title: Antiasthmatic activity of a novel thromboxane A2 antagonist, S-1452, in guinea pigs.
abstract: We examined the effect of a potent thromboxane (Tx) A2 receptor antagonist, calcium (1R, 2S, 3S, 4S)-(5Z)-7-(((phenylsulfonyl)amino)bicyclo[2.2.1] hept-2-yl)-5-heptenoate dihydrate (S-1452), on antigen- and various allergic-spasmogen-induced contractions of guinea pig lung parenchymal strips and on the increase in insufflation pressure, an index of bronchoconstriction, in anesthetized guinea pigs. In isolated guinea pig lung parenchymal strips, S-1452 showed competitive antagonism of the contractile activity of U-46619, a TxA2 mimetic, with a pA2 value of 8.9. The compound also inhibited the contraction induced by prostaglandin (PG) D2 and PGF2 alpha, but a TxA2 synthetase inhibitor, OKY-046, did not. In contrast, both drugs inhibited not only leukotriene (LT) D4-induced contraction but also antigen-induced contraction in the presence of a histamine antagonist. In anesthetized guinea pigs, oral administration of S-1452 markedly inhibited the bronchoconstrictions induced by intravenous injection of U-46619, PGD2, PGF2 alpha, LTD4 and platelet-activating factor (PAF) with ED50 values of 0.006, 0.031, 0.112, 0.033 and 0.115 mg/kg, respectively, but OKY-046 inhibited only that by LTD4 and PAF. Additionally, bronchoconstriction following intravenous injection of antigen was almost completely suppressed by S-1452 (0.1 mg/kg) and partially by OKY-046 (300 mg/kg) in passively sensitized guinea pigs which were treated with diphenydramine and propranolol. The inhibitory effect of S-1452 against U-46619-induced broncho-constriction persisted up to 7 h after oral administration.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Shionogi Research Laboratories, Shionogi & Co., Ltd., Osaka, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Arimura
authors.forename: F
authors.initials: F
authors.lastname: Asanuma
authors.forename: A
authors.initials: A
authors.lastname: Kurosawa
authors.forename: M
authors.initials: M
authors.lastname: Harada
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000818:Animals; D001249:Asthma / Q000188:drug therapy*; D001643:Bridged Bicyclo Compounds / Q000494:pharmacology* / Q000627:therapeutic use; D016084:Bronchoconstriction / Q000187:drug effects; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology* / Q000627:therapeutic use; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008168:Lung / Q000187:drug effects / Q000502:physiology; D008297:Male; D008689:Methacrylates / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D011450:Prostaglandin Endoperoxides, Synthetic / Q000494:pharmacology; D017482:Receptors, Thromboxane / Q000187:drug effects*; D013928:Thromboxane A2 / Q000037:antagonists & inhibitors*
chemical_list: D001643:Bridged Bicyclo Compounds; D005229:Fatty Acids, Monounsaturated; D008689:Methacrylates; D011450:Prostaglandin Endoperoxides, Synthetic; D017482:Receptors, Thromboxane; C056566:S 145; D013928:Thromboxane A2; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; C034364:ozagrel