Effects of ozone inhalation on reactivity to methacholine, epithelium-derived relaxing factor (EpDRF) release, and neurogenic responses in guinea-pig tracheal preparations in vitro.
Fedan-JS; Yuan-LX; Millecchia-LL; Hubbs-A; Orsini-LE; Frazer-DG
FASEB J 1996 Mar; 10(3):A168
We examined the effects of ozone (O3) inhalation on reactivity to methacholine (MCh) and release of EpDRF in guinea-pig airways using the isolated, perfused trachea (IPT), and the effects of O3 on electric field-stimulated (EFS) neurogenic responses of tracheal strips (TS). Animals were exposed to 3 ppm O3 or air for I hr; the trachea was removed immediately (0 hr), 2 hr, or 18 hr after exposure. Concentration-response curves for serosal (extraluminal, EL) and mucosal (intraluminal, IL.) addition of MCh, and EpDRF-induced relaxation induced by adding IL NaCl to MCh-contracted tracheas; were obtained from IPT. Frequency-related biphasic contractile/relaxant responses to EFS were obtained from resting and MCh-contracted TS. At 0 and 2 hr post-exposure, the sensitivity of IPT to IL-applied MCh was increased in the presence but not the absence of the epithelium; reactivity to EL MCh was not affected. EpDRF-induced relaxation responses were attenuated by O3-treatment. By 18 hr, reactivity to IL MCh and EpDRF-induced relaxation responses were not different from air-breathing control levels. O3-treatment had no effect on EFS-induced contractile or relaxant responses of TS: These results suggest that acute exposure to O3 induces a transient increase in mucosal permeability to MCh and. a decrease in EpDRF release. Both changes could contribute to airway hyperreactivity observed after O3-exposure. However, excitatory and inhibitory nerves are not are not affected by O3-exposure.
In-vitro-study; Chemical-hypersensitivity; Laboratory-animals; Laboratory-testing; Inhalation-studies; Breathing; Air-contamination; Pulmonary-system-disorders; Lung-disease; Lung-irritants; Nervous-system-disorders; Neurological-system; Chemical-hypersensitivity
Abstract; Conference/Symposia Proceedings
The FASEB Journal