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Kuwano N, Kato TA, Setoyama D, Sato-Kasai M, Shimokawa N, Hayakawa K, Ohgidani M, Sagata N, Kubo H, Kishimoto J, Kang D, Kanba S. Tryptophan-kynurenine and lipid related metabolites as blood biomarkers for first-episode drug-naïve patients with major depressive disorder: An exploratory pilot case-control study. J Affect Disord 2018; 231:74-82. [PMID: 29454180 DOI: 10.1016/j.jad.2018.01.014] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 12/26/2017] [Accepted: 01/28/2018] [Indexed: 12/11/2022]
Abstract
BACKGROUND Early intervention in depression has been critical to prevent its negative impact including suicide. Recent blood biomarker studies for major depressive disorder (MDD) have suggested that tryptophan-kynurenine and lipid related metabolites are involved in the pathophysiology of MDD. However, there have been limited studies investigating these blood biomarkers in first-episode drug-naïve MDD, which are particularly important for early intervention in depression. METHODS As an exploratory pilot case-control study, we examined the above blood biomarkers, and analyzed how these biomarkers are associated with clinical variables in first-episode drug-naïve MDD patients, based on metabolome/lipidome analysis. RESULTS Plasma tryptophan and kynurenine levels were significantly lower in MDD group (N = 15) compared to healthy controls (HC) group (N = 19), and plasma tryptophan was the significant biomarker to identify MDD group (area under the curve = 0.740). Lower serum high density lipoprotein-cholesterol (HDL-C) was the predictive biomarker for severity of depression in MDD group (R2 = 0.444). Interestingly, depressive symptoms were variously correlated with plasma tryptophan-kynurenine and lipid related metabolites. Moreover, plasma tryptophan-kynurenine metabolites and cholesteryl esters (CEs) were significantly correlated in MDD group, but not in HC group. LIMITATIONS This study had small sample size, and we did not use the multiple test correction. CONCLUSIONS This is the first study to suggest that not only tryptophan-kynurenine metabolites but also HDL-C and CEs are important blood biomarkers for first-episode drug-naïve MDD patients. The present study sheds new light on early intervention in clinical practice in depression, and further clinical studies especially large-scale prospective studies are warranted.
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Affiliation(s)
- Nobuki Kuwano
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Takahiro A Kato
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Daiki Setoyama
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Mina Sato-Kasai
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Norihiro Shimokawa
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Kohei Hayakawa
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Masahiro Ohgidani
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Noriaki Sagata
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Hiroaki Kubo
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Junji Kishimoto
- Department of Research and Development of Next Generation Medicine, Faculty of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Dongchon Kang
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Shigenob Kanba
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
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Suga H, Asakura K, Kobayashi S, Nojima M, Sasaki S. Association between habitual tryptophan intake and depressive symptoms in young and middle-aged women. J Affect Disord 2018; 231:44-50. [PMID: 29438897 DOI: 10.1016/j.jad.2018.01.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Revised: 12/31/2017] [Accepted: 01/29/2018] [Indexed: 12/17/2022]
Abstract
BACKGROUND The intake of tryptophan, the precursor of serotonin, is assumed to affect serotonin availability and depression onset. Nevertheless, a definitive relationship between dietary tryptophan intake and depressive symptoms has not been established. We examined the association between tryptophan intake and depressive symptoms screened in a group of 4272 first-year female dietetic students and 3651 their mothers. METHODS Dietary tryptophan intake during the preceding month was assessed with a validated, self-administered diet history questionnaire. Depressive symptoms were assessed with the Center for Epidemiologic Studies Depression Scale (CES-D) using two cutoff scores: CES-D score ≥ 16 and CES-D score ≥ 19 (the optimal cutoff score for Japanese people). The multivariate adjusted prevalence ratio (PR) and 95% confidence interval (CI) for depressive symptoms were calculated using Poisson regression analysis. RESULTS The prevalence of depressive symptoms (CES-D score ≥ 16) was 50.0% for young women and 26.5% for middle-aged women. The adjusted PR (95% CI) for depressive symptoms in the highest versus lowest quintile of tryptophan intake was 0.84 (0.75, 0.93) in young women (P for trend < 0.0001) and 0.83 (0.64, 1.01) in middle-aged women (P for trend < 0.0001). These associations were stable even when depressive symptoms were defined as a CES-D score ≥ 19. LIMITATIONS This is a cross-sectional study. Depressive symptoms were assessed using a self-reported questionnaire. CONCLUSIONS This cross-sectional study showed that a higher tryptophan intake was independently associated with a lower prevalence of depressive symptoms in young Japanese women.
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Affiliation(s)
- Hitomi Suga
- Department of Social and Preventive Epidemiology, School of Public Health, The University of Tokyo, Tokyo, Japan.
| | - Keiko Asakura
- Department of Environmental and Occupational Health, School of Medicine, Toho University, Tokyo, Japan
| | - Satomi Kobayashi
- Department of Social and Preventive Epidemiology, School of Public Health, The University of Tokyo, Tokyo, Japan
| | - Masanori Nojima
- Division of Advanced Medicine Promotion, The Advanced Clinical Research Center, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Satoshi Sasaki
- Department of Social and Preventive Epidemiology, School of Public Health, The University of Tokyo, Tokyo, Japan
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Tryptophan supplementation and serotonin function: genetic variations in behavioural effects. Proc Nutr Soc 2018; 77:174-188. [DOI: 10.1017/s0029665117004451] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The neurotransmitter serotonin has a role in affective disorders such as depression and anxiety, as well as sleep, cognitive function and appetite. This review examines the evidence that serotonin-related genotypes may moderate the behavioural effects of supplementation with the serotonin precursor amino acidl-tryptophan (TRP), on which synthesis of serotonin (or 5-hydroxytryptamine; 5-HT) depends. However, 95 % of serotonin is synthesised and used in the periphery, and TRP is also metabolised via non-5-HT routes such as the kynurenine pathway. Moreover, understanding of genotypes involved in regulation of serotonin raises questions over the generalisability of TRP effects on behaviour across individuals with varied serotonergic genotypes. To date, only differences between variants of the 5-HT transporter-linked promoter region (5-HTTLPR) have been investigated in relation to behavioural effects of TRP supplementation. Effects of 5-HTTLPR genotypes are usually compared between the alleles that are either high (L/L′) or low (S/S′) expressing of mRNA for the 5-HT transporter receptor. Yet, another key genetic variable is sex: in women, the S/S′ genotype predicts sensitivity to improved mood and reduced cortisol by TRP supplementation, during stressful challenges, whereas the L/L′ genotype protects against stress-induced mood deterioration. In men, the L/L′ genotype may confer risk of stress-induced increases in negative affect; there are insufficient data to assess effects on male S/S′ genotypes. However, better-powered studies to detect sex by genotype by stress by TRP interactions, as well as consideration of more genotypes, are needed before strong conclusions and recommendations for behavioural effects of TRP treatment can be reached.
