Abstract
Intermitted ingestion of sugar or fat has been shown to induce binge-type eating, a type of addictive behaviors. Highly palatable foods such as sugar or fat may affect the brain in a similar way to addictive drugs in which nucleus accumbens (NAc) is one of the major target sites. In this study, we investigated the dopamine levels in the NAc in fat binge-type eating (FBE) using in vivo microdialysis. FBE was induced by allowing rats to access to fat for 1 hour every 2nd day without any caloric restriction. In this condition, rats developed FBE and consumed approximately triple amount in 5th 1 hour fat access compared to 1st 1hour fat access. The control group had access to fat only once to avoid neophobia. After these schedules, microdialysis probes were implanted to the NAc and dopamine responses to 20 minutes fat eating were measured. In both groups, consumption of fat increased dopamine level in NAc but the response was attenuated in FBE group. The fat consumption in the 20 minutes did not differ between FBE and control group statistically and had not correlate with dopamine increase level in NAcc through both groups. The results suggest that dopamine increase in NAc does not reflect fat consumption and is less likely to be required in an expression of FBE. [J Physiol Sci. 2007;57 Suppl:S165]
