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Coray R, Quednow BB. The role of serotonin in declarative memory: A systematic review of animal and human research. Neurosci Biobehav Rev 2022; 139:104729. [PMID: 35691469 DOI: 10.1016/j.neubiorev.2022.104729] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 05/13/2022] [Accepted: 06/06/2022] [Indexed: 10/18/2022]
Abstract
The serotonergic system is involved in diverse cognitive functions including memory. Of particular importance to daily life are declarative memories that contain information about personal experiences, general facts, and events. Several psychiatric or neurological diseases, such as depression, attention-deficit-hyperactivity disorder (ADHD), and dementia, show alterations in serotonergic signalling and attendant memory disorders. Nevertheless, understanding serotonergic neurotransmission and its influence on memory remained a challenge until today. In this systematic review, we summarize recent psychopharmacological studies in animals and humans from a psychological memory perspective, in consideration of task-specific requirements. This approach has the advantage that comparisons between serotonin (5-HT)-related neurochemical mechanisms and manipulations are each addressing specific mnemonic circuits. We conclude that applications of the same 5-HT-related treatments can differentially affect unrelated tasks of declarative memories. Moreover, the analysis of specific mnemonic phases (e.g., encoding vs. consolidation) reveals opposing impacts of increased or decreased 5-HT tones, with low 5-HT supporting spatial encoding but impairing the consolidation of objects and verbal memories. Promising targets for protein synthesis-dependent consolidation enhancements include 5-HT4 receptor agonists and 5-HT6 receptor antagonists, with the latter being of special interest for the treatment of age-related decline. Further implications are pointed out as base for the development of novel therapeutic targets for memory impairment of neuropsychiatric disorders.
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Affiliation(s)
- Rebecca Coray
- Experimental and Clinical Pharmacopsychology, Department of Psychiatry, Psychotherapy, and Psychosomatics, Psychiatric University Hospital Zurich, University of Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich and Swiss Federal Institute of Technology Zurich, Switzerland.
| | - Boris B Quednow
- Experimental and Clinical Pharmacopsychology, Department of Psychiatry, Psychotherapy, and Psychosomatics, Psychiatric University Hospital Zurich, University of Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich and Swiss Federal Institute of Technology Zurich, Switzerland
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2
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Szklany K, Engen PA, Naqib A, Green SJ, Keshavarzian A, Lopez Rincon A, Siebrand CJ, Diks MAP, van de Kaa M, Garssen J, Knippels LMJ, Kraneveld AD. Dietary Supplementation throughout Life with Non-Digestible Oligosaccharides and/or n-3 Poly-Unsaturated Fatty Acids in Healthy Mice Modulates the Gut-Immune System-Brain Axis. Nutrients 2021; 14:173. [PMID: 35011046 PMCID: PMC8746884 DOI: 10.3390/nu14010173] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/20/2021] [Accepted: 12/24/2021] [Indexed: 12/11/2022] Open
Abstract
The composition and activity of the intestinal microbial community structures can be beneficially modulated by nutritional components such as non-digestible oligosaccharides and omega-3 poly-unsaturated fatty acids (n-3 PUFAs). These components affect immune function, brain development and behaviour. We investigated the additive effect of a dietary combination of scGOS:lcFOS and n-3 PUFAs on caecal content microbial community structures and development of the immune system, brain and behaviour from day of birth to early adulthood in healthy mice. Male BALB/cByJ mice received a control or enriched diet with a combination of scGOS:lcFOS (9:1) and 6% tuna oil (n-3 PUFAs) or individually scGOS:lcFOS (9:1) or 6% tuna oil (n-3 PUFAs). Behaviour, caecal content microbiota composition, short-chain fatty acid levels, brain monoamine levels, enterochromaffin cells and immune parameters in the mesenteric lymph nodes (MLN) and spleen were assessed. Caecal content microbial community structures displayed differences between the control and dietary groups, and between the dietary groups. Compared to control diet, the scGOS:lcFOS and combination diets increased caecal saccharolytic fermentation activity. The diets enhanced the number of enterochromaffin cells. The combination diet had no effects on the immune cells. Although the dietary effect on behaviour was limited, serotonin and serotonin metabolite levels in the amygdala were increased in the combination diet group. The combination and individual interventions affected caecal content microbial profiles, but had limited effects on behaviour and the immune system. No apparent additive effect was observed when scGOS:lcFOS and n-3 PUFAs were combined. The results suggest that scGOS:lcFOS and n-3 PUFAs together create a balance-the best of both in a healthy host.
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Affiliation(s)
- Kirsten Szklany
- Division of Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584 CG Utrecht, The Netherlands; (K.S.); (A.L.R.); (C.J.S.); (M.A.P.D.); (M.v.d.K.); (J.G.); (L.M.J.K.)
| | - Phillip A. Engen
- Rush Center for Integrated Microbiome and Chronobiology Research, Rush Medical College, Rush University Medical Center, Chicago, IL 60602, USA; (P.A.E.); (A.N.); (A.K.)
| | - Ankur Naqib
- Rush Center for Integrated Microbiome and Chronobiology Research, Rush Medical College, Rush University Medical Center, Chicago, IL 60602, USA; (P.A.E.); (A.N.); (A.K.)
| | - Stefan J. Green
- Genomics and Microbiome Core Facility, Rush University Medical Center, Chicago, IL 60602, USA;
| | - Ali Keshavarzian
- Rush Center for Integrated Microbiome and Chronobiology Research, Rush Medical College, Rush University Medical Center, Chicago, IL 60602, USA; (P.A.E.); (A.N.); (A.K.)
- Department of Medicine & Physiology, Rush University Medical Center, Chicago, IL 60602, USA
| | - Alejandro Lopez Rincon
- Division of Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584 CG Utrecht, The Netherlands; (K.S.); (A.L.R.); (C.J.S.); (M.A.P.D.); (M.v.d.K.); (J.G.); (L.M.J.K.)
- Department of Data Science, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, 3584 EA Utrecht, The Netherlands
| | - Cynthia J. Siebrand
- Division of Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584 CG Utrecht, The Netherlands; (K.S.); (A.L.R.); (C.J.S.); (M.A.P.D.); (M.v.d.K.); (J.G.); (L.M.J.K.)
| | - Mara A. P. Diks
- Division of Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584 CG Utrecht, The Netherlands; (K.S.); (A.L.R.); (C.J.S.); (M.A.P.D.); (M.v.d.K.); (J.G.); (L.M.J.K.)
| | - Melanie van de Kaa
- Division of Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584 CG Utrecht, The Netherlands; (K.S.); (A.L.R.); (C.J.S.); (M.A.P.D.); (M.v.d.K.); (J.G.); (L.M.J.K.)
| | - Johan Garssen
- Division of Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584 CG Utrecht, The Netherlands; (K.S.); (A.L.R.); (C.J.S.); (M.A.P.D.); (M.v.d.K.); (J.G.); (L.M.J.K.)
- Global Centre of Excellence Immunology, Nutricia Danone Research, 3584 CT Utrecht, The Netherlands
| | - Leon M. J. Knippels
- Division of Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584 CG Utrecht, The Netherlands; (K.S.); (A.L.R.); (C.J.S.); (M.A.P.D.); (M.v.d.K.); (J.G.); (L.M.J.K.)
- Global Centre of Excellence Immunology, Nutricia Danone Research, 3584 CT Utrecht, The Netherlands
| | - Aletta D. Kraneveld
- Division of Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584 CG Utrecht, The Netherlands; (K.S.); (A.L.R.); (C.J.S.); (M.A.P.D.); (M.v.d.K.); (J.G.); (L.M.J.K.)