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Keller B, Mestre-Pinto JI, Álvaro-Bartolomé M, Martinez-Sanvisens D, Farre M, García-Fuster MJ, García-Sevilla JA, Torrens M. A Biomarker to Differentiate between Primary and Cocaine-Induced Major Depression in Cocaine Use Disorder: The Role of Platelet IRAS/Nischarin (I 1-Imidazoline Receptor). Front Psychiatry 2017; 8:258. [PMID: 29326609 PMCID: PMC5757145 DOI: 10.3389/fpsyt.2017.00258] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 11/13/2017] [Indexed: 12/29/2022] Open
Abstract
The association of cocaine use disorder (CUD) and comorbid major depressive disorder (MDD; CUD/MDD) is characterized by high prevalence and poor treatment outcomes. CUD/MDD may be primary (primary MDD) or cocaine-induced (CUD-induced MDD). Specific biomarkers are needed to improve diagnoses and therapeutic approaches in this dual pathology. Platelet biomarkers [5-HT2A receptor and imidazoline receptor antisera selected (IRAS)/nischarin] were assessed by Western blot in subjects with CUD and primary MDD (n = 16) or CUD-induced MDD (n = 9; antidepressant free, AD-; antidepressant treated, AD+) and controls (n = 10) at basal level and/or after acute tryptophan depletion (ATD). Basal platelet 5-HT2A receptor (monomer) was reduced in comorbid CUD/MDD subjects (all patients: 43%) compared to healthy controls, and this down-regulation was independent of AD medication (decreases in AD-: 47%, and in AD+: 40%). No basal differences were found for IRAS/nischarin contents in AD+ and AD- comorbid CUD/MDD subjects. The comparison of IRAS/nischarin in the different subject groups during/after ATD showed opposite modulations (i.e., increases and decreases) in response to low plasma tryptophan levels with significant differences discriminating between the subgroups of CUD with primary MDD and CUD-induced MDD. These specific alterations suggested that platelet IRAS/nischarin might be useful as a biomarker to discriminate between primary and CUD-induced MDD in this dual pathology.
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Affiliation(s)
- Benjamin Keller
- Laboratori de Neurofarmacologia, IUNICS, Universitat de les Illes Balears (UIB), Fundació Institut d’Investigació Sanitària Illes Balears (IdISBa), Palma, Majorca, Spain
- Redes Temáticas de Investigación Cooperativa en Salud – Red de Trastornos Adictivos (RETICS-RTA), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Joan-Ignasi Mestre-Pinto
- Redes Temáticas de Investigación Cooperativa en Salud – Red de Trastornos Adictivos (RETICS-RTA), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
- Hospital del Mar Medical Research Institute (IMIM), Institut de Neuropsiquiatria i addiccions (INAD), Barcelona, Spain
| | - María Álvaro-Bartolomé
- Laboratori de Neurofarmacologia, IUNICS, Universitat de les Illes Balears (UIB), Fundació Institut d’Investigació Sanitària Illes Balears (IdISBa), Palma, Majorca, Spain
- Redes Temáticas de Investigación Cooperativa en Salud – Red de Trastornos Adictivos (RETICS-RTA), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Diana Martinez-Sanvisens
- Redes Temáticas de Investigación Cooperativa en Salud – Red de Trastornos Adictivos (RETICS-RTA), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
- Hospital del Mar Medical Research Institute (IMIM), Institut de Neuropsiquiatria i addiccions (INAD), Barcelona, Spain
| | - Magí Farre
- Redes Temáticas de Investigación Cooperativa en Salud – Red de Trastornos Adictivos (RETICS-RTA), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
- Hospital del Mar Medical Research Institute (IMIM), Institut de Neuropsiquiatria i addiccions (INAD), Barcelona, Spain
- Hospital Universitari Germans Trias i Pujol (IGTP), Badalona, Spain
- Universitat Autònoma de Barcelona (UAB), Barcelona, Spain
| | - M. Julia García-Fuster
- Laboratori de Neurofarmacologia, IUNICS, Universitat de les Illes Balears (UIB), Fundació Institut d’Investigació Sanitària Illes Balears (IdISBa), Palma, Majorca, Spain
- Redes Temáticas de Investigación Cooperativa en Salud – Red de Trastornos Adictivos (RETICS-RTA), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Jesús A. García-Sevilla
- Laboratori de Neurofarmacologia, IUNICS, Universitat de les Illes Balears (UIB), Fundació Institut d’Investigació Sanitària Illes Balears (IdISBa), Palma, Majorca, Spain
- Redes Temáticas de Investigación Cooperativa en Salud – Red de Trastornos Adictivos (RETICS-RTA), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Marta Torrens
- Redes Temáticas de Investigación Cooperativa en Salud – Red de Trastornos Adictivos (RETICS-RTA), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
- Hospital del Mar Medical Research Institute (IMIM), Institut de Neuropsiquiatria i addiccions (INAD), Barcelona, Spain
- Universitat Autònoma de Barcelona (UAB), Barcelona, Spain
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Gasparini CF, Smith RA, Griffiths LR. Genetic and biochemical changes of the serotonergic system in migraine pathobiology. J Headache Pain 2017; 18:20. [PMID: 28194570 PMCID: PMC5307402 DOI: 10.1186/s10194-016-0711-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 12/09/2016] [Indexed: 12/23/2022] Open
Abstract
Migraine is a brain disorder characterized by a piercing headache which affects one side of the head, located mainly at the temples and in the area around the eye. Migraine imparts substantial suffering to the family in addition to the sufferer, particularly as it affects three times more women than men and is most prevalent between the ages of 25 and 45, the years of child rearing. Migraine typically occurs in individuals with a genetic predisposition and is aggravated by specific environmental triggers. Attempts to study the biochemistry of migraine began as early as the 1960s and were primarily directed at serotonin metabolism after an increase of 5-hydroxyindoleacetic acid (5-HIAA), the main metabolite of serotonin was observed in urine of migraineurs. Genetic and biochemical studies have primarily focused on the neurotransmitter serotonin, considering receptor binding, transport and synthesis of serotonin and have investigated serotonergic mediators including enzymes, receptors as well as intermediary metabolites. These studies have been mainly assayed in blood, CSF and urine as the most accessible fluids. More recently PET imaging technology integrated with a metabolomics and a systems biology platform are being applied to study serotonergic biology. The general trend observed is that migraine patients have alterations of neurotransmitter metabolism detected in biological fluids with different biochemistry from controls, however the interpretation of the biological significance of these peripheral changes is unresolved. In this review we present the biology of the serotonergic system and metabolic routes for serotonin and discuss results of biochemical studies with regard to alterations in serotonin in brain, cerebrospinal fluid, saliva, platelets, plasma and urine of migraine patients.
