3-5-dimethyl-2-(3-pyridyl)thiazolidin-4-one and Sneezing

To define the role of platelet activating factor (PAF) in allergic rhinitis, we examined the effects of anti-PAF agents (WEB2086, SM10661) on the changes of nasal airway resistance (NAR) and nasal symptoms after topical antigen challenge in actively sensitized guinea pigs and compared these with the changes brought by anti-leukotriene (LT) agent (FPL 55712), 5-lipoxygenase inhibitor (E6080), anti-allergic agent (azelastine), and anti-histamine agent (mepyramine maleate). We noted biphasic increase in NAR after antigen challenge; the first peak, 146.3 +/- 4.3% at 10 min and the second peak, 163.3 +/- 7.8% at 240 min after antigen challenge. The first peak response of NAR was not affected by anti-PAF agents, anti-LT agent, 5-lipoxygenase inhibitor, or azelastine; it was slightly but significantly inhibited by anti-histamine. The second NAR response was significantly inhibited by anti-PAF agents, anti-LT agent, 5-lipoxygenase inhibitor, and azelastine, but was not affected by anti-histamine. The nasal symptoms which occurred within 30 min after antigen challenge were significantly inhibited by WEB2086, E6080, azelastine, and mepyramine, but were not affected by SM10661. Our results suggest that PAF activities and LTs may play an important role in the later phase increase of NAR after topical antigen challenge.

Topics: Airway Resistance; Animals; Azepines; Chromones; Guinea Pigs; Histamine H1 Antagonists; Immunization; Lipoxygenase Inhibitors; Male; Ovalbumin; Phthalazines; Platelet Activating Factor; Pyrilamine; Rhinitis, Allergic, Perennial; Sneezing; SRS-A; Thiazoles; Thiazolidines; Triazoles