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Steding J, Ritschel F, Boehm I, Geisler D, King JA, Roessner V, Smolka MN, Zepf FD, Ehrlich S. The effects of acute tryptophan depletion on instrumental reward learning in anorexia nervosa - an fMRI study. Psychol Med 2023; 53:3426-3436. [PMID: 35343412 PMCID: PMC10277771 DOI: 10.1017/s0033291721005493] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 10/15/2021] [Accepted: 12/20/2021] [Indexed: 11/07/2022]
Abstract
BACKGROUND The serotonin (5-HT) hypothesis of anorexia nervosa (AN) posits that individuals predisposed toward or recovered from AN (recAN) have a central nervous hyperserotonergic state and therefore restrict food intake as a means to reduce 5-HT availability (via diminished tryptophan-derived precursor supply) and alleviate associated negative mood states. Importantly, the 5-HT system has also been generally implicated in reward processing, which has also been shown to be altered in AN. METHODS In this double-blind crossover study, 22 individuals recAN and 25 healthy control participants (HC) underwent functional magnetic resonance imaging (fMRI) while performing an established instrumental reward learning paradigm during acute tryptophan depletion (ATD; a dietary intervention that lowers central nervous 5-HT availability) as well as a sham depletion. RESULTS On a behavioral level, the main effects of reward and ATD were evident, but no group differences were found. fMRI analyses revealed a group × ATD × reward level interaction in the ventral anterior insula during reward anticipation as well as in the medial orbitofrontal cortex during reward consumption. DISCUSSION The precise pattern of results is suggestive of a 'normalization' of reward-related neural responses during ATD in recAN compared to HC. Our results lend further evidence to the 5-HT hypothesis of AN. Decreasing central nervous 5-HT synthesis and availability during ATD and possibly also by dieting may be a means to normalize 5-HT availability and associated brain processes.
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Affiliation(s)
- Julius Steding
- Translational Developmental Neuroscience Section, Division of Psychological and Social Medicine and Developmental Neurosciences, Faculty of Medicine, TU Dresden, Dresden, Germany
| | - Franziska Ritschel
- Translational Developmental Neuroscience Section, Division of Psychological and Social Medicine and Developmental Neurosciences, Faculty of Medicine, TU Dresden, Dresden, Germany
| | - Ilka Boehm
- Translational Developmental Neuroscience Section, Division of Psychological and Social Medicine and Developmental Neurosciences, Faculty of Medicine, TU Dresden, Dresden, Germany
| | - Daniel Geisler
- Translational Developmental Neuroscience Section, Division of Psychological and Social Medicine and Developmental Neurosciences, Faculty of Medicine, TU Dresden, Dresden, Germany
| | - Joseph A. King
- Translational Developmental Neuroscience Section, Division of Psychological and Social Medicine and Developmental Neurosciences, Faculty of Medicine, TU Dresden, Dresden, Germany
| | - Veit Roessner
- Department of Child and Adolescent Psychiatry, Faculty of Medicine, University Hospital C. G. Carus, Technische Universität Dresden, Dresden, Germany
| | - Michael N. Smolka
- Department of Psychiatry and Neuroimaging Center, Technische Universität Dresden, Dresden, Germany
| | - Florian Daniel Zepf
- Department of Child and Adolescent Psychiatry, Psychosomatic Medicine and Psychotherapy, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Stefan Ehrlich
- Translational Developmental Neuroscience Section, Division of Psychological and Social Medicine and Developmental Neurosciences, Faculty of Medicine, TU Dresden, Dresden, Germany
- Eating Disorder Treatment and Research Center, Department of Child and Adolescent Psychiatry, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
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No effects of acute tryptophan depletion on anxiety or mood in weight-recovered female patients with anorexia nervosa. Eur Arch Psychiatry Clin Neurosci 2023; 273:209-217. [PMID: 35511296 PMCID: PMC9957824 DOI: 10.1007/s00406-022-01414-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 04/11/2022] [Indexed: 11/03/2022]
Abstract
BACKGROUND Previous studies have suggested that individuals recovered from anorexia nervosa (AN) are characterized by increased serotonergic (5-HT) activity that might be related to elevated levels of anxiety. Assuming these traits to be also present in individuals at risk for AN, it was further hypothesized that restricting food intake might be a means to temporarily alleviate dysphoric affective states by reducing central nervous availability of tryptophan (TRP), the sole precursor of 5-HT. One study that supported this hypothesis found anxiolytic effects in individuals with a history of AN during an experimentally induced short-term depletion of TRP supply to the brain. METHODS In this placebo-controlled, double-blind cross-over study, 22 patients weight-recovered from AN (recAN) and 25 healthy control participants (HC) completed questionnaires assessing anxiety and momentary mood during acute tryptophan depletion (ATD), a dietary intervention that lowers central 5-HT synthesis. RESULTS The ATD procedure effectively reduced the ratio of TRP to competing for large neutral amino acids in the peripheral blood, indicating decreased TRP supply to the brain. Effects of ATD on anxiety and mood did not differ between recAN and HC. Bayesian null hypothesis testing confirmed these initial results. DISCUSSION Our results do not support the hypothesis that short-term depletion of TRP and its impact on the brain 5-HT reduces anxiety or improves mood in AN. As the evidence for the role of 5-HT dysfunction on affective processes in patients with AN is limited, further studies are needed to assess its relevance in the pathophysiology of AN.
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Saidi O, Rochette E, Del Sordo G, Peyrel P, Salles J, Doré E, Merlin E, Walrand S, Duché P. Isocaloric Diets with Different Protein-Carbohydrate Ratios: The Effect on Sleep, Melatonin Secretion and Subsequent Nutritional Response in Healthy Young Men. Nutrients 2022; 14:nu14245299. [PMID: 36558458 PMCID: PMC9782994 DOI: 10.3390/nu14245299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/01/2022] [Accepted: 12/09/2022] [Indexed: 12/15/2022] Open
Abstract
This study aimed to determine the short-term effect of two isocaloric diets differing in the ratio of protein−carbohydrate on melatonin levels, sleep, and subsequent dietary intake and physical activity in healthy young men. Twenty-four healthy men took part in a crossover design including two sessions of three days on isocaloric diets whether high-protein, low-carbohydrate (HPLC) or low-protein, high-carbohydrate (LPHC) followed by 24-h free living assessments. Sleep was measured by ambulatory polysomnography pre-post-intervention. Melatonin levels were assessed on the third night of each session on eight-point salivary sampling. Physical activity was monitored by accelerometry. On day 4, participants reported their 24-h ad-libitum dietary intake. LPHC resulted in better sleep quality and increased secretion of melatonin compared to HPLC. A significant difference was noted in sleep efficiency (p < 0.05) between the two sessions. This was mainly explained by a difference in sleep onset latency (p < 0.01) which was decreased during LPHC (PRE: 15.8 ± 7.8 min, POST: 11.4 ± 4.5 min, p < 0.001). Differences were also noted in sleep staging including time spent on REM (p < 0.05) and N1 (p < 0.05). More importantly, REM latency (PRE: 97.2 ± 19.9 min, POST 112.0 ± 20.7 min, p < 0.001) and cortical arousals (PRE: 7.2 ± 3.9 event/h, POST 8.5 ± 3.3 event/h) increased in response to HPLC diet but not LPHC. On day 4, 24-h ad-libitum energy intake was higher following HPLC compared to LPHC (+64 kcal, p < 0.05) and explained by increased snacking behavior (p < 0.01) especially from carbohydrates (p < 0.05). Increased carbohydrates intake was associated with increased cortical arousals.
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Affiliation(s)
- Oussama Saidi
- Laboratory Impact of Physical Activity on Health (IAPS), Toulon University, F-83041 Toulon, France
- Laboratory of Adaptations to Exercise under Physiological and Pathological Conditions (AME2P), Clermont Auvergne University, F-63000 Clermont-Ferrand, France
- Center for Research in Human Nutrition Auvergne, F-63000 Clermont-Ferrand, France
| | - Emmanuelle Rochette
- Laboratory Impact of Physical Activity on Health (IAPS), Toulon University, F-83041 Toulon, France
- Department of Pediatrics, Clermont-Ferrand University Hospital, F-63000 Clermont-Ferrand, France
- INSERM, CIC 1405, CRECHE Unit, Clermont Auvergne University, F-63000 Clermont-Ferrand, France
| | - Giovanna Del Sordo
- Laboratory Impact of Physical Activity on Health (IAPS), Toulon University, F-83041 Toulon, France
| | - Paul Peyrel
- Laboratory of Adaptations to Exercise under Physiological and Pathological Conditions (AME2P), Clermont Auvergne University, F-63000 Clermont-Ferrand, France
- Department of Kinesiology, Laval University, Quebec, QC G1V 0A6, Canada
- Quebec Heart and Lung Institute, Laval University, Quebec, QC G1V 4G5, Canada
| | - Jérôme Salles
- Human Nutrition Unit, INRAE, Auvergne Human Nutrition Research Center, Clermont Auvergne University, F-63000 Clermont-Ferrand, France
| | - Eric Doré
- Laboratory of Adaptations to Exercise under Physiological and Pathological Conditions (AME2P), Clermont Auvergne University, F-63000 Clermont-Ferrand, France
- Center for Research in Human Nutrition Auvergne, F-63000 Clermont-Ferrand, France
| | - Etienne Merlin
- Department of Pediatrics, Clermont-Ferrand University Hospital, F-63000 Clermont-Ferrand, France
- INSERM, CIC 1405, CRECHE Unit, Clermont Auvergne University, F-63000 Clermont-Ferrand, France
| | - Stéphane Walrand
- Human Nutrition Unit, INRAE, Auvergne Human Nutrition Research Center, Clermont Auvergne University, F-63000 Clermont-Ferrand, France
| | - Pascale Duché
- Laboratory Impact of Physical Activity on Health (IAPS), Toulon University, F-83041 Toulon, France
- Correspondence: ; Tel.: +33-(0)652-1838-91
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Boehm I, Hennig J, Ritschel F, Geisler D, King JA, Lesch I, Roessner V, Zepf FD, Ehrlich S. Acute tryptophan depletion balances altered resting-state functional connectivity of the salience network in female patients recovered from anorexia nervosa. J Psychiatry Neurosci 2022; 47:E351-E358. [PMID: 36195339 PMCID: PMC9533767 DOI: 10.1503/jpn.210161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 01/03/2022] [Accepted: 04/17/2022] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND It has been suggested that individuals predisposed to or recovered from anorexia nervosa experience a hyperserotonergic state associated with anxiety that might be mitigated by restricted food intake, because diminished levels of the tryptophan precursor lower the central availability of serotonin (5-HT). At the neural level, the salience network is a system of functionally connected brain regions; it has been closely associated with 5-HT functioning and mental disorders (including anorexia nervosa). The aim of the present study was to investigate the effect on the salience network of a temporary dietary manipulation of 5-HT synthesis in patients with anorexia nervosa. METHODS In this double-blind crossover study, we obtained data on resting-state functional connectivity from 22 weight-recovered female patients with a history of anorexia nervosa, and 22 age-matched female healthy controls. The study procedure included acute tryptophan depletion (a dietary intervention that lowers the central 5-HT synthesis rate) and a sham condition. RESULTS We identified an interaction of group and experimental condition in resting-state functional connectivity between the salience network and the orbitofrontal cortex extending to the frontal pole (F 1,42 = 12.52; p FWE = 0.026). Further analysis revealed increased resting-state functional connectivity during acute tryptophan depletion in patients recovered from anorexia nervosa, resembling that of healthy controls during the sham condition (T 42 = -0.66; p = 0.51). LIMITATIONS The effect of acute tryptophan depletion on the central availability of 5-HT can be judged only indirectly using plasma ratios of tryptophan to large neutral amino acids. Moreover, the definition of anorexia nervosa recovery varies widely across studies, limiting comparability. CONCLUSION Taken together, our findings support the notion of 5-HT dysregulation in anorexia nervosa and indicate that reduced 5-HT synthesis and availability during acute tryptophan depletion (and possibly with food restriction) may balance hyperserotonergic functioning and the associated resting-state functional connectivity of the salience network.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Stefan Ehrlich
- From the Translational Developmental Neuroscience Section, Division of Psychological and Social Medicine and Developmental Neurosciences, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany (Boehm, Hennig, Ritschel, Geisler, King, Lesch, Ehrlich); the Department of Child and Adolescent Psychiatry, Faculty of Medicine, University Hospital C. G. Carus, Technische Universität Dresden, Dresden, Germany (Roessner); the Department of Child and Adolescent Psychiatry, Psychosomatic Medicine and Psychotherapy, Jena University Hospital, Friedrich Schiller University, Jena, Germany (Zepf); the Eating Disorder Treatment and Research Centre, Department of Child and Adolescent Psychiatry, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany (Ehrlich)
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Kanen JW, Robbins TW, Trofimova IN. Harnessing temperament to elucidate the complexities of serotonin function. Curr Opin Behav Sci 2022. [DOI: 10.1016/j.cobeha.2022.101108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Kunas SL, Hilbert K, Yang Y, Richter J, Hamm A, Wittmann A, Ströhle A, Pfleiderer B, Herrmann MJ, Lang T, Lotze M, Deckert J, Arolt V, Wittchen HU, Straube B, Kircher T, Gerlach AL, Lueken U. The modulating impact of cigarette smoking on brain structure in panic disorder: a voxel-based morphometry study. Soc Cogn Affect Neurosci 2021; 15:849-859. [PMID: 32734299 PMCID: PMC7543937 DOI: 10.1093/scan/nsaa103] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 06/17/2020] [Accepted: 07/15/2020] [Indexed: 11/13/2022] Open
Abstract
Cigarette smoking increases the likelihood of developing anxiety disorders, among them panic disorder (PD). While brain structures altered by smoking partly overlap with morphological changes identified in PD, the modulating impact of smoking as a potential confounder on structural alterations in PD has not yet been addressed. In total, 143 PD patients (71 smokers) and 178 healthy controls (62 smokers) participated in a multicenter magnetic resonance imaging (MRI) study. T1-weighted images were used to examine brain structural alterations using voxel-based morphometry in a priori defined regions of the defensive system network. PD was associated with gray matter volume reductions in the amygdala and hippocampus. This difference was driven by non-smokers and absent in smoking subjects. Bilateral amygdala volumes were reduced with increasing health burden (neither PD nor smoking > either PD or smoking > both PD and smoking). As smoking can narrow or diminish commonly observed structural abnormalities in PD, the effect of smoking should be considered in MRI studies focusing on patients with pathological forms of fear and anxiety. Future studies are needed to determine if smoking may increase the risk for subsequent psychopathology via brain functional or structural alterations.
