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Nakajima Y, Tsujimura T, Tsutsui Y, Chotirungsan T, Kawada S, Dewa N, Magara J, Inoue M. Atropine facilitates water-evoked swallows via central muscarinic receptors in anesthetized rats. Am J Physiol Gastrointest Liver Physiol 2023; 325:G109-G121. [PMID: 37219016 DOI: 10.1152/ajpgi.00039.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 05/01/2023] [Accepted: 05/16/2023] [Indexed: 05/24/2023]
Abstract
Anticholinergic medication causes impaired swallowing with hyposalivation. However, the underlying mechanisms by which these drugs modulate the swallowing reflex remain unclear. This study investigated the effects of the muscarinic acetylcholine receptor (mAChR) nonspecific antagonist atropine on the initiation of swallowing. Experiments were performed on 124 urethane-anesthetized rats. A swallow was evoked by either topical laryngeal application of a small amount of distilled water (DW), saline, citric acid, or capsaicin; upper airway distention with a continuous airflow; electrical stimulation of the superior laryngeal nerve (SLN); or focal microinjection of N-methyl-d-aspartate (NMDA) into the lateral region of the nucleus of the solitary tract (L-nTS). Swallows were identified by electromyographic bursts of the digastric and thyrohyoid muscles. Either atropine, the peripheral mAChR antagonist methylatropine, or antagonists of mAChR subtypes M1-M5 were intravenously delivered. Atropine at a dose of 1 mg/kg increased the number of DW-evoked swallows compared with baseline and did not affect the number of swallows evoked by saline, citric acid, capsaicin, or upper airway distention. Methylatropine and M1-M5 antagonists did not significantly change the number of DW-evoked swallows. Bilateral SLN transection completely abolished DW-evoked swallows, and atropine decreased the swallowing threshold of SLN electrical stimulation. Finally, microinjection of NMDA receptor antagonist AP-5 into the L-nTS inhibited DW-evoked swallows, and atropine facilitated the initiation of swallowing evoked by NMDA microinjection into this region. These results suggest that atropine facilitates DW-evoked swallows via central mAChR actions.NEW & NOTEWORTHY Atropine facilitated the distilled water (DW)-evoked swallows in anesthetized rats. Atropine decreased the swallowing threshold evoked by electrical stimulation of the superior laryngeal nerve, which is a primary sensory nerve for the initiation of DW-evoked swallows. Atropine facilitated the swallows evoked by N-methyl-d-aspartate microinjection into the lateral region of the nucleus of the solitary tract, which is involved in the DW-evoked swallows. We speculate that atropine facilitates the DW-evoked swallows via central muscarinic receptor actions.
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Affiliation(s)
- Yuta Nakajima
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Takanori Tsujimura
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yuhei Tsutsui
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Titi Chotirungsan
- Department of Oral Diagnosis, Faculty of Dentistry, Naresuan University, Muang, Phitsanulok, Thailand
| | - Satomi Kawada
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Nozomi Dewa
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Jin Magara
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Makoto Inoue
- Division of Dysphagia Rehabilitation, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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Simera M, Veternik M, Martvon L, Kotmanova Z, Cibulkova L, Poliacek I. Differential inhibition of cough by GABA A and GABA B receptor antagonists in the nucleus of the solitary tract in cats. Respir Physiol Neurobiol 2023; 315:104115. [PMID: 37460080 DOI: 10.1016/j.resp.2023.104115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 06/28/2023] [Accepted: 07/14/2023] [Indexed: 07/22/2023]
Abstract
Bicuculline and saclofen were microinjected into the rostral (rNTS) and caudal nucleus of the solitary tract (cNTS) in 17 anesthetized cats. Electromyograms (EMGs) of the diaphragm (DIA) and abdominal muscles (ABD), esophageal pressures (EP), and blood pressure were recorded and analyzed. Bilateral microinjections of 1 mM bicuculline in the rNTS significantly reduced the number of coughs (CN), amplitudes of DIA and ABD EMG, inspiratory and expiratory EP, and prolonged the duration of the cough expiratory phase (CTE) as well as the total cough cycle duration (CTtot). Bilateral microinjections of 2 mM saclofen reduced only cough expiratory efforts. Bilateral microinjection of bicuculline in the cNTS significantly reduced CN and amplitudes of ABD EMG and elongated CTE and CTtot. Bilateral microinjections of saclofen in cNTS had no significant effect on analyzed cough parameters. Our results confirm a different GABAergic inhibitory system in the rNTS and cNTS acting on mechanically induced cough in cats.
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Affiliation(s)
- Michal Simera
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 03601 Martin, Slovakia
| | - Marcel Veternik
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 03601 Martin, Slovakia.
| | - Lukas Martvon
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 03601 Martin, Slovakia
| | - Zuzana Kotmanova
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 03601 Martin, Slovakia
| | - Lucia Cibulkova
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 03601 Martin, Slovakia
| | - Ivan Poliacek
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 03601 Martin, Slovakia
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McClure EW, Daniels RN. Classics in Chemical Neuroscience: Dextromethorphan (DXM). ACS Chem Neurosci 2023. [PMID: 37290117 DOI: 10.1021/acschemneuro.3c00088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023] Open
Abstract
Dextromethorphan (DXM) was introduced in 1958 as the first non-opioid cough suppressant and is indicated for multiple psychiatric disorders. It has been the most used over-the-counter cough suppressant since its emergence. However, individuals quickly noticed an intoxicating and psychedelic effect if they ingested large doses. DXM's antagonism at N-methyl-d-aspartate receptors (NMDAr) is thought to underly its efficacy in treating acute cough, but supratherapeutic doses mimic the activity of dissociative hallucinogens, such as phencyclidine and ketamine. In this Review we will discuss DXM's synthesis, manufacturing information, drug metabolism, pharmacology, adverse effects, recreational use, abuse potential, and its history and importance in therapy to present DXM as a true classic in chemical neuroscience.
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Affiliation(s)
- Elliot W McClure
- Department of Pharmaceutical Sciences, Lipscomb University College of Pharmacy, Nashville, Tennessee 37204, United States
| | - R Nathan Daniels
- Department of Pharmaceutical Sciences, Union University College of Pharmacy, Jackson, Tennessee 38305, United States
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Abstract
Coughing is a dynamic physiological process resulting from input of vagal sensory neurons innervating the airways and perceived airway irritation. Although cough serves to protect and clear the airways, it can also be exploited by respiratory pathogens to facilitate disease transmission. Microbial components or infection-induced inflammatory mediators can directly interact with sensory nerve receptors to induce a cough response. Analysis of cough-generated aerosols and transmission studies have further demonstrated how infectious disease is spread through coughing. This review summarizes the neurophysiology of cough, cough induction by respiratory pathogens and inflammation, and cough-mediated disease transmission.
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Affiliation(s)
- Kubra F Naqvi
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA;
| | - Stuart B Mazzone
- Department of Anatomy and Physiology, University of Melbourne, Victoria, Australia
| | - Michael U Shiloh
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA;
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Musselwhite MN, Shen TY, Rose MJ, Iceman KE, Poliacek I, Pitts T, Bolser DC. THE INFLUENCE OF CO 2 ON SPATIOTEMPORAL FEATURES OF MECHANICALLY INDUCED COUGH IN ANESTHETIZED CATS. Respir Physiol Neurobiol 2022; 307:103964. [PMID: 36174962 DOI: 10.1016/j.resp.2022.103964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 08/10/2022] [Accepted: 09/19/2022] [Indexed: 11/27/2022]
Abstract
Effective cough requires a significant increase in lung volume used to produce the shear forces on the airway to clear aspirated material. This increase in tidal volume during cough, along with an increase in tidal frequency during bouts of paroxysmal cough produces profound hyperventilation and thus reduces arterial CO2. While there are several reports in the literature regarding the effects of hypercapnia, hyperoxia, and hypoxia on cough, there is little research quantifying the effects of hypocapnia on the cough reflex. We hypothesized that decreased CO2 would enhance coughing. In 12 spontaneously breathing adult male cats, we compared bouts of prolonged mechanically stimulated cough, in which cough induced hyperventilation (CHV) was allowed to occur, with isocapnic cough trials where we maintained eupneic end-tidal CO2 by adding CO2 to the inspired gas. Isocapnia slightly increased cough number and decreased esophageal pressures with no change in EMG magnitudes or phase durations. The cough-to-eupnea transition was also analyzed between CHV, isocapnia, and a third group of animals that were mechanically hyperventilated to apnea. The transition to eupnea was highly sensitive to added CO2, and CHV apneas were much shorter than those produced by mechanical hyperventilation. We suggest that the cough pattern generator is relatively insensitive to CHV. In the immediate post-cough period, the appearance of breathing while CO2 is very low suggests a transient reduction in apneic threshold following a paroxysmal cough bout.
