Role of platelets in contraction of canine tracheal muscle elicited by PAF in vitro.
Role of platelets in contraction of canine tracheal muscle elicited by PAF in vitro.
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血小板在体外 PAF 引起的犬气管肌收缩中的作用。
DOI：
10.1152/jappl.1988.65.2.914
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Leff,AR
中科院分区：
文献类型：
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作者：
Popovich,KJ;Sheldon,G;Mack,M;Munoz,NM;Denberg,P;Blake,J;White,SR;Leff,AR
为探讨血小板活化因子（PAF）收缩气管平滑肌的作用机制，我们观察了PAF对45只犬203条离体气管平滑肌在血小板存在和不存在时的收缩作用。PAF（10（-11）至10（-7）M）单独使用时，即使在气道上皮存在的情况下，也不引起TSM收缩。在2 × 10（5）血小板/微升的情况下，PAF是一种非常有效的收缩激动剂（阈值10（-11）M）。该反应被PAF拮抗剂CV-3988（10（-6）M）抑制，并被5-羟色胺拮抗剂麦角新碱逆转（EC 50 = 3.7 +/- 0.79 x 10（-9）M）。阿托品和扑尔敏（10（-9）至10（-6）M）均不减弱对PAF +血小板的反应。在存在血小板的情况下，10（-7）M PAF导致灌流液中5-羟色胺浓度从0.93 +/- 0.037 x 10（-8）增加到1.7 +/- 0.046 x 10（-8）M（P <0.001）。快速耐受，以前被证明是不可逆的，被证明是一种血小板依赖性现象;收缩可以重复在相同的TSM后，添加新鲜血小板。我们证明，PAF诱导的收缩犬TSM是由释放的细胞中间体，如5-羟色胺从血小板。我们还证明了PAF诱导的快速耐受在气道平滑肌收缩的网站。
To elucidate mechanisms of platelet-activating factor (PAF)-induced contraction, we studied the effect of PAF on 203 canine tracheal smooth muscle (TSM) strips from 45 dogs in vitro in the presence and absence of platelets. PAF (10(-11) to 10(-7) M) alone caused no contraction of TSM even in the presence of airway epithelium. In the presence of 2 x 10(5) platelets/microliter, PAF was an extremely potent contractile agonist (threshold 10(-11) M). This response was inhibited by the PAF antagonist, CV-3988 (10(-6) M), and reversed by the serotonin antagonist, methysergide (EC50 = 3.7 +/- 0.79 x 10(-9) M). Neither atropine nor chlorpheniramine (10(-9) to 10(-6) M) attenuated the response to PAF + platelets. In the presence of platelets, 10(-7) M PAF caused an increase in perfusate concentration of serotonin from 0.93 +/- 0.037 x 10(-8) to 1.7 +/- 0.046 x 10(-8) M (P less than 0.001). Tachyphylaxis, previously demonstrated to be irreversible, was shown to be a platelet-dependent phenomenon; contraction could be repeated in the same TSM after addition of fresh platelets. We demonstrate that PAF-induced contraction of canine TSM is caused by the release of cellular intermediates such as serotonin from platelets. We also demonstrate the site of PAF-induced tachyphylaxis in airway smooth muscle contraction.