Quantitative comparison of ohmefentanyl isomers induced conditioning placepreference in mice

Differences of analgesia and withdrawal response among ohmefentanyl stereoi somers have been studied. In the present study, Quantitative comparison of reinforcing effects of ohmefentanyl stereoisomers and morphine was performe d by using a conditioned place preference design in mice. Results showed th at morphine and ohmefentanyl stereoisomers were able to increase significan tly the time spent in the drug-paired side with respect to vehicle treated animals. A good linear correlation between doses of drugs and number of mic e with place preference was found within a given dose range. On the basis o f the dose-response curve analysis, ohmefentanyl stereoisomers displayed a significant difference in place preference ED50. The addictive index (analg esic ED50 / place preference ED50) was used to assess the addictive potenti al of drugs. It was demonstrated that the addictive potential of ohmefentan yl stereoisomers did not exhibit a large difference as addictive index. Amo ng these stereoisomers, the addictive potential of compound F9208 was marke dly lower than that of morphine. (C) 2001 Elsevier Science Inc. All rights reserved.