title: Dopamine Depletion Reduces Food-Related Reward Activity Independent of BMI.
abstract: Reward sensitivity and possible alterations in the dopaminergic-reward system are associated with obesity. We therefore aimed to investigate the influence of dopamine depletion on food-reward processing. We investigated 34 female subjects in a randomized placebo-controlled, within-subject design (body mass index (BMI)=27.0 kg/m(2) ±4.79 SD; age=28 years ±4.97 SD) using an acute phenylalanine/tyrosine depletion drink representing dopamine depletion and a balanced amino acid drink as the control condition. Brain activity was measured with functional magnetic resonance imaging during a 'wanting' and 'liking' rating of food items. Eating behavior-related traits and states were assessed on the basis of questionnaires. Dopamine depletion resulted in reduced activation in the striatum and higher activation in the superior frontal gyrus independent of BMI. Brain activity during the wanting task activated a more distributed network than during the liking task. This network included gustatory, memory, visual, reward, and frontal regions. An interaction effect of dopamine depletion and the wanting/liking task was observed in the hippocampus. The interaction with the covariate BMI was significant in motor and control regions but not in the striatum. Our results support the notion of altered brain activity in the reward and prefrontal network with blunted dopaminergic action during food-reward processing. This effect is, however, independent of BMI, which contradicts the reward-deficiency hypothesis. This hints to the hypothesis suggesting a different or more complex mechanism underlying the dopaminergic reward function in obesity.
authors.affiliation: Institute for Medical Psychology and Behavioural Neurobiology, University of Tübingen, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Frank
authors.affiliation: Institute for Medical Psychology and Behavioural Neurobiology, University of Tübingen, Germany.|Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.|German Center for Diabetes Research, Tübingen, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Veit
authors.affiliation: Department of Psychosomatic Medicine and Psychotherapy, University Hospital Tübingen, Tübingen, Germany.
authors.forename: Helene
authors.initials: H
authors.lastname: Sauer
authors.affiliation: Department of Psychosomatic Medicine and Psychotherapy, University Hospital Tübingen, Tübingen, Germany.
authors.forename: Paul
authors.initials: P
authors.lastname: Enck
authors.affiliation: Department of General Internal Medicine and Psychosomatics, University Hospital Heidelberg, Heidelberg, Germany.|Department of Psychosomatic Medicine and Psychotherapy, The University of Duisburg-Essen.
authors.forename: Hans-Christoph
authors.initials: HC
authors.lastname: Friederich
authors.affiliation: Department of Internal Medicine IV, University Hospital Tübingen, Tübingen, Germany.
authors.forename: Theresa
authors.initials: T
authors.lastname: Unholzer
authors.affiliation: Department of Internal Medicine IV, University Hospital Tübingen, Tübingen, Germany.
authors.forename: Ute-Maria
authors.initials: UM
authors.lastname: Bauer
authors.affiliation: Department of Internal Medicine IV, University Hospital Tübingen, Tübingen, Germany.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Linder
authors.affiliation: Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.|German Center for Diabetes Research, Tübingen, Germany.|Department of Internal Medicine IV, University Hospital Tübingen, Tübingen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Heni
authors.affiliation: Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.|German Center for Diabetes Research, Tübingen, Germany.|Department of Internal Medicine IV, University Hospital Tübingen, Tübingen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Fritsche
authors.affiliation: Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.|German Center for Diabetes Research, Tübingen, Germany.|Department of Internal Medicine IV, University Hospital Tübingen, Tübingen, Germany.|Department of Pharmacy and Biochemistry, Faculty of Science, University of Tübingen, Tübingen, Germany.
authors.forename: Hubert
authors.identifier: http://orcid.org/0000-0002-8859-4661
authors.initials: H
authors.lastname: Preissl
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology; D015992:Body Mass Index; D001921:Brain / Q000000981:diagnostic imaging / Q000502:physiology; D001923:Brain Chemistry / Q000502:physiology; D003342:Corpus Striatum / Q000502:physiology; D004298:Dopamine / Q000172:deficiency / Q000502:physiology*; D005260:Female; D005502:Food; D059907:Functional Neuroimaging; D006624:Hippocampus / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D009765:Obesity / Q000503:physiopathology; D017397:Prefrontal Cortex / Q000502:physiology; D012201:Reward; D016037:Single-Blind Method; D055815:Young Adult
chemical_list: D000596:Amino Acids; D004298:Dopamine