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Affiliation(s)
- M Nicholas Musselwhite
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida. 1333 Center Dr, Gainesville, Florida, 32603, United States of America.
| | - Tabitha Y Shen
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida. 1333 Center Dr, Gainesville, Florida, 32603, United States of America
| | - Melanie J Rose
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida. 1333 Center Dr, Gainesville, Florida, 32603, United States of America
| | - Kimberly E Iceman
- Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, College of Medicine, University of Louisville. 511 S Floyd St, MDR 616, Louisville, Kentucky, 40202, United States of America
| | - Ivan Poliacek
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics. Malá hora 4A, 036 01 Martin-Záturčie, Slovakia
| | - Teresa Pitts
- Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, College of Medicine, University of Louisville. 511 S Floyd St, MDR 616, Louisville, Kentucky, 40202, United States of America.
| | - Donald C Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida. 1333 Center Dr, Gainesville, Florida, 32603, United States of America
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Sykes DL, Zhang M, Morice AH. Treatment of chronic cough: P2X3 receptor antagonists and beyond. Pharmacol Ther 2022; 237:108166. [DOI: 10.1016/j.pharmthera.2022.108166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/22/2022] [Accepted: 03/02/2022] [Indexed: 10/18/2022]
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Chung KF, McGarvey L, Song WJ, Chang AB, Lai K, Canning BJ, Birring SS, Smith JA, Mazzone SB. Cough hypersensitivity and chronic cough. Nat Rev Dis Primers 2022; 8:45. [PMID: 35773287 PMCID: PMC9244241 DOI: 10.1038/s41572-022-00370-w] [Citation(s) in RCA: 76] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/19/2022] [Indexed: 12/13/2022]
Abstract
Chronic cough is globally prevalent across all age groups. This disorder is challenging to treat because many pulmonary and extrapulmonary conditions can present with chronic cough, and cough can also be present without any identifiable underlying cause or be refractory to therapies that improve associated conditions. Most patients with chronic cough have cough hypersensitivity, which is characterized by increased neural responsivity to a range of stimuli that affect the airways and lungs, and other tissues innervated by common nerve supplies. Cough hypersensitivity presents as excessive coughing often in response to relatively innocuous stimuli, causing significant psychophysical morbidity and affecting patients' quality of life. Understanding of the mechanisms that contribute to cough hypersensitivity and excessive coughing in different patient populations and across the lifespan is advancing and has contributed to the development of new therapies for chronic cough in adults. Owing to differences in the pathology, the organs involved and individual patient factors, treatment of chronic cough is progressing towards a personalized approach, and, in the future, novel ways to endotype patients with cough may prove valuable in management.
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Affiliation(s)
- Kian Fan Chung
- Experimental Studies Unit, National Heart & Lung Institute, Imperial College London, London, UK
- Department of Respiratory Medicine, Royal Brompton and Harefield Hospital, London, UK
| | - Lorcan McGarvey
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK
| | - Woo-Jung Song
- Department of Allergy and Clinical Immunology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
| | - Anne B Chang
- Australian Centre for Health Services Innovation, Queensland's University of Technology and Department of Respiratory and Sleep Medicine, Queensland Children's Hospital, Brisbane, Queensland, Australia
- Division of Child Health, Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Kefang Lai
- The First Affiliated Hospital of Guangzhou Medical University, National Center of Respiratory Medicine, National Clinical Research Center for Respiratory Disease, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Health, Guangzhou, China
| | | | - 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
| | - Jaclyn A Smith
- Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, University of Manchester, Manchester, UK
| | - Stuart B Mazzone
- Department of Anatomy and Physiology, University of Melbourne, Victoria, Australia.
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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: 1.0] [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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Al-Kandery ASA, Rao MS, El-Hashim AZ. Prostaglandin E 2 sensitizes the cough reflex centrally via EP3 receptor-dependent activation of NaV 1.8 channels. Respir Res 2021; 22:296. [PMID: 34794450 PMCID: PMC8603488 DOI: 10.1186/s12931-021-01889-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 11/05/2021] [Indexed: 11/29/2022] Open
Abstract
Background Cough hypersensitivity is a major characteristic feature associated with several types of cough, including chronic cough, but its underlying mechanisms remain to be fully understood. Inflammatory mediators, such as prostaglandin E2 (PGE2), have been implicated in both peripheral induction and sensitization of the cough reflex. In this study, using a conscious guinea pig model of cough, we investigated whether PGE2 can sensitize the cough reflex via central actions and, if so, via which mechanisms. Methods All drugs were administered by intracerebroventricular (i.c.v.) route and whole-body plethysmograph set-up was used for both induction, using aerosolized citric acid (0.2 M), and recording of cough. Immunohistochemistry was performed to confirm the expression of NaV 1.8 channels in the nucleus tractus solitarius (nTS). Results We show that both PGE2 and the non-selective EP1/EP3 agonist, sulprostone, dose-dependently enhanced the citric acid-induced cough (P ≤ 0.001, P ≤ 0.01, respectively). Pretreatment with the EP1 antagonist, ONO-8130, did not affect the sulprostone-induced cough sensitization, whilst the EP3 antagonist, L-798,106, dose-dependently inhibited this effect (P ≤ 0.05). Furthermore, treatment with either the EP2 agonist, butaprost or the EP4 agonist, L-902,688, had no effect on cough sensitization. Additionally, pretreatment with either the TRPV1 antagonist, JNJ-17203212 or the TRPA1 antagonist, HC-030031, alone or in combination, nor with the NaV 1.1, 1.2, 1.3, 1.4, 1.6 and 1.7 channel blocker, tetrodotoxin, had any effect on the cough. In contrast, pretreatment with the NaV 1.8 antagonist, A-803467, dose-dependently inhibited this effect (P ≤ 0.05). Furthermore, NaV 1.8 channels were shown to be expressed in the nTS. Conclusion Collectively, our findings show that PGE2 sensitizes the cough reflex centrally via EP3 receptor-dependent activation of NaV 1.8 but independently of TRPV1,TRPA1 and TTX-sensitive sodium channel activation. These results indicate that PGE2 plays an important role in central sensitization of the cough reflex and suggest that central EP3 receptors and/or NaVv 1.8 channels may represent novel antitussive molecular targets. Graphical Abstract ![]()
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Affiliation(s)
- Al-Shaimaa A Al-Kandery
- Department of Pharmacology & Therapeutics, Faculty of Pharmacy, Kuwait University, Kuwait City, Kuwait
| | - Muddanna S Rao
- Department of Anatomy, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Ahmed Z El-Hashim
- Department of Pharmacology & Therapeutics, Faculty of Pharmacy, Kuwait University, Kuwait City, Kuwait.
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10
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Sykes DL, Morice AH. The Cough Reflex: The Janus of Respiratory Medicine. Front Physiol 2021; 12:684080. [PMID: 34267675 PMCID: PMC8277195 DOI: 10.3389/fphys.2021.684080] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 06/09/2021] [Indexed: 01/11/2023] Open
Abstract
In clinical practice, we commonly face adversity when encountering dysfunction of the cough reflex. Similar to ancient Roman deity Janus, it often presents with one of two opposing "faces". Continual aberrant activation of the cough reflex, also known as chronic cough, can cause great detriment to quality of life and many of these patients are left misdiagnosed and undertreated. In contrast, loss of normal functioning of the cough reflex is the cause of a significant proportion of mortality in the elderly, primarily through the development of aspiration pneumonia. In this review we discuss both hyper- and hypo-activation of the cough reflex and how airway reflux and chronic aspiration may be involved in the aetiology and sequalae of both disease states. We detail the physiological and pharmacological mechanisms involved in cough, and how the recent development of P2X3 receptor antagonists may lead to the first pharmaceutical agent licensed for chronic cough. The treatment and prevention of loss of the cough reflex, which has been largely neglected, is also discussed as novel low-cost interventions could help prevent a number of hospital and domiciliary deaths from both acute and chronic aspiration.
