O3-induced mucosa-linked airway muscle hyperresponsiveness in the guinea pig
- Rush Univ., Chicago, IL (USA)
We investigated the effects of ozone exposure (3.0 ppm, 2 h) on the responsiveness of guinea pig airway muscle in vitro from animals developing bronchial hyperreactivity. Muscarinic reactivity in vivo was determined by measuring specific airway resistance (sRaw) in response to increasing concentrations of aerosolized acetylcholine (ACh) administered before and 30 min after exposure. Immediately after reactivity testing, multiple tracheal rings from ozone- and air-exposed animals were prepared and the contractile responses to increasing concentrations of substance P, ACh, or KCl were assessed in the presence of 10 microM indomethacin with or without 1 microM phosphoramidon, an inhibitor of neutral endopeptidase. Isometric force generation in vitro was measured on stimulation by cumulative concentrations of the agonists, and force generation (in g/cm2) was calculated after determination of muscle cross-sectional area. The smooth muscle of mucosa-intact airways from guinea pigs with ozone-induced bronchial hyper-reactivity proved to be hyperresponsive in vitro to substance P and ACh but not to KCl. Pretreatment with phosphoramidon abolished the increase in substance P responsiveness but had no effect on muscarinic hyperresponsiveness after ozone exposure. Furthermore, substance P responsiveness was not augmented in ozone-exposed airways in which the mucosa had been removed before testing in vitro. Likewise, muscarinic hyperresponsiveness was not present in ozone-exposed airways without mucosa. Our data indicate that airway smooth muscle responsiveness is increased in guinea pigs with ozone-induced bronchial hyperreactivity and suggest that this hyperresponsiveness may be linked to non-cyclooxygenase mucosa-derived factors.
- OSTI ID:
- 6364681
- Journal Information:
- Journal of Applied Physiology (1985); (USA), Journal Name: Journal of Applied Physiology (1985); (USA) Vol. 69:1; ISSN JAPHE; ISSN 8750-7587
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACETYLCHOLINE
AMINES
AMMONIUM COMPOUNDS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BIOLOGICAL EFFECTS
BRONCHI
DRUGS
ENZYME INHIBITORS
ESTERS
GUINEA PIGS
MAMMALS
MEMBRANES
MUCOUS MEMBRANES
NEUROREGULATORS
ORGANIC COMPOUNDS
OZONE
PARASYMPATHOMIMETICS
PEPTIDES
PROTEINS
QUATERNARY COMPOUNDS
RESPIRATORY SYSTEM
RODENTS
SENSITIVITY
TRACHEA
VERTEBRATES