Effects of olopatadine hydrochloride on the release of thromboxane B2 and histamine from nasal mucosa after antigen–antibody reaction in guinea pigs

Abstract

Various mediators, such as thromboxane (TX) A 2 , peptide leukotrienes (P-LT) and histamine, are involved in allergic nasal obstruction. The aim of the present study was to investigate the mechanism whereby olopatadine hydrochloride, a novel anti-allergic drug, ameliorated the allergic nasal obstruction. The levels of TXB 2 , P-LT and histamine in nasal lavage fluid (NLF) were measured after intranasal antigen challenge in sensitized guinea pigs. Histamine and TXB 2 levels in the NLF increased eight- and threefold, respectively, 10 min after antigen challenge, whereas the P-LT level was under the detection limit. Oral administration of olopatadine at 0.1, 1 and 3 mg/kg significantly inhibited the increases in TXB 2 and histamine levels. At 3 mg/kg, olopatadine also ameliorated the nasal obstruction caused 10 min after antigen challenge, as determined by acoustic rhinometry. These results suggest that the amelioration by olopatadine of the allergic nasal obstruction involves the inhibition of the release of TXA 2 and histamine.