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Affiliation(s)
- Dominic L Sykes
- Hull University Teaching Hospitals NHS Trust, Hull, United Kingdom
| | - Alyn H Morice
- Hull York Medical School, University of York, York, United Kingdom
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11
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Musselwhite MN, Shen TY, Rose MJ, Iceman KE, Poliacek I, Pitts T, Bolser DC. Differential effects of acute cerebellectomy on cough in spontaneously breathing cats. PLoS One 2021; 16:e0253060. [PMID: 34153070 PMCID: PMC8216514 DOI: 10.1371/journal.pone.0253060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/27/2021] [Indexed: 11/29/2022] Open
Abstract
The role of the cerebellum in controlling the cough motor pattern is not well understood. We hypothesized that cerebellectomy would disinhibit motor drive to respiratory muscles during cough. Cough was induced by mechanical stimulation of the tracheobronchial airways in anesthetized, spontaneously breathing adult cats (8 male, 1 female), and electromyograms (EMGs) were recorded from upper airway, chest wall, and abdominal respiratory muscles. Cough trials were performed before and at two time points after total cerebellectomy (10 minutes and >1 hour). Unlike a prior report in paralyzed, decerebrated, and artificially ventilated animals, we observed that cerebellectomy had no effect on cough frequency. After cerebellectomy, thoracic inspiratory muscle EMG magnitudes increased during cough (diaphragm EMG increased by 14% at 10 minutes, p = 0.04; parasternal by 34% at 10 minutes and by 32% at >1 hour, p = 0.001 and 0.03 respectively). During cough at 10 minutes after cerebellectomy, inspiratory esophageal pressure was increased by 44% (p = 0.004), thyroarytenoid (laryngeal adductor) muscle EMG amplitude increased 13% (p = 0.04), and no change was observed in the posterior cricoarytenoid (laryngeal abductor) EMG. Cough phase durations did not change. Blood pressure and heart rate were reduced after cerebellectomy, and respiratory rate also decreased due to an increase in duration of the expiratory phase of breathing. Changes in cough-related EMG magnitudes of respiratory muscles suggest that the cerebellum exerts inhibitory control of cough motor drive, but not cough number or phase timing in response to mechanical stimuli in this model early after cerebellectomy. However, results varied widely at >1 hour after cerebellectomy, with some animals exhibiting enhancement or suppression of one or more components of the cough motor behavior. These results suggest that, while the cerebellum and behavior-related sensory feedback regulate cough, it may be difficult to predict the nature of the modulation based on total cerebellectomy.
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Affiliation(s)
- M. Nicholas Musselwhite
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
- * E-mail: (MNM); (TP)
| | - Tabitha Y. Shen
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Melanie J. Rose
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Kimberly E. Iceman
- Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, College of Medicine, University of Louisville, Louisville, Kentucky, United States of America
| | - Ivan Poliacek
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Martin, Slovak Republic
| | - Teresa Pitts
- Department of Neurological Surgery and Kentucky Spinal Cord Injury Research Center, College of Medicine, University of Louisville, Louisville, Kentucky, United States of America
- * E-mail: (MNM); (TP)
| | - Donald C. Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
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12
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Effect of dextromethorphan in the mouse forced swim and tail suspension tests: Evidence for involvement of the alpha receptors. LEARNING AND MOTIVATION 2021. [DOI: 10.1016/j.lmot.2021.101722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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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: 9] [Impact Index Per Article: 2.3] [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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14
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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: 50] [Impact Index Per Article: 12.5] [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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15
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Foucaud L, Demoulin B, Leblanc AL, Ioan I, Schweitzer C, Demoulin-Alexikova S. Modulation of protective reflex cough by acute immune driven inflammation of lower airways in anesthetized rabbits. PLoS One 2019; 14:e0226442. [PMID: 31887143 PMCID: PMC6936810 DOI: 10.1371/journal.pone.0226442] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 11/26/2019] [Indexed: 11/19/2022] Open
Abstract
Chronic irritating cough in patients with allergic disorders may reflect behavioral or reflex response that is inappropriately matched to the stimulus present in the respiratory tract. Such dysregulated response is likely caused by sensory nerve damage driven by allergic mediators leading to cough hypersensitivity. Some indirect findings suggest that even acid-sensitive, capsaicin-insensitive A-δ fibers called “cough receptors” that are likely responsible for protective reflex cough may be modulated through immune driven inflammation. The aim of this study was to find out whether protective reflex cough is altered during acute allergic airway inflammation in rabbits sensitized to ovalbumin. In order to evaluate the effect of such inflammation exclusively on protective reflex cough, C-fiber mediated cough was silenced using general anesthesia. Cough provocation using citric acid inhalation and mechanical stimulation of trachea was realized in 16 ovalbumin (OVA) sensitized, anesthetized and tracheotomised rabbits 24h after OVA (OVA group, n = 9) or saline challenge (control group, n = 7). Number of coughs provoked by citric acid inhalation did not differ between OVA and control group (12,2 ±6,1 vs. 17,9 ± 6,9; p = 0.5). Allergic airway inflammation induced significant modulation of cough threshold (CT) to mechanical stimulus. Mechanically induced cough reflex in OVA group was either up-regulated (subgroup named “responders” CT: 50 msec (50–50); n = 5 p = 0.003) or down-regulated (subgroup named “non responders”, CT: 1200 msec (1200–1200); n = 4 p = 0.001) when compared to control group (CT: 150 msec (75–525)). These results advocate that allergen may induce longer lasting changes of reflex cough pathway, leading to its up- or down-regulation. These findings may be of interest as they suggest that effective therapies for chronic cough in allergic patients should target sensitized component of both, reflex and behavioral cough.
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Affiliation(s)
- Laurent Foucaud
- Research Unit EA 3450 DevAH—Development, Adaptation and Handicap, Campus Biologie Santé, University of Lorraine, Vandœuvre-Lès-Nancy, France
| | - Bruno Demoulin
- Research Unit EA 3450 DevAH—Development, Adaptation and Handicap, Campus Biologie Santé, University of Lorraine, Vandœuvre-Lès-Nancy, France
| | - Anne-Laure Leblanc
- Research Unit EA 3450 DevAH—Development, Adaptation and Handicap, Campus Biologie Santé, University of Lorraine, Vandœuvre-Lès-Nancy, France
| | - Iulia Ioan
- Research Unit EA 3450 DevAH—Development, Adaptation and Handicap, Campus Biologie Santé, University of Lorraine, Vandœuvre-Lès-Nancy, France
- Department of Pediatric Functional Testing, Hôpital d’Enfants, CHRU de Nancy, Vandoeuvre-Les-Nancy, France
| | - Cyril Schweitzer
- Research Unit EA 3450 DevAH—Development, Adaptation and Handicap, Campus Biologie Santé, University of Lorraine, Vandœuvre-Lès-Nancy, France
- Department of Pediatric Functional Testing, Hôpital d’Enfants, CHRU de Nancy, Vandoeuvre-Les-Nancy, France
| | - Silvia Demoulin-Alexikova
- Research Unit EA 3450 DevAH—Development, Adaptation and Handicap, Campus Biologie Santé, University of Lorraine, Vandœuvre-Lès-Nancy, France
- Department of Pediatric Functional Testing, Hôpital d’Enfants, CHRU de Nancy, Vandoeuvre-Les-Nancy, France
- * E-mail:
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16
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Bautista TG, Leech J, Mazzone SB, Farrell MJ. Regional brain stem activations during capsaicin inhalation using functional magnetic resonance imaging in humans. J Neurophysiol 2019; 121:1171-1182. [DOI: 10.1152/jn.00547.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Coughing is an airway protective behavior elicited by airway irritation. Animal studies show that airway sensory information is relayed via vagal sensory fibers to termination sites within dorsal caudal brain stem and thereafter relayed to more rostral sites. Using functional magnetic resonance imaging (fMRI) in humans, we previously reported that inhalation of the tussigenic stimulus capsaicin evokes a perception of airway irritation (“urge to cough”) accompanied by activations in a widely distributed brain network including the primary sensorimotor, insular, prefrontal, and posterior parietal cortices. Here we refine our imaging approach to provide a directed survey of brain stem areas activated by airway irritation. In 15 healthy participants, inhalation of capsaicin at a maximal dose that elicits a strong urge to cough without behavioral coughing was associated with activation of medullary regions overlapping with the nucleus of the solitary tract, paratrigeminal nucleus, spinal trigeminal nucleus and tract, cardiorespiratory regulatory areas homologous to the ventrolateral medulla in animals, and the midline raphe. Interestingly, the magnitude of activation within two cardiorespiratory regulatory areas was positively correlated ( r2 = 0.47, 0.48) with participants’ subjective ratings of their urge to cough. Capsaicin-related activations were also observed within the pons and midbrain. The current results add to knowledge of the representation and processing of information regarding airway irritation in the human brain, which is pertinent to the pursuit of novel cough therapies. NEW & NOTEWORTHY Functional brain imaging in humans was optimized for the brain stem. We provide the first detailed description of brain stem sites activated in response to airway irritation. The results are consistent with findings in animal studies and extend our foundational knowledge of brain processing of airway irritation in humans.
