductase, MTHFR, gene) or rs4597545 (SCN9A gene) polymorphisms who were physically active reported lower scores on fatigue compared to their inactive counterparts. Highly sedentary carriers of the homozygous genotype of the rs7607967 polymorphism (AA/GG genotype; SCN9A gene) presented more reduced activity (a dimension of fatigue) than those with lower levels of sedentary behavior. Collectively, findings from the present study suggest that the contribution of genetics and gene-physical activity interaction to fatigue in fibromyalgia is modest.
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Affiliation(s)
- Fernando Estévez-López
- Department of Child and Adolescent Psychiatry/Psychology, Erasmus MC University Medical Center, 3015 GD Rotterdam, The Netherlands;
| | - Diego F. Salazar-Tortosa
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85719, USA
- Correspondence:
| | - Daniel Camiletti-Moirón
- Department of Physical Education, Faculty of Education Sciences, University of Cádiz, 11519 Cádiz, Spain; (D.C.-M.); (B.G.-C.); (V.S.-J.); (I.C.Á.-G.); (A.C.-B.)
| | - Blanca Gavilán-Carrera
- Department of Physical Education, Faculty of Education Sciences, University of Cádiz, 11519 Cádiz, Spain; (D.C.-M.); (B.G.-C.); (V.S.-J.); (I.C.Á.-G.); (A.C.-B.)
| | - Virginia A. Aparicio
- Department of Physiology, Faculty of Pharmacy, University of Granada, 18011 Granada, Spain;
- Biomedical Research Centre (CIBM), Institute of Nutrition and Food Technology (INYTA), University of Granada, 18016 Granada, Spain
| | - Pedro Acosta-Manzano
- Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, 18010 Granada, Spain; (P.A.-M.); (M.D.-F.)
| | - Víctor Segura-Jiménez
- Department of Physical Education, Faculty of Education Sciences, University of Cádiz, 11519 Cádiz, Spain; (D.C.-M.); (B.G.-C.); (V.S.-J.); (I.C.Á.-G.); (A.C.-B.)
| | - Inmaculada C. Álvarez-Gallardo
- Department of Physical Education, Faculty of Education Sciences, University of Cádiz, 11519 Cádiz, Spain; (D.C.-M.); (B.G.-C.); (V.S.-J.); (I.C.Á.-G.); (A.C.-B.)
| | - Ana Carbonell-Baeza
- Department of Physical Education, Faculty of Education Sciences, University of Cádiz, 11519 Cádiz, Spain; (D.C.-M.); (B.G.-C.); (V.S.-J.); (I.C.Á.-G.); (A.C.-B.)
| | - Diego Munguía-Izquierdo
- Physical Performance and Sports Research Center, Department of Sports and Computer Science, Section of Physical Education and Sports, Faculty of Sport Sciences, Universidad Pablo de Olavide, 41013 Seville, Spain;
| | - Rinie Geenen
- Department of Psychology, Faculty of Social and Behavioural Sciences, Utrecht University, 3508 TC Utrecht, The Netherlands;
| | - Eliana Lacerda
- Department of Clinical Research, Faculty of Infectious & Tropical Disease, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK;
| | - Manuel Delgado-Fernández
- Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, 18010 Granada, Spain; (P.A.-M.); (M.D.-F.)
| | - Luis J. Martínez-González
- GENYO, Centre for Genomics and Oncological Research, Pfizer, University of Granada, Andalusian Regional Government, PTS Granada, Av. Ilustracion, 114, 18016 Granada, Spain;
| | - Jonatan R. Ruiz
- PROFITH—“PROmoting FITness and Health Through Physical Activity” Research Group, Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, 18071 Granada, Spain;
| | - María J. Álvarez-Cubero
- Department of Biochemistry and Molecular Biology III, Faculty of Medicine, University of Granada, 18010 Granada, Spain;
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Brozmanova M, Pavelkova N. The Prospect for Potent Sodium Voltage-Gated Channel Blockers to Relieve an Excessive Cough. Physiol Res 2021; 69:S7-S18. [PMID: 32228007 DOI: 10.33549/physiolres.934395] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
An excessive, irritable, productive or non-productive coughing associated with airway inflammation belongs to pathological cough. Increased activation of airway vagal nociceptors in pathological conditions results from dysregulation of the neural pathway that controls cough. A variety of mediators associated with airway inflammation overstimulate these vagal airway fibers including C-fibers leading to hypersensitivity and hyperreactivity. Because current antitussives have limited efficacy and unwanted side effects there is a continual demand for the development of a novel more effective antitussives for a new efficacious and safe cough treatment. Therefore, inhibiting the activity of these vagal C-fibers represents a rational approach to the development of effective antitussive drugs. This may be achieved by blocking inflammatory mediator receptors or by blocking the generator potential associated with the specific ion channels. Because voltage-gated sodium channels (NaVs) are absolutely required for action potentials initiation and conduction irrespective of the stimulus, NaVs become a promising neural target. There is evidence that NaV1.7, 1.8 and 1.9 subtypes are predominantly expressed in airway cough-triggering nerves. The advantage of blocking these NaVs is suppressing C-fiber irrespective to stimuli, but the disadvantage is that by suppressing the nerves is may also block beneficial sensations and neuronal reflex behavior. The concept is that new antitussive drugs would have the benefit of targeting peripheral airway nociceptors without inhibiting the protective cough reflex.
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Affiliation(s)
- M Brozmanova
- Department of Pathophysiology, Jessenius Faculty of Medicine, Comenius University, Martin, Slovakia.
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Taylor-Clark TE. Molecular identity, anatomy, gene expression and function of neural crest vs. placode-derived nociceptors in the lower airways. Neurosci Lett 2020; 742:135505. [PMID: 33197519 DOI: 10.1016/j.neulet.2020.135505] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/02/2020] [Accepted: 11/09/2020] [Indexed: 12/11/2022]
Abstract
The lower airways (larynx to alveoli) are protected by a complex array of neural networks that regulate respiration and airway function. Harmful stimuli trigger defensive responses such as apnea, cough and bronchospasm by activating a subpopulation of sensory afferent nerves (termed nociceptors) which are found throughout the airways. Airway nociceptive fibers are projected from the nodose vagal ganglia, the jugular vagal ganglia and the dorsal root ganglia, which are derived from distinct embryological sources: the former from the epibranchial placodes, the latter two from the neural crest. Embryological source determines nociceptive gene expression of receptors and neurotransmitters and recent evidence suggests that placode- and neural crest-derived nociceptors have distinct stimuli sensitivity, innervation patterns and functions. Improved understanding of the function of each subset in specific reflexes has substantial implications for therapeutic targeting of the neuronal components of airway disease such as asthma, viral infections and chronic obstructive pulmonary disease.
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Affiliation(s)
- Thomas E Taylor-Clark
- Molecular Pharmacology & Physiology, Morsani College of Medicine, University of South Florida, 12901 Bruce B Downs Blvd., Tampa, FL 33612, USA.