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Affiliation(s)
- Claudia Francesca Gasparini
- Menzies Health Institute Queensland, Griffith University Gold Coast, Parklands Drive, Southport, QLD, 4222, Australia
| | - Robert Anthony Smith
- Genomics Research Centre, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology, Musk Ave, Kelvin Grove, QLD, 4059, Australia
| | - Lyn Robyn Griffiths
- Genomics Research Centre, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Queensland University of Technology, Musk Ave, Kelvin Grove, QLD, 4059, Australia.
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Hamedinia M, Sharifi M, Hosseini-Kakhak A. The Effect of Eight Weeks of Aerobic, Anaerobic and Resistance Training on some factor of Endocannabinoid System, Serotonin, Beta-Endorphin and BDNF in Young Men. ACTA ACUST UNITED AC 2017. [DOI: 10.13005/bbra/2562] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
ABSTRACT: The aim of this study was investigated the effect of eight weeks of aerobic, anaerobic and resistance training on some endocannabinoid, serotonin, beta-endorphin and BDNF agents of young men. Thirty-two young men (19 to 25 years old) who did not have regular physical activity were randomly divided into four groups, and each of them were participated in various sports exercises for eight weeks. A group for aerobic exercises (two exercises with 65-70 maximum heart rate 3 sessions per week), an anaerobic exercise group (two exercises with a maximum intensity of 3 sessions per week), a group for circular resistance exercises (6-8 Station Which is repeated 8-12 times, and for three times a week) and finally a group was selected as a control. ELISA method was used to measure endocannabinoid system, serotonin, beta-endorphin and BDNF factors. The results showed that eight weeks aerobic training significantly increased serotonin levels and eight weeks aerobic and anaerobic exercise significantly increased BDNF. Aerobic, anaerobic, and resistive exercises have no significant effect on arachidonoyl glycerol (2-AG), anandamide(AEA) and beta-endorphin. There was a significant increase in happiness in all three training groups compared to the control group.The results of this study indicated an increase in mediation associated with pleasure and happiness in humans. Concerning the particular effect of long-term exercise on the endocannabinoid system, it is difficult to conclude.
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Affiliation(s)
- Mohammadreza Hamedinia
- Department of Sport Physiology, Faculty of Physical Education and Sports Science, Hakim Sabzevari University, Sabzevar, Iran
| | - Moslem Sharifi
- Department of Sport Physiology, Faculty of Physical Education and Sports Science, Hakim Sabzevari University, Sabzevar, Iran
| | - Alireza Hosseini-Kakhak
- Department of Sport Physiology, Faculty of Physical Education and Sports Science, Hakim Sabzevari University, Sabzevar, Iran
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Wong-Lin K, Wang DH, Moustafa AA, Cohen JY, Nakamura K. Toward a multiscale modeling framework for understanding serotonergic function. J Psychopharmacol 2017; 31:1121-1136. [PMID: 28417684 PMCID: PMC5606304 DOI: 10.1177/0269881117699612] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Despite its importance in regulating emotion and mental wellbeing, the complex structure and function of the serotonergic system present formidable challenges toward understanding its mechanisms. In this paper, we review studies investigating the interactions between serotonergic and related brain systems and their behavior at multiple scales, with a focus on biologically-based computational modeling. We first discuss serotonergic intracellular signaling and neuronal excitability, followed by neuronal circuit and systems levels. At each level of organization, we will discuss the experimental work accompanied by related computational modeling work. We then suggest that a multiscale modeling approach that integrates the various levels of neurobiological organization could potentially transform the way we understand the complex functions associated with serotonin.
