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Pan S, Karey E, Nieves-Cintron M, Chen YJ, Hwang SH, Hammock BD, Pinkerton KE, Chen CY. Effects of chronic secondhand smoke exposure on cardiovascular regulation and the role of soluble epoxide hydrolase in mice. Front Physiol 2023; 14:1185744. [PMID: 37362438 PMCID: PMC10285070 DOI: 10.3389/fphys.2023.1185744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 05/30/2023] [Indexed: 06/28/2023] Open
Abstract
Background: Secondhand smoke (SHS) is a significant risk factor for cardiovascular morbidity and mortality with an estimated 80% of SHS-related deaths attributed to cardiovascular causes. Public health measures and smoking bans have been successful both in reducing SHS exposure and improving cardiovascular outcomes in non-smokers. Soluble epoxide hydrolase (sEH) inhibitors have been shown to attenuate tobacco exposure-induced lung inflammatory responses, making them a promising target for mitigating SHS exposure-induced cardiovascular outcomes. Objectives: The objectives of this study were to determine 1) effects of environmentally relevant SHS exposure on cardiac autonomic function and blood pressure (BP) regulation and 2) whether prophylactic administration of an sEH inhibitor (TPPU) can reduce the adverse cardiovascular effects of SHS exposure. Methods: Male C57BL/6J mice (11 weeks old) implanted with BP/electrocardiogram (ECG) telemetry devices were exposed to filtered air or 3 mg/m3 of SHS (6 hr/d, 5 d/wk) for 12 weeks, followed by 4 weeks of recovery in filtered air. Some mice received TPPU in drinking water (15 mg/L) throughout SHS exposure. BP, heart rate (HR), HR variability (HRV), baroreflex sensitivity (BRS), and BP variability were determined monthly. Results: SHS exposure significantly decreased 1) short-term HRV by ∼20% (p < 0.05) within 4 weeks; 2) overall HRV with maximum effect at 12 weeks (-15%, p < 0.05); 3) pulse pressure (-8%, p < 0.05) as early as week 4; and 4) BRS with maximum effect at 12 weeks (-11%, p < 0.05). Four weeks of recovery following 12 weeks of SHS ameliorated all SHS-induced cardiovascular detriments. Importantly, mice exposed to TPPU in drinking water during SHS-related exposure were protected from SHS cardiovascular consequences. Discussion: The data suggest that 1) environmental relevant SHS exposure significantly alters cardiac autonomic function and BP regulation; 2) cardiovascular consequences from SHS can be reversed by discontinuing SHS exposure; and 3) inhibiting sEH can prevent SHS-induced cardiovascular consequences.
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Affiliation(s)
- Shiyue Pan
- Department of Pharmacology, University of California Davis, Davis, CA, United States
| | - Emma Karey
- Department of Pharmacology, University of California Davis, Davis, CA, United States
| | | | - Yi-Je Chen
- Department of Pharmacology, University of California Davis, Davis, CA, United States
| | - Sung Hee Hwang
- Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California Davis, Davis, CA, United States
| | - Bruce D. Hammock
- Department of Entomology and Nematology, UC Davis Comprehensive Cancer Center, University of California Davis, Davis, CA, United States
| | - Kent E. Pinkerton
- Center for Health and the Environment, University of California Davis, Davis, CA, United States
| | - Chao-Yin Chen
- Department of Pharmacology, University of California Davis, Davis, CA, United States
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Lavorini F, Bernacchi G, Fumagalli C, Noale M, Maggi S, Mutolo D, Cinelli E, Fontana GA. Somatically evoked cough responses help to identify patients with difficult-to-treat chronic cough: a six-month observational cohort study. EClinicalMedicine 2023; 57:101869. [PMID: 36874394 PMCID: PMC9975680 DOI: 10.1016/j.eclinm.2023.101869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 01/23/2023] [Accepted: 01/30/2023] [Indexed: 02/22/2023] Open
Abstract
BACKGROUND Recently we identified in patients with chronic cough a sensory dysregulation via which the urge-to-cough (UTC) or coughing are evoked mechanically from "somatic points for cough" (SPCs) in the neck and upper trunk. We investigated the prevalence and the clinical relevance of SPCs in an unselected population of patients with chronic cough. METHODS From 2018 to 2021, symptoms of 317 consecutive patients with chronic cough (233 females) were collected on four visits (V1-V4) 2 months apart at the Cough Clinic of the University Hospital in Florence (I). Participants rated the disturbance caused by the cough (0-9 modified Borg Scale). We attempted to evoke coughing and/or UTC using mechanical actions in all participants who were subsequently categorised as responsive (somatic point for cough positive, SPC+) or unresponsive (SPC-) to these actions. An association was established between chronic cough and its commonest causes; treatments were administered accordingly. FINDINGS 169 patients were SPC+ and had a higher baseline cough score (p < 0.01). In most of the patients, the treatments reduced (p < 0.01) cough-associated symptoms. All patients reported a decrease (p < 0.01) in cough score at V2 (from 5.70 ± 1.4 to 3.43 ± 1.9 and from 5.01 ± 1.5 to 2.74 ± 1.7 for SPC+ and SPC- patients respectively). However, whilst in SPC- patients the cough score continued to decrease indicating virtually complete cough disappearance at V4 (0.97 ± 0.8), in SPC+ patients this variable remained close to V2 values during the entire follow-up. INTERPRETATION Our study suggests that the assessment of SPCs may identify patients whose cough is unresponsive and are eligible for specific treatments. FUNDING This work was funded by an unrestricted grant from Merck (Italy).
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Affiliation(s)
- Federico Lavorini
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
- Corresponding author. Department of Experimental and Clinical Medicine, Largo Brambilla 3, Florence 50134, Italy.
