Orehek J, Massari J P, Gayrard P, Grimaud C, Charpin J
J Clin Invest. 1976 Feb;57(2):301-7. doi: 10.1172/JCI108281.
Our purpose was to determine whether exposure to a realistic concentration of nitrogen dioxide (NO2) could increase the bronchial sensitivity of asthmatic patients to bronchoconstrictor agents. We established dose-response curves for changes in specific airway resistance (SRaw) in response to aerosolized carbachol in 20 asthmatics after each had spent 1 h in an exposure chamber breathing on one occasion unpolluted air and on a separate occasion 0.1 ppm NO2: sequence of exposures to unpolluted air and to low levels of NO2 were randomized in a single-blind fashion. NO2 induced a slight but significant increase in initial SRaw and enhanced the bronchoconstrictor effect of carbachol in 13 subjects: curves were shifted to the left and the mean dose of carbachol producing a twofold increase in initial SRaw was decreased from 0.66 mg to 0.36 mg (P less than 0.001). In contrast, NO2 neither modified the initial SRaw nor the bronchoconstrictor effect of carbachol in seven subjects. In 4 out of the 20 subjects, exposure to a higher concentration of NO2 (0.2 ppm) yielded variable results. Potentiation of the carbachol bronchoconstrictor response by NO2 could not be related to any physical or clinical characteristics of the subjects tested. Although the mechanisms underlying the NO2 effect remain controversial, the present results demonstrate that very low levels of NO2 can adversely affect some asthmatics.
我们的目的是确定暴露于实际浓度的二氧化氮（NO₂）是否会增加哮喘患者对支气管收缩剂的支气管敏感性。我们为20名哮喘患者建立了特定气道阻力（SRaw）变化的剂量反应曲线，这些患者在暴露室中每次分别呼吸1小时未污染空气和0.1 ppm NO₂后，对雾化卡巴胆碱的反应：暴露于未污染空气和低水平NO₂的顺序以单盲方式随机安排。NO₂使初始SRaw略有但显著增加，并增强了13名受试者中卡巴胆碱的支气管收缩作用：曲线向左移动，使初始SRaw增加两倍的卡巴胆碱平均剂量从0.66毫克降至0.36毫克（P小于0.001）。相比之下，NO₂在7名受试者中既未改变初始SRaw，也未改变卡巴胆碱的支气管收缩作用。在20名受试者中的4名中，暴露于更高浓度的NO₂（0.2 ppm）产生了不同的结果。NO₂对卡巴胆碱支气管收缩反应的增强作用与受试对象的任何身体或临床特征均无关联。尽管NO₂作用的潜在机制仍存在争议，但目前的结果表明，极低水平的NO₂会对一些哮喘患者产生不利影响。
