Comparison of the antagonistic effects of 6 beta-naltrexol and naltrexone against morphine analgesia.
- Author:
Ling-di YAN
1
;
Ze-hui GONG
;
Xia-jun YAO
;
Bo-yi QIN
Author Information
- Publication Type:Journal Article
- MeSH: Analgesia; Analgesics, Opioid; antagonists & inhibitors; Animals; Female; Male; Mice; Morphine; antagonists & inhibitors; Naltrexone; analogs & derivatives; pharmacology; Narcotic Antagonists; pharmacology; Pain Threshold; drug effects; Receptors, Opioid, mu; metabolism
- From: Acta Pharmaceutica Sinica 2003;38(8):578-581
- CountryChina
- Language:Chinese
-
Abstract:
AIMTo compare the antagonistic effects of 6 beta-naltrexol and naltrexone against morphine analgesia.
METHODSThe 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.
RESULTS6 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.
CONCLUSIONCompared with naltrexone, 6 beta-naltrexol was less potent but duration was longer.
