ISSN:
1432-1912
Schlagwort(e):
Anaphylaxis
;
Eicosapentaenoic acid
;
Lung parenchymal strips
;
Leukotriene
;
Prostaglandin
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Medizin
Notizen:
Summary Exogenous eicosapentaenoic acid (EPA, 16.5 μmol/l or 33 μmol/l) inhibited dose-dependently the anaphylactic contractile response of guinea-pig lung parenchymal strips suspended in an organ bath. As determined by radioimmunoassay, EPA inhibited in a dose-dependent manner the anaphylactic release of the cyclooxygenase products thromboxane (TX) B2 and 6-keto-prostaglandin (PG) F1α but simultaneously enhanced the release of sulfidopeptide (SP)-leukotrienes (LT). Indomethacin (2.8 μmol/1) abolished the release of cyclooxygenase products but potentiated the release of SP-LT. However, indomethacin treatment did not affect the inhibitory action of EPA on the contractile response of the anaphylactic lung strips. The lipoxygenase inhibitor, esculetin (50 μmol/1), inhibited the release of SP-LT and also that of cyclooxygenase products of polyunsaturated fatty acid metabolism. The combination of esculetin and EPA resulted in enhanced inhibition of the anaphylactic contractile response as compared to EPA alone. By reversed phase high pressure liquid chromatography (HPLC), SP-LT from anaphylactic lung parenchymal strips was shown to consist of LTD4 and LTE4. EPA-pretreated lung strips released upon immunologic challenge additional immunoreactivity comigrating with authentic LTC4, LTC5, LTD5 and LTE5. While anaphylactic control strips also released LTB4, in the bath fluid of EPA-treated strips, an additional immunoreactive compound migrating with the retention time of LTB5 was observed. In non-sensitized guinea-pig lung parenchymal strips EPA inhibited the myotropic activity of exogenous mediators such as histamine (9 gmol/1), LTC4 (16 nmol/1) and the TX mimetic U 46619 (28.4 nmol/1), an effect which was neither affected by indomethacin (2.8 gmol/1) nor by the lipoxygenase inhibitor nordihydroguaiaretic acid (NDGA, 10 gmol/1). We conclude that exogenous EPA is able to inhibit the myotropic activity of endogenous and exogenous mediators of the anaphylactic reaction in the guinea-pig lung parenchymal strip. Thus, EPA itself and not a metabolite of the cyclooxygenase or lipoxygenase pathway of polyunsaturated fatty acid metabolism seems to act as a functional antagonist to various anaphylactic mediators in lung tissue.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00166982
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