Prefrontal and striatal dopamine metabolism during enhanced rebound hyperphagia induced by space restriction--a rat model of binge eating

BACKGROUND: Several lines of evidence indicate that abnormalities in brain dopamine and serotonin metabolism may play an important role in bulimia nervosa. However, the regional neurochemical mechanism of the binge eating is poorly understood. Our purpose was to elucidate brain neurochemical mechanisms of binge eating using a rat model. METHODS: The dopamine release and metabolism in the prefrontal cortex (PFC) and in the ventrolateral striatum (VLS) of rats were studied using microdialysis during enhanced rebound hyperphagia induced by space restriction (an animal model of binge eating). RESULTS: The rats showed rebound hyperphagic state when they were released from scheduled feeding (2 hours/day feeding for 7 days). The hyperphagia was further enhanced when they were put in a space-restricted cage where their mobility was restricted. Dopamine release and metabolism were increased both in the PFC and in the VLS during the enhanced rebound hyperphagia. CONCLUSIONS: These results tentatively suggest that increased dopamine release and metabolism in the PFC and in the VLS may be related to space restriction and to activation of motor function involved in feeding behavior, respectively. The enhanced rebound hyperphagia induced by space restriction may be useful as an animal model of binge eating.