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Affiliation(s)
- Tara G. Bautista
- The Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria, Australia
- Monash Biomedicine Discovery Institute and Department of Medical Imaging and Radiation Sciences, Monash University, Clayton, Victoria, Australia
| | - Jennifer Leech
- Monash Biomedicine Discovery Institute and Department of Medical Imaging and Radiation Sciences, Monash University, Clayton, Victoria, Australia
| | - Stuart B. Mazzone
- The Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria, Australia
| | - Michael J. Farrell
- Monash Biomedicine Discovery Institute and Department of Medical Imaging and Radiation Sciences, Monash University, Clayton, Victoria, Australia
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17
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Chen Z, Gu D, Fan L, Zhang W, Sun L, Chen H, Dong R, Lai K. Neuronal Activity of the Medulla Oblongata Revealed by Manganese-Enhanced Magnetic Resonance Imaging in a Rat Model of Gastroesophageal Reflux-Related Cough. Physiol Res 2018; 68:119-127. [PMID: 30433807 DOI: 10.33549/physiolres.933791] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We investigated neuronal activity of the medulla oblongata during gastroesophageal reflux-related cough (GERC). A rat model of GERC was generated by perfusing HCl into lower esophagus and inducing cough with citric acid. The HCl group rat was received HCl perfusion without citric acid-induced cough. The saline control rat was perfused with saline instead and cough was induced. Citric acid-induced cough rat was only induced by citric acid. Blank group rats were fed normally. Fos expressions were observed in medulla oblongata nuclei using immunohistochemistry. Manganese-enhanced magnetic resonance imaging (MEMRI) was performed to detect the Mn(2+) signal following intraperitoneal injection of MnCl(2). HCl perfusion and citric acid-induced cough caused Fos expressions in the nucleus of solitary tract (nTS), dorsal motor nucleus of the vagus (DMV), paratrigeminal nucleus (Pa5), and intermediate reticular nucleus (IRt), which was higher than HCl group, saline control group, citric acid-induced cough group, and blank group. A high Mn(2+) signal was also observed in most of these nuclei in model rats, compared with blank group animals. The Mn(2+) signal was also higher in the HCl, saline and citric acid-induced cough group animals, compared with blank group animals. The study showed medulla oblongata neurons were excited in a HCl perfusion and citric acid-induced cough rat model, and nTS, DMV, Pa5 and IRt neurons maybe involved in the cough process and signal integrate.
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Affiliation(s)
- Zhe Chen
- The First People's Hospital of Kunshan, Jiangsu University, Suzhou, China
| | - Dachuan Gu
- Fu Wai Hospital, Peking Union Medical College, Beijing, China
| | - Linfeng Fan
- The Second Affiliated Hospital of Zhejiang University School of Medicine, Zhejiang University, Hangzhou, China
| | - Weitao Zhang
- Zhongshan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Lejia Sun
- Peking Union Medical College, Beijing, China
| | - Hui Chen
- First Affiliated Hospital of Soochow University, Suzhou, China
| | - Rong Dong
- Medical School of Southeast University, Nanjing, China
| | - Kefang Lai
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Institute of Respiratory Disease, Guangzhou, China
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18
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El‐Hashim AZ, Mathews S, Al‐Shamlan F. Central adenosine A 1 receptors inhibit cough via suppression of excitatory glutamatergic and tachykininergic neurotransmission. Br J Pharmacol 2018; 175:3162-3174. [PMID: 29767468 PMCID: PMC6031887 DOI: 10.1111/bph.14360] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 03/02/2018] [Accepted: 04/10/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND AND PURPOSE The adenosine A1 receptor is reported to mediate several excitatory effects in the airways and has inhibitory effects in the CNS. In this study, we investigated the role of peripheral and central A1 receptors in regulating cough and airway obstruction. EXPERIMENTAL APPROACH Drugs were administered to guinea pigs via inhalation or i.c.v. infusion. Following the administration of different drugs, cough was induced by exposing guinea pigs to aerosolized 0.4 M citric acid. An automated analyser recorded both cough and airway obstruction simultaneously using whole-body plethysmography. KEY RESULTS The A1 receptor agonist, cyclopentyladenosine (CPA, administered by inhalation), dose-dependently inhibited cough and also inhibited airway obstruction. Similarly, CPA, administered i.c.v., inhibited both the citric acid-induced cough and airway obstruction; this was prevented by pretreatment with the A1 receptor antagonist DPCPX (i.c.v.). Treatment with DPCPX alone dose-dependently enhanced the citric acid-induced cough and airway obstruction. This effect was reversed following treatment with either the glutamate GluN1 receptor antagonist D-AP5 or the neurokinin NK1 receptor antagonist FK-888. CONCLUSIONS AND IMPLICATIONS These findings suggest that activation of either peripheral or central adenosine A1 receptors inhibits citric acid-induced cough and airway obstruction. The data also suggest that tonic activation of central adenosine A1 receptors serves as a negative regulator of cough and airway obstruction, secondary to inhibition of excitatory glutamatergic and tachykininergic neurotransmission.
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Affiliation(s)
- Ahmed Z El‐Hashim
- Department of Pharmacology and Therapeutics, Faculty of PharmacyKuwait UniversityKuwait
| | - Seena Mathews
- Department of Pharmacology and Therapeutics, Faculty of PharmacyKuwait UniversityKuwait
| | - Fajer Al‐Shamlan
- Department of Pharmacology and Therapeutics, Faculty of PharmacyKuwait UniversityKuwait
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19
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Chen Z, Sun L, Chen H, Gu D, Zhang W, Yang Z, Peng T, Dong R, Lai K. Dorsal Vagal Complex Modulates Neurogenic Airway Inflammation in a Guinea Pig Model With Esophageal Perfusion of HCl. Front Physiol 2018; 9:536. [PMID: 29867575 PMCID: PMC5962767 DOI: 10.3389/fphys.2018.00536] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 04/24/2018] [Indexed: 12/29/2022] Open
Abstract
Neurogenic airway inflammation in chronic cough and bronchial asthma related to gastroesophageal reflux (GER) is involved in the esophageal–bronchial reflex, but it is unclear whether this reflex is mediated by central neurons. This study aimed to investigate the regulatory effects of the dorsal vagal complex (DVC) on airway inflammation induced by the esophageal perfusion of hydrochloric acid (HCl) following the microinjection of nuclei in the DVC in guinea pigs. Airway inflammation was evaluated by measuring the extravasation of Evans blue dye (EBD) and substance P (SP) expression in the airway. Neuronal activity was indicated by Fos expression in the DVC. The neural pathways from the lower esophagus to the DVC and the DVC to the airway were identified using DiI tracing and pseudorabies virus Bartha (PRV-Bartha) retrograde tracing, respectively. HCl perfusion significantly increased plasma extravasation, SP expression in the trachea, and the expression of SP and Fos in the medulla oblongata nuclei, including the nucleus of the solitary tract (NTS) and the dorsal motor nucleus of the vagus (DMV). The microinjection of glutamic acid (Glu) or exogenous SP to enhance neuronal activity in the DVC significantly potentiated plasma extravasation and SP release induced by intra-esophageal perfusion. The microinjection of γ-aminobutyric acid (GABA), lidocaine to inhibit neuronal activity or anti-SP serum in the DVC alleviated plasma extravasation and SP release. In conclusion, airway inflammation induced by the esophageal perfusion of HCl is regulated by DVC. This study provides new insight for the mechanism of airway neurogenic inflammation related to GER.
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Affiliation(s)
- Zhe Chen
- The First People's Hospital of Kunshan, Jiangsu University, Kunshan, China.,State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Lejia Sun
- Department of Hepatobiliary Surgery, Peking Union Medical College, Chinese Academy of Medical Sciences (CAMS), Beijing, China
| | - Hui Chen
- ICU, First Affiliated Hospital of Soochow University, Suzhou, China
| | - Dachuan Gu
- Department of Cardiothoracic Surgery, Fu Wai Hospital, Beijing, China
| | - Weitao Zhang
- Department of Urology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Zifeng Yang
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Tao Peng
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Rong Dong
- Department of Physiology, Medical School of Southeast University, Nanjing, China
| | - Kefang Lai
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
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20
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Inhibitory modulation of the cough reflex by acetylcholine in the caudal nucleus tractus solitarii of the rabbit. Respir Physiol Neurobiol 2018; 257:93-99. [PMID: 29369803 DOI: 10.1016/j.resp.2018.01.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 01/08/2018] [Accepted: 01/15/2018] [Indexed: 12/16/2022]
Abstract
A cholinergic system has been described in the nucleus tractus solitarii (NTS). However, no information is available on the role played by acetylcholine (ACh) in the modulation of the cough reflex within the caudal NTS that has an important function in cough regulation. We addressed this issue making use of bilateral microinjections (30-50 nl) of 10 mM ACh combined with 5 mM physostigmine as well as of 10 mM mecamylamine or 10 mM scopolamine into the caudal NTS of pentobarbital sodium-anesthetized, spontaneously breathing rabbits. Microinjections of ACh/physostigmine caused depressant effects on the cough reflex induced by mechanical and chemical stimulation of the tracheobronchial tree. They also elicited transient increases in respiratory frequency and decreases in abdominal activity. These effects were prevented by scopolamine, but not by mecamylamine. The results show for the first time that ACh exerts an inhibitory modulation of the cough reflex through muscarinic receptors within the caudal NTS. They also may provide hints for novel antitussive approaches.
