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Awad-Igbaria Y, Dadon S, Shamir A, Livoff A, Shlapobersky M, Bornstein J, Palzur E. Characterization of Early Inflammatory Events Leading to Provoked Vulvodynia Development in Rats. J Inflamm Res 2022; 15:3901-3923. [PMID: 35845089 PMCID: PMC9286136 DOI: 10.2147/jir.s367193] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 06/16/2022] [Indexed: 11/23/2022] Open
Abstract
Background Provoked vulvodynia (PV) is the main cause of vulvar pain and dyspareunia. The etiology of PV has not yet been elucidated. However, PV is associated with a history of recurrent inflammation, and its often accompanied by increases in the numbers of mast cells (MCs) and sensory hyperinnervation in the vulva. Therefore, this study aimed to examine the role of MCs and the early inflammatory events in the development of chronic vulvar pain in a rat model of PV. Methods Mechanical and thermal vulvar sensitivity was measured for 5 months following zymosan vulvar challenges. Vulvar changes in glutamate and nerve growth factor (NGF) were analyzed using ELISA. Immunofluorescence (IF) staining of the vulvar section after 20, 81, and 160 days of the zymosan challenge were performed to test MCs accumulation, hyperinnervation, and expression of pain channels (transient receptor potential vanilloid/ankyrin-1-TRPV1 & TRPA1) in vulvar neurons. Changes in the development of vulvar pain were evaluated following the administration of the MCs stabilizer ketotifen fumarate (KF) during zymosan vulvar challenges. Results Zymosan-challenged rats developed significant mechanical and thermal vulvar sensitivity that persisted for over 160 days after the zymosan challenge. During inflammation, increased local concentrations of NGF and glutamate and a robust increase in MCs degranulation were observed in zymosan-challenged rats. In addition, zymosan-challenged rats displayed sensory hyperinnervation and an increase in the expression of TRPV1 and TRPA1. Treatment with KF attenuated the upregulated level of NGF during inflammation, modulated the neuronal modifications, reduced MCs accumulation, and enhanced mechanical hypersensitivity after repeated inflammation challenges. Conclusion The present findings suggest that vulvar hypersensitivity is mediated by MCs accumulation, nerve growth, and neuromodulation of TRPV1 and TRPA1. Hence, KF treatment during the critical period of inflammation contributes to preventing chronic vulvar pain development.
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Affiliation(s)
- Yaseen Awad-Igbaria
- Faculty of Medicine in the Galilee, Bar-Ilan University, Safed, Israel.,The Research Institute of Galilee Medical Center, Nahariya, Israel
| | - Shilo Dadon
- Faculty of Medicine in the Galilee, Bar-Ilan University, Safed, Israel.,The Research Institute of Galilee Medical Center, Nahariya, Israel
| | - Alon Shamir
- Psychobiology Research Laboratory, Mazor Mental Health Center, Akko, Israel.,The Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Alejandro Livoff
- Pathology Department, Barzilai University Medical Center, Ashkelon, Israel
| | - Mark Shlapobersky
- Pathology Department, Barzilai University Medical Center, Ashkelon, Israel
| | - Jacob Bornstein
- Faculty of Medicine in the Galilee, Bar-Ilan University, Safed, Israel.,The Research Institute of Galilee Medical Center, Nahariya, Israel
| | - Eilam Palzur
- The Research Institute of Galilee Medical Center, Nahariya, Israel
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Eosinophils in the Gastrointestinal Tract: Key Contributors to Neuro-Immune Crosstalk and Potential Implications in Disorders of Brain-Gut Interaction. Cells 2022; 11:cells11101644. [PMID: 35626681 PMCID: PMC9139532 DOI: 10.3390/cells11101644] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/10/2022] [Accepted: 05/11/2022] [Indexed: 02/07/2023] Open
Abstract
Eosinophils are innate immune granulocytes actively involved in defensive responses and in local and systemic inflammatory processes. Beyond these effector roles, eosinophils are fundamental to maintaining homeostasis in the tissues they reside. Gastrointestinal eosinophils modulate barrier function and mucosal immunity and promote tissue development through their direct communication with almost every cellular component. This is possible thanks to the variety of receptors they express and the bioactive molecules they store and release, including cytotoxic proteins, cytokines, growth factors, and neuropeptides and neurotrophines. A growing body of evidence points to the eosinophil as a key neuro-immune player in the regulation of gastrointestinal function, with potential implications in pathophysiological processes. Eosinophil–neuron interactions are facilitated by chemotaxis and adhesion molecules, and the mediators released may have excitatory or inhibitory effects on each cell type, with physiological consequences dependent on the type of innervation involved. Of special interest are the disorders of the brain–gut interaction (DBGIs), mainly functional dyspepsia (FD) and irritable bowel syndrome (IBS), in which mucosal eosinophilia and eosinophil activation have been identified. In this review, we summarize the main roles of gastrointestinal eosinophils in supporting gut homeostasis and the evidence available on eosinophil–neuron interactions to bring new insights that support the fundamental role of this neuro-immune crosstalk in maintaining gut health and contributing to the pathophysiology of DBGIs.
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Jean EE, Good O, Rico JMI, Rossi HL, Herbert DR. Neuroimmune regulatory networks of the airway mucosa in allergic inflammatory disease. J Leukoc Biol 2021; 111:209-221. [PMID: 33857344 PMCID: PMC8674821 DOI: 10.1002/jlb.3ru0121-023r] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 03/16/2021] [Accepted: 03/21/2021] [Indexed: 12/11/2022] Open
Abstract
Communication between the nervous and immune systems serves a key role in host‐protective immunity at mucosal barrier sites including the respiratory tract. In these tissues, neuroimmune interactions operate in bidirectional circuits that can sense and respond to mechanical, chemical, and biologic stimuli. Allergen‐ or helminth‐induced products can produce airway inflammation by direct action on nociceptive afferents and adjacent tissues. The activity of nociceptive afferents can regulate innate and adaptive immune responses via neuropeptides and neurotransmitter signaling. This review will summarize recent work investigating the role of neuropeptides CGRP, VIP, neuromedins, substance P, and neurotransmitters dopamine and the B2‐adrenoceptor agonists epinepherine/norepinepherine, each of which influence type 2 immunity by instructing mast cell, innate lymphoid cell type 2, dendritic cell, and T cell responses, both in the airway and the draining lymph node. Afferents in the airway also contain receptors for alarmins and cytokines, allowing their activity to be modulated by immune cell secreted products, particularly those secreted by mast cells. Taken together, we propose that further investigation of how immunoregulatory neuropeptides shape respiratory inflammation in experimental systems may reveal novel therapeutic targets for addressing the increasing prevalence of chronic airway disease in humans.
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Affiliation(s)
- E Evonne Jean
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, USA
| | - Olivia Good
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, USA
| | - Juan M Inclan Rico
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, USA
| | - Heather L Rossi
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, USA
| | - De'Broski R Herbert
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, USA
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4
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Sex differences in cough reflex. Respir Physiol Neurobiol 2017; 245:122-129. [DOI: 10.1016/j.resp.2016.12.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 12/07/2016] [Accepted: 12/08/2016] [Indexed: 12/31/2022]
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5
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NGF and Its Receptors in the Regulation of Inflammatory Response. Int J Mol Sci 2017; 18:ijms18051028. [PMID: 28492466 PMCID: PMC5454940 DOI: 10.3390/ijms18051028] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 03/31/2017] [Accepted: 05/03/2017] [Indexed: 12/28/2022] Open
Abstract
There is growing interest in the complex relationship between the nervous and immune systems and how its alteration can affect homeostasis and result in the development of inflammatory diseases. A key mediator in cross-talk between the two systems is nerve growth factor (NGF), which can influence both neuronal cell function and immune cell activity. The up-regulation of NGF described in inflamed tissues of many diseases can regulate innervation and neuronal activity of peripheral neurons, inducing the release of immune-active neuropeptides and neurotransmitters, but can also directly influence innate and adaptive immune responses. Expression of the NGF receptors tropomyosin receptor kinase A (TrkA) and p75 neurotrophin receptor (p75NTR) is dynamically regulated in immune cells, suggesting a varying requirement for NGF depending on their state of differentiation and functional activity. NGF has a variety of effects that can be either pro-inflammatory or anti-inflammatory. This apparent contradiction can be explained by considering NGF as part of an endogenous mechanism that, while activating immune responses, also activates pathways necessary to dampen the inflammatory response and limit tissue damage. Decreases in TrkA expression, such as that recently demonstrated in immune cells of arthritis patients, might prevent the activation by NGF of regulatory feed-back mechanisms, thus contributing to the development and maintenance of chronic inflammation.
