Fujimura M, Kamio Y, Matsuda T
Third Department of Internal Medicine, Kanazawa University School of Medicine, Japan.
Respiration. 1992;59(2):102-6. doi: 10.1159/000196036.
To examine the role of muscarinic M1-receptors in vagally mediated basal bronchomotor tone, we studied the effects of inhaled pirenzepine, which is a M1-receptor antagonist, on basal bronchomotor tone in 8 young women. To obtain dose-response curves to inhaled pirenzepine, we measured partial and full flow-volume curves before and 30 min after inhalation of each concentration of pirenzepine (3.25-200 micrograms/ml). Maximum expiratory flow on partial flow-volume curve at 25% forced vital capacity (PEF25) was measured as an index showing basal bronchomotor tone. The dose-response curve of the percent increase in PEF25 by pirenzepine was biphasic in shape. PEF25 was significantly increased by 3.12 (14.5 +/- 5.8%), 6.25 (15.5 +/- 4.2%), 12.5 (20.0 +/- 0.29%) and 200 micrograms/ml (17.3 +/- 5.9%) of pirenzepine, but not by 25 (9.6 +/- 5.6%), 50 (9.4 +/- 6.2%) and 100 micrograms/ml (14.4 +/- 6.2%) of pirenzepine. The percent increase in PEF25 by 40 micrograms of ipratropium bromide was 66.2 +/- 14.2%. These results suggest that the role of M1-receptors in vagally mediated basal bronchomotor tone may be significant but little compared with M3-receptors in normal humans.
为了研究毒蕈碱M1受体在迷走神经介导的基础支气管运动张力中的作用，我们研究了吸入性哌仑西平（一种M1受体拮抗剂）对8名年轻女性基础支气管运动张力的影响。为了获得吸入性哌仑西平的剂量反应曲线，我们在吸入每种浓度的哌仑西平（3.25 - 200微克/毫升）之前和之后30分钟测量了部分和全流量-容积曲线。在25%用力肺活量时部分流量-容积曲线上的最大呼气流量（PEF25）被测量作为显示基础支气管运动张力的指标。哌仑西平使PEF25增加百分比的剂量反应曲线呈双相形状。3.12（14.5±5.8%）、6.25（15.5±4.2%）、12.5（20.0±0.29%）和200微克/毫升（17.3±5.9%）的哌仑西平可使PEF25显著增加，但25（9.6±5.6%）、50（9.4±6.2%）和100微克/毫升（14.4±6.2%）的哌仑西平则无此作用。40微克异丙托溴铵使PEF25增加的百分比为66.2±14.2%。这些结果表明，在正常人体内，M1受体在迷走神经介导的基础支气管运动张力中的作用可能显著，但与M3受体相比作用较小。
