Participation in cysteinyl leukotrienes and thromboxaneA2 in nasal congestion model in Brown Norway rats

The aim of this study was to investigate the involvement of chemical mediators in a nasal congestion model in Brown Norway (BN) rats. For the above purpose, we studied the effects of pranlukast and zafirlukast (cysteinyl leukotriene (cys-LT) receptor antagonists), seratrodast and ramatroban (thromboxane A2 (TXA2) receptor antagonists) on nasal congestion and sneezing induced by toluene 2, 4-diisocyanate (TDI). All of these drugs suppressed the increase of enhanced pause (Penh), the index of nasal congestion, in both early and late phase responses; however, pranlukast, zafirlukast and seratrodast failed to suppress immediate sneezing caused by TDI challenge. These results indicate that cys-LTs and TXA2 are responsible for the development of both early and late phase nasal congestion. Moreover, these chemical mediators contribute very little to immediate sneezing in a BN rat model of allergic rhinitis.