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21
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CHEN Z, CHEN H, CHEN F, GU D, SUN L, ZHANG W, FAN L, LIN Y, DONG R, LAI K. Vagotomy Decreases the Neuronal Activities of Medulla Oblongata and Alleviates Neurogenic Inflammation of Airways Induced by Repeated Intra-Esophageal Instillation of HCl in Guinea Pigs. Physiol Res 2017; 66:1021-1028. [DOI: 10.33549/physiolres.933574] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Neuronal activity in the medulla oblongata and neurogenic inflammation of airways were investigated in a guinea pig model induced by repeated intra-esophageal instillation of hydrochloric acid (HCl) after vagotomy. Unilateral vagotomy was performed in the vagotomy group, while a sham-operation was performed in the sham group. Operation was not conducted in sham control group. Airway inflammation was observed with hematoxylin and eosin (HE) staining. C-fos protein was measured by immunohistochemistry (IHC) and Western blot (WB). Substance P was examined by IHC and enzyme-linked immuno sorbent assay (ELISA). Airway microvascular permeability was detected by evans blue dye (EBD) fluorescence. Inflammation of airway was observed in the trachea and bronchi after chronic HCl perfusion into the lower esophagus, and was alleviated after unilateral vagotomy. C-fos expression in the medulla oblongata was lower in the vagotomy group compared to the sham control and sham groups. Substance P-like immunoreactivity (SP-li), concentration and microvascular leakage in airway were lower in the vagotomy group than that in the other groups. Our results suggest that vagotomy improved neurogenic inflammation of airways and decreased neuronal activities, the afferent nerves and neurons in medulla oblongata may be involved in neurogenic inflammation of airways mediated by esophageal-bronchial reflex.
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Affiliation(s)
| | | | | | | | | | | | | | | | - R. DONG
- Medical School of Southeast University, Nanjing, China
| | - K. LAI
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Institute of Respiratory Disease, Guangzhou, China
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22
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Brainstem mechanisms underlying the cough reflex and its regulation. Respir Physiol Neurobiol 2017; 243:60-76. [DOI: 10.1016/j.resp.2017.05.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 05/16/2017] [Accepted: 05/17/2017] [Indexed: 12/12/2022]
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23
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Poliacek I, Simera M, Veternik M, Kotmanova Z, Bolser DC, Machac P, Jakus J. Role of the dorsomedial medulla in suppression of cough by codeine in cats. Respir Physiol Neurobiol 2017; 246:59-66. [PMID: 28778649 DOI: 10.1016/j.resp.2017.07.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 07/23/2017] [Accepted: 07/28/2017] [Indexed: 12/24/2022]
Abstract
The modulation of cough by microinjections of codeine in 3 medullary regions, the solitary tract nucleus rostral to the obex (rNTS), caudal to the obex (cNTS) and the lateral tegmental field (FTL) was studied. Experiments were performed on 27 anesthetized spontaneously breathing cats. Electromyograms (EMG) were recorded from the sternal diaphragm and expiratory muscles (transversus abdominis and/or obliquus externus; ABD). Repetitive coughing was elicited by mechanical stimulation of the intrathoracic airways. Bilateral microinjections of codeine (3.3 or 33mM, 54±16nl per injection) in the cNTS had no effect on cough, while those in the rNTS and in the FTL reduced coughing. Bilateral microinjections into the rNTS (3.3mM codeine, 34±1 nl per injection) reduced the number of cough responses by 24% (P<0.05), amplitudes of diaphragm EMG by 19% (P<0.01), of ABD EMG by 49% (P<0.001) and of expiratory esophageal pressure by 56% (P<0.001). Bilateral microinjections into the FTL (33mM codeine, 33±3 nl per injection) induced reductions in cough expiratory as well as inspiratory EMG amplitudes (ABD by 60% and diaphragm by 34%; P<0.01) and esophageal pressure amplitudes (expiratory by 55% and inspiratory by 26%; P<0.001 and 0.01, respectively). Microinjections of vehicle did not significantly alter coughing. Breathing was not affected by microinjections of codeine. These results suggest that: 1) codeine acts within the rNTS and the FTL to reduce cough in the cat, 2) the neuronal circuits in these target areas have unequal sensitivity to codeine and/or they have differential effects on spatiotemporal control of cough, 3) the cNTS has a limited role in the cough suppression induced by codeine in cats.
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Affiliation(s)
- Ivan Poliacek
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 036 01, Martin, Slovakia
| | - Michal Simera
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 036 01, Martin, Slovakia.
| | - Marcel Veternik
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 036 01, Martin, Slovakia
| | - Zuzana Kotmanova
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 036 01, Martin, Slovakia
| | - Donald C Bolser
- Dept. of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
| | - Peter Machac
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 036 01, Martin, Slovakia
| | - Jan Jakus
- Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 036 01, Martin, Slovakia
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24
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A Randomized Clinical Trial Comparing the Effects of Antitussive Agents on Respiratory Center Output in Patients With Chronic Cough. Chest 2017; 151:1288-1294. [DOI: 10.1016/j.chest.2017.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 01/23/2017] [Accepted: 02/01/2017] [Indexed: 11/22/2022] Open
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25
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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: 325] [Impact Index Per Article: 46.4] [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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26
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Affiliation(s)
- Ahmed Z. El-Hashim
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Kuwait University, Kuwait City, Kuwait
| | - Sahar M. Jaffal
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Kuwait University, Kuwait City, Kuwait
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27
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Poliacek I, Pitts T, Rose MJ, Davenport PW, Simera M, Veternik M, Kotmanova Z, Bolser DC. Microinjection of kynurenic acid in the rostral nucleus of the tractus solitarius disrupts spatiotemporal aspects of mechanically induced tracheobronchial cough. J Neurophysiol 2017; 117:2179-2187. [PMID: 28250153 DOI: 10.1152/jn.00935.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 02/07/2017] [Accepted: 02/24/2017] [Indexed: 01/08/2023] Open
Abstract
The importance of neurons in the nucleus of the solitary tract (NTS) in the production of coughing was tested by microinjections of the nonspecific glutamate receptor antagonist kynurenic acid (kyn; 100 mM in artificial cerebrospinal fluid) in 15 adult spontaneously breathing anesthetized cats. Repetitive coughing was elicited by mechanical stimulation of the intrathoracic airway. Electromyograms (EMG) were recorded from inspiratory parasternal and expiratory transversus abdominis (ABD) muscles. Bilateral microinjections of kyn into the NTS rostral to obex [55 ± 4 nl total in 2 locations (n = 6) or 110 ± 4 nl total in 4 locations (n = 5)], primarily the ventrolateral subnucleus, reduced cough number and expiratory cough efforts (amplitudes of ABD EMG and maxima of esophageal pressure) compared with control. These microinjections also markedly prolonged the inspiratory phase, all cough-related EMG activation, and the total cough cycle duration as well as some other cough-related time intervals. In response to microinjections of kyn into the NTS rostral to the obex respiratory rate decreased, and there were increases in the durations of the inspiratory and postinspiratory phases and mean blood pressure. However, bilateral microinjections of kyn into the NTS caudal to obex as well as control vehicle microinjections in the NTS location rostral to obex had no effect on coughing or cardiorespiratory variables. These results are consistent with the existence of a critical component of the cough rhythmogenic circuit located in the rostral ventral and lateral NTS. Neuronal structures of the rostral NTS are significantly involved specifically in the regulation of cough magnitude and phase timing.NEW & NOTEWORTHY The nucleus of the solitary tract contains significant neuronal structures responsible for control of 1) cough excitability, 2) motor drive during cough, 3) cough phase timing, and 4) cough rhythmicity. Significant elimination of neurons in the solitary tract nucleus results in cough apraxia (incomplete and/or disordered cough pattern). The mechanism of the cough impairment is different from that for the concomitant changes in breathing.
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Affiliation(s)
- Ivan Poliacek
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida.,Institute of Medical Biophysics, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovak Republic; and
| | - Teresa Pitts
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida.,Kentucky Spinal Cord Injury Research Center, Department of Neurological Surgery, University of Louisville, Louisville, Kentucky
| | - Melanie J Rose
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Paul W Davenport
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Michal Simera
- Institute of Medical Biophysics, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovak Republic; and
| | - Marcel Veternik
- Institute of Medical Biophysics, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovak Republic; and
| | - Zuzana Kotmanova
- Institute of Medical Biophysics, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovak Republic; and
| | - Donald C Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida;
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28
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Taylor CP, Traynelis SF, Siffert J, Pope LE, Matsumoto RR. Pharmacology of dextromethorphan: Relevance to dextromethorphan/quinidine (Nuedexta®) clinical use. Pharmacol Ther 2016; 164:170-82. [PMID: 27139517 DOI: 10.1016/j.pharmthera.2016.04.010] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Dextromethorphan (DM) has been used for more than 50years as an over-the-counter antitussive. Studies have revealed a complex pharmacology of DM with mechanisms beyond blockade of N-methyl-d-aspartate (NMDA) receptors and inhibition of glutamate excitotoxicity, likely contributing to its pharmacological activity and clinical potential. DM is rapidly metabolized to dextrorphan, which has hampered the exploration of DM therapy separate from its metabolites. Coadministration of DM with a low dose of quinidine inhibits DM metabolism, yields greater bioavailability and enables more specific testing of the therapeutic properties of DM apart from its metabolites. The development of the drug combination DM hydrobromide and quinidine sulfate (DM/Q), with subsequent approval by the US Food and Drug Administration for pseudobulbar affect, led to renewed interest in understanding DM pharmacology. This review summarizes the interactions of DM with brain receptors and transporters and also considers its metabolic and pharmacokinetic properties. To assess the potential clinical relevance of these interactions, we provide an analysis comparing DM activity from in vitro functional assays with the estimated free drug DM concentrations in the brain following oral DM/Q administration. The findings suggest that DM/Q likely inhibits serotonin and norepinephrine reuptake and also blocks NMDA receptors with rapid kinetics. Use of DM/Q may also antagonize nicotinic acetylcholine receptors, particularly those composed of α3β4 subunits, and cause agonist activity at sigma-1 receptors.
