Effects of coptis japonica on morphine-induced conditioned place preference in mice

Academic Article
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publication date

  • July 2003

abstract

  • Morphine, an analgesic with significant abuse potential, is considered addictive because of drug craving and psychological dependence. It is reported that repeated treatment of morphine can produce conditioned place preference (CPP) showing a reinforcing effect in mice. CPP is a useful method for the screening of morphine-induced psychological dependence. In the present study, we investigated the effect of the methanolic extract of Coptis japonica (MCJ) on morphine-induced CPP in mice. Furthermore, we examined c-fos expression in the parietal cortex, piriform cortex, striatum, nucleus accumbens, and hippocampus of the morphine-induced CPP mouse brain. Treatment of MCJ 100 mg/kg inhibited morphine-induced CPP. Expression of c-fos was increased in the cortex, striatum, nucleus accumbens, and hippocampus of the morphine-induced CPP mouse brain. These increases of expression were inhibited by treatment with MCJ 100 mg/kg, compared to the morphine control group. Taken together, these results suggest that MCJ inhibits morphine-induced CPP through the regulation of c-fos expression in the mouse brain.