| | - Guja Bernacchi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Carlo Fumagalli
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Marianna Noale
- Italian National Research Council (CNR), Neuroscience Institute, Aging Branch, Padua, Italy
| | - Stefania Maggi
- Italian National Research Council (CNR), Neuroscience Institute, Aging Branch, Padua, Italy
| | - Donatella Mutolo
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Eliana Cinelli
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Giovanni A. Fontana
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
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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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Sun J, Pan S, Karey E, Chen YJ, Pinkerton KE, Wilson CG, Chen CY. Secondhand Smoke Decreased Excitability and Altered Action Potential Characteristics of Cardiac Vagal Neurons in Mice. Front Physiol 2021; 12:727000. [PMID: 34630146 PMCID: PMC8498211 DOI: 10.3389/fphys.2021.727000] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 08/30/2021] [Indexed: 11/13/2022] Open
Abstract
Background: Secondhand smoke (SHS), a major indoor pollutant, is a significant risk factor for cardiovascular morbidity and mortality including arrhythmias and sudden cardiac death. Exposure to SHS can produce autonomic imbalance, as evidenced by reduced heart rate variability (HRV)—a clinical metric of cardiac vagal regulation. Currently, the mechanisms through which SHS changes the vagal preganglionic neuronal inputs to the heart to produce this remains unknown. Objectives: To characterize the effect of SHS on both the excitability and action potential (AP) characteristics of anatomically identified cardiac vagal neurons (CVNs) in the nucleus ambiguus and examine whether SHS alters small conductance calcium-activated potassium (SK) channel activity of these CVNs. Methods: Adult male mice were exposed to four weeks of filtered air or SHS (3 mg/m3) 6 h/day, 5 day/week. Using patch-clamp recordings on identified CVNs in brainstem slices, we determined neuronal excitability and AP characteristics with depolarizing step- and ramp-current injections. Results: Four weeks of SHS exposure reduced spiking responses to depolarizing current injections and increased AP voltage threshold in CVNs. Perfusion with apamin (20 nM) magnified these SHS-induced effects, suggesting reduced SK channel activity may serve to minimize the SHS-induced decreases in CVNs excitability. Medium afterhyperpolarization (a measurement of SK channel activity) was smaller in the SHS group, further supporting a lower SK channel activity. AP amplitude, rise rate, fast afterhyperpolarization amplitude (a measurement of voltage-gated channel activity), and decay rate were higher in the SHS group at membrane voltages more positive to 0 mV, suggesting altered inactivation properties of voltage-dependent channels underlying APs. Discussion: SHS exposure reduced neuronal excitability of CVNs with compensatory attenuation of SK channel activity and altered AP characteristics. Neuroplasticity of CVNs could blunt regulatory cardiac vagal signaling and contribute to the cardiovascular consequences associated with SHS exposure, including reduced HRV.
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Affiliation(s)
- Junqing Sun
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Shiyue Pan
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Emma Karey
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Yi-Je Chen
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Kent E Pinkerton
- Department of Pediatrics and Center for Health and the Environment, University of California, Davis, Davis, CA, United States
| | - Christopher G Wilson
- Department of Basic Sciences, Loma Linda University, Loma Linda, CA, United States
| | - Chao-Yin Chen
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
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Chen Z, Chen F, Fang Z, Zhao H, Zhan C, Li C, He Y, Huang C, Long L, Lai K. Glial activation and inflammation in the NTS in a rat model after exposure to diesel exhaust particles. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2021; 83:103584. [PMID: 33460804 DOI: 10.1016/j.etap.2021.103584] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 01/03/2021] [Accepted: 01/11/2021] [Indexed: 06/12/2023]
Abstract
Airway pollution can affect the central nervous system, but whether this causes glial activation and inflammation in the nucleus of solitary tract (NTS) remains unclear. We used a rat model with exposure to diesel exhaust particulate matter (DEP) at 200 μg/m3 (low exposure) and 1000 μg/m3 (high exposure) for 14 days. Activation of microglia and astrocytes in the NTS was assessed using Iba-1 and glial fibrillary acidic protein (GFAP) staining. The expression of neurotrophic factors including brain-derived neurotrophic factor (BDNF), glial-derived neurotrophic factor (GDNF), and nerve growth factor (NGF) in the NTS were evaluated by immunofluorescence. Changes in the intracellular structure of NTS neurons were observed via electron microscopy. Inflammatory cytokines and oxidant stress levels in the medulla were also measured. Exposure to DEP can cause NTS inflammation as well as airway inflammation, especially in the H-exposure group. We showed that the numbers of microglia and astrocytes in the NTS, as well as NGF expression in the NTS, were significantly higher in both exposure groups than in controls, but BDNF or GDNF expression was not detected. Exposure to DEP induced ultrastructural changes in NTS neurons as reflected by endoplasmic reticulum dilation, ribosomal loss, mitochondrial vacuolization, and a sparse myelin sheath. Medulla inflammation and an imbalance of oxidants and antioxidants also resulted from exposure to DEP. The H-exposure group showed an imbalance of oxidants and antioxidants with decreased levels of SOD and GSH and increased levels of MDA and ROS compared to the control group (both p < 0.01) in the medulla. Inflammatory cytokines (IL-1β, IL-6, and TNF-α) were also significantly increased in the H-exposure group. Fourteen days of exposure to DEP can affect the NTS neurons in rat. Glial activation and inflammation may play important roles in the response of the NTS to DEP.
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Affiliation(s)
- Zhe Chen
- Department of Pulmonary and Critical Care Medicine, Laboratory of Immunology, Affiliated Kunshan Hospital of Jiangsu University, Suzhou, Jiangsu, 215300, China; State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, 510120, China
| | - Fagui Chen
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, 510120, China; Department of Pulmonary and Critical Care Medicine, Shantou Central Hospital, Affiliated Shantou Hospital of Sun Yat-sen University, Shantou, Guangdong, 515031, China
| | - Zhangfu Fang
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, 510120, China
| | - Huasi Zhao
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, 510120, China; Department of Pulmonary and Critical Care Medicine, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, 450052, China
| | - Chen Zhan
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, 510120, China
| | - Chenhui Li
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, 510120, China
| | - Yaowei He
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, 510120, China
| | - Chuqin Huang
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, 510120, China
| | - Li Long
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, 510120, China
| | - Kefang Lai
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, 510120, China.
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Pincus AB, Fryer AD, Jacoby DB. Mini review: Neural mechanisms underlying airway hyperresponsiveness. Neurosci Lett 2021; 751:135795. [PMID: 33667601 DOI: 10.1016/j.neulet.2021.135795] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 02/22/2021] [Accepted: 02/23/2021] [Indexed: 12/25/2022]
Abstract
Neural changes underly hyperresponsiveness in asthma and other airway diseases. Afferent sensory nerves, nerves within the brainstem, and efferent parasympathetic nerves all contribute to airway hyperresponsiveness. Inflammation plays a critical role in these nerve changes. Chronic inflammation and pre-natal exposures lead to increased airway innervation and structural changes. Acute inflammation leads to shifts in neurotransmitter expression of afferent nerves and dysfunction of M2 muscarinic receptors on efferent nerve endings. Eosinophils and macrophages drive these changes through release of inflammatory mediators. Novel tools, including optogenetics, two photon microscopy, and optical clearing and whole mount microscopy, allow for improved studies of the structure and function of airway nerves and airway hyperresponsiveness.
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Affiliation(s)
- Alexandra B Pincus
- Oregon Health and Science University, 3181 SW Sam Jackson Park Road, BRB 440, Portland, OR, 97239, USA.
| | - Allison D Fryer
- Oregon Health and Science University, 3181 SW Sam Jackson Park Road, BRB 440, Portland, OR, 97239, USA
| | - David B Jacoby
- Oregon Health and Science University, 3181 SW Sam Jackson Park Road, BRB 440, Portland, OR, 97239, USA
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Badri H, Smith JA. Emerging targets for cough therapies; NK1 receptor antagonists. Pulm Pharmacol Ther 2019; 59:101853. [PMID: 31622673 DOI: 10.1016/j.pupt.2019.101853] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 10/11/2019] [Accepted: 10/13/2019] [Indexed: 01/31/2023]
Abstract
Cough is mediated by vagal afferent fibres innervating the larynx and proximal airways. Pre-clinical studies suggest that vagal C fibres produce Substance P, one of the tachykinin family of neuropeptides, which has been shown to enhance cough via the neurokinin-1 (NK-1) receptor and studies in animal models have also shown that NK-1 antagonists are effective at blocking induced cough. In the past, tachykinin receptor antagonists have yielded disappointing results in treating asthma and cough, however most of the activity of the agents tested was restricted to the peripheral nervous system and also the outcomes measures evaluating cough not optimal. More recently a small proof of concept study has suggest that aprepitant, an NK-1 antagonist licensed for the prevention of chemotherapy induced nausea and vomiting, might have beneficial effects on cough frequency in patients with lung cancer. In this review we investigate the current evidence for the anti-tussive effect of these therapies and the clinical trials in progress.
