Department of Physics, University of Helsinki, Finland.
Respir Physiol Neurobiol. 2013 Dec 1;189(3):465-72. doi: 10.1016/j.resp.2013.08.024. Epub 2013 Sep 4.
We measured bronchoconstriction in central bronchi, and in small peripheral airways causing the emergence of ventilation defects (VD), through two delivery routes: intravenous (IV) and inhaled MCh, in 2 groups of rabbits (A: n=5; B: n=4), using synchrotron imaging of regional lung structure and ventilation. We assessed the effect an initial IV challenge on a subsequent inhaled challenge in group B. Inhaled MCh decreased central airway cross-sections (CA) by 13-22%, but increased VD area by 25-49%. IV MCh decreased CA by 44% but increased the area of ventilation defects (VD) by 13% only. An initial IV MCh challenge reduced regional ventilation heterogeneity following a subsequent inhaled MCh challenge, suggesting the role of agonist-receptor interaction in the response pattern. Heterogeneous agonist distribution due to uneven aerosol deposition could explain the different patterns of response between IV and inhaled routes. This mechanism could participate in the emergence of ventilation heterogeneities during bronchial challenge, or exposure to allergen in asthmatic patients.
我们通过两种给药途径（静脉内[IV]和吸入 MCh）在两组兔子（A：n=5；B：n=4）中测量了支气管收缩，在中央支气管和导致通气缺陷（VD）出现的小外周气道中测量了支气管收缩，使用同步辐射成像技术评估了区域肺结构和通气。我们评估了 B 组中初始 IV 挑战对随后吸入挑战的影响。吸入 MCh 使中央气道横截面（CA）减少了 13-22%，但增加了 VD 面积 25-49%。IV MCh 使 CA 减少了 44%，但仅增加了 13%的通气缺陷（VD）面积。初始 IV MCh 挑战降低了随后吸入 MCh 挑战后的区域性通气异质性，表明激动剂-受体相互作用在反应模式中的作用。由于气溶胶沉积不均匀导致的不均匀激动剂分布可以解释 IV 和吸入途径之间不同的反应模式。这种机制可能参与了支气管激发期间通气异质性的出现，或在哮喘患者中暴露于变应原时的出现。