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3
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Tryptophan Improves Memory Independent of Its Role as a Serotonin Precursor: Potential Involvement of Microtubule Proteins. J Mol Neurosci 2020; 70:559-567. [DOI: 10.1007/s12031-019-01457-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 11/28/2019] [Indexed: 12/17/2022]
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Szklany K, Wopereis H, de Waard C, van Wageningen T, An R, van Limpt K, Knol J, Garssen J, Knippels LMJ, Belzer C, Kraneveld AD. Supplementation of dietary non-digestible oligosaccharides from birth onwards improve social and reduce anxiety-like behaviour in male BALB/c mice. Nutr Neurosci 2019; 23:896-910. [PMID: 30871432 DOI: 10.1080/1028415x.2019.1576362] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Objective: The intestinal microbiota is acknowledged to be essential in brain development and behaviour. Their composition can be modulated by prebiotics such as short-chain galacto-oligosaccharides (scGOS) and long-chain fructo-oligosaccharide (lcFOS). Several studies reported potential health benefit of prebiotics on behaviour. As the prebiotic mixture of scGOS and lcFOS is included in infant formula, we investigated the effects of dietary supplementation with this specific mixture from the day of birth onwards on behaviour and intestinal microbiota development in mice. Method: Healthy male BALB/cByJ mice received, from day of birth, a dietary supplement with or without 3% scGOS:lcFOS (9:1). Behavioural tests were performed pre-weaning, in adolescence, early adulthood and adulthood. We assessed faecal microbiota compositions over time, caecal short-chain fatty acids as well as brain mRNA expression of Htr1a, Htr1b and Tph2 and monoamine levels. Results: Compared to control fed mice, scGOS:lcFOS fed mice showed reduced anxiety-like and repetitive behaviour over time and improved social behaviour in adulthood. The serotonergic system in the prefrontal cortex (PFC) and somatosensory cortex (SSC) was affected by the scGOS:lcFOS. In the PFC, mRNA expression of brain-derived neurotrophic factor (Bdnf) was enhanced in scGOS:lcFOS fed mice. Although the bacterial diversity of the intestinal microbiota was unaffected by the scGOS:lcFOS diet, microbiota composition differed between the scGOS:lcFOS and the control fed mice over time. Moreover, an increased saccharolytic and decreased proteolytic fermentation activity were observed in caecum content. Discussion: Supplementing the diet with scGOS:lcFOS from the day of birth is associated with reduced anxiety-like and improved social behaviour during the developmental period and later in life, and modulates the composition and activity of the intestinal microbiota in healthy male BALB/c mice. These data provide further evidence of the potential impact of scGOS:lcFOS on behaviour at several developmental stages throughout life and strengthen the insights in the interplay between the developing intestine and brain.
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Affiliation(s)
- Kirsten Szklany
- Division of Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Harm Wopereis
- Department of Gut Biology and Microbiology, Danone Nutricia Research, Utrecht, Netherlands.,Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Cindy de Waard
- Division of Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Thecla van Wageningen
- Division of Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Ran An
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Kees van Limpt
- Department of Gut Biology and Microbiology, Danone Nutricia Research, Utrecht, Netherlands
| | - Jan Knol
- Department of Gut Biology and Microbiology, Danone Nutricia Research, Utrecht, Netherlands.,Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Johan Garssen
- Division of Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, Netherlands.,Department of Immunology, Danone Nutricia Research, Utrecht, Netherlands
| | - Leon M J Knippels
- Division of Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, Netherlands.,Department of Immunology, Danone Nutricia Research, Utrecht, Netherlands
| | - Clara Belzer
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, Netherlands
| | - Aletta D Kraneveld
- Division of Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, Netherlands.,Institute for Risk Assessment Sciences, Faculty of Veterinary Sciences, Utrecht University, Netherlands
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5
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Tanaka M, Sato A, Kasai S, Hagino Y, Kotajima-Murakami H, Kashii H, Takamatsu Y, Nishito Y, Inagaki M, Mizuguchi M, Hall FS, Uhl GR, Murphy D, Sora I, Ikeda K. Brain hyperserotonemia causes autism-relevant social deficits in mice. Mol Autism 2018; 9:60. [PMID: 30498565 PMCID: PMC6258166 DOI: 10.1186/s13229-018-0243-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 11/08/2018] [Indexed: 12/19/2022] Open
Abstract
Background Hyperserotonemia in the brain is suspected to be an endophenotype of autism spectrum disorder (ASD). Reducing serotonin levels in the brain through modulation of serotonin transporter function may improve ASD symptoms. Methods We analyzed behavior and gene expression to unveil the causal mechanism of ASD-relevant social deficits using serotonin transporter (Sert) knockout mice. Results Social deficits were observed in both heterozygous knockout mice (HZ) and homozygous knockout mice (KO), but increases in general anxiety were only observed in KO mice. Two weeks of dietary restriction of the serotonin precursor tryptophan ameliorated both brain hyperserotonemia and ASD-relevant social deficits in Sert HZ and KO mice. The expression of rather distinct sets of genes was altered in Sert HZ and KO mice, and a substantial portion of these genes was also affected by tryptophan depletion. Tryptophan depletion in Sert HZ and KO mice was associated with alterations in the expression of genes involved in signal transduction pathways initiated by changes in extracellular serotonin or melatonin, a derivative of serotonin. Only expression of the AU015836 gene was altered in both Sert HZ and KO mice. AU015836 expression and ASD-relevant social deficits normalized after dietary tryptophan restriction. Conclusions These findings reveal a Sert gene dose-dependent effect on brain hyperserotonemia and related behavioral sequelae in ASD and a possible therapeutic target to normalize brain hyperserotonemia and ASD-relevant social deficits. Electronic supplementary material The online version of this article (10.1186/s13229-018-0243-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Miho Tanaka
- 1Department of Psychiatry and Behavioral Sciences, Addictive Substance Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506 Japan.,2Molecular and Cellular Medicine, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan.,3Department of Developmental Disorders, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Atsushi Sato
- 1Department of Psychiatry and Behavioral Sciences, Addictive Substance Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506 Japan.,4Department of Pediatrics, The University of Tokyo Hospital, Tokyo, Japan
| | - Shinya Kasai
- 1Department of Psychiatry and Behavioral Sciences, Addictive Substance Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506 Japan
| | - Yoko Hagino
- 1Department of Psychiatry and Behavioral Sciences, Addictive Substance Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506 Japan
| | - Hiroko Kotajima-Murakami
- 1Department of Psychiatry and Behavioral Sciences, Addictive Substance Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506 Japan
| | - Hirofumi Kashii
- 1Department of Psychiatry and Behavioral Sciences, Addictive Substance Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506 Japan
| | - Yukio Takamatsu
- 1Department of Psychiatry and Behavioral Sciences, Addictive Substance Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506 Japan
| | - Yasumasa Nishito
- 5Center for Basic Technology Research, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Masumi Inagaki
- 3Department of Developmental Disorders, National Institute of Mental Health, National Center of Neurology and Psychiatry, Tokyo, Japan
| | - Masashi Mizuguchi
- 6Department of Developmental Medical Sciences, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - F Scott Hall
- 7Department of Pharmacology and Experimental Therapeutics, College of Pharmacy and Pharmaceutical Sciences, The University of Toledo, Toledo, OH USA
| | - George R Uhl
- 8Branch of Molecular Neurobiology, National Institute on Drug Abuse, Baltimore, MD USA.,9Research Service, New Mexico VA Health Care System, Albuquerque, NM USA
| | - Dennis Murphy
- 10Laboratory of Clinical Science, National Institutes of Health, Bethesda, MD USA
| | - Ichiro Sora
- 11Department of Psychiatry, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kazutaka Ikeda
- 1Department of Psychiatry and Behavioral Sciences, Addictive Substance Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 156-8506 Japan.,2Molecular and Cellular Medicine, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
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Korte-Bouws GAH, van Heesch F, Westphal KGC, Ankersmit LMJ, van Oosten EM, Güntürkün O, Korte SM. Bacterial Lipopolysaccharide Increases Serotonin Metabolism in Both Medial Prefrontal Cortex and Nucleus Accumbens in Male Wild Type Rats, but Not in Serotonin Transporter Knockout Rats. Pharmaceuticals (Basel) 2018; 11:ph11030066. [PMID: 29976854 PMCID: PMC6160917 DOI: 10.3390/ph11030066] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 06/29/2018] [Accepted: 07/02/2018] [Indexed: 11/19/2022] Open
Abstract
It is well known that bacterial lipopolysaccharides (LPS) both increases proinflammatory cytokines and produces sickness behavior, including fatigue and anhedonia (i.e., the inability to experience pleasure). Previously, we have shown that intraperitoneally (i.p.) administered LPS increased extracellular monoamine metabolite levels in the nucleus accumbens (NAc) and medial prefrontal cortex (mPFC), which was completely, or at least partly, prevented by pretreatment with a triple reuptake inhibitor that also blocks the serotonin (5-HT) transporter (SERT). This suggests indirectly, that LPS may enhance SERT transporter activity, and consequently, increase removal of 5-HT from the synaptic cleft, and increase metabolism of 5-HT. In the present study, we focus more specifically on the role of SERT in this increased metabolism by using rats, that differ in SERT expression. Therefore, the effects of an intraperitoneal LPS injection on extracellular concentrations of 5-HT and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) were investigated by in vivo microdialysis in the NAc and mPFC of wild type (SERT+/+), heterozygous (SERT+/−) and knockout (SERT−/−) rats. Here, we show that LPS-induced 5-HIAA formation in male rats, is significantly increased in SERT+/+ rats in both the NAc and mPFC, whereas this increase is partly or totally abolished in SERT+/− and SERT−/− rats, respectively. Thus, the present study supports the hypothesis that systemic LPS in male rats increases SERT function and consequently enhances 5-HT uptake and metabolism in both the NAc and mPFC.