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Muccino DR, Morice AH, Birring SS, Dicpinigaitis PV, Pavord ID, Assaid C, Kleijn HJ, Hussain A, La Rosa C, McGarvey L, Smith JA. Design and rationale of two phase 3 randomised controlled trials (COUGH-1 and COUGH-2) of gefapixant, a P2X3 receptor antagonist, in refractory or unexplained chronic cough. ERJ Open Res 2020; 6:00284-2020. [PMID: 33263037 PMCID: PMC7682670 DOI: 10.1183/23120541.00284-2020] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 07/29/2020] [Indexed: 11/06/2022] Open
Abstract
Background We present study designs, dose selection and preliminary patient characteristics from two phase 3 clinical trials of gefapixant, a P2X3 receptor antagonist, in refractory chronic cough (RCC) or unexplained chronic cough (UCC). Methods COUGH-1 (NCT03449134) and COUGH-2 (NCT03449147) are randomised, placebo-controlled, double-blind, parallel-group trials in subjects with RCC or UCC (age ≥18 years; cough duration ≥1 year; Cough Severity Visual Analogue Scale score ≥40 mm). The primary efficacy study periods are 12 weeks (40-week extension; COUGH-1) and 24 weeks (28-week extension; COUGH-2). Interventions include placebo, gefapixant 15 mg and gefapixant 45 mg (1:1:1 ratio). The primary efficacy endpoints are average 24-h cough frequency at Week 12 (COUGH-1) and Week 24 (COUGH-2). Awake cough frequency, patient-reported outcomes and responder analyses are secondary endpoints. Results The doses of 45 mg (to provide maximal efficacy and acceptable tolerability) and 15 mg (to provide acceptable efficacy and improved tolerability) were selected based on phase 1 and 2 studies. In COUGH-1, 730 participants have been randomised and treated; 74% are female with mean age of 59 years (39% over 65 years), and mean baseline duration of cough of 11.5 years. In COUGH-2, 1314 participants have been randomised and treated; 75% are female with mean age of 58 years (33% over 65 years), and mean baseline duration of cough of 11.1 years. Conclusions These global studies include participants with baseline characteristics consistent with previous RCC and UCC studies and will inform the efficacy and safety profile of gefapixant in the treatment of patients with RCC and UCC. This protocol describes the design of two global, phase 3 studies with >2000 participants with refractory or unexplained chronic cough, designed to confirm efficacy and safety of gefapixant, a P2X3 receptor antagonist, at doses of 45 mg and 15 mghttps://bit.ly/2Xzgu74
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Affiliation(s)
| | | | - Surinder S Birring
- Centre for Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, King's College London, London, UK
| | | | - Ian D Pavord
- Oxford NIHR Respiratory BRC, Nuffield Dept of Medicine, University of Oxford, Oxford, UK
| | | | | | | | | | - Lorcan McGarvey
- Wellcome-Wolfson Institute of Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - Jaclyn A Smith
- Division of Infection, Immunity and Respiratory Medicine, University of Manchester and Manchester University NHS Trust, Manchester, UK
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Grabczak EM, Dabrowska M, Birring SS, Krenke R. Looking ahead to novel therapies for chronic cough. Part 1 - peripheral sensory nerve targeted treatments. Expert Rev Respir Med 2020; 14:1217-1233. [PMID: 32804594 DOI: 10.1080/17476348.2020.1811686] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Due to a relatively high prevalence and negative impact on quality of life chronic cough (CC) is a challenge for both patients and clinicians. There is ongoing research to address the unmet need and develop more effective antitussive treatment options. This is the first part of a series of two reviews of new antitussive medications. Medical databases (Medline, Embase and SCOPUS) and trial registries (ClinicalTrials.gov and EudraCT) were searched for studies on antitussive drugs targeting peripheral sensory nerves. AREAS COVERED This review presents current knowledge of peripheral receptors that are not only involved in evoking the cough reflex, but are also potentially responsible for more sustained neural alterations. Blockage of the receptors and ion channels is discussed in terms of its potential antitussive effect. EXPERT OPINION Although better understanding of CC mechanisms has facilitated the development of novel treatments including P2X2/3 receptor inhibitors (e.g. gefapixant), there remain several gaps in the knowledge about the mechanisms and treatment of CC. These include the lack of tests to diagnose cough hypersensitivity syndrome and predictors of response to specific treatments. Further research into cough phenotypes and endotypes will yield important insights and a personalized approach to cough management.
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Affiliation(s)
- Elzbieta M Grabczak
- Department of Internal Medicine, Pulmonary Diseases and Allergy, Medical University of Warsaw , Warsaw, Poland
| | - Marta Dabrowska
- Department of Internal Medicine, Pulmonary Diseases and Allergy, Medical University of Warsaw , Warsaw, Poland
| | - Surinder S Birring
- Centre for Human & Applied Physiological Sciences, School of Basic & Medical Biosciences, Faculty of Life Sciences & Medicine, King's College London , London, UK
| | - Rafal Krenke
- Department of Internal Medicine, Pulmonary Diseases and Allergy, Medical University of Warsaw , Warsaw, Poland
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Singh N, Driessen AK, McGovern AE, Moe AAK, Farrell MJ, Mazzone SB. Peripheral and central mechanisms of cough hypersensitivity. J Thorac Dis 2020; 12:5179-5193. [PMID: 33145095 PMCID: PMC7578480 DOI: 10.21037/jtd-2020-icc-007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Chronic cough is a difficult to treat symptom of many respiratory and some non-respiratory diseases, indicating that varied pathologies can underpin the development of chronic cough. However, clinically and experimentally it has been useful to collate these different pathological processes into the single unifying concept of cough hypersensitivity. Cough hypersensitivity syndrome is reflected by troublesome cough often precipitated by levels of stimuli that ordinarily don't cause cough in healthy people, and this appears to be a hallmark feature in many patients with chronic cough. Accordingly, a strong argument has emerged that changes in the excitability and/or normal regulation of the peripheral and central neural circuits responsible for cough are instrumental in establishing cough hypersensitivity and for causing excessive cough in disease. In this review, we explore the current peripheral and central neural mechanisms that are believed to be involved in altered cough sensitivity and present possible links to the mechanism of action of novel therapies that are currently undergoing clinical trials for chronic cough.
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Affiliation(s)
- Nabita Singh
- Department of Medical Imaging and Radiation Sciences, Monash University, Clayton, Australia
| | - Alexandria K. Driessen
- Department of Anatomy and Neuroscience, School of Biomedical Science, The University of Melbourne, Parkville, Australia
| | - Alice E. McGovern
- Department of Anatomy and Neuroscience, School of Biomedical Science, The University of Melbourne, Parkville, Australia
| | - Aung Aung Kywe Moe
- Department of Anatomy and Neuroscience, School of Biomedical Science, The University of Melbourne, Parkville, Australia
| | - Michael J. Farrell
- Department of Medical Imaging and Radiation Sciences, Monash University, Clayton, Australia
- Monash Biomedical Imaging, Monash University, Clayton, Australia
| | - Stuart B. Mazzone
- Department of Anatomy and Neuroscience, School of Biomedical Science, The University of Melbourne, Parkville, Australia
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Mazzone SB, McGarvey L. Mechanisms and Rationale for Targeted Therapies in Refractory and Unexplained Chronic Cough. Clin Pharmacol Ther 2020; 109:619-636. [PMID: 32748976 PMCID: PMC7983941 DOI: 10.1002/cpt.2003] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 07/24/2020] [Indexed: 12/22/2022]
Abstract
Chronic cough, defined as a cough lasting > 8 weeks, is a common medical condition that exerts a substantial physical, mental, and social burden on patients. A subset of patients with chronic cough are troubled with a cough that persists despite optimal treatment of presumed associated common and uncommon conditions (refractory chronic cough; RCC) or in which no diagnosable cause for cough can be identified despite extensive assessment (unexplained chronic cough; UCC). Many of these patients exhibit clinical features of cough hypersensitivity, including laryngeal paresthesia, hypertussia, and allotussia. Over-the-counter cough remedies are ineffective and can lead to intolerable side effects when used for RCC/UCC, and the lack of approved treatments indicated for these conditions reflects a major unmet need. An increased understanding of the anatomy and neurophysiology of protective and pathologic cough has fostered a robust clinical development pipeline of several targeted therapies for RCC/UCC. This manuscript reviews the mechanisms presumed to underly RCC/UCC together with the rationale and clinical evidence for several targeted therapies currently under clinical investigation, including transient receptor potential channel antagonists, P2X3-receptor antagonists, voltage-gated sodium channel blockers, neuromodulators, and neurokinin-1-receptor antagonists. Finally, we provide an overview of targets that have been investigated in preclinical models of cough and other airway diseases that may hold future promise for clinical studies in RCC/UCC. Development of targeted therapies with different sites of action may foster a precision medicine approach to treat this heterogeneous, underserved patient population.
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Affiliation(s)
- Stuart B Mazzone
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, Victoria, Australia
| | - Lorcan McGarvey
- Wellcome-Wolfson Institute of Experimental Medicine, Queen's University Belfast, Belfast, UK
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Driessen AK, McGovern AE, Behrens R, Moe AAK, Farrell MJ, Mazzone SB. A role for neurokinin 1 receptor expressing neurons in the paratrigeminal nucleus in bradykinin-evoked cough in guinea-pigs. J Physiol 2020; 598:2257-2275. [PMID: 32237239 DOI: 10.1113/jp279644] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 03/16/2020] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS Airway projecting sensory neurons arising from the jugular vagal ganglia terminate centrally in the brainstem paratrigeminal nucleus, synapsing upon neurons expressing the neurokinin 1 receptor. This study aimed to assess the involvement of paratrigeminal neurokinin 1 receptor neurons in the regulation of cough, breathing and airway defensive responses. Lesioning neurokinin 1 receptor expressing paratrigeminal neurons significantly reduced cough evoked by inhaled bradykinin but not inhaled ATP or tracheal mechanical stimulation. The reduction in bradykinin-evoked cough was not accompanied by changes in baseline or evoked respiratory variables (e.g. frequency, volume or timing), animal avoidance behaviours or the laryngeal apnoea reflex. These findings warrant further investigations into targeting the jugular ganglia and paratrigeminal nucleus as a therapy for treating cough in disease. ABSTRACT Jugular vagal ganglia sensory neurons innervate the large airways and are thought to mediate cough and associated perceptions of airway irritations to a range of chemical irritants. The central terminals of jugular sensory neurons lie within the brainstem paratrigeminal nucleus, where postsynaptic neurons can be differentiated based on the absence or presence of the neurokinin 1 (NK1) receptor. Therefore, in the present study, we set out to test the hypothesis that NK1 receptor expressing paratrigeminal neurons play a role in cough evoked by inhaled chemical irritants. To test this, we performed selective neurotoxin lesions of NK1 receptor expressing neurons in the paratrigeminal nucleus in guinea-pigs using substance P conjugated to saporin (SSP-SAP). Sham lesion control or SSP-SAP lesion guinea-pigs received nebulised challenges, with the pan-nociceptor stimulant bradykinin or the nodose ganglia specific stimulant adenosine 5'-triphosphate (ATP), in conscious whole-body plethysmography to study cough and associated behaviours. Laryngeal apnoea reflexes and cough evoked by mechanical stimulation of the trachea were additionally investigated in anaesthetised guinea-pigs. SSP-SAP significantly and selectively reduced the number of NK1 receptor expressing neurons in the paratrigeminal nucleus. This was associated with a significant reduction in bradykinin-evoked cough, but not ATP-evoked cough, mechanical cough or laryngeal apnoeic responses. These data provide further evidence for a role of jugular vagal pathways in cough, and additionally suggest an involvement of NK1 receptor expressing neurons in the paratrigeminal nucleus. Therefore, this neural pathway may provide novel therapeutic opportunities to treat conditions of chronic cough.