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Affiliation(s)
- KongFatt Wong-Lin
- Intelligent Systems Research Centre, School of Computing and Intelligent Systems, University of Ulster, Magee Campus, Derry~Londonderry, UK
| | - Da-Hui Wang
- School of Systems Science, and National Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
| | - Ahmed A Moustafa
- School of Social Sciences and Psychology, and Marcs Institute for Brain and Behaviour, University of Western Sydney, Sydney, Australia
| | - Jeremiah Y Cohen
- Solomon H. Snyder Department of Neuroscience, Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Kae Nakamura
- Department of Physiology, Kansai Medical University, Hirakata, Osaka, Japan
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Kautzky A, James GM, Philippe C, Baldinger-Melich P, Kraus C, Kranz GS, Vanicek T, Gryglewski G, Wadsak W, Mitterhauser M, Rujescu D, Kasper S, Lanzenberger R. The influence of the rs6295 gene polymorphism on serotonin-1A receptor distribution investigated with PET in patients with major depression applying machine learning. Transl Psychiatry 2017; 7:e1150. [PMID: 28608854 PMCID: PMC5537636 DOI: 10.1038/tp.2017.108] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 04/08/2017] [Accepted: 04/20/2017] [Indexed: 12/25/2022] Open
Abstract
Major depressive disorder (MDD) is the most common neuropsychiatric disease and despite extensive research, its genetic substrate is still not sufficiently understood. The common polymorphism rs6295 of the serotonin-1A receptor gene (HTR1A) is affecting the transcriptional regulation of the 5-HT1A receptor and has been closely linked to MDD. Here, we used positron emission tomography (PET) exploiting advances in data mining and statistics by using machine learning in 62 healthy subjects and 19 patients with MDD, which were scanned with PET using the radioligand [carbonyl-11C]WAY-100635. All the subjects were genotyped for rs6295 and genotype was grouped in GG vs C allele carriers. Mixed model was applied in a ROI-based (region of interest) approach. ROI binding potential (BPND) was divided by dorsal raphe BPND as a specific measure to highlight rs6295 effects (BPDiv). Mixed model produced an interaction effect of ROI and genotype in the patients' group but no effects in healthy controls. Differences of BPDiv was demonstrated in seven ROIs; parahippocampus, hippocampus, fusiform gyrus, gyrus rectus, supplementary motor area, inferior frontal occipital gyrus and lingual gyrus. For classification of genotype, 'RandomForest' and Support Vector Machines were used, however, no model with sufficient predictive capability could be computed. Our results are in line with preclinical data, mouse model knockout studies as well as previous clinical analyses, demonstrating the two-pronged effect of the G allele on 5-HT1A BPND for, we believe, the first time. Future endeavors should address epigenetic effects and allosteric heteroreceptor complexes. Replication in larger samples of MDD patients is necessary to substantiate our findings.
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Affiliation(s)
- A Kautzky
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - G M James
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - C Philippe
- Department of Biomedical Imaging and Image-Guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria
| | - P Baldinger-Melich
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - C Kraus
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - G S Kranz
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - T Vanicek
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - G Gryglewski
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - W Wadsak
- Department of Biomedical Imaging and Image-Guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria,Center for Biomarker Research in Medicine (CBmed), Graz, Austria
| | - M Mitterhauser
- Department of Biomedical Imaging and Image-Guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria,Ludwig Boltzmann Institute for Applied Diagnostics, Vienna, Austria
| | - D Rujescu
- University Clinic for Psychiatry, Psychotherapy and Psychosomatic, Martin-Luther-University Halle-Wittenberg, Halle, Germany
| | - S Kasper
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - R Lanzenberger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria,Department of Psychiatry and Psychotherapy, Medical University of Vienna, Währinger Gürtel 18-20, Vienna A-1090, Austria. E-mail:
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Abstract
INTRODUCTION Although there is clear evidence for the serotonergic regulation of descending control of pain in animals, little direct evidence exists in humans. The majority of our knowledge comes from the use of serotonin (5-HT)-modulating antidepressants as analgesics in the clinical management of chronic pain. OBJECTIVES Here, we have used an acute tryptophan depletion (ATD) to manipulate 5-HT function and examine its effects of ATD on heat pain threshold and tolerance, attentional manipulation of nociceptive processing and mood in human volunteers. METHODS Fifteen healthy participants received both ATD and balanced amino acid (BAL) drinks on two separate sessions in a double-blind cross-over design. Pain threshold and tolerance were determined 4 h post-drink via a heat thermode. Additional attention, distraction and temperature discrimination paradigms were completed using a laser-induced heat pain stimulus. Mood was assessed prior and throughout each session. RESULTS Our investigation reported that the ATD lowered plasma TRP levels by 65.05 ± 7.29% and significantly reduced pain threshold and tolerance in response to the heat thermode. There was a direct correlation between the reduction in total plasma TRP levels and reduction in thermode temperature. In contrast, ATD showed no effect on laser-induced pain nor significant impact of the distraction-induced analgesia on pain perception but did reduce performance of the painful temperature discrimination task. Importantly, all findings were independent of any effects of ATD on mood. CONCLUSION As far as we are aware, it is the first demonstration of 5-HT effects on pain perception which are not confounded by mood changes.
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Linden M, Helmbold K, Kempf J, Sippas S, Filss C, Langen KJ, Eisert A, Zepf FD. Dietary tryptophan depletion in humans using a simplified two amino acid formula - a pilot study. Food Nutr Res 2016; 60:29272. [PMID: 27989269 PMCID: PMC5165058 DOI: 10.3402/fnr.v60.29272] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 09/26/2016] [Accepted: 11/03/2016] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Acute tryptophan depletion (ATD) is a well-established dietary method in translational brain research used to briefly lower central nervous serotonin (5-hydroxytryptamine (5-HT)) synthesis. A simplified two amino acid ATD formula (ATDPHE/LEU) was developed while reducing the overall amount of amino acids (AAs), with the objective of administration especially in children and adolescents in future studies. OBJECTIVE This study investigated tryptophan (TRP) influx rates across the blood-brain barrier (BBB) after dietary ATDPHE/LEU administration relative to the ATD Moja-De protocol that has been established for use in children and adolescents. DESIGN Seventy-two healthy adults (50% females) were randomized into four groups and administered ATD Moja-De, its TRP-balanced control condition (BAL), ATDPHE/LEU, or its respective control mixture (BALPHE/LEU) in a counterbalanced, double-blind, between-subjects design. Blood samples were collected at baseline and at hourly intervals for 6 h after AA intake. Questionnaires about mood, taste, and challenge tolerance were completed at fixed time points. RESULTS Both challenge mixtures significantly reduced central nervous TRP influx as calculated by Michaelis-Menten kinetics relative to baseline and the respective control conditions with only mild and comparable side effects. A greater decline in TRP influx over the BBB after ATDPHE/LEU administration when compared with ATD Moja-De was detected without group effects for taste, challenge tolerance, and mood. There was unintended initial short increase in plasma TRP concentrations observed after ATDPHE/LEU intake, and a possible redistribution between free and protein-bound TRP triggered by protein synthesis stimulated by the ingested AAs may account for this finding. Moreover, a decline in TRP influx after BALPHE/LEU administration over a 6-h period was observed, and the large amount of PHE in the BALPHE/LEU mixture may be a possible explanation for this particular phenomenon, which could have led to an unexpected increase in displacement of TRP at the BBB in this control condition. CONCLUSIONS This pilot study provides preliminary evidence for the possibility of lowering TRP influx as calculated by Michaelis-Menten kinetics into the brain by using a simplified ATD protocol in humans. The simplified composition of only two AAs, the lower overall AA amount, and the appropriate tolerance are characteristics of the newly developed ATDPHE/LEU protocol. Future studies focusing on the effects of the ATDPHE/LEU protocol and its respective control condition on CSF 5-HIAA concentrations, as well as neurochemical studies in rodents, are needed to further validate this newly developed AA mixture before definite conclusions about its usability in ATD-related research in humans, its specificity, and additional effects can be made.
