Perretti F, Manzini S
Pharmacology Department, Istituto Farmacobiologico Malesci s.p.a., Firenze, Italy.
Am Rev Respir Dis. 1993 Oct;148(4 Pt 1):927-31. doi: 10.1164/ajrccm/148.4_Pt_1.927.
In anesthetized guinea pigs, a slow intravenous infusion of platelet activating factor (PAF) (600 ng/kg over 1 h) but not of the carrier molecule bovine serum albumin (0.25%) induced immediate and transient bronchoconstriction and a fall in arterial blood pressure followed by an increase in bronchial responsiveness to histamine (0.56 to 1.8 microgram/kg intravenously). Pretreatment of guinea pigs with capsaicin (55 mg/kg subcutaneously over 2 days) 1 wk before the experiments, or with ruthenium red (5 mg/kg subcutaneously) 1 h before, completely inhibited capsaicin (2.5 micrograms/kg intravenously)-induced bronchoconstriction, and completely inhibited PAF-induced bronchial hyperresponsiveness. On the other hand, PAF-induced immediate bronchoconstriction and decreases in mean arterial blood pressure were not affected by capsaicin and/or ruthenium red pretreatment. However, pretreatment of guinea pigs with the PAF antagonist WEB 2086 resulted in a complete inhibition of PAF-induced direct bronchoconstriction, fall in arterial blood pressure, and bronchial hyperresponsiveness to histamine. It is suggested that in the guinea pig, PAF-induced bronchial hyperresponsiveness to histamine may be secondary to the activation of capsaicin-sensitive sensory fibers.
在麻醉的豚鼠中，缓慢静脉输注血小板活化因子（PAF）（1小时内输注600 ng/kg）可诱发即刻且短暂的支气管收缩以及动脉血压下降，随后支气管对组胺（静脉注射0.56至1.8微克/千克）的反应性增加，而输注载体分子牛血清白蛋白（0.25%）则不会出现上述情况。在实验前1周用辣椒素（2天内皮下注射55毫克/千克）或在实验前1小时用钌红（皮下注射5毫克/千克）预处理豚鼠，可完全抑制辣椒素（静脉注射2.5微克/千克）诱发的支气管收缩，并完全抑制PAF诱发的支气管高反应性。另一方面，PAF诱发的即刻支气管收缩和平均动脉血压下降不受辣椒素和/或钌红预处理的影响。然而，用PAF拮抗剂WEB 2086预处理豚鼠可完全抑制PAF诱发的直接支气管收缩、动脉血压下降以及支气管对组胺的高反应性。提示在豚鼠中，PAF诱发的支气管对组胺的高反应性可能继发于辣椒素敏感感觉纤维的激活。
