Regional mu-opioid receptor binding in insular cortex is decreased in bulimia nervosa and correlates inversely with fasting behavior.

UNLABELLED: The endogenous opioid system of the brain has been implicated in feeding behavior. Abnormal repeated activation of this system may constitute a neural substrate for the compulsive eating behavior observed in bulimia nervosa. This study examined the binding potential of the brain mu-opioid receptor (mu-OR) in bulimia nervosa.

METHODS

Eight women with bulimia nervosa and 8 female controls underwent brain MRI followed by (11)C-carfentanil PET. Voxel-based methods were used to assess group differences in mu-OR binding between controls and bulimic subjects and to correlate mu-OR binding with the frequency of recent self-reported abnormal eating behaviors in bulimic subjects.

RESULTS

mu-OR binding in the left insular cortex was less in bulimic subjects than in controls and correlated negatively with recent fasting behavior.

CONCLUSION

Changes in mu-OR binding in the insula may be important in the pathogenesis or maintenance of the self-perpetuating behavioral cycle of bulimic subjects because the insula is the primary gustatory cortex and has repeatedly been implicated in the processing of the reward value of food.