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Demoulin-Alexikova S, Plevkova J, Mazurova L, Zatko T, Alexik M, Hanacek J, Tatar M. Impact of Air Pollution on Age and Gender Related Increase in Cough Reflex Sensitivity of Healthy Children in Slovakia. Front Physiol 2016; 7:54. [PMID: 26941651 PMCID: PMC4763033 DOI: 10.3389/fphys.2016.00054] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 02/04/2016] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Numerous studies show higher cough reflex sensitivity (CRS) and cough outcomes in children compared to adults and in females compared to males. Despite close link that exists between cough and environment the potential influence of environmental air pollution on age- and gender -related differences in cough has not been studied yet. PURPOSE The purpose of our study was to analyse whether the effects of exposure to environmental tobacco smoke (ETS) from parental smoking and PM10 from living in urban area are implied in age- and gender-related differences in cough outcomes of healthy, non-asthmatic children. Assessment of CRS using capsaicin and incidence of dry and wet cough was performed in 290 children (mean age 13.3 ± 2.6 years (138 females/152 males). RESULTS CRS was significantly higher in girls exposed to ETS [22.3 μmol/l (9.8-50.2 μmol/l)] compared to not exposed girls [79.9 μmol/l (56.4-112.2 μmol/l), p = 0.02] as well as compared to exposed boys [121.4 μmol/l (58.2-253.1 μmol/l), p = 0.01]. Incidence of dry cough lasting more than 3 weeks was significantly higher in exposed compared to not exposed girls. CRS was significantly higher in school-aged girls living in urban area [22.0 μmol/l (10.6-45.6 μmol/l)] compared to school-aged girls living in rural area [215.9 μmol/l (87.3-533.4 μmol/l); p = 0.003], as well as compared to teenage girls living in urban area [108.8 μmol/l (68.7-172.9 μmol/l); p = 0.007]. No CRS differences were found between urban and rural boys when controlled for age group. No CRS differences were found between school-aged and teenage boys when controlled for living area. CONCLUSIONS Our results have shown that the effect of ETS on CRS was gender specific, linked to female gender and the effect of PM10 on CRS was both gender and age specific, related to female gender and school-age. We suggest that age and gender related differences in incidence of cough and CRS might be, at least partially, ascribed to the effect of environmental pollutants. The role of age and gender in the effect of air pollution on cough strongly suggest some interplay of development with biological and behavioral factors.
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Affiliation(s)
- Silvia Demoulin-Alexikova
- Department of Pathophysiology, Jessenius Faculty of Medicine in Martin, Comenius University in BratislavaBratislava, Slovakia; Service d'Explorations Fonctionnelles Pédiatriques, Hôpital d'Enfants, Centre Hospitalier Universitaire de NancyVandœuvre-lès-Nancy, France; EA 3450 DevAH - Laboratoire de Physiologie, Faculté de Médecine, Université de LorraineVandœuvre-lès-Nancy, France
| | - Jana Plevkova
- Department of Pathophysiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava Bratislava, Slovakia
| | - Lenka Mazurova
- Department of Pathophysiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava Bratislava, Slovakia
| | - Tomas Zatko
- Department of Pathophysiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava Bratislava, Slovakia
| | - Mikulas Alexik
- Department of Ophthalmology, Faculty Hospital of Žilina Žilina, Slovakia
| | - Jan Hanacek
- Department of Pathophysiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava Bratislava, Slovakia
| | - Milos Tatar
- Department of Pathophysiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava Bratislava, Slovakia
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Exposure to Allergen Causes Changes in NTS Neural Activities after Intratracheal Capsaicin Application, in Endocannabinoid Levels and in the Glia Morphology of NTS. BIOMED RESEARCH INTERNATIONAL 2015; 2015:980983. [PMID: 25866824 PMCID: PMC4383154 DOI: 10.1155/2015/980983] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 09/25/2014] [Accepted: 10/06/2014] [Indexed: 11/17/2022]
Abstract
Allergen exposure may induce changes in the brainstem secondary neurons, with neural sensitization of the nucleus solitary tract (NTS), which in turn can be considered one of the causes of the airway hyperresponsiveness, a characteristic feature of asthma. We evaluated neurofunctional, morphological, and biochemical changes in the NTS of naive or sensitized rats. To evaluate the cell firing activity of NTS, in vivo electrophysiological experiments were performed before and after capsaicin challenge in sensitized or naive rats. Immunohistochemical studies, endocannabinoid, and palmitoylethanolamide quantification in the NTS were also performed. This study provides evidence that allergen sensitization in the NTS induced: (1) increase in the neural firing response to intratracheal capsaicin application, (2) increase of endocannabinoid anandamide and palmitoylethanolamide, a reduction of 2-arachidonoylglycerol levels in the NTS, (3) glial cell activation, and (4) prevention by a Group III metabotropic glutamate receptor activation of neural firing response to intratracheal application of capsaicin in both naïve and sensitized rats. Therefore, normalization of ovalbumin-induced NTS neural sensitization could open up the prospect of new treatments based on the recovery of specific brain nuclei function and for extensive studies on acute or long-term efficacy of selective mGlu ligand, in models of bronchial hyperreactivity.
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Pacheco A. Chronic cough: from a complex dysfunction of the neurological circuit to the production of persistent cough. Thorax 2014; 69:881-3. [PMID: 24969642 DOI: 10.1136/thoraxjnl-2014-205661] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Chronic cough or cough that lasts more than 8 weeks, once a chest x-ray and spirometry are confirmed normal, is caused by an alteration in a section of the route between peripheral receptors, mainly in the upper and lower airway and oesophagus, spinal cord and the cough centre in the brain stem involving the cortex. These mechanisms of cough have their homology in the circuit of chronic pain, and on that basis, should expand future research of chronic cough. Clinically chronic cough is easy to diagnose by an excessive response or hypertussia to low-intensity stimuli or banal stimuli, which we now call hypersensitivity cough syndrome, quantified by a positive reflex cough with capsaicin or citric acid. However, hypersensitivity cough syndrome can be impossible to quantify in the laboratory when the hyper-responsiveness originates in the central nervous system. This is normally caused by excessive peripheral input or convergence of stimuli from different sources. Once central hypersensitivity is acquired, peripheral input is not as important for activation of the cough.
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9
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Liu C, Chen R, Luo W, Lai K, Zhong N. Neurogenic airway inflammation induced by repeated intra-esophageal instillation of HCl in guinea pigs. Inflammation 2013; 36:493-500. [PMID: 23225164 DOI: 10.1007/s10753-012-9570-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
This study was conducted to investigate if repeated intra-esophageal acid administrations may induce neurogenic inflammation in the airways and nodose ganglion in a guinea pig model. Guinea pigs were sedated and perfused with 0.1 N HCl in the distal esophagus via a nasoesophageal catheter for 14 consecutive days. Substance P (SP), neurokinin A (NKA), neurokinin B (NKB), and calcitonin gene-related peptide concentration were measured by ELISA or radioimmunoassay. Neuropeptide expression in the airways and nodose ganglion was detected by immunohistochemistry and assessed semi-quantitatively. Inflammation was found in the trachea and bronchi. There was a threefold increase in substance P concentration in the trachea, main bronchi, and lung homogenate and a twofold increase in NKA and NKB concentration in the main bronchi, lung homogenate, and bronchial alveolus lavage fluid, respectively. The SP and NKA expressions in the airways and nodose ganglion were also significantly increased. Chronic intra-esophageal acid instillation induces significant neurogenic inflammation in the airways and nodose ganglion in the vagus nerve in guinea pigs.
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Affiliation(s)
- Chunli Liu
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical College, 151 Yanjiang Rd., Guangzhou, 510120, China
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10
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Delescluse I, Mace H, Adcock JJ. Inhibition of airway hyper-responsiveness by TRPV1 antagonists (SB-705498 and PF-04065463) in the unanaesthetized, ovalbumin-sensitized guinea pig. Br J Pharmacol 2012; 166:1822-32. [PMID: 22320181 DOI: 10.1111/j.1476-5381.2012.01891.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND AND PURPOSE Airway sensory nerves play a key role in respiratory cough, dyspnoea, airway hyper-responsiveness (AHR), all fundamental features of airway diseases [asthma and chronic obstructive pulmonary disease (COPD)]. Vagally mediated airway reflexes such as cough, bronchoconstriction and chest tightness originate from stimulation of airway sensory nerve endings. The transient receptor potential vanilloid 1 receptor (TRPV1) is present on peripheral terminals of airway sensory nerves and modulation of its activity represents a potential target for the pharmacological therapy of AHR in airway disease. EXPERIMENTAL APPROACH As guinea pig models can provide some of the essential features of asthma, including AHR, we have established the model with some classical pharmacological agents and examined the effect of the TRPV1 antagonists, SB-705498 and PF-04065463 on AHR to histamine evoked by ovalbumin (OA) in unanaesthetized sensitized guinea pigs restrained in a double chamber plethysmograph. Specific airway conductance (sGaw) derived from the airflow was calculated as a percentage of change from baseline. KEY RESULTS Cetirizine and salbutamol significantly inhibited OA-evoked bronchoconstriction [sGaw area under the curve (AUC): 70 and 78%, respectively]. Atropine, SB-705498 and PF-04065463 significantly inhibited OA-evoked AHR to histamine in unanaesthetized, OA-sensitized guinea pigs (sGaw AUC: 94%, 57% and 73%, respectively). Furthermore, this effect was not related to antagonism of histamine's activity. CONCLUSION AND IMPLICATIONS These data suggest that TRPV1 receptors located on airway sensory nerves are important in the development of AHR and that modulation of TRPV1-receptor activity represents a potential target for the pharmacological therapy of AHR in airway disease.