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Affiliation(s)
- Huda Badri
- North Manchester General Hospital, Manchester, UK; Division of Infection, Immunity and Respiratory Medicine, The University of Manchester, Manchester, UK
| | - Jaclyn A Smith
- North Manchester General Hospital, Manchester, UK; Manchester University NHS Foundation Trust, UK.
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Getsy PM, Mayer CA, MacFarlane PM, Jacono FJ, Wilson CG. Acute lung injury in neonatal rats causes postsynaptic depression in nucleus tractus solitarii second-order neurons. Respir Physiol Neurobiol 2019; 269:103250. [PMID: 31352011 DOI: 10.1016/j.resp.2019.103250] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 06/14/2019] [Accepted: 07/02/2019] [Indexed: 12/28/2022]
Abstract
Acute Lung Injury (ALI) alters pulmonary reflex responses, in part due to changes in modulation within the lung and airway neuronal control networks. We hypothesized that synaptic efficacy of nucleus tractus solitarii (nTS) neurons, receiving input from lung, airway, and other viscerosensory afferent fibers, would decrease following ALI. Sprague Dawley neonatal rats (postnatal days 9-11) were given intratracheal installations of saline or bleomycin (a well-characterized model that reproduces the pattern of ALI) and then, one week later, in vitro slices were prepared for whole-cell and perforated whole-cell patch-clamp experiments (postnatal days 16-21). In preparations from ALI rats, 2nd-order nTS neurons had significantly decreased amplitudes of both spontaneous and miniature excitatory postsynaptic currents (sEPSCs and mEPSCs), compared to saline controls. Rise and decay times of sEPSCs were slower in whole-cell recordings from ALI animals. Similarly, the amplitude of tractus solitarii evoked EPSCs (TS-eEPSCs) were significantly lower in 2nd-order nTS neurons from ALI rats. Overall these results suggest the presence of postsynaptic depression at TS-nTS synapses receiving lung, airway, and other viscerosensory afferent tractus solitarii input after bleomycin-induced ALI.
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Affiliation(s)
- Paulina M Getsy
- Department of Physiology and Biophysics, CWRU School of Medicine, Cleveland, OH, 44106, United States; Department of Pediatrics, Rainbow Babies & Children's Hospital, CWRU School of Medicine, Cleveland, OH, 44106, United States
| | - Catherine A Mayer
- Department of Pediatrics, Rainbow Babies & Children's Hospital, CWRU School of Medicine, Cleveland, OH, 44106, United States
| | - Peter M MacFarlane
- Department of Pediatrics, Rainbow Babies & Children's Hospital, CWRU School of Medicine, Cleveland, OH, 44106, United States
| | - Frank J Jacono
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, CWRU School of Medicine, Cleveland, OH, 44106, United States; Division of Pulmonary, Critical Care and Sleep Medicine, Louis Stokes VA Medical Center, Cleveland, OH, 44106, United States
| | - Christopher G Wilson
- Department of Pediatrics and Lawrence D. Long, MD Center for Perinatal Biology Loma Linda University Loma Linda, CA, United States.
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Cough: New Pharmacology. THE JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY-IN PRACTICE 2019; 7:1731-1738. [DOI: 10.1016/j.jaip.2019.04.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 04/02/2019] [Indexed: 02/07/2023]
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10
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Abstract
Cough is a physiological defense reflex for protecting the airways from aspiration and irritation. Thus, roles of environmental triggers are postulated in the pathogenesis of chronic cough. There are several lines of epidemiological evidence demonstrating the relationships between environmental irritant and pollutant exposure and chronic cough. However, positive findings from cross-sectional studies just reflect the protective nature of cough but may not properly address the true impact of environmental triggers. If harmful inhalation is repeated, cough may be seen as chronic but indeed is protective in nature. Therefore, long-term residual outcomes would be the key for understanding the effects of environmental triggers on chronic cough. The present review aims to summarize the associations between chronic cough and environmental pollutants or irritant exposure, with a focus on the long-term residual effects of (1) chronic persistent exposure and (2) acute high-intensity exposure on chronic cough, and also to examine (3) whether childhood irritant/pollutant exposure may increase the risk of chronic cough in adulthood.
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Affiliation(s)
- Eun-Jung Jo
- Department of Internal Medicine, Pusan National University Hospital, Busan, Korea
| | - Woo-Jung Song
- Airway Sensation and Cough Research Laboratory, Department of Allergy and Clinical Immunology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
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Wang Z, Wang L, Tapa S, Pinkerton KE, Chen CY, Ripplinger CM. Exposure to Secondhand Smoke and Arrhythmogenic Cardiac Alternans in a Mouse Model. ENVIRONMENTAL HEALTH PERSPECTIVES 2018; 126:127001. [PMID: 30675795 PMCID: PMC6371715 DOI: 10.1289/ehp3664] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 11/02/2018] [Accepted: 11/07/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND Epidemiological evidence suggests that a majority of deaths attributed to secondhand smoke (SHS) exposure are cardiovascular related. However, to our knowledge, the impact of SHS on cardiac electrophysiology, [Formula: see text] handling, and arrhythmia risk has not been studied. OBJECTIVES The purpose of this study was to investigate the impact of an environmentally relevant concentration of SHS on cardiac electrophysiology and indicators of arrhythmia. METHODS Male C57BL/6 mice were exposed to SHS [total suspended particles (THS): [Formula: see text], nicotine: [Formula: see text], carbon monoxide: [Formula: see text], or filtered air (FA) for 4, 8, or 12 wk ([Formula: see text]]. Hearts were excised and Langendorff perfused for dual optical mapping with voltage- and [Formula: see text]-sensitive dyes. RESULTS At slow pacing rates, SHS exposure did not alter baseline electrophysiological parameters. With increasing pacing frequency, action potential duration (APD), and intracellular [Formula: see text] alternans magnitude progressively increased in all groups. At 4 and 8 wk, there were no statistical differences in APD or [Formula: see text] alternans magnitude between SHS and FA groups. At 12 wk, both APD and [Formula: see text] alternans magnitude were significantly increased in the SHS compared to FA group ([Formula: see text]). SHS exposure did not impact the time constant of [Formula: see text] transient decay ([Formula: see text]) at any exposure time point. At 12 wk exposure, the recovery of [Formula: see text] transient amplitude with premature stimuli was slightly (but nonsignificantly) delayed in SHS compared to FA hearts, suggesting that [Formula: see text] release via ryanodine receptors may be impaired. CONCLUSIONS In male mice, chronic exposure to SHS at levels relevant to social situations in humans increased their susceptibility to cardiac alternans, a known precursor to ventricular arrhythmia. https://doi.org/10.1289/EHP3664.
