Cerebral serotonin transporter binding is inversely related to body mass index

• Published in: NeuroImage (Orlando, Fla.) Fla.), 2010-08, Vol.52 (1), p.284-289
• Main Authors: Erritzoe, D., Frokjaer, V.G., Haahr, M.T., Kalbitzer, J., Svarer, C., Holst, K.K., Hansen, D.L., Jernigan, T.L., Lehel, S., Knudsen, G.M.
• Format: Article
• Language: English
• Subjects: Adult; Age; Alcohol Drinking - metabolism; Benzylamines; Body Mass Index; Brain - diagnostic imaging; Brain - metabolism; Brain research; Carbon Radioisotopes; Female; Gender; Human subjects; Humans; Imaging; Linear Models; Magnetic Resonance Imaging; Male; Medical imaging; Menstruation; Middle Aged; Obesity; Obesity - metabolism; PET; Photic Stimulation; Positron-Emission Tomography; Protozoan Proteins; Questionnaires; Serotonin; Serotonin Plasma Membrane Transport Proteins - metabolism; Serotonin transporter; Sex Characteristics; Signal Processing, Computer-Assisted; Smoking - metabolism; Studies; Tobacco; Weight control
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2010.03.086

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 [11C]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/m2). 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.