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Affiliation(s)
- I Delescluse
- Allergy & Respiratory Biology, Pfizer Global R&D, Sandwich, UK
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11
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Direct and indirect effects of particulate matter on the cardiovascular system. Toxicol Lett 2011; 208:293-9. [PMID: 22119171 DOI: 10.1016/j.toxlet.2011.11.008] [Citation(s) in RCA: 152] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 11/08/2011] [Accepted: 11/09/2011] [Indexed: 01/17/2023]
Abstract
Human exposure to particulate matter (PM) elicits a variety of responses on the cardiovascular system through both direct and indirect pathways. Indirect effects of PM on the cardiovascular system are mediated through the autonomic nervous system, which controls heart rate variability, and inflammatory responses, which augment acute cardiovascular events and atherosclerosis. Recent research demonstrates that PM also affects the cardiovascular system directly by entry into the systemic circulation. This process causes myocardial dysfunction through mechanisms of reactive oxygen species production, calcium ion interference, and vascular dysfunction. In this review, we will present key evidence in both the direct and indirect pathways, suggest clinical applications of the current literature, and recommend directions for future research.
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Cyphert JM, Allen IC, Church RJ, Latour AM, Snouwaert JN, Coffman TM, Koller BH. Allergic inflammation induces a persistent mechanistic switch in thromboxane-mediated airway constriction in the mouse. Am J Physiol Lung Cell Mol Physiol 2011; 302:L140-51. [PMID: 21984570 DOI: 10.1152/ajplung.00152.2011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Actions of thromboxane (TXA(2)) to alter airway resistance were first identified over 25 years ago. However, the mechanism underlying this physiological response has remained largely undefined. Here we address this question using a novel panel of mice in which expression of the thromboxane receptor (TP) has been genetically manipulated. We show that the response of the airways to TXA(2) is complex: it depends on expression of other G protein-coupled receptors but also on the physiological context of the signal. In the healthy airway, TXA(2)-mediated airway constriction depends on expression of TP receptors by smooth muscle cells. In contrast, in the inflamed lung, the direct actions of TXA(2) on smooth muscle cell TP receptors no longer contribute to bronchoconstriction. Instead, in allergic lung disease, TXA(2)-mediated airway constriction depends on neuronal TP receptors. Furthermore, this mechanistic switch persists long after resolution of pulmonary inflammation. Our findings demonstrate the powerful ability of lung inflammation to modify pathways leading to airway constriction, resulting in persistent changes in mechanisms of airway reactivity to key bronchoconstrictors. Such alterations are likely to shape the pathogenesis of asthmatic lung disease.
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Affiliation(s)
- Jaime M Cyphert
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7264, USA
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13
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Li BY, Glazebrook P, Kunze DL, Schild JH. KCa1.1 channel contributes to cell excitability in unmyelinated but not myelinated rat vagal afferents. Am J Physiol Cell Physiol 2011; 300:C1393-403. [PMID: 21325638 DOI: 10.1152/ajpcell.00278.2010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
High conductance calcium-activated potassium (BK(Ca)) channels can modulate cell excitability and neurotransmitter release at synaptic and afferent terminals. BK(Ca) channels are present in primary afferents of most, if not, all internal organs and are an intriguing target for pharmacological manipulation of visceral sensation. Our laboratory has a long-standing interest in the neurophysiological differences between myelinated and unmyelinated visceral afferent function. Here, we seek to determine whether there is a differential distribution of BK(Ca) channels in myelinated and unmyelinated vagal afferents. Immunocytochemistry studies with double staining for the BK-type K(Ca)1.1 channel protein and isolectin B4 (IB4), a reliable marker of unmyelinated peripheral afferents, reveal a pattern of IB4 labeling that strongly correlates with the expression of the K(Ca)1.1 channel protein. Measures of cell size and immunostaining intensity for K(Ca)1.1 and IB4 cluster into two statistically distinct (P < 0.05) populations of cells. Smaller diameter neurons most often presented with strong IB4 labeling and are presumed to be unmyelinated (n = 1,390) vagal afferents. Larger diameter neurons most often lacked or exhibited a very weak IB4 labeling and are presumed to be myelinated (n = 58) vagal afferents. Complimentary electrophysiological studies reveal that the BK(Ca) channel blockers charybdotoxin (ChTX) and iberiotoxin (IbTX) bring about a comparable elevation in excitability and action potential widening in unmyelinated neurons but had no effect on the excitability of myelinated vagal afferents. This study is the first to demonstrate using combined immunohistochemical and electrophysiological techniques that K(Ca)1.1 channels are uniquely expressed in unmyelinated C-type vagal afferents and do not contribute to the dynamic discharge characteristics of myelinated A-type vagal afferents. This unique functional distribution of BK-type K(Ca) channels may provide an opportunity for afferent selective pharmacological intervention across a wide range of visceral pathophysiologies, particularly those with a reflexogenic etiology and pain.
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Affiliation(s)
- Bai-Yan Li
- Dept. of Biomedical Engineering, Indiana University Purdue University, 723 W. Michigan St., Indianapolis, IN 46202, USA
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14
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Farraj AK, Hazari MS, Haykal-Coates N, Lamb C, Winsett DW, Ge Y, Ledbetter AD, Carll AP, Bruno M, Ghio A, Costa DL. ST depression, arrhythmia, vagal dominance, and reduced cardiac micro-RNA in particulate-exposed rats. Am J Respir Cell Mol Biol 2010; 44:185-96. [PMID: 20378750 DOI: 10.1165/rcmb.2009-0456oc] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Recently, investigators demonstrated associations between fine particulate matter (PM)-associated metals and adverse health effects. Residual oil fly ash (ROFA), a waste product of fossil fuel combustion from boilers, is rich in the transition metals Fe, Ni, and V, and when released as a fugitive particle, is an important contributor to ambient fine particulate air pollution. We hypothesized that a single-inhalation exposure to transition metal-rich PM will cause concentration-dependent cardiovascular toxicity in spontaneously hypertensive (SH) rats. Rats implanted with telemeters to monitor heart rate and electrocardiogram were exposed once by nose-only inhalation for 4 hours to 3.5 mg/m(3), 1.0 mg/m(3), or 0.45 mg/m(3) of a synthetic PM (dried salt solution), similar in composition to a well-studied ROFA sample consisting of Fe, Ni, and V. Exposure to the highest concentration of PM decreased T-wave amplitude and area, caused ST depression, reduced heart rate (HR), and increased nonconducted P-wave arrhythmias. These changes were accompanied by increased pulmonary inflammation, lung resistance, and vagal tone, as indicated by changes in markers of HR variability (increased root of the mean of squared differences of adjacent RR intervals [RMSSD], low frequency [LF], high frequency [HF], and decreased LF/HF), and attenuated myocardial micro-RNA (RNA segments that suppress translation by targeting messenger RNA) expression. The low and intermediate concentrations of PM had less effect on the inflammatory, HR variability, and micro-RNA endpoints, but still caused significant reductions in HR. In addition, the intermediate concentration caused ST depression and increased QRS area, whereas the low concentration increased the T-wave parameters. Thus, PM-induced cardiac dysfunction is mediated by multiple mechanisms that may be dependent on PM concentration and myocardial vulnerability (this abstract does not reflect the policy of the United States Environmental Protection Agency).
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Affiliation(s)
- Aimen K Farraj
- Environmental Public Health Division, United States Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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15
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Tsai TL, Chang SY, Ho CY, Kou YR. Role of ATP in the ROS-mediated laryngeal airway hyperreactivity induced by laryngeal acid-pepsin insult in anesthetized rats. J Appl Physiol (1985) 2009; 106:1584-92. [PMID: 19246655 DOI: 10.1152/japplphysiol.91517.2008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The pathogenetic mechanisms of laryngeal airway hyperreactivity (LAH) in patients with extraesophageal reflux are unclear. We recently reported that a laryngeal acid-pepsin insult produces LAH that is mediated through sensitization of the capsaicin-sensitive laryngeal afferent fibers by reactive oxygen species (ROS) in rats. Since ROS may promote the release of ATP from cells, we hypothesized that activation of P2X purinoceptors by ATP subsequent to an increase in ROS induces LAH in an inflamed larynx that has been insulted by acid-pepsin or H(2)O(2) (a major type of ROS). The larynxes of 208 anesthetized rats were functionally isolated while the animals breathed spontaneously. Ammonia vapor was delivered into the larynx to measure laryngeal reflex reactivity. Laryngeal insult with acid-pepsin or H(2)O(2) produced LAH with similar characteristics. The H(2)O(2)-induced LAH was prevented by laryngeal pretreatment with dimethylthiourea (a hydroxyl radical scavenger), suggesting a critical role for ROS. The LAH induced by both insults were completely prevented by ATP scavengers (a combination of apyrase and adenosine deaminase) or a P2X receptor antagonist (iso-pyridoxalphosphate-6-azophenyl-2',5'-disulfonate). Laryngeal application of a P2X receptor agonist (alpha,beta-methylene-ATP) also produced LAH. An insult with either acid-pepsin or H(2)O(2) similarly promoted an increase in the levels of ATP, lipid peroxidation, and inflammation in the larynx. Our findings suggest that laryngeal insult with acid-pepsin or H(2)O(2) induces inflammation and produces excess ROS in the rat's larynx. The latter may in turn promote the release of ATP to activate P2X receptors, resulting in sensitization of capsaicin-sensitive laryngeal afferent fibers and LAH.