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Affiliation(s)
| | - Stephen F Traynelis
- Dept. of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | - Joao Siffert
- Avanir Pharmaceuticals, Inc., Aliso Viejo, CA, USA
| | - Laura E Pope
- Avanir Pharmaceuticals, Inc., Aliso Viejo, CA, USA
| | - Rae R Matsumoto
- College of Pharmacy, Touro University California, Vallejo, CA, USA
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Pitts T, Morris KF, Segers LS, Poliacek I, Rose MJ, Lindsey BG, Davenport PW, Howland DR, Bolser DC. Feed-forward and reciprocal inhibition for gain and phase timing control in a computational model of repetitive cough. J Appl Physiol (1985) 2016; 121:268-78. [PMID: 27283917 PMCID: PMC4967248 DOI: 10.1152/japplphysiol.00790.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 06/08/2016] [Indexed: 11/22/2022] Open
Abstract
We investigated the hypothesis, motivated in part by a coordinated computational cough network model, that second-order neurons in the nucleus tractus solitarius (NTS) act as a filter and shape afferent input to the respiratory network during the production of cough. In vivo experiments were conducted on anesthetized spontaneously breathing cats. Cough was elicited by mechanical stimulation of the intrathoracic airways. Electromyograms of the parasternal (inspiratory) and rectus abdominis (expiratory) muscles and esophageal pressure were recorded. In vivo data revealed that expiratory motor drive during bouts of repetitive coughs is variable: peak expulsive amplitude increases from the first cough, peaks about the eighth or ninth cough, and then decreases through the remainder of the bout. Model simulations indicated that feed-forward inhibition of a single second-order neuron population is not sufficient to account for this dynamic feature of a repetitive cough bout. When a single second-order population was split into two subpopulations (inspiratory and expiratory), the resultant model produced simulated expiratory motor bursts that were comparable to in vivo data. However, expiratory phase durations during these simulations of repetitive coughing had less variance than those in vivo. Simulations in which reciprocal inhibitory processes between inspiratory-decrementing and expiratory-augmenting-late neurons were introduced exhibited increased variance in the expiratory phase durations. These results support the prediction that serial and parallel processing of airway afferent signals in the NTS play a role in generation of the motor pattern for cough.
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Affiliation(s)
- Teresa Pitts
- Department of Neurologic Surgery and Kentucky Spinal Cord Injury Research Center, College of Medicine, University of Louisville, Louisville, Kentucky; Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida;
| | - Kendall F Morris
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida; and
| | - Lauren S Segers
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida; and
| | - Ivan Poliacek
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida; Institute of Medical Biophysics, Jessenius Faculty of Medicine, Comenius University, Martin, Slovak Republic
| | - Melanie J Rose
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Bruce G Lindsey
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida; and
| | - Paul W Davenport
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Dena R Howland
- Department of Neurologic Surgery and Kentucky Spinal Cord Injury Research Center, College of Medicine, University of Louisville, Louisville, Kentucky
| | - Donald C Bolser
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
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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: 39] [Impact Index Per Article: 4.9] [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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31
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Lv H, Yue J, Chen Z, Chai S, Cao X, Zhan J, Ji Z, Zhang H, Dong R, Lai K. Effect of transient receptor potential vanilloid-1 on cough hypersensitivity induced by particulate matter 2.5. Life Sci 2016; 151:157-166. [PMID: 26926080 DOI: 10.1016/j.lfs.2016.02.064] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 02/05/2016] [Accepted: 02/16/2016] [Indexed: 12/29/2022]
Abstract
AIMS The mechanism of cough hypersensitivity induced by particulate matter 2.5 (PM2.5) remains elusive. The current study was designed to explore the effect of transient receptor potential vanilloid-1 (TRPV1) on cough hypersensitivity in airway and central nervous system. MAIN METHODS The PM2.5-induced chronic cough model of guinea pig was established by exposure to different doses of PM2.5 for three weeks. After exposure, the animals were microinjected with TRPV1 agonist capsaicine, antagonist capsazepine in the dorsal vagal complex respectively. Cough sensitivity was measured by determining the provocative concentration of citric acid inducing 5 or more coughs (C5). Airway inflammation was detected by hematoxylin eosin (HE) staining and Evans blue fluorescence, and substance P (SP) and TRPV1 expressions in airway were observed by immunohistochemical staining. TRPV1 expressions in the dorsal vagal complex were observed by immunofluorescence. Retrograde tracing by pseudorabies virus-Bartha (PRV-Bartha) was conducted to confirm the regulatory pathway between airway and central nervous system. KEY FINDINGS PM2.5 induced TRPV1 expressions in both of airway and dorsal vagal complex and airway neurogenic inflammation. Airway vascular permeability increased after being exposed to PM2.5. The expressions of SP in the airway and airway inflammation was increased after microinjecting TRPV1 agonist, and decreased after microinjecting TRPV1 antagonist. PRV infected neurons in medulla oblongata mainly located in the dorsal vagal complex. SIGNIFICANCE These findings show that TRPV1 in the dorsal vagal complex could promote airway neurogenic inflammation and cough reflex sensitivity through neural pathways of vagal complex-airways, which indicate the therapeutic potential of specific inhibition of TRPV1 for chronic cough induced by PM2.5.
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Affiliation(s)
- Haining Lv
- Medical School, Southeast University, China
| | | | - Zhe Chen
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University, China
| | | | - Xu Cao
- Medical School, Southeast University, China
| | - Jie Zhan
- Medical School, Southeast University, China
| | - Zhenjun Ji
- Medical School, Southeast University, China
| | - Hui Zhang
- Key Laboratory of Environmental Medicine and Engineering Ministry of Education, School of Public Health, Southeast University, China
| | - Rong Dong
- Department of Physiology and Pharmacology, Southeast University, China.
| | - Kefang Lai
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, First Affiliated Hospital of Guangzhou Medical University, China.
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Chung KF, Canning B, McGarvey L. Eight International London Cough Symposium 2014: Cough hypersensitivity syndrome as the basis for chronic cough. Pulm Pharmacol Ther 2015; 35:76-80. [PMID: 26341666 DOI: 10.1016/j.pupt.2015.08.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 08/31/2015] [Indexed: 02/01/2023]
Abstract
At the Eighth International London Cough Conference held in London in July 2014, the focus was on the relatively novel concept of cough hypersensitivity syndrome (CHS) as forming the basis of chronic cough. This concept has been formulated following understanding of the neuronal pathways for cough and a realisation that not all chronic cough is usually associated with a cause. The CHS is defined by troublesome coughing triggered by low level of thermal, mechanical or chemical exposure. It also encompasses other symptoms or sensations such as laryngeal hypersensitivity, nasal hypersensitivity and possibly also symptoms related to gastrooesopahgeal reflux. The pathophysiologic basis of the CHS is now being increasingly linked to an enhancement of the afferent pathways of the cough reflex both at the peripheral and central levels. Mechanisms involved include the interactions of inflammatory mechanisms with cough sensors in the upper airways and with neuronal pathways of cough, associated with a central component. Tools for assessing CHS in the clinic need to be developed. New drugs may be developed to control CHS. A roadmap is suggested from the inception of the CHS concept towards the development of newer antitussives at the Symposium.
