Abstract
RATIONALE: Cocaine addiction is a chronic relapsing disorder that lacks of an effective treatment. Isoflavones are a family of compounds present in different plants and vegetables like soybeans that share a common chemical structure. Previous studies have described that synthetic derivatives from the natural isoflavone daidzin can modulate cocaine addiction, by a mechanism suggested to involve aldehyde-dehydrogenase (ALDH) activities. OBJECTIVES: Based on these previous studies, we investigated the effects of three natural isoflavones, daidzin, daidzein, and genistein, on the modulation of the cocaine reinforcing effects and on cue-induced reinstatement in an operant mouse model of cocaine self-administration. RESULTS: Chronic treatment with daidzein or genistein decreased operant responding to obtain cocaine intravenous infusions. On the other hand, daidzein and daidzin, but not genistein, were effective in decreasing cue-induced cocaine reinstatement. Complementary studies revealed that daidzein effects on cocaine reinforcement were mediated through a mechanism that involved dopamine type-2/3 receptors (DA-D2/3) activities. CONCLUSIONS: Our results suggest that these natural compounds alone or in combination can be a potential therapeutic approach for cocaine addiction. Further clinical studies are required in order to ascertain their potential therapeutic use.