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Affiliation(s)
- Zhen Wang
- Department of Pharmacology, University of California, Davis, Davis, California, USA
| | - Lianguo Wang
- Department of Pharmacology, University of California, Davis, Davis, California, USA
| | - Srinivas Tapa
- Department of Pharmacology, University of California, Davis, Davis, California, USA
| | - Kent E Pinkerton
- Center for Health and the Environment, University of California, Davis, Davis, California, USA
| | - Chao-Yin Chen
- Department of Pharmacology, University of California, Davis, Davis, California, USA
| | - Crystal M Ripplinger
- Department of Pharmacology, University of California, Davis, Davis, California, USA
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12
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McGovern AE, Short KR, Kywe Moe AA, Mazzone SB. Translational review: Neuroimmune mechanisms in cough and emerging therapeutic targets. J Allergy Clin Immunol 2018; 142:1392-1402. [DOI: 10.1016/j.jaci.2018.09.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 09/12/2018] [Accepted: 09/18/2018] [Indexed: 12/27/2022]
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13
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Litvin DG, Dick TE, Smith CB, Jacono FJ. Lung-injury depresses glutamatergic synaptic transmission in the nucleus tractus solitarii via discrete age-dependent mechanisms in neonatal rats. Brain Behav Immun 2018; 70:398-422. [PMID: 29601943 PMCID: PMC6075724 DOI: 10.1016/j.bbi.2018.03.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 03/20/2018] [Accepted: 03/26/2018] [Indexed: 12/26/2022] Open
Abstract
Transition periods (TPs) are brief stages in CNS development where neural circuits can exhibit heightened vulnerability to pathologic conditions such as injury or infection. This susceptibility is due in part to specialized mechanisms of synaptic plasticity, which may become activated by inflammatory mediators released under pathologic conditions. Thus, we hypothesized that the immune response to lung injury (LI) mediated synaptic changes through plasticity-like mechanisms that depended on whether LI occurred just before or after a TP. We studied the impact of LI on brainstem 2nd-order viscerosensory neurons located in the nucleus tractus solitarii (nTS) during a TP for respiratory control spanning (postnatal day (P) 11-15). We injured the lungs of Sprague-Dawley rats by intratracheal instillation of Bleomycin (or saline) just before (P9-11) or after (P17-19) the TP. A week later, we prepared horizontal slices of the medulla and recorded spontaneous and evoked excitatory postsynaptic currents (sEPSCs/eEPSCs) in vitro from neurons in the nTS that received monosynaptic glutamatergic input from the tractus solitarii (TS). In rats injured before the TP (pre-TP), neurons exhibited blunted sEPSCs and TS-eEPSCs compared to controls. The decreased TS-eEPSCs were mediated by differences in postsynaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic-acid receptors (AMPAR). Specifically, compared to controls, LI rats had more Ca2+-impermeable AMPARs (CI-AMPARs) as indicated by: 1) the absence of current-rectification, 2) decreased sensitivity to polyamine, 1-Naphthyl-acetyl-spermine-trihydrochloride (NASPM) and 3) augmented immunoreactive staining for the CI-AMPAR GluA2. Thus, pre-TP-LI acts postsynaptically to blunt glutamatergic transmission. The neuroimmune response to pre-TP-LI included microglia hyper-ramification throughout the nTS. Daily intraperitoneal administration of minocycline, an inhibitor of microglial/macrophage function prevented hyper-ramification and abolished the pre-TP-LI evoked synaptic changes. In contrast, rat-pups injured after the TP (post-TP) exhibited microglia hypo-ramification in the nTS and had increased sEPSC amplitudes/frequencies, and decreased TS-eEPSC amplitudes compared to controls. These synaptic changes were not associated with changes in CI-AMPARs, and instead involved greater TS-evoked use-dependent depression (reduced paired pulse ratio), which is a hallmark of presynaptic plasticity. Thus we conclude that LI regulates the efficacy of TS → nTS synapses through discrete plasticity-like mechanisms that are immune-mediated and depend on whether the injury occurs before or after the TP for respiratory control.
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Affiliation(s)
- David G Litvin
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Division of Pulmonary, Critical Care and Sleep Medicine, Louis Stokes VA Medical Center, Cleveland, OH 44106, United States
| | - Thomas E Dick
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States
| | - Corey B Smith
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States
| | - Frank J Jacono
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States; Division of Pulmonary, Critical Care and Sleep Medicine, Louis Stokes VA Medical Center, Cleveland, OH 44106, United States.
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Driessen AK, McGovern AE, Narula M, Yang SK, Keller JA, Farrell MJ, Mazzone SB. Central mechanisms of airway sensation and cough hypersensitivity. Pulm Pharmacol Ther 2017; 47:9-15. [DOI: 10.1016/j.pupt.2017.01.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 01/25/2017] [Indexed: 12/11/2022]
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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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Song WJ, Morice AH. Cough Hypersensitivity Syndrome: A Few More Steps Forward. ALLERGY, ASTHMA & IMMUNOLOGY RESEARCH 2017; 9:394-402. [PMID: 28677352 PMCID: PMC5500693 DOI: 10.4168/aair.2017.9.5.394] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 03/07/2017] [Accepted: 03/09/2017] [Indexed: 01/17/2023]
Abstract
Cough reflex is a vital protective mechanism against aspiration, but when dysregulated, it can become hypersensitive. In fact, chronic cough is a significant medical problem with a high degree of morbidity. Recently, a unifying paradigm of cough hypersensitivity syndrome has been proposed. It represents a clinical entity in which chronic cough is a major presenting problem, regardless of the underlying condition. Although it remains a theoretical construct, emerging evidence suggests that aberrant neurophysiology is the common etiology of this syndrome. Recent success in randomized clinical trials using a P2X3 receptor antagonist is the first major advance in the therapeutics of cough in the past 30 years; it at last provides a strategy for treating intractable cough as well as an invaluable tool for dissecting the mechanism underpinning cough hypersensitivity. Additionally, several cough measurement tools have been validated for use and will help assess the clinical relevance of cough in various underlying conditions. Along with this paradigm shift, our understanding of cough mechanisms has improved during the past decades, allowing us to continue to take more steps forward in the future.
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Affiliation(s)
- Woo Jung Song
- Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Alyn H Morice
- Centre for Cardiovascular and Metabolic Research, University of Hull, Hull York Medical School, Castle Hill Hospital, Cottingham, East Yorkshire, United Kingdom.