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Affiliation(s)
- Stefanie L Kunas
- Department of Psychology, Humboldt-Universität zu Berlin, Berlin 10117, Germany.,Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité - Universitätsmedizin Berlin, Berlin 10117, Germany
| | - Kevin Hilbert
- Department of Psychology, Humboldt-Universität zu Berlin, Berlin 10117, Germany
| | - Yunbo Yang
- Department of Psychiatry and Psychotherapy and Center for Mind Brain and Behavior (CMBB), Philipps-University Marburg, Marburg 35037, Germany
| | - Jan Richter
- Department of Biological and Clinical Psychology/Psychotherapy, University of Greifswald, Greifswald 17489, Germany
| | - Alfons Hamm
- Department of Biological and Clinical Psychology/Psychotherapy, University of Greifswald, Greifswald 17489, Germany
| | - André Wittmann
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité - Universitätsmedizin Berlin, Berlin 10117, Germany
| | - Andreas Ströhle
- Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité - Universitätsmedizin Berlin, Berlin 10117, Germany
| | - Bettina Pfleiderer
- Department of Clinical Radiology, University of Münster, Münster 48149, Germany
| | - Martin J Herrmann
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University Hospital of Würzburg, University of Würzburg, Würzburg 97080, Germany
| | - Thomas Lang
- Christoph-Dornier-Foundation for Clinical Psychology, Bremen 28359, Germany.,Department of Psychiatry and Psychotherapy, University of Hamburg, Hamburg 20146, Germany
| | - Martin Lotze
- Functional Imaging Unit, Institute for Diagnostic Radiology and Neuroradiology, University of Greifswald, Greifswald 17489, Germany
| | - Jürgen Deckert
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University Hospital of Würzburg, University of Würzburg, Würzburg 97080, Germany
| | - Volker Arolt
- Department of Psychiatry, University of Münster, Münster 48149, Germany
| | - Hans-Ulrich Wittchen
- Institute of Clinical Psychology and Psychotherapy, Technische Universität Dresden, Dresden 01069, Germany
| | - Benjamin Straube
- Department of Psychiatry and Psychotherapy and Center for Mind Brain and Behavior (CMBB), Philipps-University Marburg, Marburg 35037, Germany
| | - Tilo Kircher
- Department of Psychiatry and Psychotherapy and Center for Mind Brain and Behavior (CMBB), Philipps-University Marburg, Marburg 35037, Germany
| | - Alexander L Gerlach
- Department of Psychiatry and Psychotherapy and Center for Mind Brain and Behavior (CMBB), Philipps-University Marburg, Marburg 35037, Germany
| | - Ulrike Lueken
- Department of Psychology, Humboldt-Universität zu Berlin, Berlin 10117, Germany
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Effects of tryptophan depletion on anxiety, a systematic review. Transl Psychiatry 2021; 11:118. [PMID: 33574223 PMCID: PMC7878770 DOI: 10.1038/s41398-021-01219-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 10/30/2020] [Accepted: 11/16/2020] [Indexed: 12/11/2022] Open
Abstract
Vulnerability markers for onset of anxiety disorders are scarce. In depression, patients at risk tend to respond with a negative mood to 'acute tryptophan depletion' (ATD), while healthy volunteers and current patients do not. The serotonergic system thus provides indications for vulnerability for depression. It is unknown whether ATD reveals vulnerability in anxiety too. This study systematically reviews the effects of ATD on anxiety and assesses whether challenging anxiety modifies the response. PubMed, Embase and PsychInfo were systematically searched up to April 2019 for studies in which (1) healthy volunteers or patients with a (remitted) anxiety disorder underwent ATD and (2) levels of anxiety were reported. In total, 21 studies were included. Studies conducted in healthy volunteers (n = 13), and patients with a remitted (n = 6) or current (panic, social or generalised) anxiety disorder (n = 4). Studies were mostly of poor quality and heterogeneous regarding population, challenge test used and outcome measures. ATD did not consistently affect anxiety in any of the groups. Moreover, a challenge test after ATD (n = 17 studies) did not consistently provoke anxiety in healthy volunteers or remitted patients. A 35% CO2 challenge did consistently increase anxiety in patients with a current panic disorder (PD). To conclude, this systematic review found no clear indications that ATD provokes anxiety in those at risk for anxiety disorders. Hence, unlike in depression, ATD does not indicate vulnerability to develop an anxiety disorder. Because included studies were heterogeneous and mostly of poor quality, there is an urgent need for high quality research in homogeneous samples.
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Kanen JW, Arntz FE, Yellowlees R, Cardinal RN, Price A, Christmas DM, Apergis-Schoute AM, Sahakian BJ, Robbins TW. Serotonin depletion amplifies distinct human social emotions as a function of individual differences in personality. Transl Psychiatry 2021; 11:81. [PMID: 33518708 PMCID: PMC7847998 DOI: 10.1038/s41398-020-00880-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 05/28/2020] [Accepted: 05/29/2020] [Indexed: 01/08/2023] Open
Abstract
Serotonin is involved in a wide range of mental capacities essential for navigating the social world, including emotion and impulse control. Much recent work on serotonin and social functioning has focused on decision-making. Here we investigated the influence of serotonin on human emotional reactions to social conflict. We used a novel computerised task that required mentally simulating social situations involving unjust harm and found that depleting the serotonin precursor tryptophan-in a double-blind randomised placebo-controlled design-enhanced emotional responses to the scenarios in a large sample of healthy volunteers (n = 73), and interacted with individual differences in trait personality to produce distinctive human emotions. Whereas guilt was preferentially elevated in highly empathic participants, annoyance was potentiated in those high in trait psychopathy, with medium to large effect sizes. Our findings show how individual differences in personality, when combined with fluctuations of serotonin, may produce diverse emotional phenotypes. This has implications for understanding vulnerability to psychopathology, determining who may be more sensitive to serotonin-modulating treatments, and casts new light on the functions of serotonin in emotional processing.
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Affiliation(s)
- Jonathan W Kanen
- Department of Psychology, University of Cambridge, Cambridge, UK.
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK.
| | - Fréderique E Arntz
- Department of Psychology, University of Cambridge, Cambridge, UK
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
- Department of Psychology, Leiden University, Leiden, The Netherlands
| | - Robyn Yellowlees
- Department of Psychology, University of Cambridge, Cambridge, UK
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
- Section of Eating Disorders, Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Rudolf N Cardinal
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
- Department of Psychiatry, University of Cambridge, Cambridge, UK
- Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK
| | - Annabel Price
- Department of Psychiatry, University of Cambridge, Cambridge, UK
- Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK
| | - David M Christmas
- Department of Psychiatry, University of Cambridge, Cambridge, UK
- Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK
| | - Annemieke M Apergis-Schoute
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
- Department of Neuroscience, Psychology, and Behaviour, University of Leicester, Leicester, UK
| | - Barbara J Sahakian
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
- Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - Trevor W Robbins
- Department of Psychology, University of Cambridge, Cambridge, UK
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
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Kanen JW, Arntz FE, Yellowlees R, Christmas DM, Price A, Apergis-Schoute AM, Sahakian BJ, Cardinal RN, Robbins TW. Effect of Tryptophan Depletion on Conditioned Threat Memory Expression: Role of Intolerance of Uncertainty. BIOLOGICAL PSYCHIATRY: COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2021; 6:590-598. [PMID: 33631385 PMCID: PMC8099731 DOI: 10.1016/j.bpsc.2020.12.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 12/02/2022]
Abstract
Background Responding emotionally to danger is critical for survival. Normal functioning also requires flexible alteration of emotional responses when a threat becomes safe. Aberrant threat and safety learning occur in many psychiatric disorders, including posttraumatic stress disorder, obsessive-compulsive disorder, and schizophrenia, in which emotional responses can persist pathologically. While there is evidence that threat and safety learning can be modulated by the serotonin systems, there have been few studies in humans. We addressed a critical clinically relevant question: How does lowering serotonin affect memory retention of conditioned threat and safety memory? Methods Forty-seven healthy participants underwent conditioning to two stimuli predictive of threat on day 1. One stimulus but not the other was subsequently presented in an extinction session. Emotional responding was assessed by the skin conductance response. On day 2, we employed acute dietary tryptophan depletion to lower serotonin temporarily, in a double-blind, placebo-controlled, randomized between-groups design. We then tested for the retention of conditioned threat and extinction memory. We also measured self-reported intolerance of uncertainty, known to modulate threat memory expression. Results The expression of emotional memory was attenuated in participants who had undergone tryptophan depletion. Individuals who were more intolerant of uncertainty showed even greater attenuation of emotion following depletion. Conclusions These results support the view that serotonin is involved in predicting aversive outcomes and refine our understanding of the role of serotonin in the persistence of emotional responsivity, with implications for individual differences in vulnerability to psychopathology.