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Affiliation(s)
- Gerdien A H Korte-Bouws
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Faculty of Science, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
| | - Floor van Heesch
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Faculty of Science, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
| | - Koen G C Westphal
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Faculty of Science, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
| | - Lisa M J Ankersmit
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Faculty of Science, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
| | - Edwin M van Oosten
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Faculty of Science, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
| | - Onur Güntürkün
- Department of Biopsychology, Faculty of Psychology, Ruhr-Universität Bochum, Universitätsstraße 150, D-44780 Bochum, Germany.
| | - S Mechiel Korte
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Faculty of Science, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
- Department of Biopsychology, Faculty of Psychology, Ruhr-Universität Bochum, Universitätsstraße 150, D-44780 Bochum, Germany.
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Neukam PT, Kroemer NB, Deza Araujo YI, Hellrung L, Pooseh S, Rietschel M, Witt SH, Schwarzenbolz U, Henle T, Smolka MN. Risk-seeking for losses is associated with 5-HTTLPR, but not with transient changes in 5-HT levels. Psychopharmacology (Berl) 2018; 235:2151-2165. [PMID: 29730700 DOI: 10.1007/s00213-018-4913-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 04/17/2018] [Indexed: 10/17/2022]
Abstract
RATIONALE Serotonin (5-HT) plays a key role in different aspects of value-based decision-making. A recent framework proposed that tonic 5-HT (together with dopamine, DA) codes future average reward expectations, providing a baseline against which possible choice outcomes are compared to guide decision-making. OBJECTIVES To test whether high 5-HT levels decrease loss aversion, risk-seeking for gains, and risk-seeking for losses. METHODS In a first session, 611 participants were genotyped for 5-HTTLPR and performed a mixed gambles (MGA) task and two probability discounting tasks for gains and losses, respectively (PDG/PDL). Afterwards, a subsample of 105 participants (44 with S/S, 6 with S/L, 55 with L/L genotype) completed the pharmacological study using a crossover design with tryptophan depletion (ATD), loading (ATL), and balanced (BAL) conditions. The same decision constructs were assessed. RESULTS We found increased risk-seeking for losses in S/S compared to L/L individuals at the first visit (p = 0.002). Neither tryptophan depletion nor loading affected decision-making, nor did we observe an interaction between intervention and 5-HTTLPR genotype. CONCLUSION Our data do not support the idea that transient changes of tonic 5-HT affect value-based decision-making. We provide evidence for an association of 5-HTTLPR with risk-seeking for losses, independent of acute 5-HT levels. This indicates that the association of 5-HTTLPR and risk-seeking for losses is mediated via other mechanisms, possibly by differences in the structural development of neural circuits of the 5-HT system during early life phases.
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Affiliation(s)
- Philipp T Neukam
- Department of Psychiatry and Neuroimaging Center, Technische Universität Dresden, Dresden, Germany
| | - Nils B Kroemer
- Department of Psychiatry and Neuroimaging Center, Technische Universität Dresden, Dresden, Germany.,Department of Psychiatry and Psychotherapy, University of Tübingen, Tübingen, Germany
| | - Yacila I Deza Araujo
- Department of Psychiatry and Neuroimaging Center, Technische Universität Dresden, Dresden, Germany
| | - Lydia Hellrung
- Department of Psychiatry and Neuroimaging Center, Technische Universität Dresden, Dresden, Germany.,Department of Economics, University of Zürich, Zürich, Switzerland
| | - Shakoor Pooseh
- Department of Psychiatry and Neuroimaging Center, Technische Universität Dresden, Dresden, Germany
| | - Marcella Rietschel
- Department of Genetic Epidemiology in Psychiatry, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Stephanie H Witt
- Department of Genetic Epidemiology in Psychiatry, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany
| | - Uwe Schwarzenbolz
- Institute of Food Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Thomas Henle
- Institute of Food Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Michael N Smolka
- Department of Psychiatry and Neuroimaging Center, Technische Universität Dresden, Dresden, Germany.
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8
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Birkl P, Kjaer JB, Szkotnicki W, Forsythe P, Harlander-Matauschek A. Acute tryptophan depletion: the first method validation in an avian species (Gallus gallus domesticus). Poult Sci 2018. [PMID: 28641389 DOI: 10.3382/ps/pex142] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Acute tryptophan depletion (ATD) is a valuable non-invasive nutritional tool in human and rodent research to study dysfunctions of the serotonergic system and related behavioral disorders. Serotonergic dysfunction is thought to be involved in the pathology of feather pecking behavior of laying hens, one of the most relevant welfare and production issues in modern intensive egg-production systems. ATD temporarily compromises the influx of tryptophan (TRP) across the blood brain barrier which reduces central availability of TRP, the substrate for serotonin (5-HT) synthesis. However, ATD has never before been developed and evaluated in birds. We hereby report that ATD in laying hens effectively depletes plasma levels of TRP to 50% of the baseline concentration, 4 hours after administration. Furthermore, ATD reduces the ratios of TRP towards aromatic amino acids (AAA) by 60% and the ratio of TRP towards large neutral amino acids (LNAA) by 70%, three hours after administration. Further studies will be needed to determine the effects of peripheral depletion on brain TRP and 5-HT levels in birds. However, our study showed for the first time in an avian species that ATD causes lowering of plasma TRP and the ratio in plasma of TRP towards other AAA or LNAA.
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Affiliation(s)
- Patrick Birkl
- Department of Animal Biosciences, University of Guelph, ON N1G 2W1 Guelph, Canada
| | - Joergen B Kjaer
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Animal Welfare and Animal Husbandry, Doernbergstrasse 25 & 27, 29223 Celle, Germany
| | - William Szkotnicki
- Department of Animal Biosciences, University of Guelph, ON N1G 2W1 Guelph, Canada
| | - Paul Forsythe
- Brain-body Institute and Firestone Institute for Respiratory Health, Department of Medicine, McMaster University, 50 Carlton Avenue East, L8N 4A6 Hamilton, Canada
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9
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Houwing DJ, Buwalda B, van der Zee EA, de Boer SF, Olivier JDA. The Serotonin Transporter and Early Life Stress: Translational Perspectives. Front Cell Neurosci 2017; 11:117. [PMID: 28491024 PMCID: PMC5405142 DOI: 10.3389/fncel.2017.00117] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Accepted: 04/07/2017] [Indexed: 01/04/2023] Open
Abstract
The interaction between the serotonin transporter (SERT) linked polymorphic region (5-HTTLPR) and adverse early life stressing (ELS) events is associated with enhanced stress susceptibility and risk to develop mental disorders like major depression, anxiety, and aggressiveness. In particular, human short allele carriers are at increased risk. This 5-HTTLPR polymorphism is absent in the rodent SERT gene, but heterozygous SERT knockout rodents (SERT+/−) show several similarities to the human S-allele carrier, therefore creating an animal model of the human situation. Many rodent studies investigated ELS interactions in SERT knockout rodents combined with ELS. However, underlying neuromolecular mechanisms of the (mal)adaptive responses to adversity displayed by SERT rodents remain to be elucidated. Here, we provide a comprehensive review including studies describing mechanisms underlying SERT variation × ELS interactions in rodents. Alterations at the level of translation and transcription but also epigenetic alterations considerably contribute to underlying mechanisms of SERT variation × ELS interactions. In particular, SERT+/− rodents exposed to adverse early rearing environment may be of high translational and predictive value to the more stress sensitive human short-allele carrier, considering the similarity in neurochemical alterations. Therefore, SERT+/− rodents are highly relevant in research that aims to unravel the complex psychopathology of mental disorders. So far, most studies fail to show solid evidence for increased vulnerability to develop affective-like behavior after ELS in SERT+/− rodents. Several reasons may underlie these failures, e.g., (1) stressors used might not be optimal or severe enough to induce maladaptations, (2) effects in females are not sufficiently studied, and (3) few studies include both behavioral manifestations and molecular correlates of ELS-induced effects in SERT+/− rodents. Of course, one should not exclude the (although unlikely) possibility of SERT+/− rodents not being sensitive to ELS. In conclusion, future studies addressing ELS-induced effects in the SERT+/− rodents should extensively study both long-term behavioral and (epi)genetic aspects in both sexes. Finally, further research is warranted using more severe stressors in animal models. From there on, we should be able to draw solid conclusions whether the SERT+/− exposed to ELS is a suitable translational animal model for studying 5-HTTLPR polymorphism and stress interactions.
