青龙木叶皂苷的镇痛作用及其机制

目的：探讨青龙木叶皂苷的镇痛效应及其机制。方法：60只Wistar大鼠随机分为5组（每组12只）：青龙木叶皂苷15、30、60 μg·kg^-1组，青龙木叶皂苷加纳洛酮组及生理盐水对照组。通过预先手术埋置的脑室套管向侧脑室注射青龙木叶皂苷，用辐射热甩尾法测定大鼠痛阈。结果：侧脑室注射3种不同剂量青龙木叶皂苷组的痛阈在注射5 min后与生理盐水对照组比较有不同程度的提高。15 μg·kg^-1组的痛阈虽然有提高，但与对照组比较差异无显著性（P>0.05）；30 μg·kg^-1组的痛阈提高持续50 min，60 μg·kg^-1组的痛阈提高可持续60 min以上，与对照组比较差异有显著性（P<0.05或P<0.01）。对照组大鼠的痛阈在60 min内无明显变化(P>0.05)。且青龙木叶皂苷镇痛效应可被纳洛酮所翻转。结论：青龙木叶皂苷具有较强镇痛效应及剂量-镇痛效应关系，其镇痛作用（痛阈升高）是通过脑内μ阿片受体实现的。

Analgesic action of total saponin of Pterocarpus Indicus and its mechanism

Objective To investigate the analgesic effect of saponin of Pterocarpus Indicus(SPI).Methods Sixty rats were divided randomly into 5 groups(n=12):SPI with doses of 15,30,60 μg·kg~(-1) groups,SPI plus naloxone group and control group.Through the cannula penetrated into lateral cerebral ventricle,SPI was injected into lateral cerebral ventricle.Then,the tail-flick latency after the injection of SPI naloxone and saline was measured.Results The tail-flick latency was increased significantly 5 min after the injection(i.c.v.) of SPI,the amplitudes were corresponding with their doses.The effect of increasing of pain threshold in 30 μg·kg~(-1) SPI group was maintained until 50 min after the injection of SPI,60 μg·kg~(1) SPI group was maintained until 60 min after the injection of SPI(P<0.05 or P<0.01).The pain threshold in control group was unchanged in 60 min(P>0.05).Naloxone could effectively antagonize the enhancement of the pain threshold induced by SPI.Conclusion SPI has a strong analgesic action and shows an obvious dose-effect relationship.The analgesic action may be mediated by(μ opioid) receptor in brain.