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Affiliation(s)
- Jonathan W Kanen
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom; Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom.
| | - Frederique E Arntz
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom; Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom; Department of Psychology, Leiden University, Leiden, the Netherlands
| | - Robyn Yellowlees
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom; Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom; Section of Eating Disorders, Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - David M Christmas
- Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, United Kingdom
| | - Annabel Price
- Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, United Kingdom
| | - Annemieke M Apergis-Schoute
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom; Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
| | - Barbara J Sahakian
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom; Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom
| | - Rudolf N Cardinal
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom; Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, United Kingdom
| | - Trevor W Robbins
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom; Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom
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Serotonin depletion impairs both Pavlovian and instrumental reversal learning in healthy humans. Mol Psychiatry 2021; 26:7200-7210. [PMID: 34429517 PMCID: PMC8873011 DOI: 10.1038/s41380-021-01240-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 07/03/2021] [Accepted: 07/09/2021] [Indexed: 02/07/2023]
Abstract
Serotonin is involved in updating responses to changing environmental circumstances. Optimising behaviour to maximise reward and minimise punishment may require shifting strategies upon encountering new situations. Likewise, autonomic responses to threats are critical for survival yet must be modified as danger shifts from one source to another. Whilst numerous psychiatric disorders are characterised by behavioural and autonomic inflexibility, few studies have examined the contribution of serotonin in humans. We modelled both processes, respectively, in two independent experiments (N = 97). Experiment 1 assessed instrumental (stimulus-response-outcome) reversal learning whereby individuals learned through trial and error which action was most optimal for obtaining reward or avoiding punishment initially, and the contingencies subsequently reversed serially. Experiment 2 examined Pavlovian (stimulus-outcome) reversal learning assessed by the skin conductance response: one innately threatening stimulus predicted receipt of an uncomfortable electric shock and another did not; these contingencies swapped in a reversal phase. Upon depleting the serotonin precursor tryptophan-in a double-blind randomised placebo-controlled design-healthy volunteers showed impairments in updating both actions and autonomic responses to reflect changing contingencies. Reversal deficits in each domain, furthermore, were correlated with the extent of tryptophan depletion. Initial Pavlovian conditioning, moreover, which involved innately threatening stimuli, was potentiated by depletion. These results translate findings in experimental animals to humans and have implications for the neurochemical basis of cognitive inflexibility.
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Smith SA, Trotter PD, McGlone FP, Walker SC. Effects of Acute Tryptophan Depletion on Human Taste Perception. Chem Senses 2020; 46:6024443. [PMID: 33277648 DOI: 10.1093/chemse/bjaa078] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Taste perception has been reported to vary with changes in affective state. Distortions of taste perception, including blunted recognition thresholds, intensity, and hedonic ratings have been identified in those suffering from depressive disorders. Serotonin is a key neurotransmitter implicated in the etiology of anxiety and depression; systemic and peripheral manipulations of serotonin signaling have previously been shown to modulate taste detection. However, the specific effects of central serotonin function on taste processing have not been widely investigated. Here, in a double-blind placebo-controlled study, acute tryptophan depletion was used to investigate the effect of reduced central serotonin function on taste perception. Twenty-five female participants aged 18-28 attended the laboratory on two occasions at least 1 week apart. On one visit, they received a tryptophan depleting drink and on the other, a control drink was administered. Approximately, 6 h after drink consumption, they completed a taste perception task which measured detection thresholds and supra-threshold perceptions of the intensity and pleasantness of four basic tastes (sweet, sour, bitter, and salt). While acutely reducing central levels of serotonin had no effect on the detection thresholds of sweet, bitter, or sour tastes, it significantly enhanced detection of salt. For supra-threshold stimuli, acutely reduced serotonin levels significantly enhanced the perceived intensity of both bitter and sour tastes and blunted pleasantness ratings of bitter quinine. These findings show manipulation of central serotonin levels can modulate taste perception and are consistent with previous reports that depletion of central serotonin levels enhances neural and behavioral responsiveness to aversive signals.
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Affiliation(s)
- Sharon A Smith
- Research Centre for Brain and Behaviour, School of Psychology, Liverpool John Moores University, Liverpool, UK
| | - Paula D Trotter
- Research Centre for Brain and Behaviour, School of Psychology, Liverpool John Moores University, Liverpool, UK
| | - Francis P McGlone
- Research Centre for Brain and Behaviour, School of Psychology, Liverpool John Moores University, Liverpool, UK.,Department of Psychology, University of Liverpool, Liverpool, UK
| | - Susannah C Walker
- Research Centre for Brain and Behaviour, School of Psychology, Liverpool John Moores University, Liverpool, UK
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12
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Tryptophan Intake and Metabolism in Older Adults with Mood Disorders. Nutrients 2020; 12:nu12103183. [PMID: 33081001 PMCID: PMC7603218 DOI: 10.3390/nu12103183] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/15/2020] [Accepted: 10/16/2020] [Indexed: 12/12/2022] Open
Abstract
The role of serotonin in the pathogenesis of depression is well-documented, while the involvement of other tryptophan (TRP) metabolites generated in the kynurenine pathway is less known. The aim of this study was to assess the intake and metabolism of TRP in elderly patients with mood disorders. Ninety subjects in three groups, 30 subjects each, were enrolled in this study: controls (healthy young adults, group I) and elderly individuals without (group II) or with (group III) symptoms of mild and moderate depression, as assessed by the Hamilton Depression Rating Scale (HAM-D) and further referred to as mood disorders. The average TRP intake was evaluated with the nutrition calculator. Urinary levels of TRP, 5-hydroxyindoleacetic acid (5-HIAA), L-kynurenine (KYN), kynurenic acid (KynA), xanthurenic acid (XA), and quinolinic acid (QA) were determined by liquid chromatography with tandem mass spectrometry and related to creatinine level. The average daily intake of TRP was significantly lower in group III than the remaining two groups, but group III was also characterized by higher urinary levels of KYN, KynA, XA, and QA as compared with younger adult individuals and elderly patients without mood disorders. Therefore, mild and moderate depression in the elderly may be associated with a lower intake of TRP and changes in its kynurenine metabolic pathway, which suggests a potential dietary TRP-based intervention in this group of patients.
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Stewart RM, Wong JWY, Mahfouda S, Morandini HAE, Rao P, Runions KC, Zepf FD. Acute Tryptophan Depletion Moja-De: A Method to Study Central Nervous Serotonin Function in Children and Adolescents. Front Psychiatry 2020; 10:1007. [PMID: 32210845 PMCID: PMC7067742 DOI: 10.3389/fpsyt.2019.01007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Accepted: 12/20/2019] [Indexed: 11/13/2022] Open
Abstract
Serotonin (5-HT) is widely implicated as a key neurotransmitter relevant to a range of psychiatric disorders and psychological processes. The role of central nervous 5-HT function underlying these processes can be examined through serotonergic challenge methodologies. Acute tryptophan depletion (ATD) is a key challenge method whereby a diminished dietary intake of tryptophan-the amino acid precursor to brain 5-HT synthesis-results in temporary diminished central nervous 5-HT synthesis. While this particular methodology has been used in adult populations, it was only recently that modifications were made to enable the use of ATD in child and adolescent populations. Additionally, the Moja-De modification of the ATD challenge methodology has demonstrated benefits over other ATD techniques used previously. The aim of this protocol paper is to describe the ATD Moja-De methodology in detail, its benefits, as well as studies that have been conducted to validate the procedure in child and adolescent samples. The ATD Moja-De protocol provides a potential methodology for investigating the role of central nervous 5-HT via manipulation of brain tryptophan availability in human psychopathology from a developmental viewpoint.
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Affiliation(s)
- Richard M. Stewart
- Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, WA, Australia
| | - Janice W. Y. Wong
- Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, WA, Australia
- Brain and Behaviour, Telethon Kids Institute, Perth, WA, Australia
- Specialised Child and Adolescent Mental Health Services, Department of Health, Perth, WA, Australia
| | - Simone Mahfouda
- Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, WA, Australia
- Brain and Behaviour, Telethon Kids Institute, Perth, WA, Australia
- School of Psychological Sciences, Faculty of Science, The University of Western Australia, Perth, WA, Australia
| | - Hugo A. E. Morandini
- Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, WA, Australia
| | - Pradeep Rao
- Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, WA, Australia
- Community Child and Adolescent Mental Health Services, Department of Health, Perth, WA, Australia
| | - Kevin C. Runions
- Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, WA, Australia
- Brain and Behaviour, Telethon Kids Institute, Perth, WA, Australia
- Community Child and Adolescent Mental Health Services, Department of Health, Perth, WA, Australia
| | - Florian D. Zepf
- Centre & Discipline of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, WA, Australia
- Brain and Behaviour, Telethon Kids Institute, Perth, WA, Australia
- Department of Child and Adolescent Psychiatry, Psychosomatic Medicine and Psychotherapy, Jena University Hospital, Friedrich Schiller University, Jena, Germany
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Al-Mokbel A, Courtney-Martin G, Elango R, Ball RO, Pencharz PB, Tomlinson C. Tryptophan Requirement in School-Age Children Determined by the Indicator Amino Acid Oxidation Method is Similar to Current Recommendations. J Nutr 2019; 149:280-285. [PMID: 30753549 DOI: 10.1093/jn/nxy250] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/09/2018] [Accepted: 09/04/2018] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The requirement for dietary tryptophan in school-age children has never been empirically derived. OBJECTIVE The objective of our study was to determine the tryptophan requirement of school-age children using the indicator amino acid oxidation technique. METHODS Volunteer healthy school-age children, between 8 and 12 y, were enrolled and the oxidation of l-[13C]-phenylalanine to 13CO2 measured in response to graded intakes of dietary tryptophan. Seven children (3 boys, 4 girls) participated in the study and received randomly assigned tryptophan intakes ranging from 0.5 to 9.75 mg.kg-1.d-1 for a total of 36 studies. The diets provided energy at 1.5 times each subject's resting energy expenditure and were isocaloric. Protein was provided as an amino acid mixture on the basis of the egg protein pattern, and phenylalanine and tyrosine were maintained constant across the protein intake concentrations at 25 and 40 mg.kg-1.d-1. All subjects were adapted for 2 d before the study day to a protein intake of 1.5 g.kg-1.d-1. The mean tryptophan requirement was determined by applying a mixed-effect change-point regression analysis to F13CO2 (label tracer oxidation in 13CO2 breath) which identified a breakpoint in the F13CO2 in response to graded amounts of tryptophan. RESULTS The mean [estimated average requirement (EAR)] and upper 95% CI, (approximating the RDA) of tryptophan requirements were estimated to be 4.7 and 6.1 mg.kg-1.d-1, respectively. CONCLUSION Our results are similar to the current recommended EAR and RDA of 5 and 6 mg.kg-1.d-1 for healthy growing children based on the factorial calculation. Clinical Trials Registration No. NCT02018588.
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Affiliation(s)
- Abeer Al-Mokbel
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Glenda Courtney-Martin
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.,Faculty of Kinesiology & Physical Education.,Departments of Nutritional Sciences
| | - Rajavel Elango
- Department of Pediatrics, School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada.,Child & Family Research Institute, BC Children's Hospital, Vancouver, British Columbia, Canada
| | - Ronald O Ball
- Departments of Nutritional Sciences.,Department of Agriculture, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Paul B Pencharz
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.,Departments of Nutritional Sciences.,Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Christopher Tomlinson
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.,Departments of Nutritional Sciences
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Abstract
OBJECTIVE Central nervous system (CNS) serotonin (5-HT) exerts both excitatory and inhibitory effects on the sympathetic nervous system (SNS) in animals. In this study, we examine the effects of tryptophan enhancement and depletion on plasma catecholamine levels in humans. METHODS The total sample consisted of 164 healthy men and women who were tested for 2 days. Seventy-nine participants were randomized to a tryptophan enhancement condition and 85 to a tryptophan depletion condition. Both protocols consisted of a "sham day," followed by an "active day." Blood samples for assessment of plasma norepinephrine and epinephrine levels were collected before and after tryptophan enhancement/depletion. Data were analyzed using general linear models. Separate analyses were conducted for each study arm and for each measure. RESULTS In the depletion condition, both epinephrine (F(5,330) = 2.69, p = .021) and norepinephrine (F(5,335) = 2.79, p = .018) showed small increases on active versus "sham" depletion days. There were also significant day by time interactions for epinephrine (F(3,171) = 39.32, p < .0001) and norepinephrine (F(3,195) = 31.09, p < .0001) levels in the enhancement arm. Tryptophan infusion resulted in a marked increase in epinephrine (Premean = 23.92 (12.23) versus Postmean = 81.57 (62.36)) and decrease in norepinephrine (Premean = 257.2 (106.11) versus Postmean = 177.04 (87.15)), whereas levels of both catecholamines were stable on the "sham day." CONCLUSIONS CNS 5-HT exerts both inhibitory and excitatory effects on SNS activity in humans, potentially due to stimulation of CNS 5-HT receptors that have shown to have inhibitory (5-HT1A) and excitatory (5-HT1A and/or 5-HT2) SNS effects in animal models.
