title: Differential effects of L-tryptophan and L-leucine administration on brain resting state functional networks and plasma hormone levels.
abstract: Depending on their protein content, single meals can rapidly influence the uptake of amino acids into the brain and thereby modify brain functions. The current study investigates the effects of two different amino acids on the human gut-brain system, using a multimodal approach, integrating physiological and neuroimaging data. In a randomized, placebo-controlled trial, L-tryptophan, L-leucine, glucose and water were administered directly into the gut of 20 healthy subjects. Functional MRI (fMRI) in a resting state paradigm (RS), combined with the assessment of insulin and glucose blood concentration, was performed before and after treatment. Independent component analysis with dual regression technique was applied to RS-fMRI data. Results were corrected for multiple comparisons. In comparison to glucose and water, L-tryptophan consistently modifies the connectivity of the cingulate cortex in the default mode network, of the insula in the saliency network and of the sensory cortex in the somatosensory network. L-leucine has lesser effects on these functional networks. L-tryptophan and L-leucine also modified plasma insulin concentration. Finally, significant correlations were found between brain modifications after L-tryptophan administration and insulin plasma levels. This study shows that acute L-tryptophan and L-leucine intake directly influence the brain networks underpinning the food-reward system and appetite regulation.
authors.affiliation: Department of Psychiatry, University Hospital of Basel, CH-4012 Basel, Switzerland.
authors.forename: Davide
authors.initials: D
authors.lastname: Zanchi
authors.affiliation: Department of Biomedicine, University Hospital, CH-4031 Basel Switzerland.
authors.forename: Anne Christin
authors.initials: AC
authors.lastname: Meyer-Gerspach
authors.affiliation: Department of Psychiatry, University Hospital of Basel, CH-4012 Basel, Switzerland.
authors.forename: Claudia
authors.initials: C
authors.lastname: Suenderhauf
authors.affiliation: Department of Biomedicine, University Hospital, CH-4031 Basel Switzerland.
authors.forename: Katharina
authors.initials: K
authors.lastname: Janach
authors.affiliation: Diabetes Complications Research Centre, Conway Institute University College Dublin, Dublin, Ireland.
authors.forename: Carel W
authors.initials: CW
authors.lastname: le Roux
authors.affiliation: Faculty of Medicine of the University of Geneva, Switzerland.|Affidea CDRC - Centre Diagnostique Radiologique de Carouge, Switzerland.|Department of Surgical Sciences, Radiology Uppsala University, Uppsala, Sweden.|Department of Neuroradiology, University Hospital Freiburg, Germany.|Faculty of Medicine of the University of Geneva, Switzerland.
authors.forename: Sven
authors.initials: S
authors.lastname: Haller
authors.affiliation: Department of Research, St. Claraspital, Switzerland.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Drewe
authors.affiliation: Department of Research, St. Claraspital, Switzerland.
authors.forename: Christoph
authors.initials: C
authors.lastname: Beglinger
authors.affiliation: Department of Biomedicine, University Hospital, CH-4031 Basel Switzerland.|Department of Research, St. Claraspital, Switzerland.
authors.forename: Bettina K
authors.initials: BK
authors.lastname: Wölnerhanssen
authors.affiliation: Department of Psychiatry, University Hospital of Basel, CH-4012 Basel, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Borgwardt
mesh_terms: D000328:Adult; D018687:Antidepressive Agents, Second-Generation / Q000008:administration & dosage*; D001786:Blood Glucose; D001921:Brain / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000502:physiology*; D005260:Female; D005947:Glucose / Q000008:administration & dosage; D064368:Healthy Volunteers; D006801:Humans; D007328:Insulin / Q000097:blood*; D007930:Leucine / Q000008:administration & dosage*; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000187:drug effects / Q000502:physiology; D010919:Placebos / Q000008:administration & dosage; D010949:Plasma / Q000737:chemistry*; D014364:Tryptophan / Q000008:administration & dosage*; D014867:Water / Q000008:administration & dosage; D055815:Young Adult
chemical_list: D018687:Antidepressive Agents, Second-Generation; D001786:Blood Glucose; D007328:Insulin; D010919:Placebos; D014867:Water; D014364:Tryptophan; D007930:Leucine; D005947:Glucose