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Affiliation(s)
- Alexandria K Driessen
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Alice E McGovern
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Robert Behrens
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Aung Aung Kywe Moe
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Michael J Farrell
- Department of Medical Imaging and Radiation Sciences, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Stuart B Mazzone
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, 3010, Australia
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Undem BJ, Sun H. Molecular/Ionic Basis of Vagal Bronchopulmonary C-Fiber Activation by Inflammatory Mediators. Physiology (Bethesda) 2020; 35:57-68. [PMID: 31799905 PMCID: PMC6985783 DOI: 10.1152/physiol.00014.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 05/30/2019] [Accepted: 06/03/2019] [Indexed: 12/11/2022] Open
Abstract
Stimulation of bronchopulmonary vagal afferent C fibers by inflammatory mediators can lead to coughing, chest tightness, and changes in breathing pattern, as well as reflex bronchoconstriction and secretions. These responses serve a defensive function in healthy lungs but likely contribute to many of the signs and symptoms of inflammatory airway diseases. A better understanding of the mechanisms underlying the activation of bronchopulmonary C-fiber terminals may lead to novel therapeutics that would work in an additive or synergic manner with existing anti-inflammatory strategies.
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Affiliation(s)
| | - Hui Sun
- Johns Hopkins University, Baltimore, Maryland
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15
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Kollarik M, Sun H, Herbstsomer RA, Ru F, Kocmalova M, Meeker SN, Undem BJ. Different role of TTX-sensitive voltage-gated sodium channel (Na V 1) subtypes in action potential initiation and conduction in vagal airway nociceptors. J Physiol 2019; 596:1419-1432. [PMID: 29435993 DOI: 10.1113/jp275698] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 01/23/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The action potential initiation in the nerve terminals and its subsequent conduction along the axons of afferent nerves are not necessarily dependent on the same voltage-gated sodium channel (NaV 1) subunits. The action potential initiation in jugular C-fibres within airway tissues is not blocked by TTX; nonetheless, conduction of action potentials along the vagal axons of these nerves is often dependent on TTX-sensitive channels. This is not the case for nodose airway Aδ-fibres and C-fibres, where both action potential initiation and conduction is abolished by TTX or selective NaV 1.7 blockers. The difference between the initiation of action potentials within the airways vs. conduction along the axons should be considered when developing NaV 1 blocking drugs for topical application to the respiratory tract. ABSTRACT The action potential (AP) initiation in the nerve terminals and its subsequent AP conduction along the axons do not necessarily depend on the same subtypes of voltage-gated sodium channels (NaV 1s). We evaluated the role of TTX-sensitive and TTX-resistant NaV 1s in vagal afferent nociceptor nerves derived from jugular and nodose ganglia innervating the respiratory system. Single cell RT-PCR was performed on vagal afferent neurons retrogradely labelled from the guinea pig trachea. Almost all of the jugular neurons expressed the TTX-sensitive channel NaV 1.7 along with TTX-resistant NaV 1.8 and NaV 1.9. Tracheal nodose neurons also expressed NaV 1.7 but, less frequently, NaV 1.8 and NaV 1.9. NaV 1.6 were expressed in ∼40% of the jugular and 25% of nodose tracheal neurons. Other NaV 1 α subunits were only rarely expressed. Single fibre recordings were made from the vagal nodose and jugular nerve fibres innervating the trachea or lung in the isolated perfused vagally-innervated preparations that allowed for selective drug delivery to the nerve terminal compartment (AP initiation) or to the desheathed vagus nerve (AP conduction). AP initiation in jugular C-fibres was unaffected by TTX, although it was inhibited by NaV 1.8 blocker (PF-01247324) and abolished by combination of TTX and PF-01247324. However, AP conduction in the majority of jugular C-fibres was abolished by TTX. By contrast, both AP initiation and conduction in nodose nociceptors was abolished by TTX or selective NaV 1.7 blockers. Distinction between the effect of a drug with respect to inhibiting AP in the nerve terminals within the airways vs. at conduction sites along the vagus nerve is relevant to therapeutic strategies involving inhaled NaV 1 blocking drugs.
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Affiliation(s)
- M Kollarik
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Pathophysiology, Biomedical Center Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia
| | - H Sun
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - R A Herbstsomer
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - F Ru
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - M Kocmalova
- Department of Pharmacology, Biomedical Center Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia
| | - S N Meeker
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - B J Undem
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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16
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Regulation of Cough by Voltage-Gated Sodium Channels in Airway Sensory Nerves. ACTA MEDICA MARTINIANA 2019. [DOI: 10.2478/acm-2018-0012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Abstract
Chronic cough is a significant clinical problem in many patients. Current cough suppressant therapies are largely ineffective and have many dangerous adverse effects. Therefore, the identification of novel therapeutic targets and strategies for chronic cough treatment may lead to development of novel effective antitussive therapies with fewer adverse effects. The experimental research in the area of airway sensory nerves suggests that there are two main vagal afferent nerve subtypes that can directly activate cough – extrapulmonary airway C-fibres and Aδ-fibres (described as cough receptors) innervating the trachea. There are different receptors on the vagal nerve terminals that can trigger coughing, such as TRP channels and P2X2/3 receptors. However, in many patients with chronic respiratory diseases multiple activation of these receptors could be involved and it is also difficult to target these receptors. For that reason, a strategy that would inhibit cough-triggering nerve afferents regardless of activated receptors would be of great benefit. In recent years huge progress in understanding of voltage-gated sodium channels (NaVs) leads to a hypothesis that selective targeting of NaVs in airways may represent an effective treatment of pathological cough. The NaVs (NaV1.1 – NaV1.9) are essential for initiation and conduction of action potentials in these nerve fibres. Effective blocking of NaVs will prevent communication between airways and central nervous system and that would inhibit provoked cough irrespective to stimuli. This review provides an overview of airway afferent nerve subtypes that have been described in respiratory tract of human and in animal models. Moreover, the review highlights the current knowledge about cough, the sensory nerves involved in cough, and the voltage-gated sodium channels as a novel neural target in regulation of cough.
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Chew LA, Bellampalli SS, Dustrude ET, Khanna R. Mining the Na v1.7 interactome: Opportunities for chronic pain therapeutics. Biochem Pharmacol 2019; 163:9-20. [PMID: 30699328 DOI: 10.1016/j.bcp.2019.01.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 01/24/2019] [Indexed: 12/14/2022]
Abstract
The peripherally expressed voltage-gated sodium NaV1.7 (gene SCN9A) channel boosts small stimuli to initiate firing of pain-signaling dorsal root ganglia (DRG) neurons and facilitates neurotransmitter release at the first synapse within the spinal cord. Mutations in SCN9A produce distinct human pain syndromes. Widely acknowledged as a "gatekeeper" of pain, NaV1.7 has been the focus of intense investigation but, to date, no NaV1.7-selective drugs have reached the clinic. Elegant crystallographic studies have demonstrated the potential of designing highly potent and selective NaV1.7 compounds but their therapeutic value remains untested. Transcriptional silencing of NaV1.7 by a naturally expressed antisense transcript has been reported in rodents and humans but whether this represents a viable opportunity for designing NaV1.7 therapeutics is currently unknown. The demonstration that loss of NaV1.7 function is associated with upregulation of endogenous opioids and potentiation of mu- and delta-opioid receptor activities, suggests that targeting only NaV1.7 may be insufficient for analgesia. However, the link between opioid-dependent analgesic mechanisms and function of sodium channels and intracellular sodium-dependent signaling remains controversial. Thus, additional new targets - regulators, modulators - are needed. In this context, we mine the literature for the known interactome of NaV1.7 with a focus on protein interactors that affect the channel's trafficking or link it to opioid signaling. As a case study, we present antinociceptive evidence of allosteric regulation of NaV1.7 by the cytosolic collapsin response mediator protein 2 (CRMP2). Throughout discussions of these possible new targets, we offer thoughts on the therapeutic implications of modulating NaV1.7 function in chronic pain.
