Ozone-induced stimulation of pulmonary sympathetic fibers: a protective mechanism against edema.
Tropospheric ozone exerts well-described toxic effects on the respiratory tract. Less documented, by contrast, is the ability of ozone to induce protective mechanisms against agents that are toxic to the lungs. In particular, interactions between ozone and the sympathetic nervous system have never been considered. Using a model of permeability edema in isolated perfused rabbit lungs, we report here that, immediately after exposure of rabbits to 0.4 ppm ozone for 4 hr, the pulmonary microvascular responses to acetylcholine and substance P are completely blocked. Several lines of evidence, including partial inhibition of the ozone-induced protective effect by several drugs (alpha2- and beta-adrenergic antagonists, neuropeptide Y antagonist, guanethidine), measured levels of released catecholamines in blood and urine and the in vitro response of isolated lungs exposed to 0.4 ppm ozone all seem to suggest that ozone can stimulate pulmonary adrenergic fibers and induce the local release of catecholamines and neuropeptide Y, this resulting in transient protection against pulmonary edema. We also showed that, 48 hr after the exposure, ozone increased the baseline microvascular permeability and the response to low concentrations of acetylcholine.
Delaunois
A
A
Faculty of Veterinary Medicine, University of Liège, Boulevard de Colonster B41, Liège, B-4000, Belgium.
Segura
P
P
Dessy-Doizé
C
C
Ansay
M
M
Montaño
L M
LM
Vargas
M H
MH
Gustin
P
P
D000109:Acetylcholine / Q000633:toxicity; D018663:Adrenergic Agents / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D002199:Capillary Permeability / Q000187:drug effects; D002395:Catecholamines / Q000097:blood / Q000652:urine; D004305:Dose-Response Relationship, Drug; D005260:Female; D006145:Guanethidine / Q000494:pharmacology; D008168:Lung / Q000098:blood supply / Q000187:drug effects* / Q000294:innervation; D008297:Male; D008854:Microscopy, Electron; D009412:Nerve Fibers / Q000187:drug effects* / Q000473:pathology; D009478:Neuropeptide Y / Q000037:antagonists & inhibitors; D010126:Ozone / Q000633:toxicity*; D011654:Pulmonary Edema / Q000139:chemically induced* / Q000517:prevention & control; D011669:Pulmonary Wedge Pressure / Q000187:drug effects; D011817:Rabbits; D013373:Substance P / Q000633:toxicity; D013997:Time Factors
D018663:Adrenergic Agents; D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D002395:Catecholamines; D009478:Neuropeptide Y; D013373:Substance P; D010126:Ozone; D000109:Acetylcholine; D006145:Guanethidine