Foresi A, Chetta A, Corbo G M, Cuomo A, Olivieri D
Chest. 1987 Sep;92(3):455-9. doi: 10.1378/chest.92.3.455.
This study was carried out to compare bronchial responses to inhaled propranolol (P) and methacholine (M) in a group of asthmatic subjects with mild to moderate bronchial hyperresponsiveness to M; to determine the short term reproducibility of bronchial response to propranolol; and to examine the shape of dose-response curve to P relative to that of M. Doses of M and P were given in mumoles and bronchial responses to both agents were expressed as the provocative dose that induced a 20 percent fall in FEV1 (PD20 FEV1). In 16 asthmatic patients, there was no correlation between the PD20 of the two agents. Mean PD20 M (+/- SD in log scale) was approximately nine times lower than mean PD20 P (0.64 +/- 0.96 and 5.80 +/- 1.65, respectively). This difference was statistically significant (t = 4.58, p less than 0.001). In six asthmatic patients, the reproducibility of PD20 P was similar to that of M (intraclass correlation coefficient 0.969 and 0.957, respectively). The shape of the dose-response curves to P was different from that of M in five of nine asthmatic patients when all experimental points were analyzed by double-reciprocal plot. We noticed that even small doses of inhaled P may cause a severe bronchoconstriction. Therefore, special caution should be taken to increase P doses very gradually, when studying the dose-response curve. We demonstrated that P inhalation induced a measurable bronchoconstriction in subjects with mild to moderate hyperresponsiveness and it was reproducible. However, the bronchial sensitivity to P was lower than to M. Our findings suggest that P and M have different mechanisms of action.
本研究旨在比较一组对乙酰甲胆碱（M）有轻度至中度支气管高反应性的哮喘患者对吸入普萘洛尔（P）和乙酰甲胆碱（M）的支气管反应；确定支气管对普萘洛尔反应的短期可重复性；并检查相对于M，P的剂量反应曲线形状。M和P的剂量以微摩尔为单位给出，对两种药物的支气管反应均表示为诱导第一秒用力呼气容积（FEV1）下降20%的激发剂量（PD20 FEV1）。在16名哮喘患者中，两种药物的PD20之间无相关性。平均PD20 M（对数尺度下的±标准差）比平均PD20 P低约9倍（分别为0.64±0.96和5.80±1.65）。这种差异具有统计学意义（t = 4.58，p < 0.001）。在6名哮喘患者中，PD20 P的可重复性与M相似（组内相关系数分别为0.969和0.957）。当通过双倒数图分析所有实验点时，9名哮喘患者中有5名对P的剂量反应曲线形状与M不同。我们注意到，即使吸入小剂量的P也可能导致严重的支气管收缩。因此，在研究剂量反应曲线时，应特别谨慎地非常缓慢地增加P的剂量。我们证明，吸入P在轻度至中度高反应性受试者中可诱导可测量的支气管收缩，且具有可重复性。然而，支气管对P的敏感性低于对M的敏感性。我们的研究结果表明，P和M具有不同的作用机制。
