乙酰甲胆碱诱导的支气管收缩和丙卡特罗诱导的支气管扩张对咳嗽感受器对吸入辣椒素和酒石酸敏感性的影响。
Effects of methacholine induced bronchoconstriction and procaterol induced bronchodilation on cough receptor sensitivity to inhaled capsaicin and tartaric acid.
作者信息
Fujimura M, Sakamoto S, Kamio Y, Matsuda T
机构信息
Third Department of Internal Medicine, Kanazawa University School of Medicine, Japan.
出版信息
Thorax. 1992 Jun;47(6):441-5. doi: 10.1136/thx.47.6.441.
BACKGROUND
The direct effect of bronchoconstriction on cough receptor sensitivity is unknown, and the antitussive effect of beta 2 adrenergic agonists in man has been controversial. This study was designed to throw light on these questions.
METHODS
The threshold of the cough response to inhaled capsaicin, a stimulant acting on C fibre endings, and tartaric acid, a chemostimulant, was measured before and 10 minutes after inhalation of methacholine, which caused a nearly 20% fall in forced expiratory volume in one second (FEV1), in 14 normal subjects (study 1), and also before and 30 minutes after inhalation of procaterol (30 micrograms), placebo, and saline in eight normal subjects (study 2). Progressively increasing concentrations of capsaicin and tartaric acid solutions were inhaled for 15 seconds by mouth tidal breathing at one minute intervals and cough threshold was defined as the lowest concentration of capsaicin and tartaric acid that elicited five or more coughs.
RESULTS
In study 1 the geometric mean values of the cough threshold of response to capsaicin and tartaric acid before methacholine callenge, 2.98 (GSE 1.30) micrograms/ml and 46.6 (1.22) mg/ml, were not significantly different from those of the response to methacholine inhalation, 3.45 (1.33) micrograms/ml and 32.9 (1.37) mg/ml. In study 2 the geometric mean value of the cough threshold of response to capsaicin before inhalation of procaterol (4.61 (GSE 1.84) micrograms/ml) was not different from that after inhalation of procaterol (4.61 (GSE 1.84) micrograms/ml), which had significant bronchodilator effects. The cough threshold was not altered by placebo or saline.
CONCLUSIONS
These findings suggest that muscarinic receptor stimulation, bronchoconstriction, beta 2 receptor stimulation, or bronchodilation might have no direct effect on the sensitivity of the cough receptors in normal subjects.
背景
支气管收缩对咳嗽感受器敏感性的直接影响尚不清楚，并且β2肾上腺素能激动剂在人体中的镇咳作用一直存在争议。本研究旨在阐明这些问题。
方法
在14名正常受试者中（研究1），测量吸入乙酰甲胆碱（导致一秒用力呼气量（FEV1）下降近20%）之前和之后10分钟，对吸入辣椒素（一种作用于C纤维末梢的刺激物）和酒石酸（一种化学刺激物）的咳嗽反应阈值；在8名正常受试者中（研究2），还测量吸入丙卡特罗（30微克）、安慰剂和生理盐水之前和之后30分钟对辣椒素的咳嗽反应阈值。以一分钟的间隔通过口潮式呼吸吸入浓度逐渐增加的辣椒素和酒石酸溶液15秒，咳嗽阈值定义为引发五次或更多次咳嗽的辣椒素和酒石酸的最低浓度。
结果
在研究1中，乙酰甲胆碱激发前对辣椒素和酒石酸咳嗽反应阈值的几何平均值分别为2.98（几何标准差1.30）微克/毫升和46.6（1.22）毫克/毫升，与吸入乙酰甲胆碱后的反应值3.45（1.33）微克/毫升和32.9（1.37）毫克/毫升无显著差异。在研究2中，吸入丙卡特罗前对辣椒素咳嗽反应阈值的几何平均值（4.61（几何标准差1.84）微克/毫升）与吸入具有显著支气管扩张作用的丙卡特罗后（4.61（几何标准差1.84）微克/毫升）无差异。安慰剂或生理盐水未改变咳嗽阈值。
结论
这些发现表明，毒蕈碱受体刺激、支气管收缩、β2受体刺激或支气管扩张可能对正常受试者咳嗽感受器的敏感性没有直接影响。
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