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16
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Peixoto MF, Cesaretti M, Hood SD, Tavares A. Effects of SSRI medication on heart rate and blood pressure in individuals with hypertension and depression. Clin Exp Hypertens 2018; 41:428-433. [PMID: 30047786 DOI: 10.1080/10641963.2018.1501058] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
OBJECTIVE To test the role of escitalopram on blood pressure and heart rate of individuals with hypertension and depression. METHODS A total of 30 individuals participated in this study who were being treated for hypertension and were diagnosed with major depression. Escitalopram (10-20 mg) was administered to 15 individuals, while the other 15 received placebo. These individuals were followed for 8 weeks with regular monitoring of blood pressure and heart rate. Scores on the Hamilton Depression Rating Scale were evaluated within the first, second, fourth, and eighth weeks of the study onset. RESULTS Comparing with placebo, heart rate was lower in the escitalopram group (66.79 ± 9.85 vs. 74.10 ± 9.52 bpm, p = 0.044). There was not a significant decrease of systolic blood pressure (140.80 ± 16.48 vs 139.61 ± 18.92 mmHg, p = 0.85) and diastolic blood pressure (80.55 ± 12.64 vs 80.18 ± 16.36 mmHg, p = 0.94). CONCLUSION Escitalopram decreases HR, but not BP, in individuals with hypertension and depression. Abbreviation: SH: systemic hypertension; BP: blood pressure; DSM: Diagnostic and Statistical Manual of Mental Disorders; SRQ 20: Self-Report Questionnaire; SCID: Structured Clinical Interview for DSM-IV; HR: heart rate; SNS: Sympathetic nervous system; HPA: hypothalamus-pituitary-adrenal axis; RAA: renin, angiotensin, aldosterone system; NE: norepinephrine; CSF: cerebrospinal fluid; HAM-D: Hamilton Depression Rating Scale; CRF: corticotropin releasing factor; ACTH: adrenocorticotropic hormone; BMI: Body mass index; SBP: systolic blood pressure; DBP: diastolic blood pressure; t: time.
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Affiliation(s)
- M F Peixoto
- a Internal Medicine Department, Division of Nephrology , Federal University of Sao Paulo , Sao Paulo , Brazil
| | - Mlr Cesaretti
- a Internal Medicine Department, Division of Nephrology , Federal University of Sao Paulo , Sao Paulo , Brazil
| | - S D Hood
- b Division of Psychiatry, UWA Medical School, Faculty of Health & Medical Sciences , The University of Western Australia , Perth , Australia
| | - A Tavares
- a Internal Medicine Department, Division of Nephrology , Federal University of Sao Paulo , Sao Paulo , Brazil
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Hood SD, Broyd A, Robinson H, Lee J, Hudaib AR, Hince DA. Effects of tryptophan depletion on selective serotonin reuptake inhibitor-remitted patients with obsessive compulsive disorder. J Psychopharmacol 2017; 31:1615-1623. [PMID: 29095069 DOI: 10.1177/0269881117736916] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Serotonergic antidepressants are first-line medication therapies for obsessive-compulsive disorder, however it is not known if synaptic serotonin availability is important for selective serotonin reuptake inhibitor efficacy. The present study tested the hypothesis that temporary reduction in central serotonin transmission, through acute tryptophan depletion, would result in an increase in anxiety in selective serotonin reuptake inhibitor-remitted obsessive-compulsive disorder patients. METHODS Eight patients (four males) with obsessive-compulsive disorder who showed sustained clinical improvement with selective serotonin reuptake inhibitor treatment underwent acute tryptophan depletion in a randomized, double-blind, placebo-controlled, within-subjects design, over two days one week apart. Five hours after consumption of the depleting/sham drink the participants performed a personalized obsessive-compulsive disorder symptom exposure task. Psychological responses were measured using the Spielberger State Anxiety Inventory, Yale-Brown Obsessive Compulsive Scale and Visual Analogue Scales. RESULTS Free plasma tryptophan to large neutral amino acid ratio decreased by 93% on the depletion day and decreased by 1% on the sham day, as anticipated. Psychological rating scores as measured by Visual Analogue Scale showed a significant decrease in perceived control and increase in interfering thoughts at the time of provocation on the depletion day but not on the sham day. A measure of convergent validity, namely Visual Analogue Scale Similar to past, was significantly higher at the time of provocation on both the depletion and sham days. Both the depletion and time of provocation scores for Visual Analogue Scale Anxiety, Spielberger State Anxiety Inventory, Yale-Brown Obsessive Compulsive Scale and blood pressure were not significant. CONCLUSIONS Acute tryptophan depletion caused a significant decrease in perceived control and increase in interfering thoughts at the time of provocation. Acute tryptophan depletion had no effect on the Spielberger State Anxiety Inventory or Visual Analogue Scale Anxiety measures, which suggests that the mechanism of action of selective serotonin reuptake inhibitors may be different to that seen in panic, social anxiety and post-traumatic stress disorder. Successful selective serotonin reuptake inhibitor treatment of obsessive-compulsive disorder may involve the ability of serotonin to switch habitual responding to goal-directed behaviour.
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Affiliation(s)
- Sean D Hood
- Division of Psychiatry, UWA Medical School, The University of Western Australia, Perth, Australia
| | - Annabel Broyd
- Division of Psychiatry, UWA Medical School, The University of Western Australia, Perth, Australia
| | - Hayley Robinson
- Division of Psychiatry, UWA Medical School, The University of Western Australia, Perth, Australia
| | - Jessica Lee
- Division of Psychiatry, UWA Medical School, The University of Western Australia, Perth, Australia
| | - Abdul-Rahman Hudaib
- Division of Psychiatry, UWA Medical School, The University of Western Australia, Perth, Australia
| | - Dana A Hince
- Division of Psychiatry, UWA Medical School, The University of Western Australia, Perth, Australia
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18
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Trotter PD, McGlone F, McKie S, McFarquhar M, Elliott R, Walker SC, Deakin JFW. Effects of acute tryptophan depletion on central processing of CT-targeted and discriminatory touch in humans. Eur J Neurosci 2016; 44:2072-83. [DOI: 10.1111/ejn.13298] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 05/18/2016] [Accepted: 06/13/2016] [Indexed: 02/03/2023]
Affiliation(s)
- Paula Diane Trotter
- Research Centre in Brain and Behaviour; School of Natural Sciences & Psychology; Liverpool John Moores University; Byrom Street Liverpool L3 3AF UK
| | - Francis McGlone
- Research Centre in Brain and Behaviour; School of Natural Sciences & Psychology; Liverpool John Moores University; Byrom Street Liverpool L3 3AF UK
- Institute of Psychology, Health and Society; University of Liverpool; Liverpool UK
| | - Shane McKie
- Neuroscience and Psychiatry Unit; The University of Manchester; Manchester UK
| | - Martyn McFarquhar
- Neuroscience and Psychiatry Unit; The University of Manchester; Manchester UK
| | - Rebecca Elliott
- Neuroscience and Psychiatry Unit; The University of Manchester; Manchester UK
| | - Susannah Claire Walker
- Research Centre in Brain and Behaviour; School of Natural Sciences & Psychology; Liverpool John Moores University; Byrom Street Liverpool L3 3AF UK
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Hsiao CY, Tsai HC, Chi MH, Chen KC, Chen PS, Lee IH, Yeh TL, Yang YK. The Association between Baseline Subjective Anxiety Rating and Changes in Cardiac Autonomic Nervous Activity in Response to Tryptophan Depletion in Healthy Volunteers. Medicine (Baltimore) 2016; 95:e3498. [PMID: 27175645 PMCID: PMC4902487 DOI: 10.1097/md.0000000000003498] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The aim of this study was to investigate the influence of serotonin on anxiety and autonomic nervous system (ANS) function; the correlation between subjective anxiety rating and changes of ANS function following tryptophan depletion (TD) in healthy volunteers was examined. Twenty-eight healthy participants, consisting of 15 females and 13 males, with an average age of 33.3 years, were recruited.Baseline Chinese Symptom Checklist-90-Revised and ANS function measurements were taken. TD was carried out on the testing day, and participants provided blood samples right before and 5 hours after TD. ANS function, somatic symptoms, and Visual Analogue Scales (VASs) were determined after TD. Wilcoxon signed rank test and Spearman ρ correlation were adapted for analyses of the results.The TD procedure reduced total and free plasma tryptophan effectively. After TD, the sympathetic nervous activity increased and parasympathetic nervous activity decreased. Baseline anxiety ratings positively correlated with post-TD changes in sympathetic nervous activity, VAS ratings, and physical symptoms. However, a negative correlation with post-TD changes in parasympathetic nervous activity was found.The change in ANS function after TD was associated with the severity of anxiety in healthy volunteers. This supports the fact that the effect of anxiety on heart rate variability is related to serotonin vulnerability. Furthermore, it also shows that the subjective anxiety rating has a biological basis related to serotonin.
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Affiliation(s)
- Chih Yin Hsiao
- From the Department of Psychiatry, National Cheng Kung University Hospital (CYH, HCT, MHC, KCC, PSC, IHL, TLY, YKY), College of Medicine; Addiction Research Center (CYH, KCC, PSC, IHL, TLY, YKY), National Cheng Kung University, Tainan; Department of Psychiatry (HCT, KCC, YKY), National Cheng Kung University Hospital, Dou-Liou Branch, Yunlin; and Institute of Behavioral Medicine (YKY), College of Medicine, National Cheng Kung University, Tainan, Taiwan
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20
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Roomruangwong C, Kanchanatawan B, Sirivichayakul S, Anderson G, Carvalho AF, Duleu S, Geffard M, Maes M. IgA/IgM responses to tryptophan and tryptophan catabolites (TRYCATs) are differently associated with prenatal depression, physio-somatic symptoms at the end of term and premenstrual syndrome. Mol Neurobiol 2016; 54:3038-3049. [PMID: 27037573 DOI: 10.1007/s12035-016-9877-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 03/18/2016] [Indexed: 12/13/2022]
Abstract
There is some evidence that lowered tryptophan and an activated tryptophan catabolite (TRYCAT) pathway play a role in depression, somatoform disorder, and postpartum blues. The aim of this study is to delineate the associations between the TRYCAT pathway and premenstrual syndrome (PMS) and perinatal depressive and physio-somatic symptoms. We examine the associations between end of term serum IgM and IgA responses to tryptophan and 9 TRYCATs in relation to zinc, C-reactive protein (CRP), and haptoglobin and prenatal physio-somatic (previously known as psychosomatic) symptoms (fatigue, back pain, muscle pain, dyspepsia, obstipation) and prenatal and postnatal depression and anxiety symptoms as measured using the Edinburgh Postnatal Depression Scale (EPDS), Hamilton Depression Rating Scale (HAMD), and Spielberger's State Anxiety Inventory (STAI). We included pregnant females with (n = 24) and without depression (n = 25) and 24 non-pregnant females. There were no significant associations between the IgA/IgM responses to tryptophan and TRYCATs and prenatal and postnatal depression/anxiety symptoms, except for lowered IgA responses to anthranilic acid in prenatal depression. A large part of the variance in IgA responses to most TRYCATs was explained by PMS and haptoglobin (positively) and CRP (inversely) levels. The IgA responses to TRYCATs were significantly increased in PMS, in particular picolinic, anthranilic, xanthurenic and kynurenic acid, and 3OH-kynurenine. Variance (62.5%) in physio-somatic symptoms at the end of term was explained by PMS, previous depressions, zinc (inversely), CRP and haptoglobin (both positively), and the IgM responses to quinolinic acid (positively), anthranilic acid, and tryptophan (both negatively). The results suggest that mucosa-derived TRYCAT pathway activation is significantly associated with PMS, but not with perinatal depression/anxiety symptoms. Physio-somatic symptoms in pregnancy have an immune-inflammatory pathophysiology. Induction of the TRYCAT pathway appears to be more related to physio-somatic than to depression symptoms.