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Demoulin-Alexikova S, Plevkova J, Mazurova L, Zatko T, Alexik M, Hanacek J, Tatar M. Impact of Air Pollution on Age and Gender Related Increase in Cough Reflex Sensitivity of Healthy Children in Slovakia. Front Physiol 2016; 7:54. [PMID: 26941651 PMCID: PMC4763033 DOI: 10.3389/fphys.2016.00054] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 02/04/2016] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Numerous studies show higher cough reflex sensitivity (CRS) and cough outcomes in children compared to adults and in females compared to males. Despite close link that exists between cough and environment the potential influence of environmental air pollution on age- and gender -related differences in cough has not been studied yet. PURPOSE The purpose of our study was to analyse whether the effects of exposure to environmental tobacco smoke (ETS) from parental smoking and PM10 from living in urban area are implied in age- and gender-related differences in cough outcomes of healthy, non-asthmatic children. Assessment of CRS using capsaicin and incidence of dry and wet cough was performed in 290 children (mean age 13.3 ± 2.6 years (138 females/152 males). RESULTS CRS was significantly higher in girls exposed to ETS [22.3 μmol/l (9.8-50.2 μmol/l)] compared to not exposed girls [79.9 μmol/l (56.4-112.2 μmol/l), p = 0.02] as well as compared to exposed boys [121.4 μmol/l (58.2-253.1 μmol/l), p = 0.01]. Incidence of dry cough lasting more than 3 weeks was significantly higher in exposed compared to not exposed girls. CRS was significantly higher in school-aged girls living in urban area [22.0 μmol/l (10.6-45.6 μmol/l)] compared to school-aged girls living in rural area [215.9 μmol/l (87.3-533.4 μmol/l); p = 0.003], as well as compared to teenage girls living in urban area [108.8 μmol/l (68.7-172.9 μmol/l); p = 0.007]. No CRS differences were found between urban and rural boys when controlled for age group. No CRS differences were found between school-aged and teenage boys when controlled for living area. CONCLUSIONS Our results have shown that the effect of ETS on CRS was gender specific, linked to female gender and the effect of PM10 on CRS was both gender and age specific, related to female gender and school-age. We suggest that age and gender related differences in incidence of cough and CRS might be, at least partially, ascribed to the effect of environmental pollutants. The role of age and gender in the effect of air pollution on cough strongly suggest some interplay of development with biological and behavioral factors.
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Affiliation(s)
- Silvia Demoulin-Alexikova
- Department of Pathophysiology, Jessenius Faculty of Medicine in Martin, Comenius University in BratislavaBratislava, Slovakia; Service d'Explorations Fonctionnelles Pédiatriques, Hôpital d'Enfants, Centre Hospitalier Universitaire de NancyVandœuvre-lès-Nancy, France; EA 3450 DevAH - Laboratoire de Physiologie, Faculté de Médecine, Université de LorraineVandœuvre-lès-Nancy, France
| | - Jana Plevkova
- Department of Pathophysiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava Bratislava, Slovakia
| | - Lenka Mazurova
- Department of Pathophysiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava Bratislava, Slovakia
| | - Tomas Zatko
- Department of Pathophysiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava Bratislava, Slovakia
| | - Mikulas Alexik
- Department of Ophthalmology, Faculty Hospital of Žilina Žilina, Slovakia
| | - Jan Hanacek
- Department of Pathophysiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava Bratislava, Slovakia
| | - Milos Tatar
- Department of Pathophysiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava Bratislava, Slovakia
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Song WJ, Chang YS. Cough hypersensitivity as a neuro-immune interaction. Clin Transl Allergy 2015; 5:24. [PMID: 26180629 PMCID: PMC4503292 DOI: 10.1186/s13601-015-0069-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 06/09/2015] [Indexed: 12/31/2022] Open
Abstract
Cough is an intrinsic protective reflex. However, chronic cough affects a considerable proportion of general population and has a major impact on quality of life. A recent paradigm shift to ‘cough hypersensitivity syndrome’ suggests that chronic cough arises from hypersensitivity of the airway sensory nerves. As cough reflex is determined by interaction of the nervous system with immune system, persistent dysregulation of one or both of these systems may lead to chronic cough hypersensitivity. Here we review the current evidence for the neuro-immune interactions that underlie cough hypersensitivity and discuss future therapeutic strategies.
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Affiliation(s)
- Woo-Jung Song
- Department of Internal Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Chongno-gu, Seoul, 110-744 South Korea ; Institute of Allergy and Clinical Immunology, Seoul National University Medical Research Center, Seoul, South Korea
| | - Yoon-Seok Chang
- Department of Internal Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Chongno-gu, Seoul, 110-744 South Korea ; Institute of Allergy and Clinical Immunology, Seoul National University Medical Research Center, Seoul, South Korea ; Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do South Korea
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Slotkin TA, Skavicus S, Card J, Levin ED, Seidler FJ. Amelioration strategies fail to prevent tobacco smoke effects on neurodifferentiation: Nicotinic receptor blockade, antioxidants, methyl donors. Toxicology 2015; 333:63-75. [PMID: 25891525 DOI: 10.1016/j.tox.2015.04.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 03/12/2015] [Accepted: 04/14/2015] [Indexed: 12/12/2022]
Abstract
Tobacco smoke exposure is associated with neurodevelopmental disorders. We used neuronotypic PC12 cells to evaluate the mechanisms by which tobacco smoke extract (TSE) affects neurodifferentiation. In undifferentiated cells, TSE impaired DNA synthesis and cell numbers to a much greater extent than nicotine alone; TSE also impaired cell viability to a small extent. In differentiating cells, TSE enhanced cell growth at the expense of cell numbers and promoted emergence of the dopaminergic phenotype. Nicotinic receptor blockade with mecamylamine was ineffective in preventing the adverse effects of TSE and actually enhanced the effect of TSE on the dopamine phenotype. A mixture of antioxidants (vitamin C, vitamin E, N-acetyl-l-cysteine) provided partial protection against cell loss but also promoted loss of the cholinergic phenotype in response to TSE. Notably, the antioxidants themselves altered neurodifferentiation, reducing cell numbers and promoting the cholinergic phenotype at the expense of the dopaminergic phenotype, an effect that was most prominent for N-acetyl-l-cysteine. Treatment with methyl donors (vitamin B12, folic acid, choline) had no protectant effect and actually enhanced the cell loss evoked by TSE; they did have a minor, synergistic interaction with antioxidants protecting against TSE effects on growth. Thus, components of tobacco smoke perturb neurodifferentiation through mechanisms that cannot be attributed to the individual effects of nicotine, oxidative stress or interference with one-carbon metabolism. Consequently, attempted amelioration strategies may be partially effective at best, or, as seen here, can actually aggravate injury by interfering with normal developmental signals and/or by sensitizing cells to TSE effects on neurodifferentiation.
