Release of cysteinyl-leukotrienes is of minor importance in PAF induced reduction of perfusion rate in the gastric vascular bed.

In the isolated rat gastric vascular bed, PAF dosedependently decreased the perfusion rate and increased the formation of cysteinyl-leukotrienes, TXB2 and 6-keto F1 alpha (measured by radioimmunoassay). Inhibition of cysteinyl-leukotrienes biosynthesis by NDGA or antagonism of cysteinyl-leukotrienes receptors by FPL 55712 did not prevent the PAF induced reduction of gastric flow. Inhibition of cyclooxygenase by indomethacin aggravated the PFA-induced reduction of flow, however in the later period of experiment. BN 552021 - the PAF receptor antagonist, completely prevented the release of cysteinyl-leukotrienes, TXB2 and 6-keto F1 alpha into perfusate, however was not able to prevent completely the PAF induced reduction of gastric flow. We conclude that the reduction of flow observed after PAF administration seems to be related rather to the vasocongestion induced by PAF itself.