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Affiliation(s)
- Kian Fan Chung
- Experimental Studies, National Heart and Lung Institute, Imperial College London, UK; Royal Brompton NIHR Biomedical Research Unit, London, UK.
| | - Brendan Canning
- The Johns Hopkins Asthma and Allergy Center, Baltimore, MD 21224, USA
| | - Lorcan McGarvey
- Department of Respiratory Medicine, Centre for Infection and Immunity, Queen's University Belfast, UK
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Cinelli E, Bongianni F, Pantaleo T, Mutolo D. The cough reflex is upregulated by lisinopril microinjected into the caudal nucleus tractus solitarii of the rabbit. Respir Physiol Neurobiol 2015; 219:9-17. [PMID: 26234277 DOI: 10.1016/j.resp.2015.07.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 07/27/2015] [Accepted: 07/27/2015] [Indexed: 11/16/2022]
Abstract
We have previously shown that cough potentiation induced by intravenous administration of the AT1 receptor antagonist losartan is lower than that induced by the ACE inhibitor lisinopril in anesthetized and awake rabbits. Since losartan and lisinopril cross the blood-brain barrier, their central action on the cough reflex can be hypothesized. Mechanical stimulation of the tracheobronchial tree and citric acid inhalation were used to induce cough reflex responses in pentobarbital sodium-anesthetized, spontaneously breathing rabbits. Bilateral microinjections (30-50 nl) of losartan (5mM), lisinopril (1mM), bradykinin (0.05 mM), HOE-140 (0.2mM, a bradykinin B2 receptor antagonist) and CP-99,994 (1mM, an NK1 receptor antagonist) were performed into the caudal nucleus tractus solitarii, the predominant site of termination of cough-related afferents. Lisinopril, but not losartan increased the cough number. This effect was reverted by HOE-140 or CP-99,994. Cough potentiation was also induced by bradykinin. The results support for the first time a central protussive action of lisinopril mediated by an accumulation of bradykinin and substance P.
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Affiliation(s)
- Elenia Cinelli
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Viale G.B. Morgagni 63, 50134 Firenze, Italy
| | - Fulvia Bongianni
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Viale G.B. Morgagni 63, 50134 Firenze, Italy
| | - Tito Pantaleo
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Viale G.B. Morgagni 63, 50134 Firenze, Italy
| | - Donatella Mutolo
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Viale G.B. Morgagni 63, 50134 Firenze, Italy.
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Clinical features of the urge-to-cough in patients with chronic cough. Respir Med 2015; 109:701-7. [DOI: 10.1016/j.rmed.2015.03.011] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 03/22/2015] [Accepted: 03/27/2015] [Indexed: 11/20/2022]
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NMDA and GABA receptors as potential targets in cough hypersensitivity syndrome. Curr Opin Pharmacol 2015; 22:29-36. [DOI: 10.1016/j.coph.2015.03.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 03/02/2015] [Accepted: 03/02/2015] [Indexed: 12/21/2022]
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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 2015; 146:1633-1648. [PMID: 25188530 PMCID: PMC4251621 DOI: 10.1378/chest.14-1481] [Citation(s) in RCA: 168] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [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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Mazzone SB, McGovern AE, Farrell MJ. Endogenous central suppressive mechanisms regulating cough as potential targets for novel antitussive therapies. Curr Opin Pharmacol 2015; 22:1-8. [PMID: 25704497 DOI: 10.1016/j.coph.2015.02.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 02/04/2015] [Accepted: 02/04/2015] [Indexed: 02/05/2023]
Abstract
Cough and the accompanying sensation known as the urge-to-cough are complex neurobiological phenomena dependent on sensory and motor neural processing at many levels of the neuraxis. In addition to the excitatory neural circuits that provide the positive drive for inducing cough and the urge-to-cough, recent studies have highlighted the existence of likely inhibitory central neural processes that can be engaged to suppress cough sensorimotor processing. In many respects, the balance between excitatory and inhibitory central cough control may be a critical determinant of cough in health and disease which argues for the importance of understanding the biology of these putative central inhibitory processes. This brief review summarises the current knowledge of the central circuits that govern voluntary and involuntary cough suppression and posits the notion of targeting central suppressive mechanisms as a treatment for disordered cough in disease.
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Affiliation(s)
- Stuart B Mazzone
- School of Biomedical Sciences, The University of Queensland, Australia.
| | - Alice E McGovern
- School of Biomedical Sciences, The University of Queensland, Australia
| | - Michael J Farrell
- Department of Medical Imaging and Radiation Sciences, Monash University, Australia
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38
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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: 12] [Impact Index Per Article: 1.3] [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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Narula M, McGovern AE, Yang SK, Farrell MJ, Mazzone SB. Afferent neural pathways mediating cough in animals and humans. J Thorac Dis 2014; 6:S712-9. [PMID: 25383205 DOI: 10.3978/j.issn.2072-1439.2014.03.15] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 03/04/2014] [Indexed: 12/12/2022]
Abstract
The airways and lungs are densely innervated by sensory nerves, which subserve multiple roles in both the normal physiological control of respiratory functions and in pulmonary defense. These sensory nerves are therefore not homogeneous in nature, but rather have physiological, molecular and anatomical phenotypes that reflect their purpose. All sensory neuron subtypes provide input to the central nervous system and drive reflex changes in respiratory and airway functions. But less appreciated is that ascending projections from these brainstem inputs to higher brain regions can also induce behavioural changes in respiration. In this brief review we provide an overview of the current understanding of airway sensory pathways, with specific reference to those involved in reflex and behavioural cough responses following airways irritation.
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Affiliation(s)
- Monica Narula
- 1 School of Biomedical Sciences, University of Queensland, QLD 4072, Australia ; 2 The Florey Institute of Neuroscience and Mental Health, VIC 3010, Australia
| | - Alice E McGovern
- 1 School of Biomedical Sciences, University of Queensland, QLD 4072, Australia ; 2 The Florey Institute of Neuroscience and Mental Health, VIC 3010, Australia
| | - Seung-Kwon Yang
- 1 School of Biomedical Sciences, University of Queensland, QLD 4072, Australia ; 2 The Florey Institute of Neuroscience and Mental Health, VIC 3010, Australia
| | - Michael J Farrell
- 1 School of Biomedical Sciences, University of Queensland, QLD 4072, Australia ; 2 The Florey Institute of Neuroscience and Mental Health, VIC 3010, Australia
| | - Stuart B Mazzone
- 1 School of Biomedical Sciences, University of Queensland, QLD 4072, Australia ; 2 The Florey Institute of Neuroscience and Mental Health, VIC 3010, Australia
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Ando A, Farrell MJ, Mazzone SB. Cough-related neural processing in the brain: A roadmap for cough dysfunction? Neurosci Biobehav Rev 2014; 47:457-68. [DOI: 10.1016/j.neubiorev.2014.09.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 06/29/2014] [Accepted: 09/25/2014] [Indexed: 01/05/2023]
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Dicpinigaitis PV, Morice AH, Birring SS, McGarvey L, Smith JA, Canning BJ, Page CP. Antitussive drugs--past, present, and future. Pharmacol Rev 2014; 66:468-512. [PMID: 24671376 PMCID: PMC11060423 DOI: 10.1124/pr.111.005116] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Cough remains a serious unmet clinical problem, both as a symptom of a range of other conditions such as asthma, chronic obstructive pulmonary disease, gastroesophageal reflux, and as a problem in its own right in patients with chronic cough of unknown origin. This article reviews our current understanding of the pathogenesis of cough and the hypertussive state characterizing a number of diseases as well as reviewing the evidence for the different classes of antitussive drug currently in clinical use. For completeness, the review also discusses a number of major drug classes often clinically used to treat cough but that are not generally classified as antitussive drugs. We also reviewed a number of drug classes in various stages of development as antitussive drugs. Perhaps surprising for drugs used to treat such a common symptom, there is a paucity of well-controlled clinical studies documenting evidence for the use of many of the drug classes in use today, particularly those available over the counter. Nonetheless, there has been a considerable increase in our understanding of the cough reflex over the last decade that has led to a number of promising new targets for antitussive drugs being identified and thus giving some hope of new drugs being available in the not too distant future for the treatment of this often debilitating symptom.
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Affiliation(s)
- P V Dicpinigaitis
- King's College London, Franklin Wilkins Building, 100 Stamford St., London, SE1 9NH, UK.
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Cinelli E, Bongianni F, Pantaleo T, Mutolo D. Suppression of the cough reflex by α 2-adrenergic receptor agonists in the rabbit. Physiol Rep 2013; 1:e00122. [PMID: 24400133 PMCID: PMC3871446 DOI: 10.1002/phy2.122] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 09/16/2013] [Accepted: 09/18/2013] [Indexed: 01/26/2023] Open
Abstract
The α2-adrenergic receptor agonist clonidine has been shown to inhibit citric acid-induced cough responses in guinea pigs when administered by aerosol, but not orally. In contrast, oral or inhaled clonidine had no effect on capsaicin-induced cough and reflex bronchoconstriction in humans. In addition, intravenous administration of clonidine has been shown to depress fentanyl-induced cough in humans. We investigated the effects of the α2-adrenergic receptor agonists, clonidine and tizanidine, on cough responses induced by mechanical and chemical (citric acid) stimulation of the tracheobronchial tree. Drugs were microinjected (30–50 nL) into the caudal nucleus tractus solitarii (cNTS) and the caudal ventral respiratory group (cVRG) as well as administered intravenously in pentobarbital sodium-anesthetized, spontaneously breathing rabbits. Bilateral microinjections of clonidine into the cNTS or the cVRG reduced cough responses at 0.5 mmol/L and abolished the cough reflex at 5 mmol/L. Bilateral microinjections of 0.5 mmol/L tizanidine into the cNTS completely suppressed cough responses, whereas bilateral microinjections of 5 mmol/L into the cVRG only caused mild reductions in them. Depressant effects on the cough reflex of clonidine and tizanidine were completely reverted by microinjections of 10 mmol/L yohimbine. Intravenous administration of clonidine (80–120 μg/kg) or tizanidine (150–300 μg/kg) strongly reduced or completely suppressed cough responses. These effects were reverted by intravenous administration of yohimbine (300 μg/kg). The results demonstrate that activation of α2-adrenergic receptors in the rabbit exerts potent inhibitory effects on the central mechanism generating the cough motor pattern with a clear action at the level of the cNTS and the cVRG.
