Pharmacological modulation of the late eosinophilia induced by antigen in actively sensitized rats.
The intrathoracic injection of ovalbumin (12 micrograms/cavity) into actively sensitized rats led to a long-lasting eosinophil recruitment, which appeared 24 h after stimulation. In this study, pharmacological antagonists were used in order to evaluate the potential involvement of arachidonic acid metabolites and PAF-acether in the pleural eosinophil accumulation by antigen. Administration of the cyclooxygenase inhibitor indomethacin (2 mg/kg, i.p.), 1 h before the antigen challenge, failed to modify the 24-hour eosinophilia. In contrast, the dual cyclooxygenase and lipoxygenase inhibitor BW 755C and the more selective inhibitor BW A4C (5 and 10 micrograms/cavity, i.t.), injected 1 h before the antigen, were effective. Similarly, the PAF-acether antagonists BN 52021 and WEB 2086 (20 mg/kg, i.p.) abrogated the eosinophil accumulation, which was also sensitive to the topical treatment with the glucocorticoid dexamethasone (5 and 10 micrograms/cavity). Our findings suggest that the antigen-induced eosinophil mobilization is dependent on lipoxygenase derivatives and PAF-acether, but not on prostaglandins.
e Silva
P M
PM
Depto de Fisiologia e Farmacodinâmica, Fundação Oswaldo Cruz, Manguinhos, Rio de Janeiro, Brasil.
Martins
M A
MA
Lima
M C
MC
Alves
A C
AC
Diaz
B L
BL
Cordeiro
R S
RS
D000818:Animals; D000941:Antigens / Q000276:immunology; D016718:Arachidonic Acid / Q000378:metabolism*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004802:Eosinophilia / Q000276:immunology* / Q000378:metabolism; D005260:Female; D007958:Leukocyte Count; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology; D008297:Male; D010047:Ovalbumin / Q000276:immunology; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors / Q000502:physiology*; D010998:Pleurisy / Q000276:immunology; D051381:Rats; D017208:Rats, Wistar
D000941:Antigens; D016861:Cyclooxygenase Inhibitors; D016859:Lipoxygenase Inhibitors; D010972:Platelet Activating Factor; D016718:Arachidonic Acid; D010047:Ovalbumin