Responses of isolated pulmonary arteries to the C5a anaphylatoxin.
Responses of isolated pulmonary arteries to the C5a anaphylatoxin.
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离体肺动脉对 C5a 过敏毒素的反应。
DOI：
10.1152/ajpheart.1990.259.5.h1325
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Reed,WP
中科院分区：
文献类型：
--
作者：
Crowell,RE;VanEpps,DE;Reed,WP
过敏毒素C5 a在平滑肌组织中具有致痉挛活性。在这项研究中，我们研究了在各种实验条件下C5 a对离体兔肺动脉（PA）环段的影响。C5 a（1-100 nM）引起PA在静息张力下的短暂收缩。组胺H1受体拮抗剂吡拉明（1 μ M）不影响C5 a诱导的PA收缩，但环氧合酶抑制剂吲哚美辛（1 μ M）显著降低。血管内皮层的破坏对静息PA中的C5 a活性没有影响。然而，用去甲肾上腺素（5 μ M）预收缩的PA在静息张力下对C5 a的反应与PA不同。C5 a（1-10 nM）在预收缩的PA中诱导双相反应，最初引起进一步收缩，随后是更大程度的松弛，导致PA张力的总体降低。吲哚美辛可完全消除预收缩PA对C5 a的所有反应，而内皮细胞破坏可显著抑制预收缩PA对C5 a的所有反应。这些数据表明，C5 a直接与分离的兔PA相互作用，但PA对这种肽的反应的性质取决于几个变量，包括是否存在活性PA张力和环氧合酶代谢物，以及是否存在完整的内皮。
The anaphylatoxin C5a possesses spasmogenic activity in smooth muscle tissues. In this study, we examined the effect of C5a on isolated rabbit pulmonary artery (PA) ring segments under a variety of experimental conditions. C5a (1-100 nM) caused transient constriction of PA at resting tension. C5a-induced PA constriction was not affected by the histamine H1-receptor antagonist pyrilamine (1 microM) but was significantly decreased by the cyclooxygenase inhibitor indomethacin (1 microM). Disruption of the endothelial layer of the vessel had no effect on C5a activity in resting PA. PA, which had been preconstricted with norepinephrine (5 microM), exhibited a different response to C5a than PA at resting tension, however. C5a (1-10 nM) induced a biphasic response in preconstricted PA, initially causing further constriction followed by a greater degree of relaxation resulting in an overall decrease in PA tension. All responses of preconstricted PA to C5a were completely eliminated by indomethacin and significantly depressed by endothelial disruption. These data indicate that C5a interacts directly with isolated rabbit PA, but the nature of the PA response to this peptide depends on several variables including the presence or absence of active PA tension and cyclooxygenase metabolites, and the presence of intact endothelium.