Hunger and disinhibition but not cognitive restraint are associated with central norepinephrine transporter availability.

The relationship between food-intake related behaviours measured by the Three-Factor Eating Questionnaire (TFEQ) and in vivo norepinephrine transporter (NET) availability has not been explored yet. We investigated ten obese individuals (body mass index (BMI) 42.4 ± 3.7 kg/m2) and ten normal-weight healthy controls (HC, BMI 23.9 ± 2.5 kg/m2) with (S,S)-[11C]-O-methylreboxetine ([11C]MRB) positron emission tomography (PET). All participants completed the TFEQ, which measures cognitive restraint, disinhibition and hunger. Image analysis required magnetic resonance imaging data sets onto which volumes-of-interests were drawn. Tissue time activity curves (TACs) were obtained from the dynamic PET data followed by kinetic modeling of these regional brain TACs applying the multilinear reference tissue model (2 parameters) with the occipital cortex as reference region. Obese individuals scored significantly higher on the hunger subscale of the TFEQ. Correlative data analysis showed that a higher degree of hunger correlated negatively with the NET availability of the insular cortex in both obese individuals and HC; however, this finding was more pronounced in obesity. Further, for obese individuals, a negative correlation between disinhibition and NET BPND of the locus coeruleus was detected. In conclusion, these initial data provide in vivo imaging support for the involvement of the central NE system in maladaptive eating behaviors such as susceptibility to hunger.