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Affiliation(s)
- Tung-Lung Tsai
- Institute of Physiology, School of Medicine, National Yang-Ming Univ., Taipei 11221, Taiwan
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16
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Shen S, Zhao Y, Yang W, Xu L, Sun Z, Chen X, Ji T, Zhang C. Decreased nerve distribution in mixed venous-lymphatic malformation. Int J Oral Maxillofac Surg 2008; 37:1106-10. [PMID: 18945592 DOI: 10.1016/j.ijom.2008.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 05/15/2008] [Accepted: 09/01/2008] [Indexed: 10/21/2022]
Abstract
In order to investigate the nerve distribution in mixed venous-lymphatic malformations (MVLMs), 57 postoperative patients diagnosed with MVLMs of the tongue were selected. Immunohistochemistry staining for neurofilament (NF) was used to detect sensory nerve fibers. Distribution of NF in samples from MVLMs was compared with distribution of NF in normal tongue tissue, venous malformations, lymphatic malformations and venular malformations. Results showed that the number of NF-positive nerve fibers in MVLMs was comparable to that in venous malformations and lymphatic malformations. The number of nerve fibers in MVLMs was significantly lower than in normal tissues. NF distribution in MVLMs was not affected by the patient's age or the coexistence of infection. These data suggest that the decreased distribution of sensory nerve fibers in MVLMs may be involved in the pathogenesis of MVLM of the tongue.
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Affiliation(s)
- S Shen
- Department of Oral and Maxillofacial Surgery, Affiliated Shanghai Ninth People's Hospital, Shanghai Jiao Tong University, Shanghai, PR China
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17
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Taylor-Clark TE, McAlexander MA, Nassenstein C, Sheardown SA, Wilson S, Thornton J, Carr MJ, Undem BJ. Relative contributions of TRPA1 and TRPV1 channels in the activation of vagal bronchopulmonary C-fibres by the endogenous autacoid 4-oxononenal. J Physiol 2008; 586:3447-59. [PMID: 18499726 DOI: 10.1113/jphysiol.2008.153585] [Citation(s) in RCA: 165] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Transient receptor potential (TRP) A1 channels are cation channels found preferentially on nociceptive sensory neurones, including capsaicin-sensitive TRPV1-expressing vagal bronchopulmonary C-fibres, and are activated by electrophilic compounds such as mustard oil and cinnamaldehyde. Oxidative stress, a pathological feature of many respiratory diseases, causes the endogenous formation of a number of reactive electrophilic alkenals via lipid peroxidation. One such alkenal, 4-hydroxynonenal (4HNE), activates TRPA1 in cultured sensory neurones. However, our data demonstrate that 100 microm 4HNE was unable to evoke significant action potential discharge or tachykinin release from bronchopulmonary C-fibre terminals. Instead, another endogenously produced alkenal, 4-oxononenal (4ONE, 10 microm), which is far more electrophilic than 4HNE, caused substantial action potential discharge and tachykinin release from bronchopulmonary C-fibre terminals. The activation of mouse bronchopulmonary C-fibre terminals by 4ONE (10-100 microm) was mediated entirely by TRPA1 channels, based on the absence of responses in C-fibre terminals from TRPA1 knockout mice. Interestingly, although the robust increases in calcium caused by 4ONE (0.1-10 microm) in dissociated vagal neurones were essentially abolished in TRPA1 knockout mice, at 100 microm 4ONE caused a large TRPV1-dependent response. Furthermore, 4ONE (100 microm) was shown to activate TRPV1 channel-expressing HEK cells. In conclusion, the data support the hypothesis that 4-ONE is a relevant endogenous activator of vagal C-fibres via an interaction with TRPA1, and at less relevant concentrations, it may activate nerves via TRPV1.
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Affiliation(s)
- T E Taylor-Clark
- Division of Allergy & Clinical Immunology, Johns Hopkins School of Medicine, Baltimore, MA, USA
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18
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Bucelli RC, Gonsiorek EA, Kim WY, Bruun D, Rabin RA, Higgins D, Lein PJ. Statins decrease expression of the proinflammatory neuropeptides calcitonin gene-related peptide and substance P in sensory neurons. J Pharmacol Exp Ther 2007; 324:1172-80. [PMID: 18079356 DOI: 10.1124/jpet.107.132795] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Clinical and experimental observations suggest that statins may be useful for treating diseases presenting with predominant neurogenic inflammation, but the mechanism(s) mediating this potential therapeutic effect are poorly understood. In this study, we tested the hypothesis that statins act directly on sensory neurons to decrease expression of proinflammatory neuropeptides that trigger neurogenic inflammation, specifically calcitonin gene-related peptide (CGRP) and substance P. Reverse transcriptase-polymerase chain reaction, radioimmunoassay, and immunocytochemistry were used to quantify CGRP and substance P expression in dorsal root ganglia (DRG) harvested from adult male rats and in primary cultures of sensory neurons derived from embryonic rat DRG. Systemic administration of statins at pharmacologically relevant doses significantly reduced CGRP and substance P levels in DRG in vivo. In cultured sensory neurons, statins blocked bone morphogenetic protein (BMP)-induced CGRP and substance P expression and decreased expression of these neuropeptides in sensory neurons pretreated with BMPs. These effects were concentration-dependent and occurred independent of effects on cell survival or axon growth. Statin inhibition of neuropeptide expression was reversed by supplementation with mevalonate and cholesterol, but not isoprenoid precursors. BMPs signal via Smad activation, and cholesterol depletion by statins inhibited Smad1 phosphorylation and nuclear translocation. These findings identify a novel action of statins involving down-regulation of proinflammatory neuropeptide expression in sensory ganglia via cholesterol depletion and decreased Smad1 activation and suggest that statins may be effective in attenuating neurogenic inflammation.
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Affiliation(s)
- Robert C Bucelli
- Oregon Health Science University, CROET/L606, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
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19
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Basic Mechanisms of Cough: Current Understanding and Remaining Questions. Lung 2007; 186 Suppl 1:S10-6. [DOI: 10.1007/s00408-007-9060-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Accepted: 11/09/2007] [Indexed: 11/25/2022]
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20
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McLeod RL, Correll CC, Jia Y, Anthes JC. TRPV1 antagonists as potential antitussive agents. Lung 2007; 186 Suppl 1:S59-65. [PMID: 17926096 DOI: 10.1007/s00408-007-9032-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Accepted: 08/15/2007] [Indexed: 12/17/2022]
Abstract
Cough is an important defensive pulmonary reflex that removes irritants, fluids, or foreign materials from the airways. However, when cough is exceptionally intense or when it is chronic and/or nonproductive it may require pharmacologic suppression. For many patients, antitussive therapies consist of OTC products with inconsequential efficacies. On the other hand, the prescription antitussive market is dominated by older opioid drugs such as codeine. Unfortunately, "codeine-like" drugs suppress cough at equivalent doses that also often produce significant ancillary liabilities such as GI constipation, sedation, and respiratory depression. Thus, the discovery of a novel and effective antitussive drug with an improved side effect profile relative to codeine would fulfill an unmet clinical need in the treatment of cough. Afferent pulmonary nerves are endowed with a multitude of potential receptor targets, including TRPV1, that could act to attenuate cough. The evidence linking TRPV1 to cough is convincing. TRPV1 receptors are found on sensory respiratory nerves that are important in the generation of the cough reflex. Isolated pulmonary vagal afferent nerves are responsive to TRPV1 stimulation. In vivo, TRPV1 agonists such as capsaicin elicit cough when aerosolized and delivered to the lungs. Pertinent to the debate on the potential use of TRPV1 antagonist as antitussive agents are the observations that airway afferent nerves become hypersensitive in diseased and inflamed lungs. For example, the sensitivity of capsaicin-induced cough responses following upper respiratory tract infection and in airway inflammatory diseases such as asthma and COPD is increased relative to that of control responses. Indeed, we have demonstrated that TRPV1 antagonism can attenuate antigen-induced cough in the allergic guinea pig. However, it remains to be determined if the emerging pharmacologic profile of TRPV1 antagonists will translate into a novel human antitussive drug. Current efforts in clinical validation of TRPV1 antagonists revolve around various pain indications; therefore, clinical evaluation of TRPV1 antagonists as antitussive agents will have to await those outcomes.
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Affiliation(s)
- Robbie L McLeod
- Department of Neurobiology, Schering-Plough Research Institute, Kenilworth, NJ 07033-0539, USA.