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Affiliation(s)
- Chutima Roomruangwong
- Department of Psychiatry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Buranee Kanchanatawan
- Department of Psychiatry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Sunee Sirivichayakul
- Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | | | - André F Carvalho
- Department of Clinical Medicine and Translational Psychiatry Research Group, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | | | - Michel Geffard
- Research Department, IDRPHT, Talence, France.,GEMAC, Lieu-Dit Berganton, Saint Jean d'Illac, France
| | - Michael Maes
- Department of Psychiatry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. .,Department of Psychiatry, Faculty of Medicine, State University of Londrina, Londrina, Brazil. .,Department of Psychiatry, Medical University Plovdiv, Plovdiv, Bulgaria. .,Revitalis, Waalre, The Netherlands. .,IMPACT Research Center, Deakin University, Geelong, Australia. .,IMPACT Strategic Research Center, Barwon Health, Deakin University, Geelong, VIC, Australia.
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21
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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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Sanchez CL, Biskup CS, Herpertz S, Gaber TJ, Kuhn CM, Hood SH, Zepf FD. The Role of Serotonin (5-HT) in Behavioral Control: Findings from Animal Research and Clinical Implications. Int J Neuropsychopharmacol 2015; 18:pyv050. [PMID: 25991656 PMCID: PMC4648158 DOI: 10.1093/ijnp/pyv050] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 04/29/2015] [Indexed: 11/13/2022] Open
Abstract
The neurotransmitters serotonin and dopamine both have a critical role in the underlying neurobiology of different behaviors. With focus on the interplay between dopamine and serotonin, it has been proposed that dopamine biases behavior towards habitual responding, and with serotonin offsetting this phenomenon and directing the balance toward more flexible, goal-directed responding. The present focus paper stands in close relationship to the publication by Worbe et al. (2015), which deals with the effects of acute tryptophan depletion, a neurodietary physiological method to decrease central nervous serotonin synthesis in humans for a short period of time, on the balance between hypothetical goal-directed and habitual systems. In that research, acute tryptophan depletion challenge administration and a following short-term reduction in central nervous serotonin synthesis were associated with a shift of behavioral performance towards habitual responding, providing further evidence that central nervous serotonin function modulates the balance between goal-directed and stimulus-response habitual systems of behavioral control. In the present focus paper, we discuss the findings by Worbe and colleagues in light of animal experiments as well as clinical implications and discuss potential future avenues for related research.
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Affiliation(s)
- C L Sanchez
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany (Drs Sanchez, Biskup, and Mr Gaber); Jülich Aachen Research Alliance, JARA Translational Brain Medicine, Aachen & Jülich, Germany (Drs Sanchez, Biskup, and Mr Gaber); Department of Pharmacology and Cancer Biology, Duke University, Durham, NC (Drs Sanchez and Kuhn); Department of Psychiatry, Psychotherapy and Psychosomatics, University of Heidelberg, Heidelberg, Germany (Dr Herpertz); School of Psychiatry and Clinical Neurosciences (Dr Hood), and Department of Child and Adolescent Psychiatry, School of Psychiatry and Clinical Neurosciences & School of Paediatrics and Child Health (Dr ZEPF), Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia, Perth, WA, Australia; Specialised Child and Adolescent Mental Health Services, Department of Health in Western Australia, Perth, WA, Australia (Dr ZEPF)
| | - C S Biskup
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany (Drs Sanchez, Biskup, and Mr Gaber); Jülich Aachen Research Alliance, JARA Translational Brain Medicine, Aachen & Jülich, Germany (Drs Sanchez, Biskup, and Mr Gaber); Department of Pharmacology and Cancer Biology, Duke University, Durham, NC (Drs Sanchez and Kuhn); Department of Psychiatry, Psychotherapy and Psychosomatics, University of Heidelberg, Heidelberg, Germany (Dr Herpertz); School of Psychiatry and Clinical Neurosciences (Dr Hood), and Department of Child and Adolescent Psychiatry, School of Psychiatry and Clinical Neurosciences & School of Paediatrics and Child Health (Dr ZEPF), Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia, Perth, WA, Australia; Specialised Child and Adolescent Mental Health Services, Department of Health in Western Australia, Perth, WA, Australia (Dr ZEPF)
| | - S Herpertz
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany (Drs Sanchez, Biskup, and Mr Gaber); Jülich Aachen Research Alliance, JARA Translational Brain Medicine, Aachen & Jülich, Germany (Drs Sanchez, Biskup, and Mr Gaber); Department of Pharmacology and Cancer Biology, Duke University, Durham, NC (Drs Sanchez and Kuhn); Department of Psychiatry, Psychotherapy and Psychosomatics, University of Heidelberg, Heidelberg, Germany (Dr Herpertz); School of Psychiatry and Clinical Neurosciences (Dr Hood), and Department of Child and Adolescent Psychiatry, School of Psychiatry and Clinical Neurosciences & School of Paediatrics and Child Health (Dr ZEPF), Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia, Perth, WA, Australia; Specialised Child and Adolescent Mental Health Services, Department of Health in Western Australia, Perth, WA, Australia (Dr ZEPF)
| | - T J Gaber
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany (Drs Sanchez, Biskup, and Mr Gaber); Jülich Aachen Research Alliance, JARA Translational Brain Medicine, Aachen & Jülich, Germany (Drs Sanchez, Biskup, and Mr Gaber); Department of Pharmacology and Cancer Biology, Duke University, Durham, NC (Drs Sanchez and Kuhn); Department of Psychiatry, Psychotherapy and Psychosomatics, University of Heidelberg, Heidelberg, Germany (Dr Herpertz); School of Psychiatry and Clinical Neurosciences (Dr Hood), and Department of Child and Adolescent Psychiatry, School of Psychiatry and Clinical Neurosciences & School of Paediatrics and Child Health (Dr ZEPF), Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia, Perth, WA, Australia; Specialised Child and Adolescent Mental Health Services, Department of Health in Western Australia, Perth, WA, Australia (Dr ZEPF)
| | - C M Kuhn
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany (Drs Sanchez, Biskup, and Mr Gaber); Jülich Aachen Research Alliance, JARA Translational Brain Medicine, Aachen & Jülich, Germany (Drs Sanchez, Biskup, and Mr Gaber); Department of Pharmacology and Cancer Biology, Duke University, Durham, NC (Drs Sanchez and Kuhn); Department of Psychiatry, Psychotherapy and Psychosomatics, University of Heidelberg, Heidelberg, Germany (Dr Herpertz); School of Psychiatry and Clinical Neurosciences (Dr Hood), and Department of Child and Adolescent Psychiatry, School of Psychiatry and Clinical Neurosciences & School of Paediatrics and Child Health (Dr ZEPF), Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia, Perth, WA, Australia; Specialised Child and Adolescent Mental Health Services, Department of Health in Western Australia, Perth, WA, Australia (Dr ZEPF)
| | - S H Hood
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany (Drs Sanchez, Biskup, and Mr Gaber); Jülich Aachen Research Alliance, JARA Translational Brain Medicine, Aachen & Jülich, Germany (Drs Sanchez, Biskup, and Mr Gaber); Department of Pharmacology and Cancer Biology, Duke University, Durham, NC (Drs Sanchez and Kuhn); Department of Psychiatry, Psychotherapy and Psychosomatics, University of Heidelberg, Heidelberg, Germany (Dr Herpertz); School of Psychiatry and Clinical Neurosciences (Dr Hood), and Department of Child and Adolescent Psychiatry, School of Psychiatry and Clinical Neurosciences & School of Paediatrics and Child Health (Dr ZEPF), Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia, Perth, WA, Australia; Specialised Child and Adolescent Mental Health Services, Department of Health in Western Australia, Perth, WA, Australia (Dr ZEPF)
| | - F D Zepf
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany (Drs Sanchez, Biskup, and Mr Gaber); Jülich Aachen Research Alliance, JARA Translational Brain Medicine, Aachen & Jülich, Germany (Drs Sanchez, Biskup, and Mr Gaber); Department of Pharmacology and Cancer Biology, Duke University, Durham, NC (Drs Sanchez and Kuhn); Department of Psychiatry, Psychotherapy and Psychosomatics, University of Heidelberg, Heidelberg, Germany (Dr Herpertz); School of Psychiatry and Clinical Neurosciences (Dr Hood), and Department of Child and Adolescent Psychiatry, School of Psychiatry and Clinical Neurosciences & School of Paediatrics and Child Health (Dr ZEPF), Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia, Perth, WA, Australia; Specialised Child and Adolescent Mental Health Services, Department of Health in Western Australia, Perth, WA, Australia (Dr ZEPF)
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Politis M, Niccolini F. Serotonin in Parkinson's disease. Behav Brain Res 2015; 277:136-45. [DOI: 10.1016/j.bbr.2014.07.037] [Citation(s) in RCA: 182] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 07/21/2014] [Accepted: 07/22/2014] [Indexed: 02/04/2023]
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The GKH, Verkes RJ, Fekkes D, Bleijenberg G, van der Meer JWM, Buitelaar JK. Tryptophan depletion in chronic fatigue syndrome, a pilot cross-over study. BMC Res Notes 2014; 7:650. [PMID: 25227994 PMCID: PMC4176591 DOI: 10.1186/1756-0500-7-650] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Accepted: 09/13/2014] [Indexed: 11/25/2022] Open
Abstract
Background Chronic fatigue syndrome (CFS) is still an enigmatic disorder. CFS can be regarded as a complex disorder with tremendous impact on lives of CFS-patients. Full recovery without treatment is rare. A somatic explanation for the fatigue is lacking. There is clinical and experimental evidence implicating enhanced serotonergic neurotransmission in CFS. Genetic studies and imaging studies support the hypothesis of upregulated serotonin system in CFS. In line with the hypothesis of an increased serotonergic state in CFS, we performed a randomised clinical trial investigated the effect of 5-HT3 receptor antagonism in CFS. No benefit was found of the 5-HT3 receptor antagonist ondansetron compared to placebo. To further investigate the involvement of serotonin in CFS we performed a placebo controlled cross over pilot study investigating the effect of Acute Tryptophan Depletion. Findings Five female CFS-patients who met the US Center for Disease Control and Prevention criteria for CFS were recruited. There were two test days, one week apart. Each participant received placebo and ATD. To evaluate the efficacy of the ATD procedure tryptophan and the large neutral amino acids were measured. The outcome measures were fatigue severity, concentration and mood states. ATD resulted in a significant plasma tryptophan to large neutral amino acid ratio reduction of 96%. There were no significant differences in fatigue-, depression and concentration between the placebo- and ATD condition. Conclusions These first five CFS-patients did not respond to the ATD procedure. However, a much larger sample size is needed to draw final conclusions on the hypothesis of an increased serotonergic state in the pathophysiology of CFS. Trial registration ISRCTN07518149
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Affiliation(s)
- Gerard K H The
- Department of General Internal Medicine, Nijmegen Expert Centre Chronic Fatigue, Radboud University Nijmegen Medical Centre, Reinier Postlaan 4, 6525 GC Nijmegen, The Netherlands.