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Affiliation(s)
- Lindsey A Chew
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - Shreya S Bellampalli
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85724, USA
| | - Erik T Dustrude
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Rajesh Khanna
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85724, USA; Graduate Interdisciplinary Program in Neuroscience, College of Medicine, University of Arizona, Tucson, AZ, USA; The Center for Innovation in Brain Sciences, The University of Arizona Health Sciences, Tucson, AZ 85724, USA.
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Lidocaine, a Non–selective Inhibitor of Voltage-Gated Sodium Channels, Blocks Chemically-Induced Cough in Awake Naïve Guinea Pigs. ADVANCES IN PULMONARY MEDICINE: RESEARCH AND INNOVATIONS 2019; 1160:1-9. [DOI: 10.1007/5584_2018_326] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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19
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Blocking voltage-gated sodium channels as a strategy to suppress pathological cough. Pulm Pharmacol Ther 2017; 47:38-41. [DOI: 10.1016/j.pupt.2017.05.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 05/10/2017] [Accepted: 05/12/2017] [Indexed: 12/31/2022]
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20
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Chou YL, Mori N, Canning BJ. Opposing effects of bronchopulmonary C-fiber subtypes on cough in guinea pigs. Am J Physiol Regul Integr Comp Physiol 2017; 314:R489-R498. [PMID: 29187382 DOI: 10.1152/ajpregu.00313.2017] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We have addressed the hypothesis that the opposing effects of bronchopulmonary C-fiber activation on cough are attributable to the activation of C-fiber subtypes. Coughing was evoked in anesthetized guinea pigs by citric acid (0.001-2 M) applied topically in 100-µl aliquots to the tracheal mucosa. In control preparations, citric acid evoked 10 ± 1 coughs cumulatively. Selective activation of the pulmonary C fibers arising from the nodose ganglia with either aerosols or continuous intravenous infusion of adenosine or the 5-HT3 receptor-selective agonist 2-methyl-5-HT nearly abolished coughing evoked subsequently by topical citric acid challenge. Delivering adenosine or 2-methyl-5-HT directly to the tracheal mucosa (where few if any nodose C fibers terminate) was without effect on citric acid-evoked cough. These actions of pulmonary administration of adenosine and 2-methyl-5-HT were accompanied by an increase in respiratory rate, but it is unlikely that the change in respiratory pattern caused the decrease in coughing, as the rapidly adapting receptor stimulant histamine also produced a marked tachypnea but was without effect on cough. In awake guinea pigs, adenosine failed to evoke coughing but reduced coughing induced by the nonselective C-fiber stimulant capsaicin. We conclude that bronchopulmonary C-fiber subtypes in guinea pigs have opposing effects on cough, with airway C fibers arising from the jugular ganglia initiating and/or sensitizing the cough reflex and the intrapulmonary C fibers arising from the nodose ganglia actively inhibiting cough upon activation.
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Affiliation(s)
- Yang-Ling Chou
- Johns Hopkins Asthma and Allergy Center , Baltimore, Maryland
| | - Nanako Mori
- Johns Hopkins Asthma and Allergy Center , Baltimore, Maryland
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21
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Keller JA, McGovern AE, Mazzone SB. Translating Cough Mechanisms Into Better Cough Suppressants. Chest 2017; 152:833-841. [DOI: 10.1016/j.chest.2017.05.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 05/14/2017] [Accepted: 05/17/2017] [Indexed: 12/19/2022] Open
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22
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Mazzone SB, Undem BJ. Vagal Afferent Innervation of the Airways in Health and Disease. Physiol Rev 2017; 96:975-1024. [PMID: 27279650 DOI: 10.1152/physrev.00039.2015] [Citation(s) in RCA: 382] [Impact Index Per Article: 47.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Vagal sensory neurons constitute the major afferent supply to the airways and lungs. Subsets of afferents are defined by their embryological origin, molecular profile, neurochemistry, functionality, and anatomical organization, and collectively these nerves are essential for the regulation of respiratory physiology and pulmonary defense through local responses and centrally mediated neural pathways. Mechanical and chemical activation of airway afferents depends on a myriad of ionic and receptor-mediated signaling, much of which has yet to be fully explored. Alterations in the sensitivity and neurochemical phenotype of vagal afferent nerves and/or the neural pathways that they innervate occur in a wide variety of pulmonary diseases, and as such, understanding the mechanisms of vagal sensory function and dysfunction may reveal novel therapeutic targets. In this comprehensive review we discuss historical and state-of-the-art concepts in airway sensory neurobiology and explore mechanisms underlying how vagal sensory pathways become dysfunctional in pathological conditions.
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Affiliation(s)
- Stuart B Mazzone
- School of Biomedical Sciences, The University of Queensland, St Lucia, Brisbane, Australia; and Department of Medicine, Johns Hopkins University Medical School, Asthma & Allergy Center, Baltimore, Maryland
| | - Bradley J Undem
- School of Biomedical Sciences, The University of Queensland, St Lucia, Brisbane, Australia; and Department of Medicine, Johns Hopkins University Medical School, Asthma & Allergy Center, Baltimore, Maryland
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23
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Contrasting effects of ATP and adenosine on capsaicin challenge in asthmatic patients. Pulm Pharmacol Ther 2017; 45:13-18. [PMID: 28392320 DOI: 10.1016/j.pupt.2017.04.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 02/28/2017] [Accepted: 04/05/2017] [Indexed: 11/23/2022]
Abstract
BACKGROUND Adenosine 5'-triphosphate (ATP) stimulates pulmonary vagal slow conducting C-fibres and fast conducting Aδ-fibres with rapidly adapting receptors (RARs). Pulmonary C-fibres but not RARs are also sensitive to capsaicin, a potent tussigenic agent in humans. Thus, the aim of this study was to determine the effects of ATP and its metabolite adenosine (given as adenosine 5'-monophosphate, AMP) on capsaicin challenge in asthmatic patients. METHODS Cough (quantified as visual analogue scale, VAS), dyspnoea (quantified as Borg score), and FEV1 were quantified following bronchoprovocation using capsaicin, adenosine and ATP in healthy non-smokers (age 40±4y, 6 males), smokers (45±4y, 5 males) and asthmatic patients (37±3y, 5 males); n = 10 in each group. RESULTS None of the healthy non-smokers responded to either AMP or ATP. AMP induced bronchoconstriction in one smoker and eight asthmatics, and ATP in two smokers and all ten asthmatics. The geometric mean of capsaicin causing ≥5 coughs (C5) increased from 134 to 203 μM in non-smokers and from 117 to 287 μM in asthmatics after AMP, whereas it decreased from 203 to 165 μM and 125 to 88 μM, respectively after ATP. AMP decreased C5 from 58 to 29 μM and ATP increased from 33 to 47 μM in smokers. However, due to intergroup variability, these effects of ATP and AMP were not statistically significant (0.125 ≤ p ≤ 0.998). That notwithstanding, in healthy and asthmatic subjects the effects of the ATP showed a tendency to be greater than those of AMP (p < 0.053). Dyspnea, assessed by Borg score, increased after ATP (p < 0.001) and AMP (p < 0.001) only in asthmatic patients. Intensity of cough assessed by VAS increased (p < 0.05) after second capsaicin challenges performed after AMP in all groups, but not after ATP. CONCLUSIONS Asthmatic patients exhibit hypersensitivity to aerosolized AMP and ATP, but aerosolized AMP does not mimic the effects of ATP and the effects of ATP are not mediated by adenosine.