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Affiliation(s)
- Theodore A Slotkin
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
| | - Samantha Skavicus
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Jennifer Card
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - Frederic J Seidler
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
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20
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Middlekauff HR, Park J, Moheimani RS. Adverse effects of cigarette and noncigarette smoke exposure on the autonomic nervous system: mechanisms and implications for cardiovascular risk. J Am Coll Cardiol 2015; 64:1740-50. [PMID: 25323263 DOI: 10.1016/j.jacc.2014.06.1201] [Citation(s) in RCA: 149] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Revised: 06/24/2014] [Accepted: 06/30/2014] [Indexed: 11/27/2022]
Abstract
This review summarizes the detrimental effects of cigarette and noncigarette emission exposure on autonomic function, with particular emphasis on the mechanisms of acute and chronic modulation of the sympathetic nervous system. We propose that the nicotine and fine particulate matter in tobacco smoke lead to increased sympathetic nerve activity, which becomes persistent via a positive feedback loop between sympathetic nerve activity and reactive oxidative species. Furthermore, we propose that baroreflex suppression of sympathetic activation is attenuated in habitual smokers; that is, the baroreflex plays a permissive role, allowing sympathoexcitation to occur without restraint in the setting of increased pressor response. This model is also applicable to other nontobacco cigarette emission exposures (e.g., marijuana, waterpipes [hookahs], electronic cigarettes, and even air pollution). Fortunately, emerging data suggest that baroreflex sensitivity and autonomic function may be restored after smoking cessation, providing further evidence in support of the health benefits of smoking cessation.
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Affiliation(s)
- Holly R Middlekauff
- Division of Cardiology, Department of Medicine, University of California-Los Angeles, Los Angeles, California.
| | - Jeanie Park
- Renal Division, Department of Medicine, Emory University School of Medicine, and the Veterans Affairs Medical Center, Atlanta, Georgia
| | - Roya S Moheimani
- David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, California
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21
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Khalid S, Murdoch R, Newlands A, Smart K, Kelsall A, Holt K, Dockry R, Woodcock A, Smith JA. Transient receptor potential vanilloid 1 (TRPV1) antagonism in patients with refractory chronic cough: a double-blind randomized controlled trial. J Allergy Clin Immunol 2014; 134:56-62. [PMID: 24666696 DOI: 10.1016/j.jaci.2014.01.038] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Revised: 12/29/2013] [Accepted: 01/16/2014] [Indexed: 12/27/2022]
Abstract
BACKGROUND Inhalation of capsaicin, the extract of hot chili peppers, induces coughing in both animals and human subjects through activation of transient receptor potential vanilloid 1 (TRPV1) on airway sensory nerves. Therefore the TRPV1 receptor is an attractive target for the development of antitussive agents. OBJECTIVE We sought to assess the antitussive effect of TRPV1 antagonism in patients with refractory chronic cough. METHODS Twenty-one subjects with refractory chronic cough (>8 weeks) attending a specialist clinic were recruited to a randomized, double-blind, placebo-controlled crossover trial assessing a TRPV1 antagonist (SB-705498). Cough reflex sensitivity to capsaicin (concentration of capsaicin inducing at least 5 coughs) and 24-hour cough frequency were coprimary end points assessed after a single dose of SB-705498 (600 mg) and matched placebo. Cough severity and urge to cough were reported on visual analog scales, and cough-specific quality of life data were also collected. RESULTS Treatment with SB-705498 produced a significant improvement in cough reflex sensitivity to capsaicin at 2 hours and a borderline significant improvement at 24 hours compared with placebo (adjusted mean difference of +1.3 doubling doses at 2 hours [95% CI, +0.3 to +2.2; P = .0049] and +0.7 doubling doses at 24 hours [95% CI, +0.0 to +1.5; P = .0259]). However, 24-hour objective cough frequency was not improved compared with placebo. Patient-reported cough severity, urge to cough, and cough-specific quality of life similarly suggested no effect of SB-705498. CONCLUSION This study raises important questions about both the role of TRVP1-mediated mechanisms in patients with refractory chronic cough and also the predictive value of capsaicin challenge testing in the assessment of novel antitussive agents.
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Affiliation(s)
- Saifudin Khalid
- Centre for Respiratory and Allergy, University of Manchester, University Hospital of South Manchester, Manchester, United Kingdom
| | | | | | | | - Angela Kelsall
- Centre for Respiratory and Allergy, University of Manchester, University Hospital of South Manchester, Manchester, United Kingdom
| | - Kimberley Holt
- Centre for Respiratory and Allergy, University of Manchester, University Hospital of South Manchester, Manchester, United Kingdom
| | - Rachel Dockry
- Centre for Respiratory and Allergy, University of Manchester, University Hospital of South Manchester, Manchester, United Kingdom
| | - Ashley Woodcock
- Centre for Respiratory and Allergy, University of Manchester, University Hospital of South Manchester, Manchester, United Kingdom
| | - Jaclyn A Smith
- Centre for Respiratory and Allergy, University of Manchester, University Hospital of South Manchester, Manchester, United Kingdom.
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Slotkin TA, Card J, Stadler A, Levin ED, Seidler FJ. Effects of tobacco smoke on PC12 cell neurodifferentiation are distinct from those of nicotine or benzo[a]pyrene. Neurotoxicol Teratol 2014; 43:19-24. [PMID: 24642111 DOI: 10.1016/j.ntt.2014.03.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 02/28/2014] [Accepted: 03/01/2014] [Indexed: 01/31/2023]
Abstract
Although nicotine accounts for a great deal of the neurodevelopmental damage associated with maternal smoking or second-hand exposure, tobacco smoke contains thousands of potentially neurotoxic compounds. We used PC12 cells, a standard in vitro model of neurodifferentiation, to compare tobacco smoke extract (TSE) to nicotine, matching TSE exposure (with its inherent nicotine content) to parallel concentrations of nicotine, or to benzo[a]pyrene, a tobacco combustion product. TSE promoted the transition from cell replication to differentiation, resulting in fewer, but larger cells with greater neurite extension. TSE also biased differentiation into the dopaminergic versus the cholinergic phenotype, evidenced by an increase in tyrosine hydroxylase activity but not choline acetyltransferase. Nicotine likewise promoted differentiation at the expense of cell numbers, but its effect on growth and neurite extension was smaller than that of TSE; furthermore, nicotine did not promote the dopaminergic phenotype. Benzo[a]pyrene had effects opposite to those of TSE, retarding neurodifferentiation, which resulted in higher cell numbers, smaller cells, reduced neurite information, and impaired emergence of both dopaminergic and cholinergic phenotypes. Our studies show that the complex mixture of compounds in tobacco smoke exerts direct effects on neural cell replication and differentiation that resemble those of nicotine in some ways but not others, and most importantly, that are greater in magnitude than can be accounted for from just the nicotine content of TSE. Thus, fetal tobacco smoke exposure, including lower levels associated with second-hand smoke, could be more injurious than would be anticipated from measured levels of nicotine or its metabolites.
