Anti-allergic effects of (E)-3-[p-(1H-imidazol-1-lylmethyl) phenyl]-2-propenoic acid (OKY-046), a specific thromboxane (TX) A2 synthetase inhibitor: effects on type I allergic reactions]

We studied the effects of OKY-046 on type I allergic reactions. OKY-046 (100 mg/kg) given orally suppressed antigen-induced bronchoconstriction and TXB2 generation in broncho alveolar lavage fluid in rats passively sensitized with anti-DNP-As monoclonal IgE. At the dose of 30 mg/kg given intraduodenally, it also inhibited antigen-induced bronchoconstriction in guinea pigs passively sensitized with anti DNP-As serum and actively sensitized with ovalbumin. However, aspirin (30 mg/kg) didn't suppressed them significantly. Azelastine (10 mg/kg) inhibited bronchoconstriction in passively sensitized rats and actively sensitized guinea pigs. In 48 hour homologous PCA reactions of rats and mice, oral administration of OKY-046 (300 mg/kg) and tranilast (100 mg/kg) suppressed the extravasated dye in the skin. OKY-046 decreased histamine release from passively sensitized rat peritoneal exudate cells. There was no effect of OKY-046 on SRS-A and leukotriene release from actively sensitized guinea pig lungs and passively sensitized rats. In conclusion, we think that OKY-046 should be an useful asthmatic drug or anti-allergic drug by oral administration.