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Kocmalova M, Kollarik M, Canning BJ, Ru F, Adam Herbstsomer R, Meeker S, Fonquerna S, Aparici M, Miralpeix M, Chi XX, Li B, Wilenkin B, McDermott J, Nisenbaum E, Krajewski JL, Undem BJ. Control of Neurotransmission by NaV1.7 in Human, Guinea Pig, and Mouse Airway Parasympathetic Nerves. J Pharmacol Exp Ther 2017; 361:172-180. [PMID: 28138042 PMCID: PMC5363765 DOI: 10.1124/jpet.116.238469] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 01/26/2017] [Indexed: 12/19/2022] Open
Abstract
Little is known about the neuronal voltage-gated sodium channels (NaVs) that control neurotransmission in the parasympathetic nervous system. We evaluated the expression of the α subunits of each of the nine NaVs in human, guinea pig, and mouse airway parasympathetic ganglia. We combined this information with a pharmacological analysis of selective NaV blockers on parasympathetic contractions of isolated airway smooth muscle. As would be expected from previous studies, tetrodotoxin potently blocked the parasympathetic responses in the airways of each species. Gene expression analysis showed that that NaV 1.7 was virtually the only tetrodotoxin-sensitive NaV1 gene expressed in guinea pig and human airway parasympathetic ganglia, where mouse ganglia expressed NaV1.1, 1.3, and 1.7. Using selective pharmacological blockers supported the gene expression results, showing that blocking NaV1.7 alone can abolish the responses in guinea pig and human bronchi, but not in mouse airways. To block the responses in mouse airways requires that NaV1.7 along with NaV1.1 and/or NaV1.3 is blocked. These results may suggest novel indications for NaV1.7-blocking drugs, in which there is an overactive parasympathetic drive, such as in asthma. The data also raise the potential concern of antiparasympathetic side effects for systemic NaV1.7 blockers.
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Affiliation(s)
- Michaela Kocmalova
- The Johns Hopkins University School of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Maryland 21224 (M.Koc., M.Kol., B.J.C., F.R., R.A.H., S.M., B.J.U.); Biomedical Center Martin, Pharmacology and Pathophysiology, Jessenius Faculty of Medicine, Comenius University, Martin 03601, Slovakia (M.Koc., M.Kol.); Almirall S.A., R&D Research Center, Barcelona 08980, Spain (S.F., M.A., M.M.); and Lilly Research Laboratories, Indianapolis, Indiana 46285 (X.C., B.L., B.W., J.M., E.N., J.L.K.)
| | - Marian Kollarik
- The Johns Hopkins University School of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Maryland 21224 (M.Koc., M.Kol., B.J.C., F.R., R.A.H., S.M., B.J.U.); Biomedical Center Martin, Pharmacology and Pathophysiology, Jessenius Faculty of Medicine, Comenius University, Martin 03601, Slovakia (M.Koc., M.Kol.); Almirall S.A., R&D Research Center, Barcelona 08980, Spain (S.F., M.A., M.M.); and Lilly Research Laboratories, Indianapolis, Indiana 46285 (X.C., B.L., B.W., J.M., E.N., J.L.K.)
| | - Brendan J Canning
- The Johns Hopkins University School of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Maryland 21224 (M.Koc., M.Kol., B.J.C., F.R., R.A.H., S.M., B.J.U.); Biomedical Center Martin, Pharmacology and Pathophysiology, Jessenius Faculty of Medicine, Comenius University, Martin 03601, Slovakia (M.Koc., M.Kol.); Almirall S.A., R&D Research Center, Barcelona 08980, Spain (S.F., M.A., M.M.); and Lilly Research Laboratories, Indianapolis, Indiana 46285 (X.C., B.L., B.W., J.M., E.N., J.L.K.)
| | - Fei Ru
- The Johns Hopkins University School of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Maryland 21224 (M.Koc., M.Kol., B.J.C., F.R., R.A.H., S.M., B.J.U.); Biomedical Center Martin, Pharmacology and Pathophysiology, Jessenius Faculty of Medicine, Comenius University, Martin 03601, Slovakia (M.Koc., M.Kol.); Almirall S.A., R&D Research Center, Barcelona 08980, Spain (S.F., M.A., M.M.); and Lilly Research Laboratories, Indianapolis, Indiana 46285 (X.C., B.L., B.W., J.M., E.N., J.L.K.)
| | - R Adam Herbstsomer
- The Johns Hopkins University School of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Maryland 21224 (M.Koc., M.Kol., B.J.C., F.R., R.A.H., S.M., B.J.U.); Biomedical Center Martin, Pharmacology and Pathophysiology, Jessenius Faculty of Medicine, Comenius University, Martin 03601, Slovakia (M.Koc., M.Kol.); Almirall S.A., R&D Research Center, Barcelona 08980, Spain (S.F., M.A., M.M.); and Lilly Research Laboratories, Indianapolis, Indiana 46285 (X.C., B.L., B.W., J.M., E.N., J.L.K.)
| | - Sonya Meeker
- The Johns Hopkins University School of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Maryland 21224 (M.Koc., M.Kol., B.J.C., F.R., R.A.H., S.M., B.J.U.); Biomedical Center Martin, Pharmacology and Pathophysiology, Jessenius Faculty of Medicine, Comenius University, Martin 03601, Slovakia (M.Koc., M.Kol.); Almirall S.A., R&D Research Center, Barcelona 08980, Spain (S.F., M.A., M.M.); and Lilly Research Laboratories, Indianapolis, Indiana 46285 (X.C., B.L., B.W., J.M., E.N., J.L.K.)
| | - Silvia Fonquerna
- The Johns Hopkins University School of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Maryland 21224 (M.Koc., M.Kol., B.J.C., F.R., R.A.H., S.M., B.J.U.); Biomedical Center Martin, Pharmacology and Pathophysiology, Jessenius Faculty of Medicine, Comenius University, Martin 03601, Slovakia (M.Koc., M.Kol.); Almirall S.A., R&D Research Center, Barcelona 08980, Spain (S.F., M.A., M.M.); and Lilly Research Laboratories, Indianapolis, Indiana 46285 (X.C., B.L., B.W., J.M., E.N., J.L.K.)
| | - Monica Aparici
- The Johns Hopkins University School of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Maryland 21224 (M.Koc., M.Kol., B.J.C., F.R., R.A.H., S.M., B.J.U.); Biomedical Center Martin, Pharmacology and Pathophysiology, Jessenius Faculty of Medicine, Comenius University, Martin 03601, Slovakia (M.Koc., M.Kol.); Almirall S.A., R&D Research Center, Barcelona 08980, Spain (S.F., M.A., M.M.); and Lilly Research Laboratories, Indianapolis, Indiana 46285 (X.C., B.L., B.W., J.M., E.N., J.L.K.)
| | - Montserrat Miralpeix
- The Johns Hopkins University School of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Maryland 21224 (M.Koc., M.Kol., B.J.C., F.R., R.A.H., S.M., B.J.U.); Biomedical Center Martin, Pharmacology and Pathophysiology, Jessenius Faculty of Medicine, Comenius University, Martin 03601, Slovakia (M.Koc., M.Kol.); Almirall S.A., R&D Research Center, Barcelona 08980, Spain (S.F., M.A., M.M.); and Lilly Research Laboratories, Indianapolis, Indiana 46285 (X.C., B.L., B.W., J.M., E.N., J.L.K.)
| | - Xian Xuan Chi
- The Johns Hopkins University School of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Maryland 21224 (M.Koc., M.Kol., B.J.C., F.R., R.A.H., S.M., B.J.U.); Biomedical Center Martin, Pharmacology and Pathophysiology, Jessenius Faculty of Medicine, Comenius University, Martin 03601, Slovakia (M.Koc., M.Kol.); Almirall S.A., R&D Research Center, Barcelona 08980, Spain (S.F., M.A., M.M.); and Lilly Research Laboratories, Indianapolis, Indiana 46285 (X.C., B.L., B.W., J.M., E.N., J.L.K.)
| | - Baolin Li
- The Johns Hopkins University School of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Maryland 21224 (M.Koc., M.Kol., B.J.C., F.R., R.A.H., S.M., B.J.U.); Biomedical Center Martin, Pharmacology and Pathophysiology, Jessenius Faculty of Medicine, Comenius University, Martin 03601, Slovakia (M.Koc., M.Kol.); Almirall S.A., R&D Research Center, Barcelona 08980, Spain (S.F., M.A., M.M.); and Lilly Research Laboratories, Indianapolis, Indiana 46285 (X.C., B.L., B.W., J.M., E.N., J.L.K.)
| | - Ben Wilenkin
- The Johns Hopkins University School of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Maryland 21224 (M.Koc., M.Kol., B.J.C., F.R., R.A.H., S.M., B.J.U.); Biomedical Center Martin, Pharmacology and Pathophysiology, Jessenius Faculty of Medicine, Comenius University, Martin 03601, Slovakia (M.Koc., M.Kol.); Almirall S.A., R&D Research Center, Barcelona 08980, Spain (S.F., M.A., M.M.); and Lilly Research Laboratories, Indianapolis, Indiana 46285 (X.C., B.L., B.W., J.M., E.N., J.L.K.)
| | - Jeff McDermott
- The Johns Hopkins University School of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Maryland 21224 (M.Koc., M.Kol., B.J.C., F.R., R.A.H., S.M., B.J.U.); Biomedical Center Martin, Pharmacology and Pathophysiology, Jessenius Faculty of Medicine, Comenius University, Martin 03601, Slovakia (M.Koc., M.Kol.); Almirall S.A., R&D Research Center, Barcelona 08980, Spain (S.F., M.A., M.M.); and Lilly Research Laboratories, Indianapolis, Indiana 46285 (X.C., B.L., B.W., J.M., E.N., J.L.K.)