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Affiliation(s)
- Danielle J Houwing
- Unit Behavioral Neuroscience, Department of Neurobiology, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of GroningenGroningen, Netherlands
| | - Bauke Buwalda
- Unit Behavioral Neuroscience, Department of Neurobiology, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of GroningenGroningen, Netherlands
| | - Eddy A van der Zee
- Unit Molecular Neurobiology, Department of Neurobiology, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of GroningenGroningen, Netherlands
| | - Sietse F de Boer
- Unit Behavioral Neuroscience, Department of Neurobiology, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of GroningenGroningen, Netherlands
| | - Jocelien D A Olivier
- Unit Behavioral Neuroscience, Department of Neurobiology, Groningen Institute for Evolutionary Life Sciences (GELIFES), University of GroningenGroningen, Netherlands
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Fernandez SP, Muzerelle A, Scotto-Lomassese S, Barik J, Gruart A, Delgado-García JM, Gaspar P. Constitutive and Acquired Serotonin Deficiency Alters Memory and Hippocampal Synaptic Plasticity. Neuropsychopharmacology 2017; 42:512-523. [PMID: 27461084 PMCID: PMC5399229 DOI: 10.1038/npp.2016.134] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 07/07/2016] [Accepted: 07/17/2016] [Indexed: 02/06/2023]
Abstract
Serotonin (5-HT) deficiency occurs in a number of brain disorders that affect cognitive function. However, a direct causal relationship between 5-HT hypo-transmission and memory and underlying mechanisms has not been established. We used mice with a constitutive depletion of 5-HT brain levels (Pet1KO mice) to analyze the contribution of 5-HT to different forms of learning and memory. Pet1KO mice exhibited a striking deficit in novel object recognition memory, a hippocampal-dependent task. No alterations were found in tasks for social recognition, procedural learning, or fear memory. Viral delivery of designer receptors exclusively activated by designer drugs was used to selectively silence the activity of 5-HT neurons in the raphe. Inhibition of 5-HT neurons in the median raphe, but not the dorsal raphe, was sufficient to impair object recognition in adult mice. In vivo electrophysiology in behaving mice showed that long-term potentiation in the hippocampus of 5-HT-deficient mice was altered, and administration of the 5-HT1A agonist 8-OHDPAT rescued the memory deficits. Our data suggest that hyposerotonergia selectively affects declarative hippocampal-dependent memory. Serotonergic projections from the median raphe are necessary to regulate object memory and hippocampal synaptic plasticity processes, through an inhibitory control mediated by 5-HT1A receptors.
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Affiliation(s)
- Sebastian P Fernandez
- Institut du Fer à Moulin, Paris, France,INSERM, UMRS-839, Paris, France,University Pierre and Marie Curie, Paris, France,Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), Université Côte d'Azur, CNRS UMR 7275, Valbonne, 0656, France, Tel: +33 4 93 95 34 41, Fax: +33 4 93 95 34 08, E-mail:
| | - Aude Muzerelle
- Institut du Fer à Moulin, Paris, France,INSERM, UMRS-839, Paris, France,University Pierre and Marie Curie, Paris, France
| | - Sophie Scotto-Lomassese
- Institut du Fer à Moulin, Paris, France,INSERM, UMRS-839, Paris, France,University Pierre and Marie Curie, Paris, France
| | - Jacques Barik
- Université Côte d'Azur, CNRS, IPMC, Valbonne, France
| | - Agnès Gruart
- Division of Neurosciences, Pablo de Olavide University, Seville, Spain
| | | | - Patricia Gaspar
- Institut du Fer à Moulin, Paris, France,INSERM, UMRS-839, Paris, France,University Pierre and Marie Curie, Paris, France
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11
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Vieira-Brock PL, McFadden LM, Nielsen SM, Smith MD, Hanson GR, Fleckenstein AE. Nicotine Administration Attenuates Methamphetamine-Induced Novel Object Recognition Deficits. Int J Neuropsychopharmacol 2015; 18:pyv073. [PMID: 26164716 PMCID: PMC4675982 DOI: 10.1093/ijnp/pyv073] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 06/23/2015] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Previous studies have demonstrated that methamphetamine abuse leads to memory deficits and these are associated with relapse. Furthermore, extensive evidence indicates that nicotine prevents and/or improves memory deficits in different models of cognitive dysfunction and these nicotinic effects might be mediated by hippocampal or cortical nicotinic acetylcholine receptors. The present study investigated whether nicotine attenuates methamphetamine-induced novel object recognition deficits in rats and explored potential underlying mechanisms. METHODS Adolescent or adult male Sprague-Dawley rats received either nicotine water (10-75 μg/mL) or tap water for several weeks. Methamphetamine (4 × 7.5mg/kg/injection) or saline was administered either before or after chronic nicotine exposure. Novel object recognition was evaluated 6 days after methamphetamine or saline. Serotonin transporter function and density and α4β2 nicotinic acetylcholine receptor density were assessed on the following day. RESULTS Chronic nicotine intake via drinking water beginning during either adolescence or adulthood attenuated the novel object recognition deficits caused by a high-dose methamphetamine administration. Similarly, nicotine attenuated methamphetamine-induced deficits in novel object recognition when administered after methamphetamine treatment. However, nicotine did not attenuate the serotonergic deficits caused by methamphetamine in adults. Conversely, nicotine attenuated methamphetamine-induced deficits in α4β2 nicotinic acetylcholine receptor density in the hippocampal CA1 region. Furthermore, nicotine increased α4β2 nicotinic acetylcholine receptor density in the hippocampal CA3, dentate gyrus and perirhinal cortex in both saline- and methamphetamine-treated rats. CONCLUSIONS Overall, these findings suggest that nicotine-induced increases in α4β2 nicotinic acetylcholine receptors in the hippocampus and perirhinal cortex might be one mechanism by which novel object recognition deficits are attenuated by nicotine in methamphetamine-treated rats.
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Affiliation(s)
- Paula L Vieira-Brock
- Department of Pharmacology and Toxicology (Dr Vieira-Brock, Dr McFadden, Ms Nielsen, Dr Smith, Dr Hanson, and Dr Fleckenstein), and School of Dentistry (Drs Smith, Hanson, and Fleckenstein), University of Utah, Salt Lake City, UT
| | - Lisa M McFadden
- Department of Pharmacology and Toxicology (Dr Vieira-Brock, Dr McFadden, Ms Nielsen, Dr Smith, Dr Hanson, and Dr Fleckenstein), and School of Dentistry (Drs Smith, Hanson, and Fleckenstein), University of Utah, Salt Lake City, UT
| | - Shannon M Nielsen
- Department of Pharmacology and Toxicology (Dr Vieira-Brock, Dr McFadden, Ms Nielsen, Dr Smith, Dr Hanson, and Dr Fleckenstein), and School of Dentistry (Drs Smith, Hanson, and Fleckenstein), University of Utah, Salt Lake City, UT
| | - Misty D Smith
- Department of Pharmacology and Toxicology (Dr Vieira-Brock, Dr McFadden, Ms Nielsen, Dr Smith, Dr Hanson, and Dr Fleckenstein), and School of Dentistry (Drs Smith, Hanson, and Fleckenstein), University of Utah, Salt Lake City, UT
| | - Glen R Hanson
- Department of Pharmacology and Toxicology (Dr Vieira-Brock, Dr McFadden, Ms Nielsen, Dr Smith, Dr Hanson, and Dr Fleckenstein), and School of Dentistry (Drs Smith, Hanson, and Fleckenstein), University of Utah, Salt Lake City, UT
| | - Annette E Fleckenstein
- Department of Pharmacology and Toxicology (Dr Vieira-Brock, Dr McFadden, Ms Nielsen, Dr Smith, Dr Hanson, and Dr Fleckenstein), and School of Dentistry (Drs Smith, Hanson, and Fleckenstein), University of Utah, Salt Lake City, UT.