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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: 1160] [Impact Index Per Article: 116.0] [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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Sobczak S, Schruers K. Can formulation affect tryptophan depletion results? Hints from studies in experimental panic. J Psychopharmacol 2014; 28:486-90. [PMID: 24429220 DOI: 10.1177/0269881113517954] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
RATIONALE Acute Tryptophan Depletion (ATD) is a specific serotonergic challenge tool. Central serotonergic effects of different ATD procedures are possibly not those that are usually assumed. OBJECTIVES In this paper we review data of ATD in an experimental fear model to investigate whether and how methodological differences may affect fear outcomes. Next we point to discrepancies of studies in our laboratory in order to test the hypotheses formulated in the review. METHODS Literature was searched in PubMed and MEDLINE and studies of our laboratory were compared. RESULTS Eight studies were included in the review: five in patients with panic disorder, three in healthy individuals. Methodologically the studies in our laboratory were quite similar except for the applied ATD mixtures. CONCLUSIONS ATD exerts fear-enhancing effects in patients with panic disorders, more than in healthy individuals. However, our findings are inconclusive. The discrepant findings of studies in our laboratory can possibly be explained by differences in the ATD mixtures used. We suggest mechanisms as to how these might have affected the central availability of tryptophan and hence serotonin.
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Affiliation(s)
- Sjacko Sobczak
- 1Mondriaan Department of Old Age Psychiatry/Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands
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27
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Duke AA, Bègue L, Bell R, Eisenlohr-Moul T. Revisiting the serotonin-aggression relation in humans: a meta-analysis. Psychol Bull 2013; 139:1148-72. [PMID: 23379963 PMCID: PMC3718863 DOI: 10.1037/a0031544] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The inverse relation between serotonin and human aggression is often portrayed as "reliable," "strong," and "well established" despite decades of conflicting reports and widely recognized methodological limitations. In this systematic review and meta-analysis, we evaluate the evidence for and against the serotonin deficiency hypothesis of human aggression across 4 methods of assessing serotonin: (a) cerebrospinal fluid levels of 5-hydroxyindoleacetic acid (CSF 5-HIAA), (b) acute tryptophan depletion, (c) pharmacological challenge, and (d) endocrine challenge. Results across 175 independent samples and over 6,500 total participants were heterogeneous, but, in aggregate, revealed a small, inverse correlation between serotonin functioning and aggression, anger, and hostility (r = -.12). Pharmacological challenge studies had the largest mean weighted effect size (r = -.21), and CSF 5-HIAA studies had the smallest (r = -.06). Potential methodological and demographic moderators largely failed to account for variability in study outcomes. Notable exceptions included year of publication (effect sizes tended to diminish with time) and self- versus other-reported aggression (other-reported aggression was positively correlated to serotonin functioning). We discuss 4 possible explanations for the pattern of findings: unreliable measures, ambient correlational noise, an unidentified higher order interaction, and a selective serotonergic effect. Finally, we provide 4 recommendations for bringing much needed clarity to this important area of research: acknowledge contradictory findings and avoid selective reporting practices; focus on improving the reliability and validity of serotonin and aggression measures; test for interactions involving personality and/or environmental moderators; and revise the serotonin deficiency hypothesis to account for serotonin's functional complexity.
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van Donkelaar EL, Prickaerts J, Akkerman S, Rutten K, Steinbusch HWM, Blokland A. No effect of acute tryptophan depletion on phosphodiesterase inhibition--related improvements of short-term object memory in male Wistar rats. Acta Psychiatr Scand 2013; 128:107-13. [PMID: 23772681 DOI: 10.1111/acps.12166] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/16/2013] [Indexed: 01/22/2023]
Abstract
OBJECTIVE To further explore the implication of the serotonin (5-HT) system in the improvement of rat short-term object recognition after administration of the type 2 phosphodiesterase inhibitor (PDE-I) BAY 60-7550 and the type 5 PDE-I vardenafil, the effect of PDE2 and PDE5 inhibition upon central amino acid levels, 5-HT, and related parameters were measured after applying acute tryptophan depletion (ATD). METHOD Wistar rats were orally administered saline or a protein-carbohydrate mixture with or without tryptophan (TRP). TRP-depleted animals additionally received an oral vehicle injection or the PDE inhibitors BAY 60-7550 or vardenafil at a dose known to improve object memory performance. RESULTS Although ATD significantly decreased TRP levels in the hippocampus 2 h after administration, 5-HT levels appeared only moderately affected, without any changes observed in the amount of 5-HIAA or 5-HT turnover rate. Moreover, no effects of PDE inhibition upon 5-HT or related parameters were observed. CONCLUSION Changes in 5-HT neurotransmitter activity might be excluded as a potential underlying mechanism of the previously reported ability of PDE inhibitors to improve short-term object memory in rats. It is suggested that a decrease in cerebral blood flow potentially underlies ATD-induced object memory deficits, most likely due to decrease in NO synthesis.
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Affiliation(s)
- E L van Donkelaar
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands.
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Moylan S, Jacka FN, Pasco JA, Berk M. How cigarette smoking may increase the risk of anxiety symptoms and anxiety disorders: a critical review of biological pathways. Brain Behav 2013; 3:302-26. [PMID: 23785661 PMCID: PMC3683289 DOI: 10.1002/brb3.137] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 02/20/2013] [Accepted: 02/27/2013] [Indexed: 12/24/2022] Open
Abstract
Multiple studies have demonstrated an association between cigarette smoking and increased anxiety symptoms or disorders, with early life exposures potentially predisposing to enhanced anxiety responses in later life. Explanatory models support a potential role for neurotransmitter systems, inflammation, oxidative and nitrosative stress, mitochondrial dysfunction, neurotrophins and neurogenesis, and epigenetic effects, in anxiety pathogenesis. All of these pathways are affected by exposure to cigarette smoke components, including nicotine and free radicals. This review critically examines and summarizes the literature exploring the role of these systems in increased anxiety and how exposure to cigarette smoke may contribute to this pathology at a biological level. Further, this review explores the effects of cigarette smoke on normal neurodevelopment and anxiety control, suggesting how exposure in early life (prenatal, infancy, and adolescence) may predispose to higher anxiety in later life. A large heterogenous literature was reviewed that detailed the association between cigarette smoking and anxiety symptoms and disorders with structural brain changes, inflammation, and cell-mediated immune markers, markers of oxidative and nitrosative stress, mitochondrial function, neurotransmitter systems, neurotrophins and neurogenesis. Some preliminary data were found for potential epigenetic effects. The literature provides some support for a potential interaction between cigarette smoking, anxiety symptoms and disorders, and the above pathways; however, limitations exist particularly in delineating causative effects. The literature also provides insight into potential effects of cigarette smoke, in particular nicotine, on neurodevelopment. The potential treatment implications of these findings are discussed in regards to future therapeutic targets for anxiety. The aforementioned pathways may help mediate increased anxiety seen in people who smoke. Further research into the specific actions of nicotine and other cigarette components on these pathways, and how these pathways interact, may provide insights that lead to new treatment for anxiety and a greater understanding of anxiety pathogenesis.
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Affiliation(s)
- Steven Moylan
- Deakin University School of Medicine Barwon Health, Geelong, Victoria, Australia
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Knott V, Thompson A, Shah D, Ilivitsky V. Neural expression of nicotine's antidepressant properties during tryptophan depletion: an EEG study in healthy volunteers at risk for depression. Biol Psychol 2012; 91:190-200. [PMID: 22743591 DOI: 10.1016/j.biopsycho.2012.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 06/06/2012] [Accepted: 06/06/2012] [Indexed: 01/09/2023]
Abstract
Nicotine amelioration of serotonergically mediated mood dysregulation may contribute to the comorbidity between cigarette smoking and depression, a disorder which is associated with aberrant activation and hemispheric asymmetry in frontal and posterior cortical regions. This randomized, double-blind study in 20 healthy volunteers with a positive family history of depression examined the effects of transdermal nicotine on mood and EEG changes accompanying transient reductions in serotonin induced by acute tryptophan depletion (ATD). Increased self-ratings of depressed mood and elevation in left frontal high alpha power (decreased activation) were evidenced with ATD (vs. balanced mixture) in participants treated with the placebo but not the nicotine treated group. Nicotine alone increased vigor and posterior high alpha bilaterally, and during ATD it prevented the reduction in left frontal high alpha that was evident in the placebo patch group. These findings indicate that in depression prone individuals, nicotine acts to stabilize the mood lowering and associated frontal functional asymmetry elicited by an acute decrease in brain serotonin.
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Affiliation(s)
- Verner Knott
- University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada.
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31
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Crowley SK, Youngstedt SD. Efficacy of light therapy for perinatal depression: a review. J Physiol Anthropol 2012; 31:15. [PMID: 22738716 PMCID: PMC3518242 DOI: 10.1186/1880-6805-31-15] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 03/20/2012] [Indexed: 11/13/2022] Open
Abstract
Perinatal depression is an important public health problem affecting 10% to 20% of childbearing women. Perinatal depression is associated with significant morbidity, and has enormous consequences for the wellbeing of the mother and child. During the perinatal period, treatment of depression, which could affect the mother and child during pregnancy and lactation, poses a complex problem for both mother and clinician. Bright light therapy may be an attractive treatment for perinatal depression because it is low cost, home-based, and has a much lower side effect profile than pharmacotherapy. The antidepressant effects of bright light are well established, and there are several rationales for expecting that bright light might also be efficacious for perinatal depression. This review describes these rationales, summarizes the available evidence on the efficacy of bright light therapy for perinatal depression, and discusses future directions for investigation of bright light therapy as a treatment for perinatal depression.
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Affiliation(s)
- Shannon K Crowley
- Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA.
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Garcia de Miguel B, Nutt DJ, Hood SD, Davies SJC. Elucidation of neurobiology of anxiety disorders in children through pharmacological challenge tests and cortisol measurements: a systematic review. J Psychopharmacol 2012; 26:431-42. [PMID: 20643698 DOI: 10.1177/0269881110372818] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Anxiety disorders are common both in adults and children. While there have been major advances in understanding the neurobiology of anxiety disorders in adults, progress has been more limited in the elucidation of the mechanisms underlying these disorders in childhood. There is a need to delineate childhood biological models, since anxiety represents a significant clinical problem in children and is a risk factor for the subsequent development of anxiety and depression in adulthood. We conducted a review of the literature regarding pharmacological challenge tests and direct hypothalamic-pituitary-adrenal axis measurement in children with anxiety disorders, with emphasis on panic disorder and social anxiety disorder. Studies identified were contrasted with those in adult panic disorder and social anxiety disorder. Despite this broad approach few studies emerged in children, with only 22 studies meeting inclusion criteria. When contrasted with adult neurobiological models of panic disorder and social anxiety disorder, children studied showed some abnormalities which mirrored those reported in adults, such as altered baseline respiration, altered responses to CO(2) challenge tests and blunted growth hormone response to yohimbine. However, results differed from adults with panic disorder and social anxiety in some aspects of noradrenergic and serotonergic function. For endpoints studied in panic disorder children, unlike adults, displayed a lack of baseline end-tidal CO(2) abnormalities and a different hypothalamic-pituitary-adrenal pattern response under low-dose CO(2). The biology of these anxiety disorders in children may only partially mirror that of adult anxiety disorders. However, caution is required as the evidence is limited, and many studies combined patients with panic disorder and social anxiety disorder with other disorders or non-specific anxiety. Further research is required to fully understand the biology and progression of childhood anxiety disorders.