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Affiliation(s)
- Theodore A Slotkin
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA.
| | - Jennifer Card
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ashley Stadler
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
| | - Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - Frederic J Seidler
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
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El-Hashim AZ, Jaffal SM, Al-Rashidi FT, Luqmani YA, Akhtar S. Nerve growth factor enhances cough via a central mechanism of action. Pharmacol Res 2013; 74:68-77. [DOI: 10.1016/j.phrs.2013.05.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 05/22/2013] [Accepted: 05/23/2013] [Indexed: 12/21/2022]
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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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Singla S, Ding Z, Mehta JL. Arterial wall-axon reflex: a potential player in atherosclerosis. Ther Adv Cardiovasc Dis 2012; 6:181-4. [PMID: 23045192 DOI: 10.1177/1753944712460421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Sekizawa SI, Horowitz JM, Horwitz BA, Chen CY. Realignment of signal processing within a sensory brainstem nucleus as brain temperature declines in the Syrian hamster, a hibernating species. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2012; 198:267-82. [PMID: 22262373 DOI: 10.1007/s00359-011-0706-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2011] [Revised: 11/28/2011] [Accepted: 12/13/2011] [Indexed: 01/24/2023]
Abstract
Crucial for survival, the central nervous system must reliably process sensory information over all stages of a hibernation bout to ensure homeostatic regulation is maintained and well-matched to dramatically altered behavioral states. Comparing neural responses in the nucleus tractus solitarius of rats and euthermic Syrian hamsters, we tested the hypothesis that hamster neurons have adaptations sustaining signal processing while conserving energy. Using patch-clamp techniques, we classified second-order neurons in the nucleus as rapid-onset or delayed-onset spiking phenotypes based on their spiking onset to a depolarizing pulse (following a -80 mV prepulse). As temperature decreased from 33 to 15°C, the excitability of all neurons decreased. However, hamster rapid-onset spiking neurons had the highest spiking response and shortest action potential width at every temperature, while hamster delayed-onset spiking neurons had the most negative resting membrane potential. The frequency of spontaneous excitatory postsynaptic currents in both phenotypes decreased as temperature decreased, yet the amplitudes of tractus solitarius stimulation-evoked currents were greater in hamsters than in rats regardless of phenotype and temperature. Changes were significant (P < 0.05), supporting our hypothesis by showing that, as temperature falls, rapid-onset neurons contribute more to signal processing but less to energy conservation than do delayed-onset neurons.
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Affiliation(s)
- Shin-Ichi Sekizawa
- Department of Pharmacology, University of California Davis, GBSF 3617, 451 Health Sciences Drive, Davis, CA 95616, USA
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Chang AB. Bronchitis. KENDIG & CHERNICKÂS DISORDERS OF THE RESPIRATORY TRACT IN CHILDREN 2012. [PMCID: PMC7152459 DOI: 10.1016/b978-1-4377-1984-0.00026-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Mazzone SB, McGovern AE, Cole LJ, Farrell MJ. Central nervous system control of cough: pharmacological implications. Curr Opin Pharmacol 2011; 11:265-71. [DOI: 10.1016/j.coph.2011.05.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 05/19/2011] [Indexed: 02/06/2023]
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Sekizawa SI, Joad JP, Pinkerton KE, Bonham AC. Distinct tachykinin NK(1) receptor function in primate nucleus tractus solitarius neurons is dysregulated after second-hand tobacco smoke exposure. Br J Pharmacol 2011; 163:782-91. [PMID: 21323902 PMCID: PMC3111680 DOI: 10.1111/j.1476-5381.2011.01271.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 12/14/2010] [Accepted: 01/10/2011] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Second-hand tobacco smoke (SHS) exposure in children increases the risk of asthma and sudden infant death syndrome. Epidemiological and experimental data have suggested SHS can alter neuroplasticity in the CNS, associated with substance P. We hypothesized that exposure to SHS in young primates changed the effect of substance P on the plasticity of neurons in the nucleus tractus solitarius (NTS), where airway sensory information is first processed in the CNS. EXPERIMENTAL APPROACH Thirteen-month-old rhesus monkeys were exposed to filtered air (FA, n= 5) or SHS (n= 5) for >6 months from 50 days of their fetal age. Whole-cell patch-clamp recordings were performed on NTS neurons in brainstem slices from these animals to record the intrinsic cell excitability in the absence or presence of the NK(1) receptor antagonist, SR140333 (3 µM). KEY RESULTS Neurons were electrophysiologically classified based on their spiking onset from a hyperpolarized membrane potential into two phenotypes: rapid-onset spiking (RS) and delayed-onset spiking (DS) types. In RS neurons, SR140333 reduced the spiking response, similarly in both FA- and SHS-exposed animals. In DS neurons, SR140333 almost abolished the spiking response in FA-exposed animals, but had no effect in SHS-exposed animals. CONCLUSIONS AND IMPLICATIONS The contribution of NK(1) receptors to cell excitability depended on firing phenotype of primate NTS neurons and was disrupted by SHS exposure, specifically in DS neurons. Our findings reveal a novel NK(1) receptor function in the primate brainstem and support the hypothesis that chronic exposure to SHS in children causes tachykinin-related neuroplastic changes in the CNS.
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Sekizawa SI, Joad JP, Pinkerton KE, Bonham AC. Secondhand smoke exposure alters K+ channel function and intrinsic cell excitability in a subset of second-order airway neurons in the nucleus tractus solitarius of young guinea pigs. Eur J Neurosci 2010; 31:673-84. [PMID: 20384811 DOI: 10.1111/j.1460-9568.2010.07093.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Extended exposure to secondhand smoke (SHS) in infants and young children increases the incidence of cough, wheeze, airway hyper-reactivity and the prevalence and earlier onset of asthma. The adverse effects may result from environmentally-induced plasticity in the neural network regulating cough and airway function. Using whole-cell patch-clamp recordings in brainstem slices containing anatomically identified second-order lung afferent neurons in the nucleus tractus solitarius (NTS), we determined the effects of extended SHS exposure in young guinea pigs for a duration equivalent to human childhood on the intrinsic excitability of NTS neurons. SHS exposure resulted in marked decreases in the intrinsic excitability of a subset of lung afferent second-order NTS neurons. The neurons exhibited a decreased spiking capacity, prolonged action potential duration, reduced afterhyperpolarization, decrease in peak and steady-state outward currents, and membrane depolarization. SHS exposure effects were mimicked by low concentrations of the K+ channel blockers 4-aminopyridine and/or tetraethyl ammonium. The data suggest that SHS exposure downregulates K+ channel function in a subset of NTS neurons, resulting in reduced cell excitability. The changes may help to explain the exaggerated neural reflex responses in children exposed to SHS.