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Affiliation(s)
- Maike Linden
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany.,JARA Translational Brain Medicine, Jülich Aachen Research Alliance, Jülich, Germany
| | - Katrin Helmbold
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany.,JARA Translational Brain Medicine, Jülich Aachen Research Alliance, Jülich, Germany
| | - Janina Kempf
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany.,JARA Translational Brain Medicine, Jülich Aachen Research Alliance, Jülich, Germany.,Faculty of Arts and Social Sciences, Maastricht University, Maastricht, The Netherlands
| | - Shabnam Sippas
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany.,JARA Translational Brain Medicine, Jülich Aachen Research Alliance, Jülich, Germany.,Faculty of Arts and Social Sciences, Maastricht University, Maastricht, The Netherlands
| | - Christian Filss
- Section JARA-Brain, Jülich-Aachen Research Alliance (JARA), Jülich, Germany
| | - Karl-Josef Langen
- Section JARA-Brain, Jülich-Aachen Research Alliance (JARA), Jülich, Germany.,Institute of Neuroscience and Medicine (INM-3, -4, -5), Research Centre Jülich, Jülich, Germany.,Department of Nuclear Medicine, RWTH Aachen University Hospital, Aachen, Germany
| | - Albrecht Eisert
- Department of Pharmacy, RWTH Aachen University, Aachen, Germany
| | - Florian Daniel Zepf
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany.,JARA Translational Brain Medicine, Jülich Aachen Research Alliance, Jülich, Germany.,Centre and Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, School of Psychiatry and Clinical Neurosciences & School of Paediatrics and Child Health, Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia, Perth, Australia.,Specialised Child and Adolescent Mental Health Services (CAMHS), Department of Health in Western Australia, Perth, Australia;
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Raab K, Kirsch P, Mier D. Understanding the impact of 5-HTTLPR, antidepressants, and acute tryptophan depletion on brain activation during facial emotion processing: A review of the imaging literature. Neurosci Biobehav Rev 2016; 71:176-197. [DOI: 10.1016/j.neubiorev.2016.08.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 07/28/2016] [Accepted: 08/26/2016] [Indexed: 12/22/2022]
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Abstract
BACKGROUND Studies using acute tryptophan depletion (ATD) to examine the effects of a rapid reduction in serotonin function have shown a reduction in global cognitive status during ATD in Alzheimer's disease (AD) and Parkinson's disease (PD). Based on the severe cholinergic loss evident in dementia with Lewy bodies (DLB) and Parkinson's disease and dementia (PDD), we predicted that a reduction of global cognitive status during ATD would be greater in these conditions than in AD. METHODS Patients having DLB or PDD underwent ATD in a double-blind, placebo-controlled, randomized, counterbalanced, crossover design. RESULTS While the study intended to test 20 patients, the protocol was poorly tolerated and terminated after six patients attempted, but only four patients - three with DLB and one with PDD - completed the protocol. The Modified Mini-Mental State Examination (3MSE) score was reduced in all three DLB patients and unchanged in the PDD and dementia patient during ATD compared with placebo. CONCLUSIONS This reduction in global cognitive function and the poor tolerability may fit with the hypothesis that people with dementia with Lewy bodies have sensitivity to the effects of reduced serotonin function.
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Godin SK, Lee AG, Baird JM, Herken BW, Bernstein KA. Tryptophan biosynthesis is important for resistance to replicative stress in Saccharomyces cerevisiae. Yeast 2016; 33:183-9. [PMID: 26804060 DOI: 10.1002/yea.3150] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 01/13/2016] [Accepted: 01/14/2016] [Indexed: 12/26/2022] Open
Abstract
Acute tryptophan depletion is used to induce low levels of serotonin in the brain. This method has been widely used in psychiatric studies to evaluate the effect of low levels of serotonin, and is generally considered a safe and reversible procedure. Here we use the budding yeast Saccharomyces cerevisiae to study the effects of tryptophan depletion on growth rate upon exposure to DNA-damaging agents. Surprisingly, we found that budding yeast undergoing tryptophan depletion were more sensitive to DNA-damaging agents such as methyl methanesulphonate (MMS) and hydroxyurea (HU). We found that this defect was independent of several DNA repair pathways, such as homologous recombination, base excision repair and translesion synthesis, and that this damage sensitivity was not due to impaired S-phase signalling. Upon further analysis, we found that the DNA-damage sensitivity of tryptophan depletion was likely due to impaired protein synthesis. These studies describe an important source of variance in budding yeast when using tryptophan as an auxotrophic marker, particularly on studies focusing on DNA repair, and suggest that further testing of the effect of tryptophan depletion on DNA repair in mammalian cells is warranted. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Stephen K Godin
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, PA, USA.,University of Pittsburgh Cancer Institute, PA, USA
| | - Alison G Lee
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, PA, USA.,University of Pittsburgh Cancer Institute, PA, USA
| | - Jared M Baird
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, PA, USA.,University of Pittsburgh Cancer Institute, PA, USA
| | - Benjamin W Herken
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, PA, USA.,University of Pittsburgh Cancer Institute, PA, USA
| | - Kara A Bernstein
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, PA, USA.,University of Pittsburgh Cancer Institute, PA, USA
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Influence of Tryptophan and Serotonin on Mood and Cognition with a Possible Role of the Gut-Brain Axis. Nutrients 2016; 8:nu8010056. [PMID: 26805875 PMCID: PMC4728667 DOI: 10.3390/nu8010056] [Citation(s) in RCA: 437] [Impact Index Per Article: 54.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 12/14/2015] [Accepted: 01/11/2016] [Indexed: 12/21/2022] Open
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.