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Browne CA, Clarke G, Dinan TG, Cryan JF. An effective dietary method for chronic tryptophan depletion in two mouse strains illuminates a role for 5-HT in nesting behaviour. Neuropharmacology 2012; 62:1903-15. [DOI: 10.1016/j.neuropharm.2011.12.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 12/01/2011] [Accepted: 12/08/2011] [Indexed: 12/31/2022]
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Sinclair LI, Nutt DJ. Anxiolytics. HANDBOOK OF CLINICAL NEUROLOGY 2012; 106:669-79. [PMID: 22608651 DOI: 10.1016/b978-0-444-52002-9.00040-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2024]
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Krämer UM, Riba J, Richter S, Münte TF. An fMRI study on the role of serotonin in reactive aggression. PLoS One 2011; 6:e27668. [PMID: 22110714 PMCID: PMC3218006 DOI: 10.1371/journal.pone.0027668] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 10/21/2011] [Indexed: 11/18/2022] Open
Abstract
Reactive aggression after interpersonal provocation is a common behavior in humans. Little is known, however, about brain regions and neurotransmitters critical for the decision-making and affective processes involved in aggressive interactions. With the present fMRI study, we wanted to examine the role of serotonin in reactive aggression by means of an acute tryptophan depletion (ATD). Participants performed in a competitive reaction time task (Taylor Aggression Paradigm, TAP) which entitled the winner to punish the loser. The TAP seeks to elicit aggression by provocation. The study followed a double-blind between-subject design including only male participants. Behavioral data showed an aggression diminishing effect of ATD in low trait-aggressive participants, whereas no ATD effect was detected in high trait-aggressive participants. ATD also led to reduced insula activity during the decision phase, independently of the level of provocation. Whereas previous reports have suggested an inverse relationship between serotonin level and aggressive behavior with low levels of serotonin leading to higher aggression and vice versa, such a simple relationship is inconsistent with the current data.
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Affiliation(s)
- Ulrike M Krämer
- Department of Neurology, University of Lübeck, Lübeck, Germany.
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Sarris J, Lake J, Hoenders R. Bipolar Disorder and Complementary Medicine: Current Evidence, Safety Issues, and Clinical Considerations. J Altern Complement Med 2011; 17:881-90. [DOI: 10.1089/acm.2010.0481] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Affiliation(s)
- Jerome Sarris
- Department of Psychiatry, Faculty of Medicine, The University of Melbourne, The Melbourne Clinic, Melbourne, Australia
- Swinburne University of Technology, Centre for Human Pyschopharmacology, Melbourne, Victoria, Australia
| | - James Lake
- Arizona Center for Integrative Medicine, Tucson, AZ
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Sarris J, Mischoulon D, Schweitzer I. Adjunctive nutraceuticals with standard pharmacotherapies in bipolar disorder: a systematic review of clinical trials. Bipolar Disord 2011; 13:454-65. [PMID: 22017215 DOI: 10.1111/j.1399-5618.2011.00945.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Studies using augmentation of pharmacotherapies with nutraceuticals in bipolar disorder (BD) have been conducted and preliminary evidence in many cases appears positive. To date, however, no specialized systematic review of this area has been conducted. We present the first systematic review of clinical trials using nutrient-based nutraceuticals in combination with standard pharmacotherapies to treat BD. A subsequent aim of this report was to discuss posited underlying mechanisms of action. METHODS PubMed, CINAHL, Web of Science, and Cochrane Library databases, and grey literature were searched during mid-2010 for human clinical trials in English using nutraceuticals such as omega-3, N-acetyl cysteine (NAC), inositol, and vitamins and minerals, in combination with pharmacotherapies to treat bipolar mania and bipolar depression. A review of the results including an effect size analysis (Cohen's d) was subsequently conducted. RESULTS In treating bipolar depression, positive evidence with large effect sizes were found for NAC (d=1.04) and a chelated mineral and vitamin formula (d=1.70). On the outcome of bipolar mania, several nutraceuticals reduced mania with strong clinical effects: a chelated mineral formula (d=0.83), L-tryptophan (d=1.47), magnesium (d=1.44), folic acid (d=0.40), and branched-chain amino acids (d=1.60). Mixed, but mainly positive, evidence was found for omega-3 for bipolar depression, while no evidentiary support was found for use in mania. No significant effect on BD outcome scales was found for inositol (possibly due to small samples). CONCLUSIONS BD treatment outcomes may potentially be improved by additional use of certain nutraceuticals with conventional pharmacotherapies. However, caution should be extended in interpreting the large effects of several isolated studies, as they have not yet been replicated in larger trials.
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Affiliation(s)
- Jerome Sarris
- Department of Psychiatry, Faculty of Medicine, University of Melbourne, The Melbourne Clinic2 Salisbury Street, Richmond, Victoria 3121, Australia.
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van Donkelaar EL, Blokland A, Ferrington L, Kelly PAT, Steinbusch HWM, Prickaerts J. Mechanism of acute tryptophan depletion: is it only serotonin? Mol Psychiatry 2011; 16:695-713. [PMID: 21339754 DOI: 10.1038/mp.2011.9] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The method of acute tryptophan depletion (ATD), which reduces the availability of the essential amino acid tryptophan (TRP), the dietary serotonin (5-hydroxytryptamine (5-HT)) precursor, has been applied in many experimental studies. ATD application leads to decreased availability of TRP in the brain and its synthesis into 5-HT. It is therefore assumed that a decrease in 5-HT release and subsequent blunted neurotransmission is the underlying mechanism for the behavioural effects of ATD. However, direct evidence that ATD decreases extracellular 5-HT concentrations is lacking. Furthermore, several studies provide support for alternative underlying mechanisms of ATD. This may question the utility of the method as a selective serotonergic challenge tool. As ATD is extensively used for investigating the role of 5-HT in cognitive functions and psychiatric disorders, the potential of alternative mechanisms and possible confounding factors should be taken into account. It is suggested that caution is required when interpreting ATD effects in terms of a selective serotonergic effect.
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Affiliation(s)
- E L van Donkelaar
- Department of Psychiatry and Neuropsychology, Faculty of Health, Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands.
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Time series fMRI measures detect changes in pontine raphé following acute tryptophan depletion. Psychiatry Res 2011; 191:112-21. [PMID: 21236648 PMCID: PMC3042244 DOI: 10.1016/j.pscychresns.2010.10.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 09/16/2010] [Accepted: 10/25/2010] [Indexed: 11/23/2022]
Abstract
Serotonin is synthesized from its precursor, tryptophan, by brainstem raphé neurons and their synaptic terminals in limbic regions. The omission of tryptophan from an Acute Tryptophan Depletion (ATD) diet transiently diminishes serotonin synthesis, alters raphé activity, and mimics symptoms of depression. Raphé functional magnetic resonance imaging (fMRI) poses challenges using signal-averaging analyses. Time-series properties of fMRI blood oxygenation level dependent (BOLD) signals may hold promise, so we analyzed raphé signals for changes with the ATD diet. Eleven remitted (previously depressed) patients were awake with eyes-closed during seven-minute resting scans with 0.5s(-1) sampling. BOLD signal time-series data were frequency-filtered using wavelet transforms, yielding three octave-width frequency bands from 0.25 to 0.03s(-1) and an unbounded band below 0.03s(-1). Spectral power, reflecting signal information, increased in pontine raphé at high frequencies (0.25 to 0.125s(-1)) during ATD (compared to control, balanced, diet, P<0.004) but was unchanged at other frequencies. Functional connectivity, the correlation between time-series data from pairs of regions, weakened between pontine raphé and anterior thalamus at low frequencies during ATD (P<0.05). This preliminarily supports using fMRI time-series features to assess pontine raphé function. Whether, and how, high frequency activity oscillations interfere with low frequency signaling requires further study.
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Rapid tryptophan depletion following cognitive behavioural therapy for panic disorder. Psychopharmacology (Berl) 2011; 213:593-602. [PMID: 19823804 DOI: 10.1007/s00213-009-1696-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Accepted: 09/23/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVE The aim of this study was to examine the effect of rapid tryptophan depletion (RTD) combined with a panicogenic challenge in patients with panic disorder who had responded to treatment with cognitive behavioural therapy (CBT). We hypothesised that RTD (compared with the control drink) would result in an increase in anxiety symptoms when provoked by a panicogenic challenge with the benzodiazepine antagonist, flumazenil. METHODS Nine patients with panic disorder who had responded to CBT received a tryptophan-free amino acid drink on one occasion and a control drink on the other in a double-blind crossover design. In addition, they received flumazenil and placebo infusions on each day. RESULTS Our hypothesis regarding the effects of RTD was supported by findings of a significant interaction between RTD and flumazenil on measures from visual analogues scales (total) and the Spielberger State Anxiety inventory. A somewhat unexpected finding was that in this group of CBT responders, the panicogenic effect of flumazenil was not completely blocked by treatment. This meant that although four of the nine subjects (44%) reported a panicogenic effect of flumazenil on the RTD day, this was not significantly different from the rate of panic attacks in response to flumazenil on the control day. CONCLUSION We suggest that the partial return of symptoms in response to flumazenil reflects a vulnerability to RTD in this group of panic disorder patients who had responded to treatment with CBT.
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Geeraerts B, Van Oudenhove L, Boesmans W, Vos R, Vanden Berghe P, Tack J. Influence of acute tryptophan depletion on gastric sensorimotor function in humans. Am J Physiol Gastrointest Liver Physiol 2011; 300:G228-35. [PMID: 20884888 DOI: 10.1152/ajpgi.00020.2010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Peripheral serotonin (5-hydrodytryptamine; 5-HT) is involved in the regulation of gastrointestinal motility and sensation, whereas centrally it plays a role in mood regulation. A dysfunctional serotonergic system may provide a plausible link between functional dyspepsia symptoms and its high psychosocial comorbidity such as anxiety and depression. The aim of this study was to evaluate the effect of decreased 5-HT synthesis by acute tryptophan depletion (ATD) on gastric sensorimotor function and nutrient tolerance, anxiety scores, and gastrointestinal mucosal 5-HT concentrations in healthy volunteers. All subjects were studied under a control condition and during ATD. Gastric sensorimotor function and nutrient tolerance were assessed using a barostat (n = 16, mean age 28.8 ± 1.4 yr) and a satiety drinking test (n = 13, mean age 27.3 ± 1.4 yr). Anxiety during the barostat was evaluated using State-Trait Anxiety Inventory (STAI) questionnaire. 5-HT concentrations were measured in fundic and duodenal mucosal biopsies by means of ELISA and immunohistochemistry. ATD significantly decreased plasma tryptophan levels compared with control in every experiment. ATD did not affect gastric sensitivity and compliance but decreased the sensation of nausea during balloon distension (AUC: 17.4 ± 4.3 vs. 11.4 ± 3.4 mm·mmHg, P = 0.030). ATD enhanced the postprandial volume increase (ANOVA, P < 0.05), but this was not accompanied by augmented nutrient tolerance (848 ± 110 vs. 837 ± 99 ml, nonsignificant). ATD had no effect on STAI state anxiety scores. No evidence was found for an effect on the number of enterochromaffin cells, but ATD reduced 5-HT levels in the duodenal mucosa. ATD alters gastric postprandial motor function and distension-induced nausea. These findings confirm involvement of 5-HT in the control of gastric accommodation and sensitivity.
