Eosinophils and neutrophils modify arachidonic acid-induced relaxation of guinea-pig trachea.
The influence of inflammatory cells on airway reactivity was investigated on arachidonic acid-induced relaxations of guinea-pig trachea and on arachidonic acid metabolism in guinea-pig tracheal epithelial cells. The presence of either eosinophils or neutrophils (1.0 x 10(7) cells/ml), from bronchoalveolar lavage, decreased the tracheal relaxations induced by arachidonic acid (1.0-30 microM). The basal synthesis of prostaglandin E2 was increased in epithelial cells (from 176 +/- 36 to 7920 +/- 898 pg/ml), eosinophils (from 360 +/- 56 to 2693 +/- 686 pg/ml) and neutrophils (from 352 +/- 81 to 4400 +/- 272 pg/ml) following incubation with arachidonic acid (10 microM). The co-incubation of either eosinophils or neutrophils with epithelial cells, in the presence of arachidonic acid, decreased the synthesis of prostaglandin E2 (2600 +/- 686 and 4400 +/- 272 pg/ml respectively) but increased the synthesis of thromboxane B2 (from 60 +/- 6 to 11634 +/- 840 and 9282 +/- 485 pg/ml respectively). Similarly, when major basic protein-treated (100 micrograms/ml) epithelial cells were incubated with arachidonic acid, the prostaglandin E2 synthesis decreased (75%) but thromboxane B2 synthesis was unaffected. The results suggest that eosinophils and neutrophils may impair arachidonic acid metabolism in guinea-pig epithelium in favor of production of bronchoconstrictor prostanoids.
Prié
S
S
Department of Pharmacology, Faculty of Medicine, University of Sherbrooke, Canada.
Conroy
D M
DM
Gleich
G J
GJ
Sirois
P
P
D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology*; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D015232:Dinoprostone / Q000378:metabolism; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D004802:Eosinophilia / Q000473:pathology; D004804:Eosinophils / Q000502:physiology*; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009504:Neutrophils / Q000502:physiology*; D013929:Thromboxane B2 / Q000378:metabolism; D014132:Trachea / Q000187:drug effects*
D016718:Arachidonic Acid; D013929:Thromboxane B2; D015232:Dinoprostone