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Ameliorating effect of spinosin, a C-glycoside flavonoid, on scopolamine-induced memory impairment in mice. Pharmacol Biochem Behav 2014; 120:88-94. [DOI: 10.1016/j.pbb.2014.02.015] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 12/20/2013] [Accepted: 02/20/2014] [Indexed: 12/22/2022]
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13
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de Theije CGM, Koelink PJ, Korte-Bouws GAH, Lopes da Silva S, Korte SM, Olivier B, Garssen J, Kraneveld AD. Intestinal inflammation in a murine model of autism spectrum disorders. Brain Behav Immun 2014; 37:240-7. [PMID: 24321212 DOI: 10.1016/j.bbi.2013.12.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 11/25/2013] [Accepted: 12/02/2013] [Indexed: 11/26/2022] Open
Abstract
Autism spectrum disorder (ASD) is a cluster of neurodevelopmental disorders characterized by impairments in communication, social interest and stereotypical behaviour. Dysfunction of the intestinal tract is reported in patients with ASD and implicated in the development and severity of ASD symptoms. However, more research is required to investigate the association of intestinal problems with ASD and the potential underlying mechanisms. The purpose of this study was to investigate comorbid symptoms of intestinal inflammation in a murine model of ASD induced by prenatal exposure to valproic acid (VPA). Pregnant BALB/c females were treated subcutaneously with 600 mg/kg VPA or phosphate buffered saline on gestational day 11. Offspring were housed with their mother until weaning on postnatal day 21 (P21). All pups were exposed to a social behaviour test on P28. Inflammatory correlates and activity of the serotonergic system were measured in brain and intestinal tissue. Here we demonstrate, in addition to reduced social behaviour and increased expression of neuroinflammatory markers in the brain, that VPA in utero- exposed male offspring showed epithelial cell loss and neutrophil infiltration in the intestinal tract. Furthermore, reduced levels of serotonin were not only observed the prefrontal cortex and amygdala of VPA in utero- exposed males, but also in the small intestine. Overall, we demonstrate that gender-specific inflammatory conditions are present in the small intestines of VPA in utero- exposed mice and are accompanied by a disturbed serotonergic system in the brain as well as in the intestinal tract.
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Affiliation(s)
- Caroline G M de Theije
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
| | - Pim J Koelink
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Gerdien A H Korte-Bouws
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Sofia Lopes da Silva
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands; Nutricia Research, Uppsalalaan 12, 3584 CT Utrecht, The Netherlands
| | - S Mechiel Korte
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Berend Olivier
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Johan Garssen
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands; Nutricia Research, Uppsalalaan 12, 3584 CT Utrecht, The Netherlands
| | - Aletta D Kraneveld
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
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14
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de Theije CG, Wu J, Koelink PJ, Korte-Bouws GA, Borre Y, Kas MJ, Lopes da Silva S, Korte SM, Olivier B, Garssen J, Kraneveld AD. Autistic-like behavioural and neurochemical changes in a mouse model of food allergy. Behav Brain Res 2014; 261:265-74. [DOI: 10.1016/j.bbr.2013.12.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 11/26/2013] [Accepted: 12/03/2013] [Indexed: 01/01/2023]
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15
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Acute tryptophan depletion reduces nitric oxide synthase in the rat hippocampus. Neurochem Res 2013; 38:2595-603. [PMID: 24170240 DOI: 10.1007/s11064-013-1177-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 10/02/2013] [Accepted: 10/05/2013] [Indexed: 10/26/2022]
Abstract
Acute tryptophan depletion (ATD) is extensively used to investigate the role of central serotonin (5-HT). However, several studies reported that ATD had no significant effect on central 5-HT concentration and some ATD-induced changes was independent of 5-HT in the rodent brain. Therefore, the potential mechanism of ATD might not be ascribed solely to changes in the central 5-HT system. In recent studies, evidence suggests that nitric oxide synthase (NOS) is closely associated with ATD-induced changes in modulation of cerebral blood flow and metabolism, cognitive, and locomotor activity. Thus, NOS is implicated to be an underlying factor contributing to ATD-induced changes. In the present study, the effect of ATD upon central NOS levels in the rat was evaluated. Male Sprague-Dawley (SD) rats were orally administered a tryptophan-free protein-carbohydrate mixture. Then, ATD effects upon affective behavior and spatial memory were assessed by the forced swimming test (FST) and Morris water maze test, respectively. Further, NOS activity and neuronal NOS (nNOS) protein levels in the hippocampus were measured after ATD. Our experimental results showed that ATD had no influence on affective behavior in the FST or spatial memory in SD rats. Interestingly, a significant reduction of both constitutive NOS activity and nNOS protein levels after ATD was found in the hippocampus. These findings demonstrate ATD does not influence affective behavior and spatial memory despite a direct effect on hippocampal NOS. Our study might provide a valuable clue for exploring earlier reported ATD-induced behavioral and neurochemical changes in rodents.
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Abstract
The most frequently described drugs in the treatment of mood disorders are selective serotonin reuptake and monoamine oxidase (MAO) inhibitors, enhancing serotonin levels in the brain. However, side-effects have been reported for these drugs. Because serotonin levels in the brain are dependent on the availability of the food-derived precursor tryptophan, foods such as chicken, soyabeans, cereals, tuna, nuts and bananas may serve as an alternative to improve mood and cognition. Here we discuss the effects of high- or low-tryptophan-containing food, as well as plant extracts with a modest monoamine reuptake and MAO-A inhibition functional profile, on mood and cognition in healthy and vulnerable human subjects and rodents. Together the studies suggest that there is an inverted U-shaped curve for plasma tryptophan levels, with low and too high tryptophan levels impairing cognition, and moderate to high tryptophan levels improving cognition. This relationship is found for both healthy and vulnerable subjects. Whereas this relationship may also exist for mood, the inverted U-shaped curve for plasma tryptophan levels and mood may be based on different tryptophan concentrations in healthyv.vulnerable individuals. Animal studies are emerging and allow further understanding of effects and the mode of action of food-derived serotonergic components on mood, cognition and mechanisms. Ultimately, insight into the concentrations of tryptophan and other serotonergic components in food having beneficial effects on mood and cognition in healthy, but particularly vulnerable, subjects may support well-being in our highly demanding society.
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Zepf FD, Landgraf M, Biskup CS, Dahmen B, Poustka F, Wöckel L, Stadler C. No effect of acute tryptophan depletion on verbal declarative memory in young persons with ADHD. Acta Psychiatr Scand 2013; 128:133-41. [PMID: 23418985 DOI: 10.1111/acps.12089] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/03/2013] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Animal experiments and studies in adults have shown that the neurotransmitter serotonin (5-HT) plays an important role in learning and memory processes. However, data on this relationship in young persons are scarce, and neurodietary research in this age group is limited compared with the extensive literature on adults. Here, we aimed to explore the effects of a diminished central nervous 5-HT synthesis, which is achieved by acute tryptophan depletion (ATD) Moja-De , on memory function in young males with attention deficit hyperactivity disorder (ADHD). METHOD Twenty-two male patients with ADHD (ages 9-15 years, mean 10.95 ± 1.17 years) received ATD, thus diminishing central nervous 5-HT synthesis, and a tryptophan-balanced amino acid load (BAL) in a randomized, double-blind, within-subject, crossover design study. Approximately 1.7 h after administration of ATD/BAL, verbal declarative memory was assessed using the 'Auditory Verbal-Learning-Test' (AVLT). RESULTS There were no significant effects of ATD administration on verbal declarative memory function. CONCLUSION In this study, changes in 5-HT neurotransmission were not associated with specific aspects of verbal declarative memory in young persons with ADHD. Future studies with healthy control groups that address effects of covarying attentional processes are warranted.
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Affiliation(s)
- F D Zepf
- Clinic for Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, RWTH Aachen University, Aachen, Germany.