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Affiliation(s)
- Brecht Geeraerts
- Dept. of Gastroenterology, Univ. Hospital Gasthuisberg, Herestraat 49, B-3000 Leuven, Belgium
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Beacher FDCC, Gray MA, Minati L, Whale R, Harrison NA, Critchley HD. Acute tryptophan depletion attenuates conscious appraisal of social emotional signals in healthy female volunteers. Psychopharmacology (Berl) 2011; 213:603-13. [PMID: 20596858 PMCID: PMC3032182 DOI: 10.1007/s00213-010-1897-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Accepted: 05/10/2010] [Indexed: 11/16/2022]
Abstract
RATIONALE Acute tryptophan depletion (ATD) decreases levels of central serotonin. ATD thus enables the cognitive effects of serotonin to be studied, with implications for the understanding of psychiatric conditions, including depression. OBJECTIVE To determine the role of serotonin in conscious (explicit) and unconscious/incidental processing of emotional information. MATERIALS AND METHODS A randomized, double-blind, cross-over design was used with 15 healthy female participants. Subjective mood was recorded at baseline and after 4 h, when participants performed an explicit emotional face processing task, and a task eliciting unconscious processing of emotionally aversive and neutral images presented subliminally using backward masking. RESULTS ATD was associated with a robust reduction in plasma tryptophan at 4 h but had no effect on mood or autonomic physiology. ATD was associated with significantly lower attractiveness ratings for happy faces and attenuation of intensity/arousal ratings of angry faces. ATD also reduced overall reaction times on the unconscious perception task, but there was no interaction with emotional content of masked stimuli. ATD did not affect breakthrough perception (accuracy in identification) of masked images. CONCLUSIONS ATD attenuates the attractiveness of positive faces and the negative intensity of threatening faces, suggesting that serotonin contributes specifically to the appraisal of the social salience of both positive and negative salient social emotional cues. We found no evidence that serotonin affects unconscious processing of negative emotional stimuli. These novel findings implicate serotonin in conscious aspects of active social and behavioural engagement and extend knowledge regarding the effects of ATD on emotional perception.
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Affiliation(s)
- Felix D C C Beacher
- Clinical Imaging Sciences Centre, Brighton and Sussex Medical School (BSMS), Brighton & Hove, UK.
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Pittler E, Schmid MG. Enantioseparation of dansyl amino acids by HPLC on a monolithic column dynamically coated with a vancomycin derivative. Biomed Chromatogr 2011; 24:1213-9. [PMID: 20954213 DOI: 10.1002/bmc.1430] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In this work a chiral stationary phase was prepared by dynamically coating a monolithic reversed-phase HPLC column with a vancomycin-derivative as chiral selector. A hydrophobic alkyl-chain was attached to the vancomycin molecule, providing the immobilization of the chiral selector on the reversed-phase material. Dansyl amino acids were chosen as model analytes for testing the separation power of the dynamically coated phase. All investigated compounds were separated into their enantiomers. Compared with a conventionally packed vancomycin-CSP, a reversal of the enantiomer elution order was obtained.
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Affiliation(s)
- Elfriede Pittler
- Institute of Pharmaceutical Sciences, Department of Pharmaceutical Chemistry, Karl-Franzens-University, Universitätsplatz 1, A-8010 Graz, Austria
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Christmas DM, Badawy AAB, Hince D, Davies SJ, Probert C, Creed T, Smithson J, Afzal M, Nutt DJ, Potokar JP. Increased serum free tryptophan in patients with diarrhea-predominant irritable bowel syndrome. Nutr Res 2010; 30:678-88. [DOI: 10.1016/j.nutres.2010.09.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Revised: 09/14/2010] [Accepted: 09/14/2010] [Indexed: 12/15/2022]
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Serotonergic neurotransmission and lapses of attention in children and adolescents with attention deficit hyperactivity disorder: availability of tryptophan influences attentional performance. Int J Neuropsychopharmacol 2010; 13:933-41. [PMID: 20196917 DOI: 10.1017/s146114571000012x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Deficiencies in serotonergic (5-HT) neurotransmission have frequently been linked to altered attention and memory processes. With attention deficit hyperactivity disorder (ADHD) being associated with impaired attention and working memory, this study investigated the effects of a diminished 5-HT turnover achieved by rapid tryptophan depletion (RTD) on attentional performance in children and adolescents with ADHD. Twenty-two male patients with ADHD (aged 9-15 yr) received the RTD procedure Moja-De and a tryptophan (Trp)-balanced placebo (Pla) in a randomized, double-blind, within-subject crossover design on two separate study days. Lapses of attention (LA) and phasic alertness (PA) were assessed within the test battery for attentional performance under depleted and sham-depleted conditions 120 (T1), 220 (T2) and 300 (T3) min after intake of RTD/Pla. At T1 there was a significant main effect for RTD, indicating more LA under intake of a Trp-balanced Pla compared to diminished 5-HT neurotransmission. For T2/T3 there were no such effects. PA was not affected by the factors RTD/Pla and time. Interactions of 5-HT with other neurotransmitters as possible underlying neurochemical processes could be subject to further investigations involving healthy controls as regards altered attentional performance in children and adolescents.
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van Donkelaar EL, Kelly PAT, Dawson N, Blokland A, Prickaerts J, Steinbusch HWM, Ferrington L. Acute tryptophan depletion potentiates 3,4-methylenedioxymethamphetamine-induced cerebrovascular hyperperfusion in adult male Wistar rats. J Neurosci Res 2010; 88:1557-68. [PMID: 19998482 DOI: 10.1002/jnr.22308] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The serotonergic (5-hydroxytryptamine; 5-HT) dysfunction found in depression may affect not only brain function (mood) but also cerebrovascular control. Similar, but possibly occult, disturbances may also be induced by 3,4-methylenedioxymethamphetamine-induced neurotoxicity (MDMA, or "ecstasy"). Acute tryptophan depletion (ATD) is widely used to identify vulnerability to depression, and we hypothesized that repeated MDMA administration would increase the sensitivity of rats to this acute serotonergic challenge. In this study, male Wistar rats were injected with MDMA (20 mg kg(-1), twice daily for 4 days) and challenged 3 weeks later with ATD, induced by intragastric administration of a nutritional mixture with tryptophan (TRP) removed. Cerebral metabolism (CMRG) and blood flow (CBF) were measured in parallel groups of animals following ATD by using quantitative [(14)C]2-deoxyglucose and [(14)C]iodoantipyrine autoradiographic techniques, respectively. A significant reduction in paroxetine binding to 5-HT transporter sites in MDMA-treated rats indicated 5HT terminal depletion, whereas the plasma TRP/sum large neutral amino acids ratio was reduced by 40% following ATD. Under all experimental conditions, the normal close correlation between CBF and metabolic demand was maintained. However, a global analysis of all brain regions revealed a significant decrease in the overall ratio of CBF to CMRG after ATD in control animals, whereas a higher ratio was observed after ATD in the MDMA-treated group. This increase in blood flow relative to cerebral metabolism suggests an ATD-induced loss of cerebrovascular tone in MDMA-treated animals that could have pathophysiological consequences and might conceivably contribute to the behavioral dysfunction of depression.
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Affiliation(s)
- Eva L van Donkelaar
- Department of Neuroscience, Faculty of Health, Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands.
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Tryptophan depletion impairs object-recognition memory in the rat: Reversal by risperidone. Behav Brain Res 2010; 208:479-83. [DOI: 10.1016/j.bbr.2009.12.030] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 12/14/2009] [Accepted: 12/17/2009] [Indexed: 11/19/2022]
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Effects of an acute α-lactalbumin manipulation on mood and food hedonics in high- and low-trait anxiety individuals. Br J Nutr 2010; 104:595-602. [DOI: 10.1017/s0007114510000838] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Serotonergic hypofunction is associated with a depressive mood state, an increased drive to eat and preference for sweet (SW) foods. High-trait anxiety individuals are characterised by a functional shortage of serotonin during stress, which in turn increases their susceptibility to experience a negative mood and an increased drive for SW foods. The present study examined whether an acute dietary manipulation, intended to increase circulating serotonin levels, alleviated the detrimental effects of a stress-inducing task on subjective appetite and mood sensations, and preference for SW foods in high-trait anxiety individuals. Thirteen high- (eleven females and two males; anxiety scores 45·5 (sd5·9); BMI 22·9 (sd3·0)kg/m2) and twelve low- (ten females and two males; anxiety scores 30·4 (sd4·8); BMI 23·4 (sd2·5) kg/m2) trait anxiety individuals participated in a placebo-controlled, two-way crossover design. Participants were provided with 40 g α-lactalbumin (LAC;l-tryptophan (Trp):large neutral amino acids (LNAA) ratio of 7·6) and 40 g casein (placebo) (Trp:LNAA ratio of 4·0) in the form of a snack and lunch on two test days. On both the test days, participants completed a stress-inducing task 2 h after the lunch. Mood and appetite were assessed using visual analogue scales. Changes in food hedonics for different taste and nutrient combinations were assessed using a computer task. The results demonstrated that the LAC manipulation did not exert any immediate effects on mood or appetite. However, LAC did have an effect on food hedonics in individuals with high-trait anxiety after acute stress. These individuals expressed a lower liking (P = 0·012) and SW food preference (P = 0·014) after the stressful task when supplemented with LAC.
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Effects of acute tryptophan depletion in serotonin reuptake inhibitor-remitted patients with generalized anxiety disorder. Psychopharmacology (Berl) 2010; 208:223-32. [PMID: 19936713 DOI: 10.1007/s00213-009-1722-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 11/01/2009] [Indexed: 12/19/2022]
Abstract
BACKGROUND Serotonergic antidepressants [selective serotonin reuptake inhibitor (SSRI)] are first-line treatments for generalised anxiety disorder (GAD); however, it is not known if synaptic serotonin (5-HT) availability is important for SSRI efficacy. The present study tested the hypothesis that temporary reduction in central 5-HT transmission, through acute tryptophan depletion (ATD), would reverse the therapeutic effect of the SSRIs in GAD patients. METHODS Twelve patients (six males) with GAD, who showed sustained clinical improvement with SSRI treatment, underwent ATD in a double-blind, placebo-controlled, within-subjects design over 2 days, 1 week apart. At the peak time of depletion, the participants inhaled 7.5% CO2 and air in random order for at least 12 min each. Psychological responses were measured using the Spielberger State Anxiety Inventory (STAI-S) and GAD-symptom visual analogue scales (VASs; e.g., worry and tense) and Profile of Mood States. RESULTS Free plasma tryptophan to large neutral amino acid (LNAA) ratio decreased by 92% on the depletion day and decreased by 2% on the control day. Irrespective of depletion condition, 7.5% CO(2) inhalation significantly increased STAI-S and GAD-related VAS scores (all p < 0.05) compared with air inhalation. ATD had no effect on any of these measures despite the substantial reduction in free tryptophan/LNAA ratio. CONCLUSIONS Although SSRIs treat GAD effectively, the present results suggest that the mechanism of action is different to that seen in panic, social anxiety, and post-traumatic stress disorders. Successful SSRI treatment of GAD may involve long-term receptor changes or alterations in other neurotransmitter systems downstream of serotonin.
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Pittler E, Grawatsch N, Paul D, Gübitz G, Schmid MG. Enantioseparation of amino acids, alpha-hydroxy acids, and dipeptides by ligand-exchange CEC using silica-based chiral stationary phases. Electrophoresis 2010; 30:2897-904. [PMID: 19655330 DOI: 10.1002/elps.200900092] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This work deals with the application of silica-based ligand-exchange chiral stationary phases (CSPs) for the enantioseparation of underivatized amino acids, alpha-hydroxy acids, and dipeptides with packed CEC. Two different possibilities of preparing silica-based CSPs are presented. One phase contains L-4-hydroxyproline chemically bonded via a spacer to 3 mum silica material. The other approach makes use of N-decyl-L-4-hydroxyproline dynamically coated on a reversed-phase packed capillary. Dynamical coating of reversed-phase material represents a simple alternative to prepare CSP. A comparison of the chemically bonded phase with the dynamically coated CSP by means of resolution of complex-forming analytes is presented. The chemically bonded phase was found to be superior to the dynamically coated phase in terms of resolution of amino acids and dipeptides. However, the dynamically coated CSP was found to be especially suitable for the separation of alpha-hydroxy acids. Both techniques are applicable for enantiomer purity tests.
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Affiliation(s)
- Elfriede Pittler
- Institute of Pharmaceutical Sciences, Department of Pharmaceutical Chemistry, Karl-Franzens-University, Austria
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