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Abstract
Eating disorders are complex and serious psychiatric illnesses whose etiology includes psychological, biological, and social factors. Treatment of eating disorders is challenging as there are few evidence-based treatments and limited understanding of the mechanisms that result in sustained recovery. In the last 20 years, we have begun to identify neural pathways that are altered in eating disorders. Consideration of how these pathways may contribute to an eating disorder can provide an understanding of expected responses to treatments. Eating disorder behaviors include restrictive eating, compulsive overeating, and purging behaviors after eating. Eating disorders are associated with changes in many neural systems. In this targeted review, we focus on three cognitive processes associated with neurocircuitry differences in subjects with eating disorders such as reward, decision-making, and social behavior. We briefly examine how each of these systems function in healthy people, using Neurosynth meta-analysis to identify key regions commonly implicated in these circuits. We review the evidence for disruptions of these regions and systems in eating disorders. Finally, we describe psychiatric and psychological treatments that are likely to function by impacting these regions.
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Affiliation(s)
- Carrie J McAdams
- University of Texas at Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry, Texas Health Presbyterian Hospital of Dallas, Dallas, TX, USA
| | - Whitney Smith
- University of Texas at Southwestern Medical Center, Dallas, TX, USA
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67
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Sánchez CL, Van Swearingen AED, Arrant AE, Biskup CS, Kuhn CM, Zepf FD. Simplified dietary acute tryptophan depletion: effects of a novel amino acid mixture on the neurochemistry of C57BL/6J mice. Food Nutr Res 2015; 59:27424. [PMID: 26278978 PMCID: PMC4538305 DOI: 10.3402/fnr.v59.27424] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 06/24/2015] [Accepted: 06/24/2015] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Diet and nutrition can impact on the biological processes underpinning neuropsychiatric disorders. Amino acid (AA) mixtures lacking a specific neurotransmitter precursor can change the levels of brain serotonin (5-HT) or dopamine (DA) in the central nervous system. The availability of these substances within the brain is determined by the blood-brain barrier (BBB) that restricts the access of peripheral AA into the brain. AA mixtures lacking tryptophan (TRP) compete with endogenous TRP for uptake into the brain across the BBB, which in turn leads to a decrease in central nervous 5-HT synthesis. OBJECTIVE The present study compared the effects of a simplified acute tryptophan depletion (SATD) mixture in mice on blood and brain serotonergic and dopaminergic metabolites to those of a commonly used acute tryptophan depletion mixture (ATD Moja-De) and its TRP-balanced control (BAL). DESIGN The SATD formula is composed of only three large neutral AAs: phenylalanine (PHE), leucine (LEU), and isoleucine (ILE). BAL, ATD Moja-De, or SATD formulas were delivered to adult male C57BL/6J mice by gavage. TRP, monoamines, and their metabolites were quantified in blood and brain regions (hippocampus, frontal cortex, amygdala, caudate putamen, and nucleus accumbens). RESULTS Both ATD Moja-De and SATD significantly decreased levels of serum and brain TRP, as well as brain 5-HIAA and 5-HT compared with BAL. SATD reduced HVA levels in caudate but did not alter total DA levels or DOPAC. SATD decreased TRP and serotonergic metabolites comparably to ATD Moja-De administration. CONCLUSION A simplified and more palatable combination of AAs can manipulate serotonergic function and might be useful to reveal underlying monoamine-related mechanisms contributing to different neuropsychiatric disorders.
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Affiliation(s)
- Cristina L Sánchez
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, JARA Brain, RWTH Aachen University, Aachen, Germany.,Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | | | - Andrew E Arrant
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Caroline S Biskup
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, JARA Brain, RWTH Aachen University, Aachen, Germany
| | - Cynthia M Kuhn
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Florian D Zepf
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, JARA Brain, RWTH Aachen University, Aachen, Germany.,Department of Child and Adolescent Psychiatry, School of Paediatrics and Child Health & School of Psychiatry and Clinical Neurosciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia, Perth, WA, Australia.,Specialised Child and Adolescent Mental Health Services (CAHMS), Department of Health, Perth, WA, Australia;
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68
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Genetic Variations in the Serotonergic System Mediate a Combined, Weakened Response to SSRI Treatment: A Proposed Model. eNeuro 2015; 2:eN-TNC-0032-14. [PMID: 26464988 PMCID: PMC4586934 DOI: 10.1523/eneuro.0032-14.2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Revised: 05/01/2015] [Accepted: 05/06/2015] [Indexed: 12/16/2022] Open
Abstract
Individuals with the short (S) allele in the promoter region of the serotonin transporter gene (5-HTTLPR) show a less favorable response to selective serotonin reuptake inhibitor (SSRI) treatment than individuals with the long (L) allele. Similarly, individuals with the C(-1019)G allele for the mutation found in the promoter region of the serotonin 1A receptor gene (5-HTR1A) have shown blunted responses to SSRI treatment when compared with individuals lacking this polymorphism. While these findings have been replicated across multiple studies, only two studies to date have reported data for a gene-gene interaction associated with response to SSRI treatment. Both of these studies reported a combined effect for these genotypes, with individuals homozygous for the L allele and the C allele (5-HTT(L/L)-1A(C/C)) reporting the most favorable response to SSRI treatment, and individuals homozygous for the S allele and the G allele (5-HTT(S/S)-1A(G/G)) reporting the least favorable response to SSRI treatment. Additionally, no neural mechanisms have been proposed to explain why this gene-gene interaction has been observed. To that end, this article provides a review of the relevant literature associated with these polymorphisms and proposes a feasible model that describes a genotype-dependent modulation of postsynaptic serotonin signaling associated with the 5-HTT and 5-HTR1A genes.
