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Higa GSV, Viana FJC, Francis-Oliveira J, Cruvinel E, Franchin TS, Marcourakis T, Ulrich H, De Pasquale R. Serotonergic neuromodulation of synaptic plasticity. Neuropharmacology 2024; 257:110036. [PMID: 38876308 DOI: 10.1016/j.neuropharm.2024.110036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 05/15/2024] [Accepted: 06/11/2024] [Indexed: 06/16/2024]
Abstract
Synaptic plasticity constitutes a fundamental process in the reorganization of neural networks that underlie memory, cognition, emotional responses, and behavioral planning. At the core of this phenomenon lie Hebbian mechanisms, wherein frequent synaptic stimulation induces long-term potentiation (LTP), while less activation leads to long-term depression (LTD). The synaptic reorganization of neuronal networks is regulated by serotonin (5-HT), a neuromodulator capable of modify synaptic plasticity to appropriately respond to mental and behavioral states, such as alertness, attention, concentration, motivation, and mood. Lately, understanding the serotonergic Neuromodulation of synaptic plasticity has become imperative for unraveling its impact on cognitive, emotional, and behavioral functions. Through a comparative analysis across three main forebrain structures-the hippocampus, amygdala, and prefrontal cortex, this review discusses the actions of 5-HT on synaptic plasticity, offering insights into its role as a neuromodulator involved in emotional and cognitive functions. By distinguishing between plastic and metaplastic effects, we provide a comprehensive overview about the mechanisms of 5-HT neuromodulation of synaptic plasticity and associated functions across different brain regions.
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Affiliation(s)
- Guilherme Shigueto Vilar Higa
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, São Paulo, SP, 05508-000, Brazil; Departamento de Bioquímica, Instituto de Química (USP), Butantã, São Paulo, SP, 05508-900, Brazil
| | - Felipe José Costa Viana
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, São Paulo, SP, 05508-000, Brazil
| | - José Francis-Oliveira
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35233, USA
| | - Emily Cruvinel
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, São Paulo, SP, 05508-000, Brazil
| | - Thainá Soares Franchin
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, São Paulo, SP, 05508-000, Brazil
| | - Tania Marcourakis
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, Butantã, São Paulo, SP, 05508-000, Brazil
| | - Henning Ulrich
- Departamento de Bioquímica, Instituto de Química (USP), Butantã, São Paulo, SP, 05508-900, Brazil
| | - Roberto De Pasquale
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, São Paulo, SP, 05508-000, Brazil.
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Arraes GC, Barreto FS, Vasconcelos GS, Lima CNDC, da Silva FER, Ribeiro WLC, de Sousa FCF, Furtado CLM, Macêdo DS. Long-term Environmental Enrichment Normalizes Schizophrenia-like Abnormalities and Promotes Hippocampal Slc6a4 Promoter Demethylation in Mice Submitted to a Two-hit Model. Neuroscience 2024; 551:205-216. [PMID: 38843988 DOI: 10.1016/j.neuroscience.2024.05.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 05/15/2024] [Accepted: 05/20/2024] [Indexed: 06/15/2024]
Abstract
Here, we explored the impact of prolonged environmental enrichment (EE) on behavioral, neurochemical, and epigenetic changes in the serotonin transporter gene in mice subjected to a two-hit schizophrenia model. The methodology involved administering the viral mimetic PolyI:C to neonatal Swiss mice as a first hit during postnatal days (PND) 5-7, or a sterile saline solution as a control. At PND21, mice were randomly assigned either to standard environment (SE) or EE housing conditions. Between PND35-44, the PolyI:C-treated group was submitted to various unpredictable stressors, constituting the second hit. Behavioral assessments were conducted on PND70, immediately after the final EE exposure. Following the completion of behavioral assessments, we evaluated the expression of proteins in the hippocampus that are indicative of microglial activation, such as Iba-1, as well as related to neurogenesis, including doublecortin (Dcx). We also performed methylation analysis on the serotonin transporter gene (Slc6a4) to investigate alterations in serotonin signaling. The findings revealed that EE for 50 days mitigated sensorimotor gating deficits and working memory impairments in two-hit mice and enhanced their locomotor and exploratory behaviors. EE also normalized the overexpression of hippocampal Iba-1 and increased the expression of hippocampal Dcx. Additionally, we observed hippocampal demethylation of the Slc6a4 gene in the EE-exposed two-hit group, indicating epigenetic reprogramming. These results contribute to the growing body of evidence supporting the protective effects of long-term EE in counteracting behavioral disruptions caused by the two-hit schizophrenia model, pointing to enhanced neurogenesis, diminished microglial activation, and epigenetic modifications of serotonergic pathways as underlying mechanisms.