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21
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Yu S, Kollarik M, Ouyang A, Myers AC, Undem BJ. Mast cell-mediated long-lasting increases in excitability of vagal C fibers in guinea pig esophagus. Am J Physiol Gastrointest Liver Physiol 2007; 293:G850-6. [PMID: 17702952 DOI: 10.1152/ajpgi.00277.2007] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Several esophageal pathologies are associated with an increased number of mast cells in the esophageal wall. We addressed the hypothesis that activation of esophageal mast cells leads to an increase in the excitability of local sensory C fibers. Guinea pigs were actively sensitized to ovalbumin. The mast cells in the esophagus were selectively activated ex vivo by superfusion with ovalbumin. Action potential discharge in guinea pig vagal nodose esophageal C-fiber nerve endings was monitored in the isolated (ex vivo) vagally innervated esophagus by extracellular recordings. Ovalbumin activated esophageal mast cells, leading to the rapid release of approximately 20% of the tissue histamine stores. This was associated with a consistent and significant increase in excitability of the nodose C fibers as reflected in a two- to threefold increase in action potential discharge frequency evoked by mechanical (increases in intraluminal pressure) stimulation. The increase in excitability persisted unchanged for at least 90 min (longest time period tested) after ovalbumin was washed from the tissue. This effect could be prevented by the histamine H1 receptor antagonist pyrilamine, but once the increase in excitability occurred, it persisted in the nominal absence of histamine and could not be reversed even with large concentrations of the histamine receptor antagonist. In conclusion, activation of esophageal mast cells leads to a pronounced and long-lived increase in nociceptive C-fiber excitability such that any sensation or reflex evoked via the vagal nociceptors will likely be enhanced. The effect is initiated by histamine acting via H1 receptor activation and maintained in the absence of the initiating stimulus.
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Affiliation(s)
- Shaoyong Yu
- Pennsylvania State University, College of Medicine, Hershey, Pennsylvania, USA
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22
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McLeod RL, Fernandez X, Correll CC, Phelps TP, Jia Y, Wang X, Hey JA. TRPV1 antagonists attenuate antigen-provoked cough in ovalbumin sensitized guinea pigs. Cough 2006; 2:10. [PMID: 17173683 PMCID: PMC1764418 DOI: 10.1186/1745-9974-2-10] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2006] [Accepted: 12/15/2006] [Indexed: 11/10/2022] Open
Abstract
We examined the molecular pharmacology and in vivo effects of a TRPV1 receptor antagonist, N-(4-Tertiarybutylphenyl)-4(3-cholorphyridin-2-yl)-tetrahydro-pyrazine1(2H) - carboxamide (BCTC) on the guinea pig TRPV1 cation channel. BCTC antagonized capsaicin-induced activation and PMA-mediated activation of guinea pig TRPV1 with IC50 values of 12.2 +/- 5.2 nM, and 0.85 +/- 0.10 nM, respectively. In addition, BCTC (100 nM) completely blocked the ability of heterologously expressed gpTRPV1 to respond to decreases in pH. Thus, BCTC is able to block polymodal activation of gpTRPV1. Furthermore, in nodose ganglia cells, capsaicin induced Ca2+ influx through TRPV1 channel was inhibited via BCTC in a concentration dependent manner. In in vivo studies capsaicin (10 - 300 muM) delivered by aerosol to the pulmonary system of non-sensitized guinea pigs produced an increase in cough frequency. In these studies, the tussigenic effects of capsaicin (300 muM) were blocked in a dose dependent fashion when BCTC (0.01-3.0 mg/kg, i.p.) was administered 30 minutes before challenge. The high dose of BCTC (3.0 mg/kg, i.p) produced a maximum inhibition of capsaicin-induced cough of 65%. We also studied the effects of BCTC (0.03 and 3.0) when administered 60 minutes before capsaicin. Under these conditions, BCTC (3.0 mg/kg, i.p) produced a maximum decrease in capsaicin-induced cough of 31%. In ovalbumin passively sensitized guinea pigs, we found that BCTC (1 and 3 mg/kg, i.p.) attenuated antigen ovalbumin (0.3%) cough responses by 27% and 60%, respectively. We conclude that TRPV1 channel activation may play role in cough mediated by antigen in sensitized guinea pigs. Our results supports increasing evidence that TRPV1 may play a role in the generation of the cough response.
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Affiliation(s)
- Robbie L McLeod
- Peripheral and Pulmonary Neurobiology Schering-Plough Research Institute, Kenilworth, NJ, 07033-0539, USA
| | - Xiomara Fernandez
- Peripheral and Pulmonary Neurobiology Schering-Plough Research Institute, Kenilworth, NJ, 07033-0539, USA
| | - Craig C Correll
- Peripheral and Pulmonary Neurobiology Schering-Plough Research Institute, Kenilworth, NJ, 07033-0539, USA
| | - Tara P Phelps
- Peripheral and Pulmonary Neurobiology Schering-Plough Research Institute, Kenilworth, NJ, 07033-0539, USA
| | - Yanlin Jia
- Peripheral and Pulmonary Neurobiology Schering-Plough Research Institute, Kenilworth, NJ, 07033-0539, USA
| | - Xin Wang
- Peripheral and Pulmonary Neurobiology Schering-Plough Research Institute, Kenilworth, NJ, 07033-0539, USA
| | - John A Hey
- Peripheral and Pulmonary Neurobiology Schering-Plough Research Institute, Kenilworth, NJ, 07033-0539, USA
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23
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McLeod RL, Jia Y, McHugh NA, Fernandez X, Mingo GG, Wang X, Parra LE, Chen J, Brown D, Bolser DC, Kreutner W, Hey JA. Sulfur-dioxide exposure increases TRPV1-mediated responses in nodose ganglia cells and augments cough in guinea pigs. Pulm Pharmacol Ther 2006; 20:750-7. [PMID: 17126052 DOI: 10.1016/j.pupt.2006.09.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2004] [Revised: 08/11/2006] [Accepted: 09/15/2006] [Indexed: 11/28/2022]
Abstract
The objective of the present experiments was to study the effects of pulmonary inflammation induced by subacute Sulfur-dioxide (SO(2)) exposure on capsaicin-induced responses in isolated primary vagal sensory neurons and cough. Additionally, we examined the effects of SO(2) exposure on respiratory function and lung histology. All experiments were conducted 24 h after 4 days of subacute SO(2) (1000 ppm, 3 h/day for 4 days) exposure. In in vitro experiments, intracellular Ca(2+) concentrations were measured in single nodose ganglia cells isolated from SO(2) treated and control guinea pigs, using a fluorescence-based methodology. In nodose ganglia cells from SO(2)-exposed animals, intracellular Ca(2+) responses evoked by capsaicin (1 x 10(-7) and 1 x 10(-6) M) were significantly augmented (87% and 59%, respectively) compared to nodose ganglia from control animals. In vivo experiments, cough responses induced by a submaximal dose of aerosolized capsaicin (30 microM) were increased approximately 50% in SO(2) exposed animals compared to control animals. The enhanced cough response produced by SO(2) was inhibited by the corticosteroid, dexamethasone (10 mg/kg, p.o. b.i.d for 4 days and 10 mg/kg, p.o. once on day 5). In separate experiments, guinea pigs exposed to SO(2) displayed a decrease in respiratory frequency and minute ventilation and an increase in enhanced pause (PenH), a surrogate measure for pulmonary obstruction. Associated with the SO(2)-induced increase in cough and changes in respiratory parameters was an increase in BAL neutrophils. BAL neutrophil counts were 5+/-4 and 691+/-141 cells x 10(3)/ml for air and SO(2)-exposed animals, respectively. The neutrophillic inflammation induced by SO(2) was attenuated by dexamethasone treatment. Finally, staining for collagen, smooth muscle and goblet cells showed inflammation, remodeling and goblet cell metaphasia in the SO(2)-exposed animals. Our results demonstrate that SO(2) exposure enhances TRPV1 receptor function at the level of the nodose ganglia. This effect occurs in parallel with an increase sensitivity of the cough response to capsaicin.
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Affiliation(s)
- R L McLeod
- Pulmonary and Peripheral Neurobiology, Schering-Plough Research Institute, Kenilworth, NJ 07033-0539, USA.
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24
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Bonham AC, Sekizawa SI, Chen CY, Joad JP. Plasticity of brainstem mechanisms of cough. Respir Physiol Neurobiol 2006; 152:312-9. [PMID: 16554189 DOI: 10.1016/j.resp.2006.02.010] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2005] [Revised: 02/07/2006] [Accepted: 02/09/2006] [Indexed: 11/27/2022]
Abstract
The cough reflex is a brainstem reflex, consisting of specific sensory afferent nerves which trigger the reflex, by transmitting the sensory input over vagal or laryngeal nerves to a brainstem circuitry which processes and ultimately transforms the sensory input into a complex motor output to generate cough. The first synaptic target for the primary cough-related sensory input is the second-order neurons in the nucleus tractus solitarius (NTS). This position in the reflex pathway and intricate local circuits within the nucleus make it a strategic site where the sensory information can be modified. Plasticity at this synapse will change the nature of the output--exaggerating it, suppressing it or transforming it into some other complex pattern. This review integrates evidence implicating the NTS in exaggerated cough with proof of the concept that NTS neurons undergo plasticity to contribute to an exaggeration of cough.
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Affiliation(s)
- Ann C Bonham
- Department of Pharmacology, University of California, Davis School of Medicine, 4150 V Street, 1104 PSSB, Sacramento, CA 95817, USA.
