Methacholine causes reflex bronchoconstriction.
Methacholine causes reflex bronchoconstriction.
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乙酰胆碱引起反射性支气管收缩。
DOI：
10.1152/jappl.1999.86.1.294
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Jacoby,DB
中科院分区：
文献类型：
--
作者：
Wagner,EM;Jacoby,DB
为了确定乙酰甲胆碱是否引起迷走神经介导的气道平滑肌反射收缩，我们通过支气管动脉或通过气管造口术将乙酰甲胆碱作为气雾剂施用到绵羊的下气道中。然后，我们测量了一个孤立的，在原位段气管平滑肌的收缩，并确定迷走神经切断术对气管反应的影响。经支气管动脉注入乙酰甲胆碱（0.5-10.0 μg/ml），引起剂量依赖性支气管收缩和气管段收缩。在最高浓度的乙酰甲胆碱下，气管平滑肌张力比基线平均增加186%。雾化吸入乙酰甲胆碱（5-7次呼吸，100 mg/ml）使气管张力增加58%，气道阻力增加183%。由于绵羊的支气管循环不供应气管，我们推测气管收缩是由下呼吸道对乙酰甲胆碱的反射反应引起的。双侧迷走神经切断术基本上消除了乙酰甲胆碱下气道激发（通过支气管动脉或通过气雾剂）后的气管反应和气道阻力变化。我们的结论是：1）乙酰甲胆碱引起气道平滑肌大量的反射性收缩; 2）人类或实验动物对乙酰甲胆碱的反应仅代表对平滑肌的直接作用的假设可能是无效的。
To determine whether methacholine causes vagally mediated reflex constriction of airway smooth muscle, we administered methacholine to sheep either via the bronchial artery or as an aerosol via tracheostomy into the lower airways. We then measured the contraction of an isolated, in situ segment of trachealis smooth muscle and determined the effect of vagotomy on the trachealis response. Administering methacholine to the subcarinal airways via the bronchial artery (0.5–10.0 μg/ml) caused dose-dependent bronchoconstriction and contraction of the tracheal segment. At the highest methacholine concentration delivered, trachealis smooth muscle tension increased an average of 186% over baseline. Aerosolized methacholine (5–7 breaths of 100 mg/ml) increased trachealis tension by 58% and airways resistance by 183%. As the bronchial circulation in the sheep does not supply the trachea, we postulated that the trachealis contraction was caused by a reflex response to methacholine in the lower airways. Bilateral vagotomy essentially eliminated the trachealis response and the airways resistance change after lower airways challenge (either via the bronchial artery or via aerosol) with methacholine. We conclude that1) methacholine causes a substantial reflex contraction of airway smooth muscle and2) the assumption may not be valid that a response to methacholine in humans or experimental animals represents solely the direct effect on smooth muscle.