The Effect of Ldopa on Creating Dependency of Morphine in Male Mature Mice Using Conditioned Place Preference (CPP) Method

Morphine and other opioid drugs through by increasing brain dopaminergic systems are used to induce dependence and craving. This study investigated the effects of Ldopa as dopamine precursor on creating dependency of morphine. In this study, 56 male mature mice (about 80 days old) with a weight of 30-35 grams were enrolled as the experimental, sham and the control groups. The experimental groups included 5 subgroups treated with either morphine, Ldopa with dose of minimum, Ldopa with dose of maximum, morphine+ Ldopa with dose of minimum and morphine+ Ldopa with dose of maximum. Morphine was used for dependency and Ldopa was used as dopamine precursor and CCP method was used to estimate dependency. The data were statistically analyzed by independent Student’s t-test using SPSS version 18.Results showed no meaningful difference between the control and the witness groups. However, there was a meaningful difference between the control group with morphine, Ldopa and Ldopa+morphine groups in preferring a location to receive morphine. And also no meaningful difference between the Ldopa+morphine group in preferring the location for receiving the drug compared with the group receiving morphine alone.Morphine through stimulating mesolimbic dopaminergic nerve pathways and Ldopa through increased production of dopamine in the brain are causes increasing dependence.