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Published on: November 6, 2018
Conditioned place preference induced by morphine and morphine-6-glucuronide in mice
Vigdis Vindenes1, Marte Handal, Ase Ripel
1Norwegian Institute of Public Health, Division of Forensic Toxicology and Drug Abuse, PO Box 4404, Nydalen, NO-0403 Oslo, Norway. vigdis.vindenes@fhi.no
Pharmacology, Biochemistry, and Behavior
|October 3, 2006
Summary
Morphine-6-glucuronide (M6G) and morphine show comparable reward effects in mice, influencing pain management. Morphine-3-glucuronide (M3G) tended to cause aversion, indicating differential metabolite properties.
Area of Science:
- Pharmacology
- Neuroscience
- Drug Metabolism
Background:
- Morphine-6-glucuronide (M6G) is an active metabolite of morphine with analgesic properties and fewer side effects.
- M6G is planned for introduction as a postoperative pain treatment.
- The reward effects of morphine glucuronides (M3G and M6G) have not been extensively studied.
Purpose of the Study:
- To investigate the reward effects of morphine, M6G, and M3G using the conditioned place preference (CPP) paradigm in mice.
- To compare the reward potential of M6G and M3G relative to the parent drug, morphine.
Main Methods:
- Conditioned place preference (CPP) was assessed in C57BL/6J-Bom mice using a biased two-compartment paradigm.
- Mice received subcutaneous injections of varying doses of morphine, M6G, or M3G during conditioning.
Main Results:
- Both morphine and M6G induced dose-dependent CPP in the 'closed' compartment, with maximal effects at 30 micromol/kg.
- In the 'open' compartment, maximal CPP for morphine and M6G occurred at 10 micromol/kg, without a clear dose response.
- M3G showed a non-significant tendency towards conditioned place aversion (CPA).
Conclusions:
- Morphine and its active metabolite M6G exhibit comparable reward effects, although dose-dependency varies by compartment.
- M6G's reward effects are similar to morphine, supporting its therapeutic potential.
- M3G may possess aversive properties, warranting further investigation.
