Early bronchial hyperresponsiveness following injection of sephadex beads in the guinea pig:: Involvement of platelet activating factor and thromboxane A2

被引:6
|
作者
Conroy, DM [1 ]
Sirois, P [1 ]
机构
[1] Univ Sherbrooke, Fac Med, Inst Pharmacol, Sherbrooke, PQ J1H 5N4, Canada
基金
英国医学研究理事会;
关键词
D O I
10.1023/A:1021913009742
中图分类号
Q2 [细胞生物学];
学科分类号
071009 ; 090102 ;
摘要
The effects of an intravenous injection (i.v.) of Sephadex beads (20 mg kg(-1)) were examined on bronchial responsiveness to ACh (1-200 mu g kg(-1) i.v.) as well as on cell accumulation in guinea-pig lung. Bronchial hyperreactivity to ACh, measured as increase in pulmonary insufflation pressure (PIP), was observed 3 h following the i.v. injection of Sephadex beads. However, no significant increase in bronchial reactivity to ACh was measured at 6 and 12 h following Sephadex injection. A second later increase in bronchial hyperresponsiveness was observed at 24 h. Bronchoalveolar lavage performed at 3 h following Sephadex treatment showed that there was no significant increase in total or differential cell number. At 6 h and 12 h, a significant increase in total cell counts was observed. At 24 h, a greater than 5-fold increase in cell number was observed and was related to a marked eosinophil, neutrophil and macrophage infiltration. A platelet-activating factor (PAF) antagonist, CV-3988 (10 mg kg(-1) i.v.), and a thromboxane A(2) (TxA(2)) antagonist, L655,240 (10 mg kg(-1) i.v.), significantly attenuated the Sephadex-induced bronchial hyperresponsiveness to ACh observed at 3 h. The results show that an i.v. injection of Sephadex beads in guinea pigs can induce an early bronchial hyperresponsiveness to ACh that is mediated by the release of both PAF and TxA(2) and is independent of airway cell infiltration.
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页码:437 / 448
页数:12
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