Tj. Mcgovern et al., OZONE-INDUCED ALTERATION IN BETA-ADRENERGIC PHARMACOLOGICAL MODULATION OF PULMONARY MACROPHAGES, Toxicology and applied pharmacology, 137(1), 1996, pp. 51-56
Ozone is a ubiquitous air pollutant which can affect numerous function
s of the respiratory system. However, previous work has not provided a
ny information concerning its ability to modulate pharmacological rece
ptors of pulmonary macrophages. This study examined, using a chemilumi
nescence assay, the beta-adrenergic modulation of pulmonary macrophage
s harvested from rabbits exposed for 3 hr/day for 5 days to 0.1, 0.3 o
r 0.6 ppm ozone (O-3) or to 3 hr/day for 20 days to 0.1 or 0.3 ppm. Re
ceptor activity was monitored using release of reactive oxygen species
(ROS) following administration to the cells of the beta(2)-receptor a
gonist, isoproterenol. An O-3-exposure concentration-dependent respons
e was observed for isoproterenol efficacy following 5-day exposures, i
n that 0.1 ppm O-3 induced a significant enhancement of beta-adrenergi
c inhibition of ROS production, 0.3 ppm ozone produced no significant
change from control, and 0.6 ppm decreased inhibition. No significant
effects on beta-adrenergic modulation were noted following the 20-day
exposures. The results of this study suggest that short-term repeated
exposures to O-3 are capable of inducing alterations in the pharmacolo
gical functioning of pulmonary macrophages, while longer term exposure
s may result in adaptation. Alterations in receptor function have impl
ications in terms of pulmonary defense and disease. (C) 1996 Academic
Press, Inc.