| | - Eric Nisenbaum
- The Johns Hopkins University School of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Maryland 21224 (M.Koc., M.Kol., B.J.C., F.R., R.A.H., S.M., B.J.U.); Biomedical Center Martin, Pharmacology and Pathophysiology, Jessenius Faculty of Medicine, Comenius University, Martin 03601, Slovakia (M.Koc., M.Kol.); Almirall S.A., R&D Research Center, Barcelona 08980, Spain (S.F., M.A., M.M.); and Lilly Research Laboratories, Indianapolis, Indiana 46285 (X.C., B.L., B.W., J.M., E.N., J.L.K.)
| | - Jeffrey L Krajewski
- The Johns Hopkins University School of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Maryland 21224 (M.Koc., M.Kol., B.J.C., F.R., R.A.H., S.M., B.J.U.); Biomedical Center Martin, Pharmacology and Pathophysiology, Jessenius Faculty of Medicine, Comenius University, Martin 03601, Slovakia (M.Koc., M.Kol.); Almirall S.A., R&D Research Center, Barcelona 08980, Spain (S.F., M.A., M.M.); and Lilly Research Laboratories, Indianapolis, Indiana 46285 (X.C., B.L., B.W., J.M., E.N., J.L.K.)
| | - Bradley J Undem
- The Johns Hopkins University School of Medicine, Division of Allergy and Clinical Immunology, Baltimore, Maryland 21224 (M.Koc., M.Kol., B.J.C., F.R., R.A.H., S.M., B.J.U.); Biomedical Center Martin, Pharmacology and Pathophysiology, Jessenius Faculty of Medicine, Comenius University, Martin 03601, Slovakia (M.Koc., M.Kol.); Almirall S.A., R&D Research Center, Barcelona 08980, Spain (S.F., M.A., M.M.); and Lilly Research Laboratories, Indianapolis, Indiana 46285 (X.C., B.L., B.W., J.M., E.N., J.L.K.)
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25
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Hewitt MM, Adams G, Mazzone SB, Mori N, Yu L, Canning BJ. Pharmacology of Bradykinin-Evoked Coughing in Guinea Pigs. J Pharmacol Exp Ther 2016; 357:620-8. [PMID: 27000801 PMCID: PMC4885511 DOI: 10.1124/jpet.115.230383] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 03/18/2016] [Indexed: 12/20/2022] Open
Abstract
Bradykinin has been implicated as a mediator of the acute pathophysiological and inflammatory consequences of respiratory tract infections and in exacerbations of chronic diseases such as asthma. Bradykinin may also be a trigger for the coughing associated with these and other conditions. We have thus set out to evaluate the pharmacology of bradykinin-evoked coughing in guinea pigs. When inhaled, bradykinin induced paroxysmal coughing that was abolished by the bradykinin B2 receptor antagonist HOE 140. These cough responses rapidly desensitized, consistent with reports of B2 receptor desensitization. Bradykinin-evoked cough was potentiated by inhibition of both neutral endopeptidase and angiotensin-converting enzyme (with thiorphan and captopril, respectively), but was largely unaffected by muscarinic or thromboxane receptor blockade (atropine and ICI 192605), cyclooxygenase, or nitric oxide synthase inhibition (meclofenamic acid and N(G)-nitro-L-arginine). Calcium influx studies in bronchopulmonary vagal afferent neurons dissociated from vagal sensory ganglia indicated that the tachykinin-containing C-fibers arising from the jugular ganglia mediate bradykinin-evoked coughing. Also implicating the jugular C-fibers was the observation that simultaneous blockade of neurokinin2 (NK2; SR48968) and NK3 (SR142801 or SB223412) receptors nearly abolished the bradykinin-evoked cough responses. The data suggest that bradykinin induces coughing in guinea pigs by activating B2 receptors on bronchopulmonary C-fibers. We speculate that therapeutics targeting the actions of bradykinin may prove useful in the treatment of cough.
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Affiliation(s)
- Matthew M Hewitt
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (G.A., N.M., B.J.C.); University of Pennsylvania, Philadelphia, Pennsylvania (M.M.H.); University of Queensland, Australia (S.B.M.); and Department of Respiratory Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai, China (L.Y.)
| | - Gregory Adams
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (G.A., N.M., B.J.C.); University of Pennsylvania, Philadelphia, Pennsylvania (M.M.H.); University of Queensland, Australia (S.B.M.); and Department of Respiratory Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai, China (L.Y.)
| | - Stuart B Mazzone
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (G.A., N.M., B.J.C.); University of Pennsylvania, Philadelphia, Pennsylvania (M.M.H.); University of Queensland, Australia (S.B.M.); and Department of Respiratory Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai, China (L.Y.)
| | - Nanako Mori
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (G.A., N.M., B.J.C.); University of Pennsylvania, Philadelphia, Pennsylvania (M.M.H.); University of Queensland, Australia (S.B.M.); and Department of Respiratory Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai, China (L.Y.)
| | - Li Yu
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (G.A., N.M., B.J.C.); University of Pennsylvania, Philadelphia, Pennsylvania (M.M.H.); University of Queensland, Australia (S.B.M.); and Department of Respiratory Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai, China (L.Y.)
| | - Brendan J Canning
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland (G.A., N.M., B.J.C.); University of Pennsylvania, Philadelphia, Pennsylvania (M.M.H.); University of Queensland, Australia (S.B.M.); and Department of Respiratory Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai, China (L.Y.)
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26
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Taylor-Clark TE. Role of reactive oxygen species and TRP channels in the cough reflex. Cell Calcium 2016; 60:155-62. [PMID: 27016063 DOI: 10.1016/j.ceca.2016.03.007] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 03/09/2016] [Accepted: 03/10/2016] [Indexed: 12/15/2022]
Abstract
The cough reflex is evoked by noxious stimuli in the airways. Although this reflex is essential for health, it can be triggered chronically in inflammatory and infectious airway disease. Neuronal transient receptor potential (TRP) channels such as ankyrin 1 (TRPA1) and vanilloid 1 (TRPV1) are polymodal receptors expressed on airway nociceptive afferent nerves. Reactive oxygen species (ROS) and other reactive compounds are associated with inflammation, from either NADPH oxidase or mitochondria. These reactive compounds cause activation and hyperexcitability of nociceptive afferents innervating the airways, and evidence suggests key contributions of TRPA1 and TRPV1.
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Affiliation(s)
- Thomas E Taylor-Clark
- Department of Molecular Pharmacology & Physiology, Morsani College of Medicine, University of South Florida, 12901 Bruce B. Downs Blvd., Tampa, FL 33612, USA.
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27
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Niimi A, Chung KF. Evidence for neuropathic processes in chronic cough. Pulm Pharmacol Ther 2015; 35:100-4. [PMID: 26474678 DOI: 10.1016/j.pupt.2015.10.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 10/09/2015] [Accepted: 10/09/2015] [Indexed: 12/16/2022]
Abstract
Chronic cough is a very common symptom for which patients seek medical attention but can often be difficult to manage, because associated causes may remain elusive and treatment of any associated causes does not always provide adequate relief. Current antitussives have limited efficacy and undesirable side-effects. Patients with chronic cough typically describe sensory symptoms suggestive of upper airway and laryngeal neural dysfunction. They often report cough triggered by low-level physical and chemical stimuli supporting the recently emerging concept of 'cough hypersensitivity syndrome'. Chronic cough is a neuropathic condition that could be secondary to sensory nerve damage caused by inflammatory, infective and allergic factors. Mechanisms underlying peripheral and central augmentation of the afferent cough pathways have been identified. Successful treatment of chronic cough with agents used for treating neuropathic pain, such as gabapentin and amitriptyline, would also support this concept. Further research of neuropathic cough may lead to the discovery of more effective antitussives in the future.
