Mast cell involvement in the rat paw oedema response to 1,8-cineole, the main constituent of eucalyptus and rosemary oils.
The present studies tested the ability of 1,8-cineole to produce inflammatory oedema in the hind paw of the rat and verified the possible involvement of mast cells in the response. Subplantar injection of 1,8-cineole (10, 15 and 20 microl/paw) induced a dose-dependent paw oedema which was apparent within 30 min. At higher doses the oedema effect was persistent, peaked at 2 h, and then decreased gradually but was still pronounced at 24 h post injection. In contrast, the oedema produced by mast cell degranulator compound 48/80 (10 microg/paw) had a rapid onset with a peak effect at the first hour, followed by a gradual decrease thereafter and at 24 h post injection it was almost absent. The oedema response to 20 microl 1,8-cineole was significantly inhibited throughout its time-course in rats pretreated with antihistaminic and antiserotonergic drugs such as diphenhydramine, methysergide and cyproheptadine or with ketotifen, a mast cell stabilizer. A more effective blockade of the oedema response was, however, observed in rats depleted of mast cell granules by systemic treatment with compound 48/80. Furthermore, 1,8-cineole was able to cause rat peritoneal mast cell degranulation (94%) in vitro, in a concentration as low as 0.3 microl/ml, which was almost comparable to that produced by 0.1 microg/ml of compound 48/80. The data provide evidence of a key role for the mast cell in 1,8-cineole-induced hind paw oedema in the rat.
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Departamento de Fisiologia e Farmacologia, Centro de Ciências da Saúde, Universidade Federal de Ceará, Fortaleza, CE, Brazil.
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D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D015550:Cell Degranulation / Q000187:drug effects; D003511:Cyclohexanols; D003907:Dexamethasone / Q000494:pharmacology; D004487:Edema / Q000188:drug therapy* / Q000473:pathology; D000077591:Eucalyptol; D005052:Eucalyptus; D006636:Histamine Release / Q000187:drug effects; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D008407:Mast Cells / Q000187:drug effects*; D008610:Menthol / Q000031:analogs & derivatives* / Q000494:pharmacology; D039821:Monoterpenes; D009822:Oils, Volatile / Q000494:pharmacology*; D010946:Plants, Medicinal / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000378:metabolism; D013373:Substance P / Q000378:metabolism; D013729:Terpenes; D013997:Time Factors; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
D000893:Anti-Inflammatory Agents; D000894:Anti-Inflammatory Agents, Non-Steroidal; D003511:Cyclohexanols; D039821:Monoterpenes; D009822:Oils, Volatile; D013729:Terpenes; D008610:Menthol; D012701:Serotonin; D013373:Substance P; D003189:p-Methoxy-N-methylphenethylamine; D003907:Dexamethasone; D000077591:Eucalyptol; D007213:Indomethacin