Immunopharmacological Studies on TBX, a New Antiallergic Drug (3) Inhibitory Effects on Histamine Release from Lung Fragments and Bronchoconstriction in Guinea Pigs

[摘要] References(29)Cited-By(11)The effects of 9-methyl-3-(lH-tetrazol-5-yl)-4H-pyrido[1, 2-a]pyrimidin-4-one potassium salt (TBX), a new antiallergic drug, on histamine release from lung fragments, experimental asthma and isolated tracheal muscle were investigated in guinea pigs. TBX (10-7 to 10-4 g/ml) dose-dependently inhibited antigen-induced histamine release from lung fragments of guinea pigs passively sensitized with homologous IgE serum. Antigen inhalation-induced experimental asthma in passively sensitized animals was inhibited in a dose-dependent fashion by i.v. (1 to 5 mg/kg) and p.o. (10 to 100 mg/kg) administrations of TBX. In vivo bronchoconstriction by platelet-activating factor (PAF, i.v.) was also inhibited by TBX (0.3 to 10 mg/kg, i.v.). However, high concentrations of TBX (more than 3 x 10-4 g/ml) were needed to inhibit PAF-induced platelet aggregation in vitro. With regard to the effect on isolated tracheal muscle, TBX itself at concentrations higher than 10-5 g/ml induced dose-dependent reduction in the resting tonus, which was not affected by pretreatment with propranolol. Neither the leukotriene D4-induced contraction nor the prostaglandin F2α-Induced one was specifically antagonized by TBX. The results obtained indicate that TBX is an antiasthmatic agent effective in inhibiting both IgE- and PAF-induced bronchoconstriction, possibly by interfering with mediator release.

[学科分类] 药理学