The effect of lipoxygenase inhibitors and leukotriene antagonists on anaphylaxis

The experiments whose results are reported here were carried out with the aim of showing a possible role for lipoxygenase products in the modulation of the Schultz-Dale reaction. For this purpose, the actions of nordihydroguaieretic acid (NDGA) and of FPL 55712 were tested during anaphylaxis in guinea-pig ileum and trachea in vitro. Isolated preparations from guinea-pigs, which had been subcutaneously sensitized with ovalbumin and incomplete Freund adjuvant, were challenged with increasing concentrations of antigen; in preparations isolated from the same animal an antigen-concentration anaphylactic-reaction curve was performed in the presence of the drugs. NDGA 3.3 X 10(-6) M was capable of inhibiting anaphylaxis in the trachea to a maximum extent of 40% but it did not affect anaphylactic reaction in the intestinal smooth muscle. FPL 55712 2 X 10(-6) M did not exert any activity on anaphylaxis in either preparations. The difference between SRS-A and histamine as mediators of anaphylaxis in the tissue preparations used could explain the fact that NDGA acted on the trachea alone.