Dopaminergic network can be modified by the blood glucose levels. The medetomidine, which is commonly used anesthesia in functional MRI, increases the blood glucose levels. In the present study, we compared the functional connectivity in fasted or non-fasted mice under isoflurane or medetomidine anesthesia. The blood glucose levels in non-fasted mice under medetomidine anesthesia significantly increased but isoflurane did not. The correlation coefficients in the dopamine network were significantly higher in fasted mice compared with non-fasted mice under medetomidine, but not under isoflurane. These results indicate that medetomidine-induced blood glucose increase altered the functional connectivity in the dopaminergic network.