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Affiliation(s)
- Greicy Coelho Arraes
- Neuropsychopharmacology and Translational Psychiatry Laboratory, Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil; Christus University Center (Unichristus-CE), Fortaleza, CE, Brazil
| | - Francisco Stefânio Barreto
- Neuropsychopharmacology and Translational Psychiatry Laboratory, Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil; Laboratory of Experimental Oncology, Postgraduate Program in Translational Medicine, Drug Research and Development Center, Federal University of Ceara, Fortaleza, Ceará, Brazil
| | - Germana Silva Vasconcelos
- Neuropsychopharmacology and Translational Psychiatry Laboratory, Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Camila Nayane de Carvalho Lima
- Neuropsychopharmacology and Translational Psychiatry Laboratory, Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil; Translational Psychiatry Program, Louis A. Faillace, MD, Department of Psychiatry and Behavioral Sciences at McGovern Medical School, The University of Texas Health Science Center at Houston (UT Health), Houston, TX, USA.
| | - Francisco Eliclécio Rodrigues da Silva
- Neuropsychopharmacology and Translational Psychiatry Laboratory, Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | | | - Francisca Cléa Florenço de Sousa
- Neuropsychopharmacology and Translational Psychiatry Laboratory, Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil.
| | - Cristiana Libardi Miranda Furtado
- Laboratory of Experimental Oncology, Postgraduate Program in Translational Medicine, Drug Research and Development Center, Federal University of Ceara, Fortaleza, Ceará, Brazil; Graduate Program in Medical Sciences, Experimental Biology Center - NUBEX, University of Fortaleza, UNIFOR, Fortaleza, Ceará, Brazil
| | - Danielle S Macêdo
- Neuropsychopharmacology and Translational Psychiatry Laboratory, Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil; National Institute for Translational Medicine (INCT-TM. CNPq), Brazil.
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3
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Sun Y, Li G, Hong H, Zhu L, Kung HF, Zhang Y, Zhu J. Serotonin transporter imaging agent as a probe for β-cells of pancreas. Nucl Med Biol 2024; 130-131:108894. [PMID: 38422917 DOI: 10.1016/j.nucmedbio.2024.108894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 02/22/2024] [Accepted: 02/23/2024] [Indexed: 03/02/2024]
Abstract
OBJECTIVE Diabetes mellitus (DM) is one of the major diseases in the world. Nuclear medicine imaging may be able to detect functional status of pancreatic β cells in vivo, which might elucidate the pathological mechanisms of diabetes and develop individualized treatment plans. In this study, we evaluated the ability of [125I]ADAM, a serotonin transporter (SERT) imaging agent, as a probe for detecting pancreatic β-cell mass (BCM). METHODS In vitro cell studies were evaluated in INS-1 cells (rat islet β cell line). Biodistribution studies were performed in male normal Sprague-Dawley rats and alloxan-induced type 1 diabetes mellitus (T1DM) rats. Distribution and expression of SERT protein in pancreas of rats were also measured by immunofluorescence staining and Western blot. RESULTS In vitro cell studies showed that the concentration of [125I]ADAM associated with the INS-1 cells was increased gradually with incubation time, and the SERT specific inhibitor, escitalopram, exhibited the inhibitory effect on this interaction. Biodistribution studies also showed that the uptake of [125I]ADAM in the pancreas of normal rats was decreased in the presence of escitalopram. However, in the T1DM rat model with a significant β cells reduction, the uptake of pancreas was increased when compared with the control. Through immunofluorescence staining and Western blot, it was found that both the endocrine and exocrine cells of the normal pancreas expressed SERT protein, and the level of SERT protein in the exocrine cells was higher than islets. In the diabetic state, the expression of SERT in the exocrine cells was further increased. CONCLUSIONS The SERT imaging agent, [125I]ADAM, at the present form will not be suitable for imaging β cells, specifically because there were extraordinarily high non-specific signals contributing from the exocrine cells of pancreas. In addition, we noticed that the level of SERT expression was abnormally elevated in the diabetic state, which might provide an unexpected target for studying the pathological mechanisms of diabetes.