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18
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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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Price JS, Strong J, Eliassen J, McQueeny T, Miller M, Padula CB, Shear P, Lisdahl K. Serotonin transporter gene moderates associations between mood, memory and hippocampal volume. Behav Brain Res 2012; 242:158-65. [PMID: 23266326 DOI: 10.1016/j.bbr.2012.11.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 11/08/2012] [Accepted: 11/12/2012] [Indexed: 11/24/2022]
Abstract
BACKGROUND The short (S) allele of the serotonin transporter gene (5-HTTLPR) is associated with reduced serotonin turnover compared to the long (L) allele in Caucasians. Few studies have examined its impact on memory and brain structure in healthy young adults. METHODS Participants included 51 healthy young adults (25 female; ages 18-25). Multiple regressions examined the independent contribution of 5-HTTLPR biomarker genotype and its interactions with gender and sub-clinical depressive symptoms on hippocampal volumes and memory. RESULTS The 5-HTTLPR genotype significantly interacted with gender in predicting larger left hippocampal volumes in S-carrying females and smaller hippocampal volumes in males (p<.03). Gender also moderated the impact of the 5-HTTLPR on neurocognition. In females, S allele carriers had poorer visual recall compared to L carriers (p<.05). A three-way interaction between 5-HTTLPR, gender, and depressive symptoms was also observed (p<.04). In females, larger left hippocampal volumes were associated with increased depressive symptoms while the opposite was seen in males. Finally, in male and female S carriers, increased depressive symptoms were marginally associated with poorer verbal memory (p<.09). CONCLUSIONS In females, the 5-HTTLPR S allele was associated with poorer memory performance, increased depressive symptoms and larger hippocampal volumes. In males, the S allele predicted smaller hippocampal volumes and increased depressive symptoms. The opposite morphometric patterns likely reflect gender differences in adolescent hippocampal development. Larger longitudinal studies are needed to examine whether the impact of 5-HTTLPR genotype on neurocognition across development differs according to extent of mood symptoms and gender.
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Affiliation(s)
- Jenessa S Price
- University of Cincinnati, Departments of Psychology, United States
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20
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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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Reichel CM, Ramsey LA, Schwendt M, McGinty JF, See RE. Methamphetamine-induced changes in the object recognition memory circuit. Neuropharmacology 2011; 62:1119-26. [PMID: 22115899 DOI: 10.1016/j.neuropharm.2011.11.003] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 11/02/2011] [Accepted: 11/06/2011] [Indexed: 11/19/2022]
Abstract
Chronic methamphetamine (meth) can lead to persisting cognitive deficits in human addicts and animal models of meth addiction. Here, we examined the impact of either contingent or non-contingent meth on memory performance using an object-in-place (OIP) task, which measures the ability to detect an object relative to its location and surrounding objects. Further, we quantified monoamine transporter levels and markers of neurotoxicity within the OIP circuitry and striatum. Male Long-Evans rats received an acute meth binge (4 × 4 mg/kg i.p., 2 h intervals) or self-administered meth (0.02 mg/infusion, i.v.; 7 days for 1 h/day, followed by 14 days for 6 h/day). Rats were tested for OIP recognition memory following one week of withdrawal. Subsequently, transporters for serotonin (SERT) and norepinephrine (NET) were quantified using Western blot in tissue obtained from the hippocampus, perirhinal cortex, and prefrontal cortex. In addition, striatal dopamine transporters, tyrosine hydroxylase, and glial fibrillary acidic protein were measured to assess potential neurotoxicity. Control (saline-treated) rats spent more time interacting with the objects in the changed locations. In contrast, contingent or non-contingent meth resulted in disrupted OIP performance as seen by similar amounts of time spent with all objects, regardless of location. While only acute meth binge produced signs of neurotoxicity, both meth regimens decreased SERT in the perirhinal cortex and hippocampus. Only meth self-administration resulted in a selective decrease in NET. Meth-induced changes in SERT function in the OIP circuitry may underlie memory deficits independently of overt neurotoxic effects. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.
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Affiliation(s)
- Carmela M Reichel
- Department of Neurosciences, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, USA.
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van den Hove DLA, Jakob SB, Schraut KG, Kenis G, Schmitt AG, Kneitz S, Scholz CJ, Wiescholleck V, Ortega G, Prickaerts J, Steinbusch H, Lesch KP. Differential effects of prenatal stress in 5-Htt deficient mice: towards molecular mechanisms of gene × environment interactions. PLoS One 2011; 6:e22715. [PMID: 21857948 PMCID: PMC3155516 DOI: 10.1371/journal.pone.0022715] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Accepted: 06/28/2011] [Indexed: 01/04/2023] Open
Abstract
Prenatal stress (PS) has been shown to influence the development of the fetal brain and to increase the risk for the development of psychiatric disorders in later life. Furthermore, the variation of human serotonin transporter (5-HTT, SLC6A4) gene was suggested to exert a modulating effect on the association between early life stress and the risk for depression. In the present study, we used a 5-Htt×PS paradigm to investigate whether the effects of PS are dependent on the 5-Htt genotype. For this purpose, the effects of PS on cognition, anxiety- and depression-related behavior were examined using a maternal restraint stress paradigm of PS in C57BL6 wild-type (WT) and heterozygous 5-Htt deficient (5-Htt +/-) mice. Additionally, in female offspring, a genome-wide hippocampal gene expression profiling was performed using the Affymetrix GeneChip® Mouse Genome 430 2.0 Array. 5-Htt +/- offspring showed enhanced memory performance and signs of reduced anxiety as compared to WT offspring. In contrast, exposure of 5-Htt +/- mice to PS was associated with increased depressive-like behavior, an effect that tended to be more pronounced in female offspring. Further, 5-Htt genotype, PS and their interaction differentially affected the expression of numerous genes and related pathways within the female hippocampus. Specifically, MAPK and neurotrophin signaling were regulated by both the 5-Htt +/- genotype and PS exposure, whereas cytokine and Wnt signaling were affected in a 5-Htt genotype×PS manner, indicating a gene×environment interaction at the molecular level. In conclusion, our data suggest that although the 5-Htt +/- genotype shows clear adaptive capacity, 5-Htt +/- mice--particularly females--at the same time appear to be more vulnerable to developmental stress exposure when compared to WT offspring. Moreover, hippocampal gene expression profiles suggest that distinct molecular mechanisms mediate the behavioral effects of the 5-Htt genotype, PS exposure, and their interaction.
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Affiliation(s)
- Daniel Louis Albert van den Hove
- Institute of Molecular Psychiatry, Laboratory of Translational Neuroscience, Department of Psychiatry, Psychosomatics and Psychotherapy, University of Wuerzburg, Wuerzburg, Germany.
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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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Homberg JR, Olivier JDA, Blom T, Arentsen T, van Brunschot C, Schipper P, Korte-Bouws G, van Luijtelaar G, Reneman L. Fluoxetine exerts age-dependent effects on behavior and amygdala neuroplasticity in the rat. PLoS One 2011; 6:e16646. [PMID: 21304948 PMCID: PMC3031607 DOI: 10.1371/journal.pone.0016646] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Accepted: 01/07/2011] [Indexed: 01/01/2023] Open
Abstract
The selective serotonin reuptake inhibitor (SSRI) Prozac® (fluoxetine) is the only registered antidepressant to treat depression in children and adolescents. Yet, while the safety of SSRIs has been well established in adults, serotonin exerts neurotrophic actions in the developing brain and thereby may have harmful effects in adolescents. Here we treated adolescent and adult rats chronically with fluoxetine (12 mg/kg) at postnatal day (PND) 25 to 46 and from PND 67 to 88, respectively, and tested the animals 7–14 days after the last injection when (nor)fluoxetine in blood plasma had been washed out, as determined by HPLC. Plasma (nor)fluoxetine levels were also measured 5 hrs after the last fluoxetine injection, and matched clinical levels. Adolescent rats displayed increased behavioral despair in the forced swim test, which was not seen in adult fluoxetine treated rats. In addition, beneficial effects of fluoxetine on wakefulness as measured by electroencephalography in adults was not seen in adolescent rats, and age-dependent effects on the acoustic startle response and prepulse inhibition were observed. On the other hand, adolescent rats showed resilience to the anorexic effects of fluoxetine. Exploratory behavior in the open field test was not affected by fluoxetine treatment, but anxiety levels in the elevated plus maze test were increased in both adolescent and adult fluoxetine treated rats. Finally, in the amygdala, but not the dorsal raphe nucleus and medial prefrontal cortex, the number of PSA-NCAM (marker for synaptic remodeling) immunoreactive neurons was increased in adolescent rats, and decreased in adult rats, as a consequence of chronic fluoxetine treatment. No fluoxetine-induced changes in 5-HT1A receptor immunoreactivity were observed. In conclusion, we show that fluoxetine exerts both harmful and beneficial age-dependent effects on depressive behavior, body weight and wakefulness, which may relate, in part, to differential fluoxetine-induced neuroplasticity in the amygdala.
