Cerebral serotonin transporter binding is inversely related to body mass index

Overweight and obesity is a health threat of increasing concern and understanding the neurobiology behind obesity is instrumental to the development of effective treatment regimes Serotonergic neurotransmission is critically involved in eating behaviour: cerebral level of serotonin (5-HT) in animal models is inversely related to food intake and body weight and some effective anti-obesity agents involve blockade of the serotonin transporter (SERT) We investigated in 60 healthy volunteers body mass index (BMI) and regional cerebral SERT binding as measured with [C-11]DASB PET In a linear regression model with adjustment for relevant covariates, we found that cortical and subcortical SERT binding was negatively correlated to BMI (-0 003 to -0 012 BPND unit per kg/m(2)) Tobacco smoking and alcohol consumption did not affect cerebral SERT binding Several effective anti-obesity drugs encompass blockade of the SERT, yet, our study is the first to demonstrate an abnormally decreased cerebral SERT binding in obese individuals Whether the SERT has a direct role in the regulation of appetite and eating behaviour or whether the finding is due to a compensatory downregulation of SERT secondary to other dysfunction(s) in the serotonergic transmitter system, such as low baseline serotonin levels, remains to be established (C) 2010 Elsevier Inc All rights reserved