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Affiliation(s)
- Yuli Sun
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Capital Medical University, Beijing 100069, China
| | - Guangwen Li
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Capital Medical University, Beijing 100069, China
| | - Haiyan Hong
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Lin Zhu
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Hank F Kung
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yan Zhang
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Capital Medical University, Beijing 100069, China.
| | - Jinxia Zhu
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Capital Medical University, Beijing 100069, China.
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Honan LE, Fraser-Spears R, Daws LC. Organic cation transporters in psychiatric and substance use disorders. Pharmacol Ther 2024; 253:108574. [PMID: 38072333 PMCID: PMC11052553 DOI: 10.1016/j.pharmthera.2023.108574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 11/01/2023] [Accepted: 11/30/2023] [Indexed: 12/23/2023]
Abstract
Psychiatric and substance use disorders inflict major public health burdens worldwide. Their widespread burden is compounded by a dearth of effective treatments, underscoring a dire need to uncover novel therapeutic targets. In this review, we summarize the literature implicating organic cation transporters (OCTs), including three subtypes of OCTs (OCT1, OCT2, and OCT3) and the plasma membrane monoamine transporter (PMAT), in the neurobiology of psychiatric and substance use disorders with an emphasis on mood and anxiety disorders, alcohol use disorder, and psychostimulant use disorder. OCTs transport monoamines with a low affinity but high capacity, situating them to play a central role in regulating monoamine homeostasis. Preclinical evidence discussed here suggests that OCTs may serve as promising targets for treatment of psychiatric and substance use disorders and encourage future research into their therapeutic potential.
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Affiliation(s)
- Lauren E Honan
- The University of Texas Health Science Center at San Antonio, Department of Cellular & Integrative Physiology, USA
| | - Rheaclare Fraser-Spears
- University of the Incarnate Word, Feik School of Pharmacy, Department of Pharmaceutical Sciences, USA
| | - Lynette C Daws
- The University of Texas Health Science Center at San Antonio, Department of Cellular & Integrative Physiology, USA; The University of Texas Health Science Center at San Antonio, Department of Pharmacology, USA.
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McDonald AJ. Functional neuroanatomy of monoaminergic systems in the basolateral nuclear complex of the amygdala: Neuronal targets, receptors, and circuits. J Neurosci Res 2023; 101:1409-1432. [PMID: 37166098 PMCID: PMC10524224 DOI: 10.1002/jnr.25201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 03/03/2023] [Accepted: 04/21/2023] [Indexed: 05/12/2023]
Abstract
This review discusses neuroanatomical aspects of the three main monoaminergic systems innervating the basolateral nuclear complex (BNC) of the amygdala (serotonergic, noradrenergic, and dopaminergic systems). It mainly focuses on immunohistochemical (IHC) and in situ hybridization (ISH) studies that have analyzed the relationship of specific monoaminergic inputs and their receptors to specific neuronal subtypes in the BNC in order to better understand the anatomical substrates of the monoaminergic modulation of BNC circuitry. First, light and electron microscopic IHC investigations identifying the main BNC neuronal subpopulations and characterizing their local circuitry, including connections with discrete PN compartments and other INs, are reviewed. Then, the relationships of each of the three monoaminergic systems to distinct PN and IN cell types, are examined in detail. For each system, the neuronal targets and their receptor expression are discussed. In addition, pertinent electrophysiological investigations are discussed. The last section of the review compares and contrasts various aspects of each of the three monoaminergic systems. It is concluded that the large number of different receptors, each with a distinct mode of action, expressed by distinct cell types with different connections and functions, should offer innumerable ways to subtlety regulate the activity of the BNC by therapeutic drugs in psychiatric diseases in which there are alterations of BNC monoaminergic modulatory systems, such as in anxiety disorders, depression, and drug addiction. It is suggested that an important area for future studies is to investigate how the three systems interact in concert at the neuronal and neuronal network levels.
