Participation of prostaglandin E2 receptor in nasal congestion of Brown Norway rats.

The aim of the present study was to clarify the involvement of prostaglandin E(2) (PGE(2)) in nasal congestion in Brown Norway (BN) rats. For this purpose, we studied the effects of PGE(2) receptor (EP(1), EP(2), EP(3) and EP(4)) agonists on nasal congestion and sneezing induced by toluene 2,4-diisocyanate (TDI). Enhanced pause (Penh) was increased 1 h (early phase) and 4 h (late phase) after TDI challenge. Sulprostone (an EP(3) receptor agonist) inhibited the increase of Penh, an index of nasal congestion, in both early and late phase responses. On the other hand, PGE(1) alcohol (an EP(4) agonist) increased Penh in the early phase response. Moreover, sulprostone inhibited sneezing, an immediate response by TDI challenge. These results indicate that EP(3) receptor is responsible for the relief of nasal congestion in both early and late phase responses, and EP(4) receptor is correlated with the development of nasal congestion in the early phase response. In addition, EP(3) receptor also participates in sneezing in allergic rhinitis induced by TDI challenge in BN rats.