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Affiliation(s)
- Akio Niimi
- Department of Respiratory Medicine, Allergy and Clinical Immunology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
| | - Kian Fan Chung
- Experimental Studies, National Heart and Lung Institute, Imperial College London, UK; Royal Brompton NIHR Biomedical Research Unit, London, UK
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28
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Benzonatate inhibition of voltage-gated sodium currents. Neuropharmacology 2015; 101:179-87. [PMID: 26386152 DOI: 10.1016/j.neuropharm.2015.09.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 08/17/2015] [Accepted: 09/15/2015] [Indexed: 11/23/2022]
Abstract
Benzonatate was FDA-approved in 1958 as an antitussive. Its mechanism of action is thought to be anesthesia of vagal sensory nerve fibers that mediate cough. Vagal sensory neurons highly express the Nav1.7 subtype of voltage-gated sodium channels, and inhibition of this channel inhibits the cough reflex. Local anesthetics inhibit voltage-gated sodium channels, but there are no reports of whether benzonatate affects these channels. Our hypothesis is that benzonatate inhibits Nav1.7 voltage-gated sodium channels. We used whole cell voltage clamp recording to test the effects of benzonatate on voltage-gated sodium (Na(+)) currents in two murine cell lines, catecholamine A differentiated (CAD) cells, which express primarily Nav1.7, and N1E-115, which express primarily Nav1.3. We found that, like local anesthetics, benzonatate strongly and reversibly inhibits voltage-gated Na(+) channels. Benzonatate causes both tonic and phasic inhibition. It has greater effects on channel inactivation than on activation, and its potency is much greater at depolarized potentials, indicating inactivated-state-specific effects. Na(+) currents in CAD cells and N1E-115 cells are similarly affected, indicating that benzonatate is not Na(+) channel subtype-specific. Benzonatate is a mixture of polyethoxy esters of 4-(butylamino) benzoic acid having varying degrees of hydrophobicity. We found that Na(+) currents are inhibited most potently by a benzonatate fraction containing the 9-ethoxy component. Detectable effects of benzonatate occur at concentrations as low as 0.3 μM, which has been reported in humans. We conclude that benzonatate has local anesthetic-like effects on voltage-gated sodium channels, including Nav1.7, which is a possible mechanism for cough suppression by the drug.
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29
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Ji RR. Neuroimmune interactions in itch: Do chronic itch, chronic pain, and chronic cough share similar mechanisms? Pulm Pharmacol Ther 2015; 35:81-6. [PMID: 26351759 DOI: 10.1016/j.pupt.2015.09.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 08/27/2015] [Accepted: 09/01/2015] [Indexed: 12/30/2022]
Abstract
Itch and pain are closely related but also clearly distinct sensations. Pain is known to suppress itch, while analgesics such as morphine can provoke itch. However, in pathological and chronic conditions, pain and itch also have similarities. Dysfunction of the nervous system, as manifested by neural plastic changes in primary sensory neurons of the peripheral nervous system (peripheral sensitization) and spinal cord and brain stem neurons in the central nervous system (central sensitization) will result in chronic pain and itch. Importantly, these diseases also result from immune dysfunction, since inflammatory mediators can directly activate or sensitize nociceptive and pruriceptive neurons in the peripheral and central nervous system, leading to pain and itch hypersensitivity. In this mini-review, I discuss the roles of Toll-like receptors (TLRs), transient receptor potential ankyrin 1 (TRPA1) ion channel, and Nav1.7 sodium channel in regulating itch and inflammation, with special emphasis of neuronal TLR signaling and the interaction of TLR7 and TRPA1. Chronic pain and chronic itch are debilitating diseases and dramatically impact the life quality of patients. Targeting TLRs for the control of inflammation, neuroinflammation (inflammation restricted in the nervous system), and hyperexcitability of nociceptors and pruriceptors will lead to new therapeutics for the relief of chronic pain and chronic itch. Finally, given the shared mechanisms among chronic cough, chronic pain, and chronic itch and the demonstrated efficacy of the neuropathic pain drug gabapentin in treating chronic cough, novel therapeutics targeting TRPA1, Nav1.7, and TLRs may also help to alleviate refractory cough via modulating neuron-immune interaction.
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Affiliation(s)
- Ru-Rong Ji
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA; Department of Neurobiology, Duke University Medical Center, Durham, NC, 27710, USA.
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30
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Yu L, Xu X, Lv H, Qiu Z. Advances in upper airway cough syndrome. Kaohsiung J Med Sci 2015; 31:223-8. [PMID: 25910556 DOI: 10.1016/j.kjms.2015.01.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 01/06/2015] [Accepted: 01/19/2015] [Indexed: 11/18/2022] Open
Abstract
Upper airway cough syndrome (UACS), previously referred to as postnasal drip syndrome, is one of the most common causes of chronic cough. However, the pathogenesis of UACS/postnasal drip syndrome remains unclear, and physicians in countries throughout the world have different definitions and ways of treating this disease. The various proposed pathogeneses of UACS include the early postnasal drip theory, subsequent chronic airway inflammation theory, and a recent sensory neural hypersensitivity theory. Additionally, some researchers suggest that UACS is a clinical phenotype of cough hypersensitivity syndrome. While the general principles involved in treating UACS are similar throughout the world, the specific details of treatment differ. This review summarizes the various definitions, pathogenic mechanisms, treatments, and other aspects of UACS, to aid clinicians in expanding their knowledge of how to diagnose and treat this syndrome.
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Affiliation(s)
- Li Yu
- Department of Respiratory Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xianghuai Xu
- Department of Respiratory Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Hanjing Lv
- Department of Respiratory Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Zhongmin Qiu
- Department of Respiratory Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai, China.
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31
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Peripheral neural circuitry in cough. Curr Opin Pharmacol 2015; 22:9-17. [PMID: 25704498 DOI: 10.1016/j.coph.2015.02.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 02/02/2015] [Accepted: 02/04/2015] [Indexed: 01/22/2023]
Abstract
Cough is a reflex that serves to protect the airways. Excessive or chronic coughing is a major health issue that is poorly controlled by current therapeutics. Significant effort has been made to understand the mechanisms underlying the cough reflex. The focus of this review is the evidence supporting the role of specific airway sensory nerve (afferent) populations in the initiation and modulation of the cough reflex in health and disease.
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32
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Tadin-Strapps M, Robinson M, Le Voci L, Andrews L, Yendluri S, Williams S, Bartz S, Johns DG. Development of Lipoprotein(a) siRNAs for Mechanism of Action Studies in Non-Human Primate Models of Atherosclerosis. J Cardiovasc Transl Res 2015; 8:44-53. [DOI: 10.1007/s12265-014-9605-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 12/29/2014] [Indexed: 01/13/2023]
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33
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Canning BJ, Chang AB, Bolser DC, Smith JA, Mazzone SB, McGarvey L. Anatomy and neurophysiology of cough: CHEST Guideline and Expert Panel report. Chest 2014; 146:1633-1648. [PMID: 25188530 PMCID: PMC4251621 DOI: 10.1378/chest.14-1481] [Citation(s) in RCA: 183] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 07/21/2014] [Indexed: 12/11/2022] Open
Abstract
Bronchopulmonary C-fibers and a subset of mechanically sensitive, acid-sensitive myelinated sensory nerves play essential roles in regulating cough. These vagal sensory nerves terminate primarily in the larynx, trachea, carina, and large intrapulmonary bronchi. Other bronchopulmonary sensory nerves, sensory nerves innervating other viscera, as well as somatosensory nerves innervating the chest wall, diaphragm, and abdominal musculature regulate cough patterning and cough sensitivity. The responsiveness and morphology of the airway vagal sensory nerve subtypes and the extrapulmonary sensory nerves that regulate coughing are described. The brainstem and higher brain control systems that process this sensory information are complex, but our current understanding of them is considerable and increasing. The relevance of these neural systems to clinical phenomena, such as urge to cough and psychologic methods for treatment of dystussia, is high, and modern imaging methods have revealed potential neural substrates for some features of cough in the human.
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Affiliation(s)
| | - Anne B Chang
- Queensland Children's Respiratory Centre, Royal Children's Hospital, Brisbane, QLD, Australia, Child Health Division, Menzies School of Health, Darwin, NT, Australia
| | - Donald C Bolser
- Department of Physiological Sciences, University of Florida, Gainesville, FL
| | - Jaclyn A Smith
- Centre for Respiratory and Allergy, University of Manchester, Manchester, England
| | - Stuart B Mazzone
- School of Biomedical Sciences, University of Queensland, Brisbane, QLD, Australia
| | - Lorcan McGarvey
- Centre for Infection and Immunity, The Queen's University of Belfast, Belfast, Northern Ireland.
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34
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Calik MW, Radulovacki M, Carley DW. A method of nodose ganglia injection in Sprague-Dawley rat. J Vis Exp 2014:e52233. [PMID: 25490160 DOI: 10.3791/52233] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Afferent signaling via the vagus nerve transmits important general visceral information to the central nervous system from many diverse receptors located in the organs of the abdomen and thorax. The vagus nerve communicates information from stimuli such as heart rate, blood pressure, bronchopulmonary irritation, and gastrointestinal distension to the nucleus of solitary tract of the medulla. The cell bodies of the vagus nerve are located in the nodose and petrosal ganglia, of which the majority are located in the former. The nodose ganglia contain a wealth of receptors for amino acids, monoamines, neuropeptides, and other neurochemicals that can modify afferent vagus nerve activity. Modifying vagal afferents through systemic peripheral drug treatments targeted at the receptors on nodose ganglia has the potential of treating diseases such as sleep apnea, gastroesophageal reflux disease, or chronic cough. The protocol here describes a method of injection neurochemicals directly into the nodose ganglion. Injecting neurochemicals directly into the nodose ganglia allows study of effects solely on cell bodies that modulate afferent nerve activity, and prevents the complication of involving the central nervous system as seen in systemic neurochemical treatment. Using readily available and inexpensive equipment, intranodose ganglia injections are easily done in anesthetized Sprague-Dawley rats.
