Ozone activates airway nerves via the selective stimulation of TRPA1 ion channels

J Physiol. 2010 Feb 1;588(Pt 3):423-33. doi: 10.1113/jphysiol.2009.183301. Epub 2009 Dec 14.

Abstract

Inhalation of ozone is a major health risk in industrialized nations. Ozone can impair lung function and induce respiratory symptoms through sensory neural-mediated pathways, yet the specific interaction of ozone with airway sensory nerves has yet to be elucidated. Here we demonstrate, using a vagally innervated ex vivo tracheal-lung mouse preparation, that ozone selectively and directly evokes action potential discharge in a subset of nociceptive bronchopulmonary nerves, namely slow conducting C-fibres. Sensitivity to ozone correlated with the transient receptor potential (TRP) A1 agonist, cinnamaldehyde, with ozone having no effect on cinnamaldehyde-insensitive fibres. C-fibre responses to ozone were abolished by ruthenium red (TRP inhibitor). Ozone also stimulated a subset of nociceptive sensory neurones isolated from vagal ganglia of wild-type mice, but failed to activate neurones isolated from transient receptor potential ankyrin 1 (TRPA1) knockout mice. Ozone activated HEK293 cells transfected with TRPA1, but failed to activate non-transfected HEK293 or HEK293 transfected with the capsaicin-sensitive transient receptor potential vanilloid 1 (TRPV1) channel. Thus, ozone is not an indiscriminate neuronal activator, but rather it potently and selectively activates a subset of airway C-fibres by directly stimulating TRPA1.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrolein / analogs & derivatives
  • Acrolein / pharmacology
  • Action Potentials / drug effects
  • Action Potentials / physiology
  • Animals
  • Calcium Channels / drug effects*
  • Calcium Channels / genetics
  • Calcium Channels / physiology
  • Cell Line
  • Evoked Potentials / drug effects
  • Evoked Potentials / physiology
  • Humans
  • Mice
  • Mice, Knockout
  • Models, Animal
  • Nerve Fibers, Unmyelinated / physiology
  • Nerve Tissue Proteins / drug effects*
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / physiology
  • Ozone / pharmacology*
  • Respiratory System / innervation*
  • Ruthenium Red / pharmacology
  • Sensory Receptor Cells / drug effects*
  • Sensory Receptor Cells / physiology
  • TRPA1 Cation Channel
  • Transient Receptor Potential Channels / drug effects*
  • Transient Receptor Potential Channels / genetics
  • Transient Receptor Potential Channels / physiology

Substances

  • Calcium Channels
  • Nerve Tissue Proteins
  • TRPA1 Cation Channel
  • TRPA1 protein, human
  • Transient Receptor Potential Channels
  • Trpa1 protein, mouse
  • Ruthenium Red
  • Ozone
  • Acrolein
  • cinnamaldehyde