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Affiliation(s)
- Alexander Joseph McDonald
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina, USA
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Janušonis S, Haiman JH, Metzler R, Vojta T. Predicting the distribution of serotonergic axons: a supercomputing simulation of reflected fractional Brownian motion in a 3D-mouse brain model. Front Comput Neurosci 2023; 17:1189853. [PMID: 37265780 PMCID: PMC10231035 DOI: 10.3389/fncom.2023.1189853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 04/24/2023] [Indexed: 06/03/2023] Open
Abstract
The self-organization of the brain matrix of serotonergic axons (fibers) remains an unsolved problem in neuroscience. The regional densities of this matrix have major implications for neuroplasticity, tissue regeneration, and the understanding of mental disorders, but the trajectories of its fibers are strongly stochastic and require novel conceptual and analytical approaches. In a major extension to our previous studies, we used a supercomputing simulation to model around one thousand serotonergic fibers as paths of superdiffusive fractional Brownian motion (FBM), a continuous-time stochastic process. The fibers produced long walks in a complex, three-dimensional shape based on the mouse brain and reflected at the outer (pial) and inner (ventricular) boundaries. The resultant regional densities were compared to the actual fiber densities in the corresponding neuroanatomically-defined regions. The relative densities showed strong qualitative similarities in the forebrain and midbrain, demonstrating the predictive potential of stochastic modeling in this system. The current simulation does not respect tissue heterogeneities but can be further improved with novel models of multifractional FBM. The study demonstrates that serotonergic fiber densities can be strongly influenced by the geometry of the brain, with implications for brain development, plasticity, and evolution.
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Affiliation(s)
- Skirmantas Janušonis
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Justin H. Haiman
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Ralf Metzler
- Institute of Physics and Astronomy, University of Potsdam, Potsdam, Germany
- Asia Pacific Center for Theoretical Physics, Pohang, South Korea
| | - Thomas Vojta
- Department of Physics, Missouri University of Science and Technology, Rolla, MO, United States
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Chen CW, Chou YH, Liou YJ, Yang KC, Hu LY, Hsieh WC, Liu MN. Amygdala substructure volumes and serotonin transporter in first-episode, drug- naïve major depressive disorder: A pilot study. J Psychiatr Res 2023; 160:210-216. [PMID: 36857985 DOI: 10.1016/j.jpsychires.2023.02.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 02/07/2023] [Accepted: 02/09/2023] [Indexed: 02/23/2023]
Abstract
INTRODUCTION Amygdala and serotonergic system abnormalities have been documented in major depressive disorder (MDD). However, most studies have been conducted on recurrent MDD, and only a few have assessed their interaction. This study aimed to concurrently examine both the amygdala and serotonergic systems and their clinical relevance in first-episode, drug-naïve MDD. METHODS This study included 27 patients with first-episode, drug-naïve MDD and 27 age- and gender-matched healthy controls (HCs). The amygdala substructure volumes were performed with Freesurfer from a 1.5 T magnetic resonance image. Serotonin transporter (SERT) availability was detected by single-photon emission computed tomography with 123I-ADAM. The Benjamini-Hochberg method was applied to adjust for multiple comparisons. RESULTS No significant difference was found in the amygdala substructure volume and SERT availability between the two groups, respectively. Within MDD patients, the right medial, cortical nucleus, and centromedial volumes were positively associated with caudate SERT availability, respectively. Moreover, the right lateral nucleus volume in the amygdala was positively correlated with depression severity. However, these significances did not survive correction for multiple testing. CONCLUSIONS There were no significant abnormalities in the amygdala substructure volumes and SERT availability in patients with first-episode, drug-naïve MDD. We did not observe an association between amygdala substructure volume and serotonergic dysregulation and their correlations with depression severity in patients with MDD. A larger sample size is warranted to elucidate the actual correlation.