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25
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Bonham AC, Chen CY, Sekizawa SI, Joad JP. Plasticity in the nucleus tractus solitarius and its influence on lung and airway reflexes. J Appl Physiol (1985) 2006; 101:322-7. [PMID: 16484366 DOI: 10.1152/japplphysiol.00143.2006] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The nucleus tractus solitarius (NTS) is the first central nervous system (CNS) site for synaptic contact of the primary afferent fibers from the lungs and airways. The signal processing at these synapses will determine the output of the sensory information from the lungs and airways to all downstream synapses in the reflex pathways. The second-order NTS neurons bring to bear their own intrinsic and synaptic properties to temporally and spatially integrate the sensory information with inputs from local networks, higher brain regions, and circulating mediators, to orchestrate a coherent reflex output. There is growing evidence that NTS neurons share the rich repertoire of forms of plasticity demonstrated throughout the CNS. This review focuses on existing evidence for plasticity in the NTS, potential targets for plasticity in the NTS, and the impact of this plasticity on lung and airway reflexes.
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Affiliation(s)
- Ann C Bonham
- Department of Medical Pharmacology, University of California, Davis, CA, USA.
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26
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Delfino RJ, Sioutas C, Malik S. Potential role of ultrafine particles in associations between airborne particle mass and cardiovascular health. ENVIRONMENTAL HEALTH PERSPECTIVES 2005; 113:934-46. [PMID: 16079061 PMCID: PMC1280331 DOI: 10.1289/ehp.7938] [Citation(s) in RCA: 442] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Numerous epidemiologic time-series studies have shown generally consistent associations of cardiovascular hospital admissions and mortality with outdoor air pollution, particularly mass concentrations of particulate matter (PM) < or = 2.5 or < or = 10 microm in diameter (PM2.5, PM10). Panel studies with repeated measures have supported the time-series results showing associations between PM and risk of cardiac ischemia and arrhythmias, increased blood pressure, decreased heart rate variability, and increased circulating markers of inflammation and thrombosis. The causal components driving the PM associations remain to be identified. Epidemiologic data using pollutant gases and particle characteristics such as particle number concentration and elemental carbon have provided indirect evidence that products of fossil fuel combustion are important. Ultrafine particles < 0.1 microm (UFPs) dominate particle number concentrations and surface area and are therefore capable of carrying large concentrations of adsorbed or condensed toxic air pollutants. It is likely that redox-active components in UFPs from fossil fuel combustion reach cardiovascular target sites. High UFP exposures may lead to systemic inflammation through oxidative stress responses to reactive oxygen species and thereby promote the progression of atherosclerosis and precipitate acute cardiovascular responses ranging from increased blood pressure to myocardial infarction. The next steps in epidemiologic research are to identify more clearly the putative PM casual components and size fractions linked to their sources. To advance this, we discuss in a companion article (Sioutas C, Delfino RJ, Singh M. 2005. Environ Health Perspect 113:947-955) the need for and methods of UFP exposure assessment.
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Affiliation(s)
- Ralph J Delfino
- Epidemiology Division, Department of Medicine, University of California, Irvine, Irvine, California 92697-7550, USA.
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27
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Schiffman SS, Studwell CE, Landerman LR, Berman K, Sundy JS. Symptomatic effects of exposure to diluted air sampled from a swine confinement atmosphere on healthy human subjects. ENVIRONMENTAL HEALTH PERSPECTIVES 2005; 113:567-76. [PMID: 15866765 PMCID: PMC1257549 DOI: 10.1289/ehp.6814] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2003] [Accepted: 02/09/2005] [Indexed: 05/02/2023]
Abstract
Aerial emissions from a swine house at North Carolina State University's field laboratory were diluted to a level that could occur at varying distances downwind from a confined animal feeding operation (CAFO) both within and beyond the property line, and these emissions were delivered to an environmental exposure chamber. The study design consisted of two 1-hr sessions, one in which 48 healthy human adult volunteers were exposed to diluted swine air and another in which they were exposed to clean air (control). Objective measures of blood pressure, temperature, heart rate, respiratory rate, lung function, nasal inflammation, secretory immunity, mood, attention, and memory were correlated with objective measures of air quality. Ratings of perceived (self-reported) health symptoms were also obtained. The mean levels of airborne constituents in the swine air condition were hydrogen sulfide (24 ppb), ammonia (817 ppb), total suspended particulates (0.0241 mg/m3), endotoxin (7.40 endotoxin units/m3), and odor (57 times above odor threshold). No statistical differences on objective measures of physical symptoms, mood, or attention resulted from the 1-hr exposure to swine emissions in the environmental chamber when compared with clean air for healthy human volunteers. However, subjects were 4.1 (p = 0.001) times more likely to report headaches, 6.1 (p = 0.004) times more likely to report eye irritation, and 7.8 (p = 0.014) times more likely to report nausea in the swine air (experimental) condition than in the control condition. These results indicate that short-term exposure in an environmental chamber to malodorous emissions from a swine house at levels expected downwind can induce clinically important symptoms in healthy human volunteers.
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Affiliation(s)
- Susan S Schiffman
- Department of Psychiatry, 54212 Woodhall Building, Duke University Medical Center, Durham, NC 27710-3259, USA.
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28
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Bonham AC, Sekizawa SI, Joad JP. Plasticity of central mechanisms for cough. Pulm Pharmacol Ther 2005; 17:453-7; discussion 469-70. [PMID: 15564091 DOI: 10.1016/j.pupt.2004.09.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2004] [Accepted: 09/13/2004] [Indexed: 11/19/2022]
Abstract
Cough is associated with plasticity of putative cough afferent fibres, but whether plasticity in the brainstem network contributes is less well understood. A key site in the CNS network is the nucleus tractus solitarius (NTS), the first synaptic contact of the primary afferent fibres. We sought to develop a conscious guinea pig model to detect enhanced cough, to focus on the NTS as a potential site for plasticity, and to test a role for substance P in the NTS since the neuropeptide has been implicated in plasticity of the vagal afferent fibres. Guinea pigs were exposed to second-hand tobacco smoke (SHS) or filtered air (FA) from 1-6 weeks of age. At 5 weeks, cannulae were implanted in the NTS. At 6 weeks, either vehicle or a neurokinin 1 (NK-1) receptor antagonist was injected into the NTS of the conscious guinea pigs who were then exposed to citric acid aerosol. SHS exposure significantly enhanced citric acid-induced cough (56%, P<0.05), an effect attenuated by NTS NK-1 receptor blockade (P<0.05). The findings suggest that one possible mechanism for plasticity in cough is related to substance P effects in the NTS. Future studies will be required to investigate the possible mechanisms underlying the role of substance P as well as other mechanisms in generating SHS-induced cough.
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Affiliation(s)
- A C Bonham
- Department of Pharmacology, University of California Davis, Tupper Hall Room 1310, One Shields Avenue, Davis, CA 95616-0635, USA
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29
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Abstract
Increased sensitivity of cough pathways has been demonstrated in numerous studies. The underlying mechanisms of this sensitization are largely unknown; however, a burgeoning body of evidence suggests that vagal primary afferent neurones that innervate the airways are likely to be involved. This plasticity includes changes in anatomy, neurochemistry and function. PGE2 is an example of an inflammatory mediator that increases responsiveness to tussive stimuli. Electrophysiological studies of neurone cell bodies isolated from afferent ganglia have revealed that prostanoids modulate the function of a variety of distinct ion channels including those that carry TTX-insensitive voltage-gated sodium currents, slow post-spike hyperpolarizations and a hyperpolarization-activated cation current. Mediator-induced modulation of the function of various voltage-gated currents operating at the peripheral terminals of airway afferent neurons would probably influence input from the airways into the central nervous system and contribute to the urge to cough and increased responsiveness to tussive stimuli.
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Affiliation(s)
- Michael J Carr
- UCB Research Inc., 840 Memorial Drive, Cambridge, MA 02139, USA.
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Theodoropoulos DS, Pecoraro DL, Efstratiadis SE. The association of gastroesophageal reflux disease with asthma and chronic cough in the adult. ACTA ACUST UNITED AC 2004; 1:133-46. [PMID: 14720067 DOI: 10.1007/bf03256602] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Gastroesophageal reflux disease (GERD) is a common condition which is particularly prevalent in patients with asthma and chronic cough. Physiologic changes caused by asthma and chronic cough promote acid reflux. GERD is also considered by many investigators as a factor contributing to airway inflammation. An etiological relationship between GERD and asthma/chronic cough and vice versa has been supported by a large number of experimental and clinical findings and refuted by others. Although further controlled studies are needed to clarify this relationship, GERD and asthma/chronic cough appear to be linked to each other. The association of GERD with asthma and chronic cough involves nerve reflexes, cytokines, inflammatory and neuroendocrine cells and, in some patients, tracheal aspiration of refluxing gastric fluids. GERD may present with typical symptoms but can also be asymptomatic. Sensitive methods for diagnosing GERD are available, which include esophageal pH monitoring, acid provocative tests, modified barium swallow and endoscopy. Consideration of the association of GERD with asthma and chronic cough is of practical value in the management of chronic cough or asthma resistant to treatment. Treatment of GERD in patients with asthma has been consistently shown to improve respiratory symptoms but not necessarily pulmonary function tests. Surgical treatment can be a useful and cost-effective approach in selected patients with asthma and GERD.
