title: Influence of Tryptophan and Serotonin on Mood and Cognition with a Possible Role of the Gut-Brain Axis.
abstract: The serotonergic system forms a diffuse network within the central nervous system and plays a significant role in the regulation of mood and cognition. Manipulation of tryptophan levels, acutely or chronically, by depletion or supplementation, is an experimental procedure for modifying peripheral and central serotonin levels. These studies have allowed us to establish the role of serotonin in higher order brain function in both preclinical and clinical situations and have precipitated the finding that low brain serotonin levels are associated with poor memory and depressed mood. The gut-brain axis is a bi-directional system between the brain and gastrointestinal tract, linking emotional and cognitive centres of the brain with peripheral functioning of the digestive tract. An influence of gut microbiota on behaviour is becoming increasingly evident, as is the extension to tryptophan and serotonin, producing a possibility that alterations in the gut may be important in the pathophysiology of human central nervous system disorders. In this review we will discuss the effect of manipulating tryptophan on mood and cognition, and discuss a possible influence of the gut-brain axis.
authors.affiliation: School of Medical Sciences, Health Innovations Research Institute, RMIT University, Melbourne, Victoria 3083, Australia. trisha.jenkins@rmit.edu.au.
authors.forename: Trisha A
authors.initials: TA
authors.lastname: Jenkins
authors.affiliation: School of Medical Sciences, Health Innovations Research Institute, RMIT University, Melbourne, Victoria 3083, Australia. jason.nguyen2@student.rmit.edu.au.
authors.forename: Jason C D
authors.initials: JC
authors.lastname: Nguyen
authors.affiliation: School of Medical Sciences, Health Innovations Research Institute, RMIT University, Melbourne, Victoria 3083, Australia. kate.polglaze@rmit.edu.au.
authors.forename: Kate E
authors.initials: KE
authors.lastname: Polglaze
authors.affiliation: School of Medical Sciences, Health Innovations Research Institute, RMIT University, Melbourne, Victoria 3083, Australia. paul.bertrand@rmit.edu.au.|School of Medical Sciences, University of New South Wales, Sydney 2052, Australia. paul.bertrand@rmit.edu.au.
authors.forename: Paul P
authors.initials: PP
authors.lastname: Bertrand
mesh_terms: D000339:Affect / Q000187:drug effects*; D001921:Brain / Q000378:metabolism* / Q000382:microbiology; D002493:Central Nervous System Diseases / Q000382:microbiology / Q000503:physiopathology; D003071:Cognition / Q000187:drug effects*; D000069196:Gastrointestinal Microbiome / Q000502:physiology; D041981:Gastrointestinal Tract / Q000382:microbiology / Q000502:physiology*; D006801:Humans; D012701:Serotonin / Q000378:metabolism*; D014364:Tryptophan / Q000378:metabolism*
chemical_list: D012701:Serotonin; D014364:Tryptophan
keywords: gut-brain axis; mood and cognition; serotonin; tryptophan