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Effect of a thromboxane A2 synthetase inhibitor (OKY-046 · HCl) on airway hyperresponsiveness in guinea pigs

1990; Elsevier BV; Volume: 184; Issue: 1 Linguagem: Inglês

10.1016/0014-2999(90)90669-w

1879-0712

Hidetada Komatsu, Yasuo Takehana, Shinji Kikuchi, Masami Kojima, Shuichiro Hamano, Hiroshi Kusama, Tadao Okegawa, Shigeru Ikeda,

Mast cells and histamine

We studied the effect of (E)-3-[p-(1H-imidazol-1-ylmethyl)phenyl]-2-propenoic acid hydrochloride monohydrate (OKY-046.HCl), a specific thromboxane (TX) A2 synthetase inhibitor, on airway hyperresponsiveness of guinea pigs. OKY-046.HCl (30-100 mg/kg, intraduodenally (i.d.) or orally (p.o.)) suppressed dose dependently the airway hyperresponsiveness to acetylcholine (ACh) induced by formyl-methionyl-leucyl-phenylalanine (FMLP), platelet activating factor (PAF) and repetitive antigen. OKY-046.HCl (100 mg/kg) also inhibited the increase in TXB2 in bronchoalveolar lavage fluid (BALF) induced by FMLP, PAF and antigen. Aspirin 10 or 30 mg/kg i.d. or p.o.) suppressed the airway hyperresponsiveness induced by FMLP and PAF but not by antigen. Azelastine (10 mg/kg i.d.) was ineffective on PAF- and antigen-induced airway hyperresponsiveness. TXA2 mimetic drugs caused airway hyperresponsiveness that was not inhibited by OKY-046.HCl (30 mg/kg i.v.). Furthermore, OKY-046.HCl showed no effect on propranolol- and physostigmine-induced airway hyperresponsiveness which did not accompany TXB2 generation in BALF. The number of eosinophils in BALF increased after FMLP exposure, an effect which was not inhibited by OKY-046.HCl. These results suggest that OKY-046.HCl inhibits airway hyperresponsiveness by suppressing TXA2 generation. We suggest that OKY-046.HCl will be a new antiasthmatic drug.