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31
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Younger PL. Environmental impacts of coal mining and associated wastes: a geochemical perspective. ACTA ACUST UNITED AC 2004. [DOI: 10.1144/gsl.sp.2004.236.01.12] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
AbstractEver since the commencement of industrial-scale coal mining (in northeast England around 1600), substantial environmental impacts have been recorded as arising from both the mined voids and from the wastes left behind at the surface. In the early days of coal mining, complaints about such impacts were strident, as the newly established industry adversely affected long-established agricultural interests. When the coal trade had come to dominate regional economies in mining districts, its negative impacts came to be accepted as a necessary byproduct of the generation of coal-based wealth. It has only been since large-scale mine closures began to take place in the major coal-mining economies of the developed world during the last few decades that the negative impacts of coal mining have once more been deemed unacceptable. The environmental impacts arising from coal mining activities are fundamentally attributable to the exposure of reduced earth materials (especially coal, pyrite, siderite, and ankerite) to the oxidizing power of the Earth’s atmosphere. The consequences range from the spontaneous combustion of coal to the release of acidic waters from pyrite oxidation. A typology of the known impacts arising from mine voids and wastes in coal mining districts has been developed, which recognizes many subcategories of impacts under five major headings: air pollution, fire hazards, ground deformation, water pollution, and water resource depletion. A robust understanding of geochemical processes is key to understanding how these impacts arise, and to developing sustainable mitigation strategies. The application of the newly developed typology is illustrated using the case of the Shilbottle Coalfield (Northumberland, UK). Although few demonstrable impacts have arisen in the categories of air pollution, fire hazards, or ground deformation, major problems of water pollution have required both preventative and remedial interventions. For the flooded underground voids, these took the form of a pump-and-treat system, whereas emissions of leachates from surface spoil heaps have necessitated the installation of an innovative ‘hybrid’ passive treatment system, comprising a permeable reactive barrier, oxidation ponds, and a wetland. Inverse geochemical modelling has clarified the linkages between the various types of water encountered in the coalfield, providing a baseline geochemical understanding upon which future investigations of remedial system sustainability can be based.
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Affiliation(s)
- Paul L. Younger
- Hydrogeochemical Engineering Research and Outreach (HERO), School of Civil Engineering and Geosciences, University of Newcastle
Newcastle upon Tyne, UK
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Patel HJ, Birrell MA, Crispino N, Hele DJ, Venkatesan P, Barnes PJ, Yacoub MH, Belvisi MG. Inhibition of guinea-pig and human sensory nerve activity and the cough reflex in guinea-pigs by cannabinoid (CB2) receptor activation. Br J Pharmacol 2003; 140:261-8. [PMID: 12970104 PMCID: PMC1574031 DOI: 10.1038/sj.bjp.0705435] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. There is considerable interest in novel therapies for cough, since currently used agents such as codeine have limited beneficial value due to the associated side effects. Sensory nerves in the airways mediate the cough reflex via activation of C-fibres and RARs. Evidence suggests that cannabinoids may inhibit sensory nerve-mediated responses. 2. We have investigated the inhibitory actions of cannabinoids on sensory nerve depolarisation mediated by capsaicin, hypertonic saline and PGE2 on isolated guinea-pig and human vagus nerve preparations, and the cough reflex in conscious guinea-pigs. 3. The non-selective cannabinoid (CB) receptor agonist, CP 55940, and the selective CB2 agonist, JWH 133 inhibited sensory nerve depolarisations of the guinea-pig vagus nerve induced by hypertonic saline, capsaicin and PGE2. These responses were abolished by the CB2 receptor antagonist SR144528, and unaffected by the CB1 antagonist SR141716A. Similarly, JWH 133 inhibited capsaicin-evoked nerve depolarisations in the human vagus nerve, and was prevented by SR144528. 4. Using a guinea-pig in vivo model of cough, JWH 133 (10 mg kg-1, i.p., 20 min) significantly reduced citric acid-induced cough in conscious guinea pigs compared to those treated with the vehicle control. 5. These data show that activation of the CB2 receptor subtype inhibits sensory nerve activation of guinea-pig and human vagus nerve, and the cough reflex in guinea-pigs, suggesting that the development of CB2 agonists, devoid of CB1-mediated central effects, will provide a new and safe antitussive treatment for chronic cough.
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MESH Headings
- Animals
- Camphanes/pharmacology
- Cannabinoids/pharmacology
- Capsaicin/pharmacology
- Consciousness
- Cough/physiopathology
- Cough/prevention & control
- Cyclohexanols/pharmacology
- Dinoprost/pharmacology
- Dose-Response Relationship, Drug
- Guinea Pigs
- Humans
- Hypertonic Solutions/pharmacology
- In Vitro Techniques
- Male
- Middle Aged
- Neurons, Afferent/drug effects
- Neurons, Afferent/physiology
- Piperidines/pharmacology
- Pyrazoles/pharmacology
- Receptor, Cannabinoid, CB1/agonists
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/agonists
- Receptor, Cannabinoid, CB2/antagonists & inhibitors
- Receptor, Cannabinoid, CB2/metabolism
- Reflex/drug effects
- Rimonabant
- Vagus Nerve/drug effects
- Vagus Nerve/physiology
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Affiliation(s)
- Hema J Patel
- Respiratory Pharmacology Group, Guy Scadding Building, The National Heart & Lung Institute, Faculty of Medicine, Imperial College London, Dovehouse Street, London SW3 6LY
| | - Mark A Birrell
- Respiratory Pharmacology Group, Guy Scadding Building, The National Heart & Lung Institute, Faculty of Medicine, Imperial College London, Dovehouse Street, London SW3 6LY
| | - Natascia Crispino
- Respiratory Pharmacology Group, Guy Scadding Building, The National Heart & Lung Institute, Faculty of Medicine, Imperial College London, Dovehouse Street, London SW3 6LY
| | - David J Hele
- Respiratory Pharmacology Group, Guy Scadding Building, The National Heart & Lung Institute, Faculty of Medicine, Imperial College London, Dovehouse Street, London SW3 6LY
| | - Priya Venkatesan
- Respiratory Pharmacology Group, Guy Scadding Building, The National Heart & Lung Institute, Faculty of Medicine, Imperial College London, Dovehouse Street, London SW3 6LY
| | - Peter J Barnes
- Department of Thoracic Medicine, Faculty of Medicine, The National Heart and Lung Institute, Imperial College London, Dovehouse Street, London SW3 6LY
| | - Magdi H Yacoub
- Respiratory Pharmacology Group, Guy Scadding Building, The National Heart & Lung Institute, Faculty of Medicine, Imperial College London, Dovehouse Street, London SW3 6LY
| | - Maria G Belvisi
- Respiratory Pharmacology Group, Guy Scadding Building, The National Heart & Lung Institute, Faculty of Medicine, Imperial College London, Dovehouse Street, London SW3 6LY
- Author for correspondence:
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Abstract
It is generally accepted that stimulation of primary afferent sensory neurons, that innervate the airways, by chemical and mechanical stimuli leads to a range of homeostatic and defensive reflexes such as cough. However, there is still much debate regarding the exact type of sensory fibre involved in evoking these reflex events. The current dogma suggests that the major fibre types implicated in participating in reflex events of a protective nature are the A delta fibres and those stimulated in response to inflammation by noxious stimuli and mediators associated with tissue damage are the unmyelinated C-fibres. Furthermore, the C-fibre afferents are also believed to be responsible for mediating local axon reflexes, the release of neuropeptides and neurogenic inflammation. This review will concentrate on describing the characteristics of these sensory fibres and their proposed role in airway defensive reflexes and their possible exaggerated function in response to the inflammatory process.
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Affiliation(s)
- Maria G Belvisi
- Cardiothoracic Surgery, National Heart and Lung Institute, Faculty of Medicine, Imperial College, Dovehouse Street, London SW3 6LY, UK.
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Widdicombe J. Functional morphology and physiology of pulmonary rapidly adapting receptors (RARs). THE ANATOMICAL RECORD. PART A, DISCOVERIES IN MOLECULAR, CELLULAR, AND EVOLUTIONARY BIOLOGY 2003; 270:2-10. [PMID: 12494484 DOI: 10.1002/ar.a.10003] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Rapidly adapting receptors (RARs) in the airway mucosa are found from the nasopharynx to the bronchi. They have thin (Adelta) vagal afferent fibres and lie in and under the epithelium, but their morphology has not been defined. They are very sensitive to mechanical stimuli, and have a rapidly adapting irregular discharge. However, with in vitro preparations they are rather insensitive to chemical stimuli, apart from acid and nonisosmolar solutions. Their pattern of response varies with site. RARs in the nasopharynx, larynx, and trachea usually respond only during the onset of stimuli, while those in the trachea often have an off-response as well. Those in the bronchi are less rapidly adapting and more chemosensitive. Their membranes have mechanosensitive and acid-sensitive ion channels, but no vanilloid receptors. In vivo RARs are sensitive to a wide range of chemical irritants and mediators, and presumably are excited secondarily to mechanical changes in the mucosa and airway smooth muscle. In the central nervous system (CNS) they interact with other vagal afferent pathways. The reflexes they cause vary with site (inspiratory efforts from the nasopharynx, cough or expiratory efforts from the larynx and trachea, and deep breaths or tachypnoea from the bronchi). Pathways from RARs and other vagal reflexes show plasticity at the peripheral, ganglionic, and CNS levels.
