6β-纳曲醇与纳曲酮拮抗吗啡镇痛作用的比较6β-纳曲醇与纳曲酮拮抗吗啡镇痛作用的比较

目的比较6β-纳曲醇(6β-naltrexol,6β-NOL)与纳曲酮(naltrexone,NTX)拮抗吗啡的镇痛作用。方法用小鼠热板法和小鼠热辐射甩尾法,sc和ig两种途径研究6β-NOL和NTX拮抗吗啡镇痛作用的强度和有效时间。用放射配体结合实验研究6β-NOL和NTX对阿片受体的亲和力。结果小鼠热板法和甩尾法显示,6β-NOL的抗吗啡镇痛作用强度和有效时间分别约为NTX的(6.1±1.7)%和3～4倍;po拮抗吗啡镇痛作用强度约为sc的30%,与NTX相近。在受体水平,6β-NOL对阿片-mu受体的亲和力约为NTX的12.5%,这与它们在整体水平拮抗吗啡镇痛作用的强度相近。结论6β-NOL抗吗啡镇痛作用比NTX弱,但作用时间长。

Comparison of the antagonistic effects of 6 beta-naltrexol and naltrexone against morphine analgesia]

AIM: To compare the antagonistic effects of 6 beta-naltrexol and naltrexone against morphine analgesia. METHODS: The effects of 6 beta-naltrexol and naltrexone against morphine analgesia were observed in mouse heat radiant tail-flick assay and in mouse (55 +/- 1) degrees C hot plate test. The displacement of 6 beta-naltrexol and naltrexone on binding to CHO-mu receptor was observed by radioligand binding study. RESULTS: 6 beta-naltrexol antagonized morphine analgesia but the potency was (6.1 +/- 1.7)% that of naltrexone. The effective duration of 6 beta-naltrexol was 3-4 times that of naltrexone and the peak time of the response was about 0.5-1 h after s.c. equivalent efficacy dose (ED95) in two models. Like naltrexone, 6 beta-naltrexol was effective by oral administration and the potency ratio of p.o./s.c. was 1/3. As an antagonist to opioid receptor, the displacement of 6 beta-naltrexol was about 12.5% that of naltrexone, which was almost in agreement with the efficacies against morphine analgesia in mouse. CONCLUSION: Compared with naltrexone, 6 beta-naltrexol was less potent but duration was longer.