title: Acid-sensing by airway afferent nerves.
abstract: Inhalation of acid aerosol or aspiration of acid solution evokes a stimulatory effect on airway C-fiber and Aδ afferents, which in turn causes airway irritation and triggers an array of defense reflex responses (e.g., cough, reflex bronchoconstriction, etc.). Tissue acidosis can also occur locally in the respiratory tract as a result of ischemia or inflammation, such as in the airways of asthmatic patients during exacerbation. The action of proton on the airway sensory neurons is generated by activation of two different current species: a transient (rapidly activating and inactivating) current mediated through the acid-sensing ion channels, and a slowly activating and sustained current mediated through the transient receptor potential vanilloid type 1 (TRPV1) receptor. In view of the recent findings that the expression and/or sensitivity of TRPV1 are up-regulated in the airway sensory nerves during chronic inflammatory reaction, the proton-evoked irritant effects on these nerves may play an important part in the manifestation of various symptoms associated with airway inflammatory diseases.
authors.affiliation: Department of Physiology, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY 40536-0298, USA. lylee@uky.edu
authors.forename: Lu-Yuan
authors.initials: LY
authors.lastname: Lee
authors.forename: Qihai
authors.initials: Q
authors.lastname: Gu
authors.forename: Fadi
authors.initials: F
authors.lastname: Xu
authors.forename: Ju-Lun
authors.initials: JL
authors.lastname: Hong
mesh_terms: D000138:Acidosis / Q000139:chemically induced; D000143:Acids / Q000009:adverse effects*; D000336:Aerosols; D000818:Animals; D003371:Cough / Q000139:chemically induced* / Q000503:physiopathology; D006801:Humans; D007249:Inflammation / Q000139:chemically induced / Q000503:physiopathology; D019570:Inhalation Exposure / Q000009:adverse effects; D009413:Nerve Fibers, Myelinated / Q000378:metabolism; D036421:Nerve Fibers, Unmyelinated / Q000378:metabolism; D009475:Neurons, Afferent / Q000187:drug effects / Q000378:metabolism*; D012137:Respiratory System / Q000187:drug effects / Q000503:physiopathology; D012140:Respiratory Tract Diseases / Q000139:chemically induced / Q000503:physiopathology; D050916:TRPV Cation Channels / Q000378:metabolism
chemical_list: D000143:Acids; D000336:Aerosols; D050916:TRPV Cation Channels; C494484:TRPV1 receptor
keywords: Acid-sensing ion channels (ASICs); Airway irritation; Cough; Inflammation; Proton; Transient receptor potential vanilloid type 1 receptor (TRPV1)