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Affiliation(s)
- Ching-Wen Chen
- Department of Pharmacy, Kaohsiung Veterans General Hospital, Kaohsiung, 813414, Taiwan; Department of Pharmacy and Master Program, College of Pharmacy and Health Care, Tajen University, Pingtung, 90741, Taiwan
| | - Yuan-Hwa Chou
- Center for Quality Management, Taipei Veterans General Hospital, Taipei, 112201, Taiwan; Department of Psychiatry, Taipei Veterans General Hospital, Taipei, 112201, Taiwan; School of Medicine, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan
| | - Ying-Jay Liou
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, 112201, Taiwan; School of Medicine, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan
| | - Kai-Chun Yang
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, 112201, Taiwan; School of Medicine, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan
| | - Li-Yu Hu
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, 112201, Taiwan; School of Medicine, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan
| | - Wen-Chi Hsieh
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, 112201, Taiwan
| | - Mu-N Liu
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, 112201, Taiwan; School of Medicine, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan.
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Holmes J, Lau T, Saylor R, Fernández-Novel N, Hersey M, Keen D, Hampel L, Horschitz S, Ladewig J, Parke B, Reed MC, Nijhout HF, Best J, Koch P, Hashemi P. Voltammetric Approach for Characterizing the Biophysical and Chemical Functionality of Human Induced Pluripotent Stem Cell-Derived Serotonin Neurons. Anal Chem 2022; 94:8847-8856. [PMID: 35713335 DOI: 10.1021/acs.analchem.1c05082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Depression is quickly becoming one of the world's most pressing public health crises, and there is an urgent need for better diagnostics and therapeutics. Behavioral models in animals and humans have not adequately addressed the diagnosis and treatment of depression, and biomarkers of mental illnesses remain ill-defined. It has been very difficult to identify biomarkers of depression because of in vivo measurement challenges. While our group has made important strides in developing in vivo tools to measure such biomarkers (e.g., serotonin) in mice using voltammetry, these tools cannot be easily applied for depression diagnosis and drug screening in humans due to the inaccessibility of the human brain. In this work, we take a chemical approach, ex vivo, to introduce a human-derived system to investigate brain serotonin. We utilize human induced pluripotent stem cells differentiated into serotonin neurons and establish a new ex vivo model of real-time serotonin neurotransmission measurements. We show that evoked serotonin release responds to stimulation intensity and tryptophan preloading, and that serotonin release and reuptake kinetics resemble those found in vivo in rodents. Finally, after selective serotonin reuptake inhibitor (SSRI) exposure, we find dose-dependent internalization of the serotonin reuptake transporters (a signature of the in vivo response to SSRI). Our new human-derived chemical model has great potential to provide an ex vivo chemical platform as a translational tool for in vivo neuropsychopharmacology.