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Affiliation(s)
- Shin-Ichi Sekizawa
- Department of Pharmacology, School of Medicine, GBSF Room 3617, 451 Health Sciences Drive, University of California Davis, Davis, CA 95616-0635, USA
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Canning BJ, Mori N. An essential component to brainstem cough gating identified in anesthetized guinea pigs. FASEB J 2010; 24:3916-26. [PMID: 20581226 DOI: 10.1096/fj.09-151068] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Coughing protects and clears the airways and lungs of inhaled irritants, particulates, pathogens, and accumulated secretions. An initial urge to cough, and an almost binary output suggests gating mechanisms that encode and modulate this defensive reflex. Whether this "gate" has a physical location for the physiological barrier it poses to cough is unknown. Here we describe a critical component to cough gating, the central terminations of the cough receptors. A novel microinjection strategy defined coordinates for microinjection of glutamate receptor antagonists that nearly abolished cough evoked from the trachea and larynx in anesthetized guinea pigs while having no effect on basal respiratory rate and little or no effect on reflexes attributed to activating other afferent nerve subtypes. Comparable microinjections in adjacent brainstem locations (0.5-2 mm distal) were without effect on coughing. Subsequent transganglionic and dual tracing studies confirmed that the central terminations of the cough receptors and their primary relay neurons are found bilaterally within nucleus tractus solitarius (nTS), lateral to the commissural subnucleus and perhaps in the medial subnuclei. These synapses possess the physiological characteristics of a cough gate. Their localization should facilitate more mechanistic studies of the encoding and gating of cough.
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Affiliation(s)
- Brendan J Canning
- Johns Hopkins Asthma and Allergy Center, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA.
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Xia L, Leiter J, Bartlett D. Gestational nicotine exposure exaggerates hyperthermic enhancement of laryngeal chemoreflex in rat pups. Respir Physiol Neurobiol 2010; 171:17-21. [DOI: 10.1016/j.resp.2010.01.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 12/22/2009] [Accepted: 01/15/2010] [Indexed: 11/25/2022]
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Bolser DC, Jefferson SC, Rose MJ, Tester NJ, Reier PJ, Fuller DD, Davenport PW, Howland DR. Recovery of airway protective behaviors after spinal cord injury. Respir Physiol Neurobiol 2009; 169:150-6. [PMID: 19635591 PMCID: PMC2789652 DOI: 10.1016/j.resp.2009.07.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 07/13/2009] [Accepted: 07/20/2009] [Indexed: 10/20/2022]
Abstract
Pulmonary morbidity is high following spinal cord injury and is due, in part, to impairment of airway protective behaviors. These airway protective behaviors include augmented breaths, the cough reflex, and expiration reflexes. Functional recovery of these behaviors has been reported after spinal cord injury. In humans, evidence for functional recovery is restricted to alterations in motor strategy and changes in the frequency of occurrence of these behaviors. In animal models, compensatory alterations in motor strategy have been identified. Crossed descending respiratory motor pathways at the thoracic spinal cord levels exist that are composed of crossed premotor axons, local circuit interneurons, and propriospinal neurons. These pathways can collectively form a substrate that supports maintenance and/or recovery of function, especially after asymmetric spinal cord injury. Local sprouting of premotor axons in the thoracic spinal cord also can occur following chronic spinal cord injury. These mechanisms may contribute to functional resiliency of the cough reflex that has been observed following chronic spinal cord injury in the cat.
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Affiliation(s)
- Donald C Bolser
- Dept. of Physiological Sciences, College of Veterinary Medicine, University of Florida, United States.
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Effect of smoking on cough reflex sensitivity: basic and preclinical studies. Lung 2009; 188 Suppl 1:S23-7. [PMID: 19844757 DOI: 10.1007/s00408-009-9191-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Accepted: 09/24/2009] [Indexed: 12/27/2022]
Abstract
In healthy nonsmokers, inhalation of one single puff of cigarette smoke immediately evoked airway irritation and cough, which were either prevented or markedly diminished after premedication with hexamethonium. Single-fiber recording experiments performed in anesthetized animals showed that both C fibers and rapidly adapting receptors in the lungs and airways were stimulated by inhalation of one breath of cigarette smoke. Application of nicotine evoked an inward current and triggered depolarization and action potentials in a concentration-dependent manner in a subset of isolated vagal pulmonary sensory neurons. Taken together, these studies showed that activation of the nicotinic acetylcholine receptors expressed on airway sensory nerves is mainly responsible for the acute airway irritation and cough reflex elicited by inhaled cigarette smoke. Chronic exposure to cigarette smoke consistently induces enhanced cough responses to various inhaled tussive agents in guinea pigs. The increased cough sensitivity involves primarily an elevated sensitivity of cough sensors and also an enhanced synaptic transmission of their afferent signals at the nucleus tractus solitaries. In contrast to the observations in animal studies, both enhanced and diminished cough sensitivities to tussive agents have been reported in chronic smokers. This discrepancy is probably related to the history of chronic smoking of the individual smokers and the severity of existing airway inflammation and dysfunction. Furthermore, several other factors possibly contributing to the regulation of cough receptor sensitivity in chronic smokers should also be considered.
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Pham H, Bonham AC, Pinkerton KE, Chen CY. Central neuroplasticity and decreased heart rate variability after particulate matter exposure in mice. ENVIRONMENTAL HEALTH PERSPECTIVES 2009; 117:1448-53. [PMID: 19750112 PMCID: PMC2737024 DOI: 10.1289/ehp.0900674] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Accepted: 05/20/2009] [Indexed: 05/02/2023]
Abstract
BACKGROUND Epidemiologic studies show that exposure to fine particulate matter [aerodynamic diameter < or = 2.5 microm (PM(2.5))] increases the total daily cardiovascular mortality. Impaired cardiac autonomic function, which manifests as reduced heart rate variability (HRV), may be one of the underlying causes. However, the cellular mechanism(s) by which PM(2.5) exposure induces decreased HRV is not known. OBJECTIVES We tested the hypothesis that exposure to PM(2.5) impairs HRV by decreasing the excitability of the cardiac vagal neurons in the nucleus ambiguus. We also determined the effect of iron on PM-exposure-induced decrease in HRV. METHODS We measured 24-hr HRV in time domains from electrocardiogram telemetry recordings obtained in conscious, freely moving mice after 3 days of exposure to PM(2.5) in the form of soot only or iron-soot. In parallel studies, we determined the intrinsic properties of identified cardiac vagal neurons, retrogradely labeled with a fluorescent dye applied to the sinoatrial node. RESULTS Soot-only exposure decreased short-term HRV (root mean square of successive difference). With the addition of iron, all HRV parameters were significantly reduced. In nonexposed mice, vagal blockade significantly reduced all HRV parameters, suggesting that HRV is, in part, under vagal regulation in mice. Iron-soot exposure had no significant effect on resting membrane potential but decreased spiking responses of the identified cardiac vagal neurons to depolarizations (p < 0.05). The decreased spiking response was accompanied with a higher minimal depolarizing current required to evoke spikes and a lower peak discharge frequency. CONCLUSIONS The data suggest that PM-induced neuroplasticity of cardiac vagal neurons may be one mechanism contributing to the cardiovascular consequences associated with PM(2.5) exposure seen in humans.
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Affiliation(s)
| | | | - Kent E. Pinkerton
- Center for Health and the Environment, University of California at Davis, Davis, California, USA
| | - Chao-Yin Chen
- Department of Pharmacology and
- Address correspondence to C.-Y. Chen, Department of Pharmacology, University of California, Davis, GBSF 3510C, One Shields Ave., Davis, CA 95616 USA. Telephone: (530) 754-6458. Fax: (530) 752-7710. E-mail:
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