关键词: 痛觉测定, 痛阈, 动物, 实验

Abstract: 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^-1SPI group was maintained until 60 min after the injection of SPI（P<0.01 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 thresho ld 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.

Key words: pain measurement, pain threshold, animals, laboratory