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Abstract
Cancer patients commonly experience depression and fatigue before, during, and after treatment. Symptoms can be debilitating, and the risks associated with unrecognized or inadequately treated depression are substantial. Inflammation may be important in the genesis of depression and fatigue in cancer patients; potential neurobiological mechanisms of inflammation-related behavioral symptoms are reviewed. Randomized studies of pharmacologic treatments for depression in cancer populations are limited, but available data are generally encouraging. Studies of pharmacologic treatments for cancer-related fatigue have been more numerous but with mixed results. A practical approach to pharmacologic treatment of depression and fatigue in cancer patients involves weighing the potential risks and benefits of specific agents, including potential for adverse or advantageous side effects. Progress in understanding the neurobiological mechanisms underlying inflammation-related behavioral symptoms will provide opportunities for the development of novel and targeted treatments.
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Hebart MN, Gläscher J. Serotonin and dopamine differentially affect appetitive and aversive general Pavlovian-to-instrumental transfer. Psychopharmacology (Berl) 2015; 232:437-51. [PMID: 25034118 DOI: 10.1007/s00213-014-3682-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 06/30/2014] [Indexed: 12/29/2022]
Abstract
RATIONALE Human motivation and decision-making is influenced by the interaction of Pavlovian and instrumental systems. The neurotransmitters dopamine and serotonin have been suggested to play a major role in motivation and decision-making, but how they affect this interaction in humans is largely unknown. OBJECTIVE We investigated the effect of these neurotransmitters in a general Pavlovian-to-instrumental transfer (PIT) task which measured the nonspecific effect of appetitive and aversive Pavlovian cues on instrumental responses. METHODS For that purpose, we used selective dietary depletion of the amino acid precursors of serotonin and dopamine: tryptophan (n = 34) and tyrosine/phenylalanine (n = 35), respectively, and compared the performance of these groups to a control group (n = 34) receiving a nondepleted (balanced) amino acid drink. RESULTS We found that PIT differed between groups: Relative to the control group that exhibited only appetitive PIT, we found reduced appetitive PIT in the tyrosine/phenylalanine-depleted group and enhanced aversive PIT in the tryptophan-depleted group. CONCLUSIONS These results demonstrate a differential involvement of serotonin and dopamine in motivated behavior. They suggest that reductions in serotonin enhance the motivational influence of aversive stimuli on instrumental behavior and do not affect the influence of appetitive stimuli, while reductions in dopamine diminish the influence of appetitive stimuli. No conclusions could be drawn about how dopamine affects the influence of aversive stimuli. The interplay of both neurotransmitter systems allows for flexible and adaptive responses depending on the behavioral context.
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Affiliation(s)
- Martin N Hebart
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, W34, Martinistraße 52, 20251, Hamburg, Germany,
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71
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Serotonin, tryptophan metabolism and the brain-gut-microbiome axis. Behav Brain Res 2014; 277:32-48. [PMID: 25078296 DOI: 10.1016/j.bbr.2014.07.027] [Citation(s) in RCA: 1146] [Impact Index Per Article: 114.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 07/08/2014] [Accepted: 07/16/2014] [Indexed: 12/14/2022]
Abstract
The brain-gut axis is a bidirectional communication system between the central nervous system and the gastrointestinal tract. Serotonin functions as a key neurotransmitter at both terminals of this network. Accumulating evidence points to a critical role for the gut microbiome in regulating normal functioning of this axis. In particular, it is becoming clear that the microbial influence on tryptophan metabolism and the serotonergic system may be an important node in such regulation. There is also substantial overlap between behaviours influenced by the gut microbiota and those which rely on intact serotonergic neurotransmission. The developing serotonergic system may be vulnerable to differential microbial colonisation patterns prior to the emergence of a stable adult-like gut microbiota. At the other extreme of life, the decreased diversity and stability of the gut microbiota may dictate serotonin-related health problems in the elderly. The mechanisms underpinning this crosstalk require further elaboration but may be related to the ability of the gut microbiota to control host tryptophan metabolism along the kynurenine pathway, thereby simultaneously reducing the fraction available for serotonin synthesis and increasing the production of neuroactive metabolites. The enzymes of this pathway are immune and stress-responsive, both systems which buttress the brain-gut axis. In addition, there are neural processes in the gastrointestinal tract which can be influenced by local alterations in serotonin concentrations with subsequent relay of signals along the scaffolding of the brain-gut axis to influence CNS neurotransmission. Therapeutic targeting of the gut microbiota might be a viable treatment strategy for serotonin-related brain-gut axis disorders.