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Affiliation(s)
- John Widdicombe
- Guy's, King's and St Thomas' School of Biomedical Sciences, Human Physiology and Aerospace Medicine, London, UK.
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Papka RE, Mowa CN. Estrogen Receptors in the Spinal Cord, Sensory Ganglia, and Pelvic Autonomic Ganglia. INTERNATIONAL REVIEW OF CYTOLOGY 2003; 231:91-127. [PMID: 14713004 DOI: 10.1016/s0074-7696(03)31003-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Until relatively recently, most studies of the effects of estradiol in the nervous system focused on hypothalamic, limbic, and other brain centers involved in reproductive hormone output, feedback, and behaviors. Almost no studies addressed estradiol effects at the spinal cord or peripheral nervous system level. Prior to the mid-1960s-1970s, few studies examined neural components of reproductive endocrine organs (e.g., ovary or testis) or the genital organs (e.g., uterus or penis) because available data supported endocrine regulation of these structures. Over the last two decades interest in and studies on the innervation of the genital organs have burgeoned. Because of the responsiveness of genital organs to sex steroid hormones, these neural studies seeded interest in whether or not autonomic and sensory neurons that innervate these organs, along with their attendant spinal cord circuits, also are responsive to sex hormones. From the mid-1980s there has been a steady growth of interest in, and studies of the neuroanatomy, neurochemistry, neural connectivity, and neural functional aspects in reproductive organs and the response of these parameters to sex steroids. Thus, with the growth of probes and techniques, has come studies of anatomy, neurochemistry, and circuitry of sex hormone-responsive neurons and circuits in the spinal cord and peripheral nervous system. This review focuses on estrogen receptors in sensory, autonomic, and spinal cord neurons in locales that are associated with innervation of female reproductive organs.
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Affiliation(s)
- R E Papka
- Department of Neurobiology, Northeastern Ohio Universities College of Medicine, Rootstown, Ohio 44272, USA
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Lamb JP, Sparrow MP. Three-dimensional mapping of sensory innervation with substance p in porcine bronchial mucosa: comparison with human airways. Am J Respir Crit Care Med 2002; 166:1269-81. [PMID: 12403698 DOI: 10.1164/rccm.2112018] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In asthma, neurogenic inflammation in bronchial airways may occur though the release of neuropeptides from C fibers via an axon reflex. Structural evidence for this neural pathway was sought in the pig and in humans by three-dimensional mapping of substance P-immunoreactive (SP-IR) nerves in whole mounts of mucosa using immunofluorescent staining and confocal microscopy. To show continuity, nerves were traced with 1,1'-didodecyl-3,3,3',3'-tetramethyl indocarbocyanine perchlorate from their epithelial endings through the mucosa. The pan-neuronal marker protein gene product 9.5 revealed an extensive apical and basal plexus of nerves in the epithelium; 94% of these were varicose SP-IR fibers. Apical SP-IR fibers had a length density of 88 mm/mm(2). Varicose apical processes followed closely around the circumference of goblet cells. Calcitonin gene-related peptide was colocalized with SP-IR in varicosites. The epithelial fibers converged into bundles as they entered the lamina propria where lateral branches ran along arterioles, often contiguous with the vascular smooth muscle. 1,1'-didodecyl-3,3,3',3'-tetramethyl indocarbocyanine perchlorate tracing showed that they projected to the epithelium. SP-IR fibers were rare near postcapillary venules. In human bronchial epithelium, protein gene product 9.5 revealed a similar apical and basal plexus of varicose fibers that weakly stained for SP-IR. Thus, a continuous sensory nerve pathway from the epithelium to arterioles provides structural support for a local axon reflex.
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Affiliation(s)
- Jasmine P Lamb
- Department of Physiology, University of Western Australia, Nedlands, Western Australia.
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Carr MJ, Hunter DD, Jacoby DB, Undem BJ. Expression of tachykinins in nonnociceptive vagal afferent neurons during respiratory viral infection in guinea pigs. Am J Respir Crit Care Med 2002; 165:1071-5. [PMID: 11956047 DOI: 10.1164/ajrccm.165.8.2108065] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Immunohistochemistry was combined with retrograde labeling to characterize the effect of respiratory infection with Sendai virus on the number of Substance P/Neurokinin A-containing vagal afferent neurons whose cell bodies resided in the nodose ganglia and whose receptive fields were located in guinea pig trachea. Of the neurons labeled from the trachea of vehicle-inoculated guinea pigs, few stained positively for Substance P/Neurokinin A (approximately 3% of total labeled neurons). These neurons had small diameter cell bodies (mode = 16-20 microm), a feature of nociceptive-like C-fibers. Viral infection (Day 4 after inoculation) was associated with a significantly greater number of labeled neurons containing Substance P/Neurokinin A (approximately 20% of total labeled neurons). The majority of these had a relatively large cell body diameter (mode = 36- 40 microm), a feature of nonnociceptive afferent neurons. This induction appeared to be reversible as there were significantly fewer Substance P/Neurokinin A positive neurons in nodose ganglia from virus-inoculated guinea pigs at Day 28 after inoculation, a time point when virus-induced airway inflammation had all but resolved. These findings support the hypothesis that viral infection leads to a qualitative change in the vagal afferent innervation of guinea pig airways such that both small diameter nociceptive-like neurons and large diameter nonnociceptive neurons express tachykinins.
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Affiliation(s)
- Michael J Carr
- The Johns Hopkins Asthma and Allergy Center, Baltimore, Maryland 21224, USA
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38
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Abstract
Asthma is a syndrome characterized by reversible episodes of wheezing, cough, and sensations of chest tightness and breathlessness. These symptoms are secondary to changes in the activity of the nervous system. The mechanisms by which the nervous system is altered such that the symptoms of asthma occur have not yet been elucidated. Airway inflammation associated with asthma may affect neuronal activity at several points along the neural reflex pathway, including the function of the primary afferent (sensory) nerves, integration within the central nervous system, synaptic transmission within autonomic ganglia, and transmission at the level of the postganglionic neuroeffector junction. We provide a brief overview of these interactions and the relevance they may have to asthma.
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Affiliation(s)
- Bradley J Undem
- Johns Hopkins Asthma and Allergy Center, Johns Hopkins School of Medicine, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA.
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39
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Abstract
Stimulation of the nasal sensory nerves leads to sensations of pain and stuffiness. Type C nociceptive nerve releases neuropeptides including substance P and calcitonin gene related peptides that increase plasma extravasation and glandular secretion. This axonal response acts as an immediate protective mucosal defense mechanism. Recruited parasympathetic reflexes cause submucosal gland secretion via acetylcholine and muscarinic M(3) receptors. Itching, sneezing, and other avoidance behaviors rapidly clear the offending agents from the upper airways and protect the lower airways. Dysfunction of these nerves may contribute to allergic rhinitis, infectious rhinitis, nasal hyperresponsiveness, and possibly sinusitis. Sympathetic arterial vasoconstriction reduces mucosal blood flow, sinusoidal filling, and mucosal thickness, and so restores nasal patency. Loss of sympathetic tone may contribute to some chronic, nonallergic rhinopathies. Human axon responses differ from those in animals, an important distinction that limits extrapolation from other species.
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Affiliation(s)
- Chih-Feng Tai
- Department of Otorhinolaryngology, Kaohsiung Medical University, Kaohsiung, Taiwan
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40
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Yeates DB, Mauderly JL. Inhaled environmental/occupational irritants and allergens: mechanisms of cardiovascular and systemic responses. Introduction. ENVIRONMENTAL HEALTH PERSPECTIVES 2001; 109 Suppl 4:479-481. [PMID: 11544150 PMCID: PMC1240568 DOI: 10.1289/ehp.01109s4479] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The articles in this monograph focus on the mechanisms whereby ambient particulate matter (PM) and co-pollutants deposited in the respiratory tract cause cardiovascular and systemic effects, especially in persons with preexisting conditions such as allergic hyperresponsiveness and pulmonary, cardiac, and vascular diseases. During the past few years, it has become clear that inhaled pollutants cause adverse effects outside the respiratory tract and that these effects may in some cases be more important than respiratory effects. Investigators pursuing traditional approaches to understanding mechanisms of air pollution effects need to be brought together with those outside that community who have expertise in pathogenetic mechanisms by which deposited air pollutants might affect nonrespiratory organs. To this end, a workshop was held and papers were developed from a broad range of scientists having specialized expertise in allergic and cardiovascular physiology. The overall goal of this monograph is to benchmark current thinking and enhance progress toward identifying and understanding the mechanisms by which nonrespiratory health effects occur and, by extension, to facilitate the appropriate management of relationships between air quality and health. This monograph contains a compilation of multidisciplinary research that forms a framework for generating and testing plausible new research hypotheses. Not only will this information stimulate the thinking of researchers, but it will also provide an improved foundation for funding agencies and advisory groups to frame research strategies, programs, and priorities.
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Affiliation(s)
- D B Yeates
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA.
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