目的观察甘草黄酮的镇咳作用及机制。方法用辣椒素气雾吸入诱导豚鼠咳嗽反射，MedLab生物信号采集处理系统记录咳嗽次数。结果甘草黄酮30、100和300 mg/kg ig给药剂量依赖地抑制辣椒素诱导的豚鼠咳嗽反射，与模型组比较咳嗽次数分别减少32.7%、49.3%和59.6%(P<0.01、0.001);甘草黄酮100 mg/kg ig给药1、4、6 h可显著抑制辣椒素诱导的豚鼠咳嗽反射次数(P<0.01、0.05)，作用8和12 h对咳嗽反射无显著影响(P>0.05)。纳洛酮0.3 mg/kg(ip)可部分阻断甘草黄酮的作用，马来酸麦角新碱3mg/kg(ip)或格列本脲20mg/kg(ip)不能阻断甘草黄酮的作用。结论甘草黄酮呈剂量依赖方式抑制辣椒素引起的豚鼠咳嗽反射，甘草黄酮(100 mg/kg，ig)作用持续时间为6h以上。纳洛酮部分阻断甘草黄酮的作用，表明甘草黄酮可能间接影响内源性的阿片系统。

Objective To investigate the antitussive activity and action sites of flavone from Glycyrrhiza uralensis. (FGU) in guinea pig. Methods Cough reflex was induced by capsaicin aerosol in guinea pigs. The cough number of times was recorded by MedLab data adoption system. Results FGU 30, 100, and 300 mg/kg (ig) inhibited capsaicin-induced cough reflex in a dose-dependent manner. Inhibitory rates of cough reflex were 32. 7%, 49. 3%, and 59. 6%, respectively. There was a significantly different comparison with those of model group (P<0. 01, 0. 001, respectively). FGU 100 mg/kg markedly decreased cough reflex number of times induced by capsaicin at 1, 4, and 6 h after ig administration ( P < 0. 01, 0. 05), but had no effect at 8 and 12 h (P>0. 05). Pretreatment with Naloxone (0. 3 mg/kg, ig ) partly blocked the effects of FGU, but neither methysergide (3 mg/kg, ig) nor glibenclamide (20 mg/kg, ig)worked. Conclusion FGU inhibits capsaicin-induced cough reflex in guinea pig in a dose-dependent manner. FGU (100 mg/kg, ig) had a continuous antitussive effect more than 6 h. Partly block effect of Naloxone on FGU suggests that FGU might indirectly influence endogenous opium system.

浙江省科技厅重点攻关项目(2006C23009)