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72
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Daly E, Ecker C, Hallahan B, Deeley Q, Craig M, Murphy C, Johnston P, Spain D, Gillan N, Gudbrandsen M, Brammer M, Giampietro V, Lamar M, Page L, Toal F, Schmitz N, Cleare A, Robertson D, Rubia K, Murphy DGM. Response inhibition and serotonin in autism: a functional MRI study using acute tryptophan depletion. ACTA ACUST UNITED AC 2014; 137:2600-10. [PMID: 25070512 PMCID: PMC4132649 DOI: 10.1093/brain/awu178] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Stereotyped, repetitive behaviours in autism may reflect deficits in serotonin-modulated inhibitory control. Daly et al. use fMRI to compare the effects of acute tryptophan depletion in adult males with autism and controls performing the Go/No-Go task. Opposite effects are seen in the two groups, consistent with altered inhibition in autism. It has been suggested that the restricted, stereotyped and repetitive behaviours typically found in autism are underpinned by deficits of inhibitory control. The biological basis of this is unknown but may include differences in the modulatory role of neurotransmitters, such as serotonin, which are implicated in the condition. However, this has never been tested directly. We therefore assessed the modifying role of serotonin on inhibitory brain function during a Go/No-Go task in 14 adults with autism and normal intelligence and 14 control subjects that did not differ in gender, age and intelligence. We undertook a double-blind, placebo-controlled, crossover trial of acute tryptophan depletion using functional magnetic resonance imaging. Following sham, adults with autism relative to controls had reduced activation in key inhibitory regions of inferior frontal cortex and thalamus, but increased activation of caudate and cerebellum. However, brain activation was modulated in opposite ways by depletion in each group. Within autistic individuals depletion upregulated fronto-thalamic activations and downregulated striato-cerebellar activations toward control sham levels, completely ‘normalizing’ the fronto-cerebellar dysfunctions. The opposite pattern occurred in controls. Moreover, the severity of autism was related to the degree of differential modulation by depletion within frontal, striatal and thalamic regions. Our findings demonstrate that individuals with autism have abnormal inhibitory networks, and that serotonin has a differential, opposite, effect on them in adults with and without autism. Together these factors may partially explain the severity of autistic behaviours and/or provide a novel (tractable) treatment target.
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Affiliation(s)
- Eileen Daly
- 1 Sackler Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Science, Institute of Psychiatry, King's College London, UK
| | - Christine Ecker
- 1 Sackler Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Science, Institute of Psychiatry, King's College London, UK
| | - Brian Hallahan
- 2 Department of Psychiatry, National University of Ireland, Galway, Ireland
| | - Quinton Deeley
- 1 Sackler Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Science, Institute of Psychiatry, King's College London, UK
| | - Michael Craig
- 1 Sackler Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Science, Institute of Psychiatry, King's College London, UK
| | - Clodagh Murphy
- 1 Sackler Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Science, Institute of Psychiatry, King's College London, UK
| | - Patrick Johnston
- 1 Sackler Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Science, Institute of Psychiatry, King's College London, UK
| | - Debbie Spain
- 1 Sackler Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Science, Institute of Psychiatry, King's College London, UK
| | - Nicola Gillan
- 1 Sackler Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Science, Institute of Psychiatry, King's College London, UK
| | - Maria Gudbrandsen
- 1 Sackler Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Science, Institute of Psychiatry, King's College London, UK
| | - Michael Brammer
- 3 Department of Neuroimaging, Institute of Psychiatry, King's College London, UK
| | - Vincent Giampietro
- 3 Department of Neuroimaging, Institute of Psychiatry, King's College London, UK
| | - Melissa Lamar
- 4 Department of Psychiatry, University of Illinois at Chicago, USA
| | - Lisa Page
- 5 Sussex Partnership NHS Foundation Trust, Brighton and Sussex Medical School, Brighton, UK
| | - Fiona Toal
- 1 Sackler Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Science, Institute of Psychiatry, King's College London, UK
| | - Nicole Schmitz
- 6 Dementia Research Unit, Institute of Neurology, University College London, UK
| | - Anthony Cleare
- 7 Department of Psychological Medicine, Institute of Psychiatry, King's College London, UK
| | - Dene Robertson
- 8 Behavioural and Developmental Clinical Academic Group, South London and Maudsley NHS Foundation
| | - Katya Rubia
- 9 Department of Child and Adolescent Psychiatry, Institute of Psychiatry, King's College London, UK
| | - Declan G M Murphy
- 1 Sackler Institute of Translational Neurodevelopment, Department of Forensic and Neurodevelopmental Science, Institute of Psychiatry, King's College London, UK
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73
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Affiliation(s)
- S N Young
- Department of Psychiatry, McGill University, Montreal, Québec, Canada.
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74
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Acute tryptophan depletion reduces nitric oxide synthase in the rat hippocampus. Neurochem Res 2013; 38:2595-603. [PMID: 24170240 DOI: 10.1007/s11064-013-1177-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 10/02/2013] [Accepted: 10/05/2013] [Indexed: 10/26/2022]
Abstract
Acute tryptophan depletion (ATD) is extensively used to investigate the role of central serotonin (5-HT). However, several studies reported that ATD had no significant effect on central 5-HT concentration and some ATD-induced changes was independent of 5-HT in the rodent brain. Therefore, the potential mechanism of ATD might not be ascribed solely to changes in the central 5-HT system. In recent studies, evidence suggests that nitric oxide synthase (NOS) is closely associated with ATD-induced changes in modulation of cerebral blood flow and metabolism, cognitive, and locomotor activity. Thus, NOS is implicated to be an underlying factor contributing to ATD-induced changes. In the present study, the effect of ATD upon central NOS levels in the rat was evaluated. Male Sprague-Dawley (SD) rats were orally administered a tryptophan-free protein-carbohydrate mixture. Then, ATD effects upon affective behavior and spatial memory were assessed by the forced swimming test (FST) and Morris water maze test, respectively. Further, NOS activity and neuronal NOS (nNOS) protein levels in the hippocampus were measured after ATD. Our experimental results showed that ATD had no influence on affective behavior in the FST or spatial memory in SD rats. Interestingly, a significant reduction of both constitutive NOS activity and nNOS protein levels after ATD was found in the hippocampus. These findings demonstrate ATD does not influence affective behavior and spatial memory despite a direct effect on hippocampal NOS. Our study might provide a valuable clue for exploring earlier reported ATD-induced behavioral and neurochemical changes in rodents.
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75
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Young SN. Appropriate amino acid mixtures for tryptophan depletion and tyrosine/phenylalanine depletion and the safety of long-term amino acid depletion in humans. Psychopharmacology (Berl) 2013; 229:377-8. [PMID: 23942520 DOI: 10.1007/s00213-013-3237-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 07/28/2013] [Indexed: 12/23/2022]
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