Aim. Endogenous opioids are involved in feeding behavior probably mediating the hedonic properties of food intake. Inhibition of mu-opioid receptors reduces subjective pleasantness of palatable foods in healthy subjects. Aim of our study was to evaluate mu receptors availability (?OR) in the brain of obese subjects by means of Positron Emission Tomography (PET) and the ?OR agonist [C-11]Carfentanil ([C-11]CARF) as radioligand. Materials and Methods. Seven normal weight (NW, BMI=23.5±1.0, age=26.5±6.1) and seven obese (OB, BMI=38.5±3.4; age=30.7±8.2) male subjects were investigated. The day of PET study, subjects underwent a battery of hemato-chemical tests in fasting condition and a psychometric evaluation. Results. As expected, increased insulin levels, HOMA-IR and reduced HDL cholesterol were found in the group of OB subjects; ?OR was reduced in different brain areas of OB subjects (caudate nucleus, thalamus, hypothalamus and prefrontal cortex; p<0.05). In the region above and in the insula, ?OR availability was negative correlated with subjects BMI and selected sub-items of feeding behaviour psychometric tests in brain region related to food intake and rewarding. In addition we found a positive correlation with circulating HDL-cholesterol (SPM analysis p<0.01). Conclusion. These findings confirm the involvement of ?OR receptors in feeding behaviour and a tight association between dopamine and opiate system and represent the clue for a better understanding of the molecular basis of food rewarding in obesity. The positive correlation with HDL cholesterol warrants further evaluation on the light of a possible association between metabolic syndrome and mood disorders.
In vivo evaluation of mu opioid receptors in obesity: a PET in vivo
Rosa Maria Moresco;Giovanna Rizzo;Mario Matarrese;
2012
Abstract
Aim. Endogenous opioids are involved in feeding behavior probably mediating the hedonic properties of food intake. Inhibition of mu-opioid receptors reduces subjective pleasantness of palatable foods in healthy subjects. Aim of our study was to evaluate mu receptors availability (?OR) in the brain of obese subjects by means of Positron Emission Tomography (PET) and the ?OR agonist [C-11]Carfentanil ([C-11]CARF) as radioligand. Materials and Methods. Seven normal weight (NW, BMI=23.5±1.0, age=26.5±6.1) and seven obese (OB, BMI=38.5±3.4; age=30.7±8.2) male subjects were investigated. The day of PET study, subjects underwent a battery of hemato-chemical tests in fasting condition and a psychometric evaluation. Results. As expected, increased insulin levels, HOMA-IR and reduced HDL cholesterol were found in the group of OB subjects; ?OR was reduced in different brain areas of OB subjects (caudate nucleus, thalamus, hypothalamus and prefrontal cortex; p<0.05). In the region above and in the insula, ?OR availability was negative correlated with subjects BMI and selected sub-items of feeding behaviour psychometric tests in brain region related to food intake and rewarding. In addition we found a positive correlation with circulating HDL-cholesterol (SPM analysis p<0.01). Conclusion. These findings confirm the involvement of ?OR receptors in feeding behaviour and a tight association between dopamine and opiate system and represent the clue for a better understanding of the molecular basis of food rewarding in obesity. The positive correlation with HDL cholesterol warrants further evaluation on the light of a possible association between metabolic syndrome and mood disorders.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