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Affiliation(s)
- Judith R Homberg
- Department of Cognitive Neuroscience, Centre for Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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Meneses A, Perez-Garcia G, Ponce-Lopez T, Tellez R, Castillo C. Serotonin transporter and memory. Neuropharmacology 2011; 61:355-63. [PMID: 21276807 DOI: 10.1016/j.neuropharm.2011.01.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 12/15/2010] [Accepted: 01/10/2011] [Indexed: 10/18/2022]
Abstract
The serotonin transporter (SERT) has been associated to diverse functions and diseases, though seldom to memory. Therefore, we made an attempt to summarize and discuss the available publications implicating the involvement of the SERT in memory, amnesia and anti-amnesic effects. Evidence indicates that Alzheimer's disease and drugs of abuse like d-methamphetamine (METH) and (+/-)3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") have been associated to decrements in the SERT expression and memory deficits. Several reports have indicated that memory formation and amnesia affected the SERT expression. The SERT expression seems to be a reliable neural marker related to memory mechanisms, its alterations and potential treatment. The pharmacological, neural and molecular mechanisms associated to these changes are of great importance for investigation.
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Affiliation(s)
- Alfredo Meneses
- Depto. de Farmacobiología, CINVESTAV-IPN, Tenorios 235, Granjas Coapa, Mexico City 14330, Mexico.
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Lin Z, Canales JJ, Björgvinsson T, Thomsen MM, Qu H, Liu QR, Torres GE, Caine SB. Monoamine transporters: vulnerable and vital doorkeepers. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 98:1-46. [PMID: 21199769 PMCID: PMC3321928 DOI: 10.1016/b978-0-12-385506-0.00001-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Transporters of dopamine, serotonin, and norepinephrine have been empirically used as medication targets for several mental illnesses in the last decades. These protein-targeted medications are effective only for subpopulations of patients with transporter-related brain disorders. Since the cDNA clonings in early 1990s, molecular studies of these transporters have revealed a wealth of information about the transporters' structure-activity relationship (SAR), neuropharmacology, cell biology, biochemistry, pharmacogenetics, and the diseases related to the human genes encoding these transporters among related regulators. Such new information creates a unique opportunity to develop transporter-specific medications based on SAR, mRNA, DNA, and perhaps transporter trafficking regulation for a number of highly relevant diseases including substance abuse, depression, schizophrenia, and Parkinson's disease.
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Affiliation(s)
- Zhicheng Lin
- Department of Psychiatry, Harvard Medical School and Division of Alcohol and Drug Abuse, McLean Hospital, Belmont, MA 02478, USA
| | - Juan J. Canales
- Department of Psychology, Behavioural Neuroscience, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
| | - Thröstur Björgvinsson
- Behavioral Health Partial Hospital and Psychology Internship Programs, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA
| | - Morgane M. Thomsen
- Department of Psychiatry, Harvard Medical School and Division of Alcohol and Drug Abuse, McLean Hospital, Belmont, MA 02478, USA
| | - Hong Qu
- Center for Bioinformatics, National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University. Beijing, 100871 China
| | - Qing-Rong Liu
- Behavioral Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, NIH/DHHS, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Gonzalo E. Torres
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - S. Barak Caine
- Department of Psychiatry, Harvard Medical School and Division of Alcohol and Drug Abuse, McLean Hospital, Belmont, MA 02478, USA
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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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Autoradiographic study of serotonin transporter during memory formation. Behav Brain Res 2010; 212:12-26. [PMID: 20226815 DOI: 10.1016/j.bbr.2010.03.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Accepted: 03/05/2010] [Indexed: 12/15/2022]
Abstract
Serotonin transporter (SERT) has been associated with drugs of abuse like d-methamphetamine (METH). METH is well known to produce effects on the monoamine systems but it is unclear how METH affects SERT and memory. Here the effects of METH and the serotonin reuptake inhibitor fluoxetine (FLX) on autoshaping and novel object recognition (NOR) were investigated. Notably, both memory tasks recruit different behavioral, neural and cognitive demand. In autoshaping task a dose-response curve for METH was determined. METH (1.0mg/kg) impaired short-term memory (STM; lasting less of 90min) in NOR and impaired both STM and long-term memory (LTM; lasting 24 and 48h) in autoshaping, indicating that METH had long-lasting effects in the latter task. A comparative autoradiography study of the relationship between the binding pattern of SERT in autoshaping new untrained vs. trained treated (METH, FLX, or both) animals was made. Considering that hemispheric dominance is important for LTM, hence right vs. left hemisphere of the brain was compared. Results showed that trained animals decreased cortical SERT binding relative to untrained ones. In untrained and trained treated animals with the amnesic dose (1.0mg/kg) of METH SERT binding in several areas including hippocampus and cortex decreased, more remarkably in the trained animals. In contrast, FLX improved memory, increased SERT binding, prevented the METH amnesic effect and re-established the SERT binding. In general, memory and amnesia seemed to make SERT more vulnerable to drugs effects.
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Walderhaug E, Herman AI, Magnusson A, Morgan MJ, Landrø NI. The short (S) allele of the serotonin transporter polymorphism and acute tryptophan depletion both increase impulsivity in men. Neurosci Lett 2010; 473:208-11. [PMID: 20188795 DOI: 10.1016/j.neulet.2010.02.048] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Revised: 02/17/2010] [Accepted: 02/19/2010] [Indexed: 11/30/2022]
Abstract
Reduced serotonergic neurotransmission is implicated in impulsive behavior. We studied the triallelic system of the serotonin transporter gene linked polymorphic region (5-HTTLPR) and acute manipulation of serotonin together to further delineate the mechanisms by which serotonergic neurotransmission affects impulsivity. Fifty-two healthy participants (38 men and 14 women) underwent acute tryptophan depletion (ATD) or placebo in a randomized, double-blind, parallel group experiment. Impulsive response style was measured on two versions of the Continuous Performance Task (CPT), and calculated using signal detection theory. We observed a dose-dependent effect for the short (S') allele of the 5-HTTLPR on impulsive response style. Individuals who had the S'/S' genotype were more impulsive than individuals with the L/S' genotype. Participants with the L/S' genotype were more impulsive than those with the L/L genotype. ATD increased impulsivity in men, and decreased impulsivity in women. These data demonstrate for the first time that reduced serotonergic tone as a result of either 5-HTTLPR genotype, or experimental ATD, are both independently and additively, associated with elevated impulsive response style in Caucasian men.
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Affiliation(s)
- Espen Walderhaug
- Department of Psychiatry, Yale University School of Medicine, West Haven, CT 06516, USA.
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Olivier JDA, Jans LAW, Blokland A, Broers NJ, Homberg JR, Ellenbroek BA, Cools AR. Serotonin transporter deficiency in rats contributes to impaired object memory. GENES BRAIN AND BEHAVIOR 2009; 8:829-34. [DOI: 10.1111/j.1601-183x.2009.00530.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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van Donkelaar EL, van den Hove DLA, Blokland A, Steinbusch HWM, Prickaerts J. Stress-mediated decreases in brain-derived neurotrophic factor as potential confounding factor for acute tryptophan depletion-induced neurochemical effects. Eur Neuropsychopharmacol 2009; 19:812-21. [PMID: 19640687 DOI: 10.1016/j.euroneuro.2009.06.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 05/19/2009] [Accepted: 06/16/2009] [Indexed: 10/20/2022]
Abstract
Acute tryptophan depletion (ATD) is extensively used to investigate the implication of serotonin (5-hydroxytryptamine; 5-HT) in the onset and treatment of depression and cognitive disorders. Brain-derived neurotrophic factor (BDNF) is strongly linked to the 5-HT system and plays an essential role in mood and memory processes. The present study investigated the effects of ATD upon BDNF in serum, hippocampus and prefrontal cortex in the rat to further explore the underlying mechanism of ATD. ATD significantly decreased peripheral tryptophan (TRP) levels and moderately interrupted 5-HT metabolism 4h after administration of the nutritional mixture. Although no direct effects of ATD upon serum or brain BDNF concentrations were found, a stress-mediated, decrease in BDNF was observed in the prefrontal cortex. Moreover, brain TRP levels correlated positively with BDNF in both the prefrontal cortex and hippocampus. Thus, BDNF-mediated mechanisms due to ATD and/or its application stress might underlie ATD-induced neurochemical and behavioural alterations.