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Affiliation(s)
- Elenia Cinelli
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze Viale G.B. Morgagni 63, 50134, Firenze, Italy
| | - Fulvia Bongianni
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze Viale G.B. Morgagni 63, 50134, Firenze, Italy
| | - Tito Pantaleo
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze Viale G.B. Morgagni 63, 50134, Firenze, Italy
| | - Donatella Mutolo
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze Viale G.B. Morgagni 63, 50134, Firenze, Italy
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Tsujimura T, Udemgba C, Inoue M, Canning BJ. Laryngeal and tracheal afferent nerve stimulation evokes swallowing in anaesthetized guinea pigs. J Physiol 2013; 591:4667-79. [PMID: 23858010 DOI: 10.1113/jphysiol.2013.256024] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
We describe swallowing reflexes evoked by laryngeal and tracheal vagal afferent nerve stimulation in anaesthetized guinea pigs. The swallowing reflexes evoked by laryngeal citric acid challenges were abolished by recurrent laryngeal nerve (RLN) transection and mimicked by electrical stimulation of the central cut ends of an RLN. By contrast, the number of swallows evoked by upper airway/pharyngeal distensions was not significantly reduced by RLN transection but they were virtually abolished by superior laryngeal nerve transection. Laryngeal citric acid-evoked swallowing was mimicked by laryngeal capsaicin challenges, implicating transient receptor potential vanilloid 1 (TRPV1)-expressing laryngeal afferent nerves arising from the jugular ganglia. The swallowing evoked by citric acid and capsaicin and evoked by electrical stimulation of either the tracheal or the laryngeal mucosa occurred at stimulation intensities that were typically subthreshold for evoking cough in these animals. Swallowing evoked by airway afferent nerve stimulation also desensitized at a much slower rate than cough. We speculate that swallowing is an essential component of airway protection from aspiration associated with laryngeal and tracheal afferent nerve activation.
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Affiliation(s)
- Takanori Tsujimura
- B. J. Canning: Johns Hopkins Asthma and Allergy Center, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA.
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Mazzone SB, McGovern AE, Yang SK, Woo A, Phipps S, Ando A, Leech J, Farrell MJ. Sensorimotor circuitry involved in the higher brain control of coughing. COUGH 2013; 9:7. [PMID: 23497672 PMCID: PMC3602068 DOI: 10.1186/1745-9974-9-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 01/16/2013] [Indexed: 02/07/2023]
Abstract
There is an overwhelming body of evidence to support the existence of higher brain circuitries involved in the sensory detection of airways irritation and the motor control of coughing. The concept that cough is purely a reflex response to airways irritation is now superseded by the recognition that perception of an urge-to-cough and altered behavioral modification of coughing are key elements of cough disorders associated with airways disease. Understanding the pathways by which airway sensory nerves ascend into the brain and the patterns of neural activation associated with airways irritation will undoubtedly provide new insights into disordered coughing. This brief review aims to explore our current understanding of higher order cough networks by summarizing data from recent neuroanatomical and functional studies in animals and humans. We provide evidence for the existence of distinct higher order network components involved in the discrimination of signals arising from the airways and the motor control of coughing. The identification of these network components provides a blueprint for future research and the development of targeted managements for cough and the urge-to-cough.
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Affiliation(s)
- Stuart B Mazzone
- School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, QLD, 4072, Australia.
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Gavliakova S, Biringerova Z, Buday T, Brozmanova M, Calkovsky V, Poliacek I, Plevkova J. Antitussive effects of nasal thymol challenges in healthy volunteers. Respir Physiol Neurobiol 2013; 187:104-7. [PMID: 23438788 DOI: 10.1016/j.resp.2013.02.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 01/29/2013] [Accepted: 02/15/2013] [Indexed: 11/18/2022]
Abstract
Eighteen healthy volunteers with normal lung function were tested for cough. Before and after nasal administration of thymol (0.025 ml, 10(-3) M) into both nostrils, urge-to-cough, cough threshold, cumulative and total count of coughs per provocation were estimated during standardized and validated capsaicin cough challenge. Nasal thymol challenges induced pleasant olfactory sensation and in 6 out of the 18 subjects also mild cooling sensation. Cough threshold was not influenced when compared with intranasal saline and vehicle challenges (12.5 vs. 13.2 vs. 10.2 μM of capsaicin to induce two or more coughs (C2), respectively), but the total count of coughs after nasal thymol challenge was significantly lower than that obtained after saline or vehicle (19 vs. 20 vs. 14 coughs/provocation, respectively; p<0.05). Importantly, subjects did not report the urge to cough, which appeared to correspond to C2. We conclude that the modulation of cough by thymol is mostly of olfactory origin.
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Affiliation(s)
- S Gavliakova
- Department of Pathophysiology, Jessenius Faculty of Medicine, Comenius University, Martin, Slovakia.
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Abstract
The airways and lungs are innervated by both sympathetic and parasympathetic nerves. Cholinergic parasympathetic innervation is well conserved in the airways while the distribution of noncholinergic parasympathetic and adrenergic sympathetic nerves varies considerably amongst species. Autonomic nerve function is regulated primarily through reflexes initiated upon bronchopulmonary vagal afferent nerves. Central regulation of autonomic tone is poorly described but some key elements have been defined.
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Affiliation(s)
- Stuart B Mazzone
- School of Biomedical Sciences, University of Queensland, St Lucia, Queensland, Australia
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48
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Cough-related neurons in the nucleus tractus solitarius of decerebrate cats. Neuroscience 2012; 218:100-9. [DOI: 10.1016/j.neuroscience.2012.05.053] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 05/21/2012] [Accepted: 05/21/2012] [Indexed: 01/09/2023]
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Poussel M, Varechova S, Demoulin B, Chalon B, Schweitzer C, Marchal F, Chenuel B. Nasal stimulation by water down-regulates cough in anesthetized rabbits. Respir Physiol Neurobiol 2012; 183:20-5. [DOI: 10.1016/j.resp.2012.05.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 05/02/2012] [Accepted: 05/23/2012] [Indexed: 12/24/2022]
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Mutolo D, Bongianni F, Cinelli E, Giovannini MG, Pantaleo T. Suppression of the cough reflex by inhibition of ERK1/2 activation in the caudal nucleus tractus solitarii of the rabbit. Am J Physiol Regul Integr Comp Physiol 2012; 302:R976-83. [DOI: 10.1152/ajpregu.00629.2011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The caudal nucleus tractus solitarii (cNTS), the predominant site of termination of cough-related afferents, has been shown to be a site of action of some centrally acting antitussive agents. A role of ERK1/2 has been suggested in acute central processing of nociceptive inputs. Because pain and cough share similar features, we investigated whether ERK1/2 activation could also be involved in the central transduction of tussive inputs. For this purpose, we undertook the present research on pentobarbital sodium-anesthetized, spontaneously breathing rabbits by using microinjections (30–50 nl) of an inhibitor of ERK1/2 activation (U0126) into the cNTS. Bilateral microinjections of 25 mM U0126 caused rapid and reversible reductions in the cough responses induced by both mechanical and chemical (citric acid) stimulation of the tracheobronchial tree. In particular, the cough number and peak abdominal activity decreased. Bilateral microinjections of 50 mM U0126 completely suppressed the cough reflex without affecting the Breuer-Hering inflation reflex, the pulmonary chemoreflex, and the sneeze reflex. These U0126-induced effects were, to a large extent, reversible. Bilateral microinjections of 50 mM U0124, the inactive analog of U0126, at the same cNTS sites had no effect. This is the first study that provides evidence that ERK1/2 activation within the cNTS is required for the mediation of cough reflex responses in the anesthetized rabbit. These results suggest a role for ERK1/2 in the observed effects via nontranscriptional mechanisms, given the short time involved. They also may provide hints for the development of novel antitussive strategies.
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Affiliation(s)
| | | | | | - Maria Grazia Giovannini
- Dipartimento di Farmacologia Preclinica e Clinica, Università degli Studi di Firenze, Firenze, Italy
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