title: Air pollutants and cough.
abstract: Epidemiological studies have shown that exposure to air pollution is associated with respiratory symptoms and decreases in lung function. This paper reviews recent literature showing that exposure to particulate matter, irritant gases, environmental tobacco smoke (ETS), mixed pollutants, and molds is associated with an increase in cough and wheeze. Some pollutants, like particulate matter and mixed pollutants, appear to increase cough at least as much as wheeze. Others, like irritant gases, appear to increase wheeze more than cough. For ETS, exposure during childhood is associated with cough and wheeze in adulthood, suggesting that the pollutant permanently alters some important aspect of the lungs, immune system or nervous system. We have shown in animal studies that pollutants change the neural control of airways and cough. Second hand smoke (SHS) exposure lengthened stimulated apnoea, increased the number of stimulated coughs, and augmented the degree of stimulated bronchoconstriction. The mechanisms included enhanced reactivity of the peripheral sensory neurones and second-order neurones in the nucleus tractus solitarius (NTS). NTS effects were due to a substance P mechanism at least in part. Ozone and allergen increased the intrinsic excitability of second-order neurones in the NTS. The animal studies suggest that the cough and wheeze experienced by humans exposed to pollutants may involve plasticity in the nervous system.
authors.affiliation: Department of Pediatrics, University of California, Davis, 2516 Stockton Blvd., Sacramento, CA 95817, USA. jesse.joad@ucdmc.ucdavis.edu
authors.forename: Jesse P
authors.initials: JP
authors.lastname: Joad
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Sekizawa
authors.forename: Chao-Yin
authors.initials: CY
authors.lastname: Chen
authors.forename: Ann C
authors.initials: AC
authors.lastname: Bonham
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000009:adverse effects*; D000397:Air Pollution / Q000009:adverse effects*; D000818:Animals; D002648:Child; D003371:Cough / Q000139:chemically induced* / Q000453:epidemiology; D004195:Disease Models, Animal; D006801:Humans; D019570:Inhalation Exposure / Q000009:adverse effects; D009434:Neural Pathways / Q000503:physiopathology; D012120:Respiration Disorders / Q000209:etiology; D012135:Respiratory Sounds / Q000187:drug effects; D017552:Solitary Nucleus / Q000503:physiopathology; D014028:Tobacco Smoke Pollution / Q000009:adverse effects
chemical_list: D000393:Air Pollutants; D014028:Tobacco Smoke Pollution