Positron emission tomography (PET) is a nuclear medicine technique that allows the measurement, in vivo in humans, with a non-invasive method, of the regional distribution of substances marked with positron emission isotopes such as C-11, in different districts bodily. Using this method it is therefore possible to directly measure at the level of the brain the distribution of receptors, enzymes, reuptake sites, as well as their interaction with various classes of drugs and the related modifications that may be present during the pathology.

The evaluation of the endogenous opiate receptor system will be implemented by comparing the in vivo binding maps of 11C carfentanil in the two groups of subjects under examination (normal weight, NOR and obese, OB, based on body mass index, BMI); in fact, experimental data deriving from previous studies support the hypothesis that the basis of obesity and incorrect eating behaviors is a dysregulation of the endogenous ligand-mu opioid receptor interaction. The comparison of the data deriving from the analysis of the PET exams performed on the two groups of subjects will therefore allow us to evaluate the alterations of the opioid system possibly present in obese subjects.

Inclusion Criteria:

• aged between 18 and 40 years;
• structured sports activity < 2 hours per week

Exclusion Criteria:

• drug allergy;
• clinical evidence of neuropsychiatric pathologies.

For the study, 10 normal male subjects and 10 obese subjects not affected by mental or physical pathological alterations will be recruited.