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Affiliation(s)
- Michael W Calik
- Center for Narcolepsy, Sleep and Health Research, University of Illinois at Chicago; Department of Biobehavioral Health Science, University of Illinois at Chicago;
| | - Miodrag Radulovacki
- Center for Narcolepsy, Sleep and Health Research, University of Illinois at Chicago; Department of Pharmacology, University of Illinois at Chicago
| | - David W Carley
- Center for Narcolepsy, Sleep and Health Research, University of Illinois at Chicago; Department of Biobehavioral Health Science, University of Illinois at Chicago
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35
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McGarvey L. Update: the search for the human cough receptor. Lung 2014; 192:459-65. [PMID: 24770379 DOI: 10.1007/s00408-014-9581-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 03/29/2014] [Indexed: 10/25/2022]
Abstract
Despite the best efforts of basic and applied science, the identity of the human "cough receptor" remains elusive. The attraction of identifying a single "catch all" cough receptor is obvious, although such an objective is unlikely to be realised given the concept of "cough hypersensitivity," which is now considered the most clinically relevant description of what underlies problem coughing. One means of progressing this area is to join the thinking and experimental effort of basic science and clinical research in an effective manner. Some of the best examples of cooperative and translational research over the years together with an update on the most recent work will be discussed in this article.
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Affiliation(s)
- Lorcan McGarvey
- Centre for Infection and Immunity, Queens University Belfast, Health Sciences Building, Lisburn Road, Belfast, BT9 7BL, Northern Ireland,
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36
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Nilius B, Szallasi A. Transient receptor potential channels as drug targets: from the science of basic research to the art of medicine. Pharmacol Rev 2014; 66:676-814. [PMID: 24951385 DOI: 10.1124/pr.113.008268] [Citation(s) in RCA: 377] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2025] Open
Abstract
The large Trp gene family encodes transient receptor potential (TRP) proteins that form novel cation-selective ion channels. In mammals, 28 Trp channel genes have been identified. TRP proteins exhibit diverse permeation and gating properties and are involved in a plethora of physiologic functions with a strong impact on cellular sensing and signaling pathways. Indeed, mutations in human genes encoding TRP channels, the so-called "TRP channelopathies," are responsible for a number of hereditary diseases that affect the musculoskeletal, cardiovascular, genitourinary, and nervous systems. This review gives an overview of the functional properties of mammalian TRP channels, describes their roles in acquired and hereditary diseases, and discusses their potential as drug targets for therapeutic intervention.
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Affiliation(s)
- Bernd Nilius
- KU Leuven, Department of Cellular and Molecular Medicine, Laboratory of Ion Channel Research, Campus Gasthuisberg, Leuven, Belgium (B.N.); and Department of Pathology, Monmouth Medical Center, Long Branch, New Jersey (A.S.)
| | - Arpad Szallasi
- KU Leuven, Department of Cellular and Molecular Medicine, Laboratory of Ion Channel Research, Campus Gasthuisberg, Leuven, Belgium (B.N.); and Department of Pathology, Monmouth Medical Center, Long Branch, New Jersey (A.S.)
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37
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Wang ZJ, Levinson SR, Sun L, Heinbockel T. Identification of both GABAA receptors and voltage-activated Na(+) channels as molecular targets of anticonvulsant α-asarone. Front Pharmacol 2014; 5:40. [PMID: 24653701 PMCID: PMC3949418 DOI: 10.3389/fphar.2014.00040] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 02/20/2014] [Indexed: 01/09/2023] Open
Abstract
Alpha (α)-asarone, a major effective component isolated from the Chinese medicinal herb Acorus tatarinowii, is clinically used as medication for treating epilepsy, cough, bronchitis, and asthma. In the present study, we demonstrated that α-asarone targets central nervous system GABAA receptor as well as voltage-gated Na(+) channels. Using whole-cell patch-clamp recording, α-asarone inhibited spontaneous firing of output neurons, mitral cells (MCs), in mouse olfactory bulb brain slice preparation and hyperpolarized the membrane potential of MCs. The inhibitory effect of α-asarone persisted in the presence of ionotropic glutamate receptor blockers but was eliminated after adding a GABAA receptor blocker, suggesting that GABAA receptors mediated the inhibition of MCs by α-asarone. This hypothesis was supported by the finding that α-asarone evoked an outward current, but did not influence inhibitory postsynaptic currents (IPSCs). In addition to inhibiting spontaneous firing, α-asarone also inhibited the Nav1.2 channel, a dominant rat brain Na(+) channel subtype. The effects of α-asarone on a defined Nav1.2 were characterized using transfected cells that stably expressed the Nav1.2 channel isoform. α-Asarone displayed strong tonic inhibition of Nav1.2 currents in a concentration- and membrane potential-dependent fashion. α-Asarone reduced channel availability in steady-state inactivation protocols by enhancing or stabilizing Na(+) channel inactivation. Both Na(+) channel blockade and activation of GABAA receptors provide a possible mechanism for the known anti-epileptic effects of α-asarone. It also suggests that α-asarone could benefit patients with cough possibly through inhibiting a Na(+) channel subtype to inhibit peripheral and/or central sensitization of cough reflexes.
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Affiliation(s)
- Ze-Jun Wang
- Department of Anatomy, College of Medicine, Howard University Washington, DC, USA
| | - Simon R Levinson
- Department of Physiology and Biophysics, University of Colorado Denver School of Medicine Aurora, CO, USA
| | - Liqin Sun
- Department of Anatomy, College of Medicine, Howard University Washington, DC, USA
| | - Thomas Heinbockel
- Department of Anatomy, College of Medicine, Howard University Washington, DC, USA
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38
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Muroi Y, Undem BJ. Targeting voltage gated sodium channels NaV1.7, Na V1.8, and Na V1.9 for treatment of pathological cough. Lung 2013; 192:15-20. [PMID: 24272479 DOI: 10.1007/s00408-013-9533-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 10/22/2013] [Indexed: 10/26/2022]
Abstract
Recent advances in our understanding of voltage-gated sodium channels (NaVs) lead to the rational hypothesis that drugs capable of selective blockade of NaV subtypes may be a safe and effective strategy for the treatment of unwanted cough. Among the nine NaV subtypes (NaV1.1-NaV1.9), the afferent nerves involved in initiating cough, in common with nociceptive neurons in the somatosensory system, express mainly NaV1.7, NaV1.8, and NaV1.9. Although knowledge about the effect of selectively blocking these channels on the cough reflex is limited, their biophysical properties indicate that each may contribute to the hypertussive and allotussive state that typifies subacute and chronic nonproductive cough.
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Plevkova J, Kollarik M, Poliacek I, Brozmanova M, Surdenikova L, Tatar M, Mori N, Canning BJ. The role of trigeminal nasal TRPM8-expressing afferent neurons in the antitussive effects of menthol. J Appl Physiol (1985) 2013; 115:268-74. [PMID: 23640596 DOI: 10.1152/japplphysiol.01144.2012] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The cold-sensitive cation channel TRPM8 is a target for menthol, which is used routinely as a cough suppressant and as an additive to tobacco and food products. Given that cold temperatures and menthol activate neurons through gating of TRPM8, it is unclear how menthol actively suppresses cough. In this study we describe the antitussive effects of (-)-menthol in conscious and anesthetized guinea pigs. In anesthetized guinea pigs, cough evoked by citric acid applied topically to the tracheal mucosa was suppressed by menthol only when it was selectively administered as vapors to the upper airways. Menthol applied topically to the tracheal mucosa prior to and during citric acid application or administered continuously as vapors or as an aerosol to the lower airways was without effect on cough. These actions of upper airway menthol treatment were mimicked by cold air delivered to the upper airways but not by (+)-menthol, the inactive isomer of menthol, or by the TRPM8/TRPA1 agonist icilin administered directly to the trachea. Subsequent molecular analyses confirmed the expression of TRPM8 in a subset of nasal trigeminal afferent neurons that do not coincidently express TRPA1 or TRPV1. We conclude that menthol suppresses cough evoked in the lower airways primarily through a reflex initiated from the nose.
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Affiliation(s)
- J Plevkova
- Department of Pathophysiology, Jessenius School of Medicine, Comenius University, Bratislava, Slovak Republic
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