The Fruit Essential oil of Cuminum cyminum L. Reduced the Acquisition but not Expression of Ineffective dose of Morphine-Induced Conditioned Place Preference in Morphine- Sensitized Mice

Background: cuminum cyminum fruit essential oil (feo) dose-dependently canattenuate the expression of morphine tolerance and dependence in morphine-dependentmice.objective: in this study, the effects of cuminum cyminum feo on acquisition andexpression of morphine-induced conditioned place preference (cpp) in morphinesensitizedmice were studied.methods: repeated subcutaneous (s.c.) administration of morphine (5 mg/kg), once dailyfor three and 5 days free of the opioid (sensitization period), increased conditioningresponse induced by ineffective doses of morphine (0.25, 0.5 and 0.75 mg/kg).results: the results showed that intra-peritoneal (i.p.) injection of cumin feo (0.001,0.01, 0.1, 0.5, 1 and 2%; 5 ml/kg) or tween-80 (0.5%; 5 ml/kg), 60 min beforeadministration of morphine or saline during sensitization period (acquisition), decreasedthe conditioning response induced by ineffective dose of morphine (0.5 mg/kg; s.c.) at thedoses of 1% (p<0.05) and 2% (p<0.001) while cumin feo (0.001-2%; i.p.), just 60 minbefore the test on post-conditioning phase (expression experiments), did not alter theconditioning scores in morphine- and non-sensitized mice.conclusion: our findings showed that the cuminum cyminum fruit essential oil reducesthe acquisition but not expression of morphine-induced conditioned place preference inmorphine-sensitized mice.