Participation of Prostaglandin E-2 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 (EP1, EP2, EP3 and EP4) 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 EP3 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 EP4 agonist) increased Penh in the early phase response. Moreover, sulprostone inhibited sneezing, an immediate response by TDI challenge. These results indicate that EP3 receptor is responsible for the relief of nasal congestion in both early and late phase responses, and EP4 receptor is correlated with the development of nasal congestion in the early phase response. In addition, EP3 receptor also participates in sneezing in allergic rhinitis induced by TDI challenge in BN rats.