Pounsford J C, Birch M J, Saunders K B
Thorax. 1985 Sep;40(9):662-7. doi: 10.1136/thx.40.9.662.
Coughing was induced in seven normal and eight asthmatic subjects by giving successive inhalations of citric acid aerosols of progressively higher concentration (range 0.5-32%). A baseline cough response was obtained on each of four experimental days, and there was no significant difference between days in this respect. Then the subjects received by inhalation either a bronchodilator (salbutamol 5 mg or ipratropium 1 mg) or placebo, in a paired double blind crossover design. A second citric acid run followed and was used for paired drug-placebo comparisons. In the asthmatic subjects the cough response was diminished by both bronchodilators (p less than 0.05), and the cough threshold was significantly higher after ipratropium but not salbutamol. In normal subjects no significant effects were found. Airways calibre was assessed, by an oscillatory technique that measures the resistance of the respiratory system (Siemens Siregnost FD 5), in four of the seven normal and all eight asthmatic subjects. The mean respiratory resistance was higher in asthmatic than in normal subjects, and fell significantly after both bronchodilators. In normal subjects smaller decreases in respiratory resistance occurred, significant only with salbutamol. The simplest hypothesis which explains the results relates change in cough response to altered neuroreceptor sensitivity associated with rapid changes in bronchial calibre.
通过依次吸入浓度逐渐升高（范围为0.5 - 32%）的柠檬酸气雾剂，诱发了7名正常受试者和8名哮喘受试者咳嗽。在四个实验日的每一天都获得了基线咳嗽反应，在这方面各天之间没有显著差异。然后，受试者采用配对双盲交叉设计，通过吸入方式接受支气管扩张剂（沙丁胺醇5毫克或异丙托溴铵1毫克）或安慰剂。随后进行第二次柠檬酸测试，并用于药物 - 安慰剂配对比较。在哮喘受试者中，两种支气管扩张剂均使咳嗽反应减弱（p < 0.05），异丙托溴铵给药后咳嗽阈值显著升高，而沙丁胺醇给药后则未升高。在正常受试者中未发现显著影响。通过一种测量呼吸系统阻力的振荡技术（西门子Siregnost FD 5），对7名正常受试者中的4名以及所有8名哮喘受试者的气道口径进行了评估。哮喘受试者的平均呼吸阻力高于正常受试者，两种支气管扩张剂给药后均显著下降。在正常受试者中，呼吸阻力下降幅度较小，仅沙丁胺醇给药后有显著下降。解释这些结果的最简单假设是，咳嗽反应的变化与支气管口径快速变化相关的神经受体敏感性改变有关。