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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, 6200 MD Maastricht, The Netherlands.
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van Donkelaar E, Ferrington L, Blokland A, Steinbusch H, Prickaerts J, Kelly P. Acute tryptophan depletion in rats alters the relationship between cerebral blood flow and glucose metabolism independent of central serotonin. Neuroscience 2009; 163:683-94. [DOI: 10.1016/j.neuroscience.2009.06.063] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 06/26/2009] [Accepted: 06/29/2009] [Indexed: 10/20/2022]
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Acute tryptophan depletion in C57BL/6 mice does not induce central serotonin reduction or affective behavioural changes. Neurochem Int 2009; 56:21-34. [PMID: 19716853 DOI: 10.1016/j.neuint.2009.08.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Accepted: 08/24/2009] [Indexed: 11/22/2022]
Abstract
Acute tryptophan depletion is extensively used to investigate the implication of serotonin in the onset of depressive disorders. In rats, it lowers peripheral tryptophan and decreases central serotonin concentrations. We aimed to establish the rat model of acute tryptophan depletion in the mouse for potential application as serotonin challenge tool in genetic mouse models of depression. Pharmacokinetic and behavioural effects of a tryptophan-free diet were examined in Swiss and C57BL/6 mice. Peripheral amino acids were measured and central tryptophan and serotonin concentrations were compared with anxiety and depression-like behaviour in the elevated zero-maze, forced swimming test or tail suspension test. While acute tryptophan depletion resulted in a 74% reduction of the plasma ratio tryptophan to the sum of other large neutral amino acids in Swiss mice 1h after administration (2x10 ml/kg, 30 min interval), there was only a 40% reduction in C57BL/6 mice. The latter did not show anxiety in the elevated zero-maze or increased immobility in the forced swimming test or tail suspension test. A higher dose (2x20 ml/kg) with a longer interval (60 min) reduced the ratio with 68% in C57BL/6 mice, lowered hippocampal serotonin turnover and had no functional effect when tested in the elevated zero-maze and forced swimming test. These findings have important implications for the use of acute tryptophan depletion in general and in particular for its application in mice. Although in healthy mice no clear central serotonin or functional effects were observed, further research is indicated using mice with pre-existing serotonin dysfunction, as they might be more vulnerable to acute tryptophan depletion.
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Honig G, Jongsma ME, van der Hart MCG, Tecott LH. Chronic citalopram administration causes a sustained suppression of serotonin synthesis in the mouse forebrain. PLoS One 2009; 4:e6797. [PMID: 19710918 PMCID: PMC2728775 DOI: 10.1371/journal.pone.0006797] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 08/04/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Serotonin (5-HT) is a neurotransmitter with important roles in the regulation of neurobehavioral processes, particularly those regulating affect in humans. Drugs that potentiate serotonergic neurotransmission by selectively inhibiting the reuptake of serotonin (SSRIs) are widely used for the treatment of psychiatric disorders. Although the regulation of serotonin synthesis may be an factor in SSRI efficacy, the effect of chronic SSRI administration on 5-HT synthesis is not well understood. Here, we describe effects of chronic administration of the SSRI citalopram (CIT) on 5-HT synthesis and content in the mouse forebrain. METHODOLOGY/PRINCIPAL FINDINGS Citalopram was administered continuously to adult male C57BL/6J mice via osmotic minipump for 2 days, 14 days or 28 days. Plasma citalopram levels were found to be within the clinical range. 5-HT synthesis was assessed using the decarboxylase inhibition method. Citalopram administration caused a suppression of 5-HT synthesis at all time points. CIT treatment also caused a reduction in forebrain 5-HIAA content. Following chronic CIT treatment, forebrain 5-HT stores were more sensitive to the depleting effects of acute decarboxylase inhibition. CONCLUSIONS/SIGNIFICANCE Taken together, these results demonstrate that chronic citalopram administration causes a sustained suppression of serotonin synthesis in the mouse forebrain. Furthermore, our results indicate that chronic 5-HT reuptake inhibition renders 5-HT brain stores more sensitive to alterations in serotonin synthesis. These results suggest that the regulation of 5-HT synthesis warrants consideration in efforts to develop novel antidepressant strategies.
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Affiliation(s)
- Gerard Honig
- Neuroscience Graduate Program, University of California San Francisco, San Francisco, CA, USA.
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Kalueff AV, Olivier JDA, Nonkes LJP, Homberg JR. Conserved role for the serotonin transporter gene in rat and mouse neurobehavioral endophenotypes. Neurosci Biobehav Rev 2009; 34:373-86. [PMID: 19698744 DOI: 10.1016/j.neubiorev.2009.08.003] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2009] [Revised: 08/12/2009] [Accepted: 08/13/2009] [Indexed: 10/20/2022]
Abstract
The serotonin transporter knockout (SERT(-/-)) mouse, generated in 1998, was followed by the SERT(-/-) rat, developed in 2006. The availability of SERT(-/-) rodents creates the unique possibility to study the conservation of gene function across species. Here we summarize SERT(-/-) mouse and rat data, and discuss species (dis)similarities in neurobehavioral endophenotypes. Both SERT(-/-) rodent models show a disturbed serotonergic system, altered nociception, higher anxiety, decreased social behavior, as well as increased negative emotionality, behavioral inhibition and decision making. Used to model a wide range of psychiatric disorders, SERT(-/-) rodents may be particularly valuable in research on neurodevelopmental disorders such as depression, anxiety, and possibly autism. We conclude that SERT function is conserved across mice and rats and that their behavioral profile arises from common neurodevelopmental alterations. Because mice and rats have species-specific characteristics that confer differential research advantages, a comparison of the two models has heuristic value in understanding the mechanisms and behavioral outcome of SERT genetic variation in humans.
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Affiliation(s)
- A V Kalueff
- Department of Pharmacology, Tulane University Medical School, New Orleans, LA 70112, USA
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Albay R, Chen A, Anderson GM, Tatevosyan M, Janusonis S. Relationships among body mass, brain size, gut length, and blood tryptophan and serotonin in young wild-type mice. BMC PHYSIOLOGY 2009; 9:4. [PMID: 19321004 PMCID: PMC2671477 DOI: 10.1186/1472-6793-9-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2008] [Accepted: 03/25/2009] [Indexed: 11/10/2022]
Abstract
Background The blood hyperserotonemia of autism is one of the most consistent biological findings in autism research, but its causes remain unclear. A major difficulty in understanding this phenomenon is the lack of information on fundamental interactions among the developing brain, gut, and blood in the mammalian body. We therefore investigated relationships among the body mass, the brain mass, the volume of the hippocampal complex, the gut length, and the whole-blood levels of tryptophan and 5-hydroxytryptamine (5-HT, serotonin) in young, sexually immature wild-type mice. Results Three-dimensional reconstructions of the hippocampal complex were obtained from serial, Nissl-stained sections and the gut was allowed to attain its maximal relaxed length prior to measurements. The tryptophan and 5-HT concentrations in the blood were assessed with high-performance liquid chromatography (HPLC) and the sex of mice was confirmed by genotyping. Statistical analysis yielded information about correlative relationships among all studied variables. It revealed a strong negative correlation between blood 5-HT concentration and body mass and a strong negative correlation between the brain mass/body mass ratio and gut length. Also, a negative correlation was found between the volume of the hippocampal complex and blood tryptophan concentration. Conclusion The study provides information on the covariance structure of several central and peripheral variables related to the body serotonin systems. In particular, the results indicate that body mass should be included as a covariate in studies on platelet 5-HT levels and they also suggest a link between brain growth and gut length.
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Affiliation(s)
- Ricardo Albay
- Department of Psychology, University of California, Santa Barbara, California, USA.
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