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Affiliation(s)
- Jordan Holmes
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Thorsten Lau
- Department of Translational Brain Research, Central Institute of Mental Health, University of Heidelberg, Medical Faculty Mannheim, 68159 Mannheim, Germany.,German Cancer Research Center, 69120 Heidelberg, Germany.,HITBR Hector Institute for Translational Brain Research gGmbH, 68159 Mannheim, Germany
| | - Rachel Saylor
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Nadine Fernández-Novel
- Department of Translational Brain Research, Central Institute of Mental Health, University of Heidelberg, Medical Faculty Mannheim, 68159 Mannheim, Germany.,German Cancer Research Center, 69120 Heidelberg, Germany.,HITBR Hector Institute for Translational Brain Research gGmbH, 68159 Mannheim, Germany
| | - Melinda Hersey
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States.,Department of Pharmacology, Physiology, & Neuroscience, University of South Carolina, Columbia, South Carolina 29209, United States
| | - Deanna Keen
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Lena Hampel
- Department of Translational Brain Research, Central Institute of Mental Health, University of Heidelberg, Medical Faculty Mannheim, 68159 Mannheim, Germany.,German Cancer Research Center, 69120 Heidelberg, Germany.,HITBR Hector Institute for Translational Brain Research gGmbH, 68159 Mannheim, Germany
| | - Sandra Horschitz
- Department of Translational Brain Research, Central Institute of Mental Health, University of Heidelberg, Medical Faculty Mannheim, 68159 Mannheim, Germany.,German Cancer Research Center, 69120 Heidelberg, Germany.,HITBR Hector Institute for Translational Brain Research gGmbH, 68159 Mannheim, Germany
| | - Julia Ladewig
- Department of Translational Brain Research, Central Institute of Mental Health, University of Heidelberg, Medical Faculty Mannheim, 68159 Mannheim, Germany.,German Cancer Research Center, 69120 Heidelberg, Germany.,HITBR Hector Institute for Translational Brain Research gGmbH, 68159 Mannheim, Germany
| | - Brenna Parke
- Department of Bioengineering, Imperial College London, London SW7 2AZ, U.K
| | - Michael C Reed
- Department of Mathematics, Duke University, Durham, North Carolina 27708, United States
| | - H Frederik Nijhout
- Department of Biology, Duke University, Durham, North Carolina 27708, United States
| | - Janet Best
- Department of Mathematics, The Ohio State University, Columbus, Ohio 43210, United States
| | - Philipp Koch
- Department of Translational Brain Research, Central Institute of Mental Health, University of Heidelberg, Medical Faculty Mannheim, 68159 Mannheim, Germany.,German Cancer Research Center, 69120 Heidelberg, Germany.,HITBR Hector Institute for Translational Brain Research gGmbH, 68159 Mannheim, Germany
| | - Parastoo Hashemi
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States.,Department of Bioengineering, Imperial College London, London SW7 2AZ, U.K
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9
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Awasthi JR, Tamada K, Overton ETN, Takumi T. Comprehensive topographical map of the serotonergic fibers in the male mouse brain. J Comp Neurol 2021; 529:1391-1429. [PMID: 32892368 DOI: 10.1002/cne.25027] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 08/14/2020] [Accepted: 08/26/2020] [Indexed: 11/11/2022]
Abstract
It is well established that serotonergic fibers distribute throughout the brain. Abnormal densities or patterns of serotonergic fibers have been implicated in neuropsychiatric disorders. Although many classical studies have examined the distribution pattern of serotonergic fibers, most of them were either limited to specific brain areas or had limitations in demonstrating the fine axonal morphology. In this study, we utilize male mice expressing green fluorescence protein under the serotonin transporter (SERT) promoter to map the topography of serotonergic fibers across the rostro-caudal extent of each brain area. We demonstrate previously unreported regional density and fine-grained anatomy of serotonergic fibers. Our findings include: (a) SERT fibers distribute abundantly in the thalamic nuclei close to the midline and dorsolateral areas, in most of the hypothalamic nuclei with few exceptions such as the median eminence and arcuate nuclei, and within the basal amygdaloid complex and lateral septal nuclei, (b) the source fibers of innervation of the hippocampus traverse through the septal nuclei before reaching its destination, (c) unique, filamentous type of straight terminal fibers within the nucleus accumbens, (d) laminar pattern of innervation in the hippocampus, olfactory bulb and cortex with heterogenicity in innervation density among the layers, (e) cortical labeling density gradually decreases rostro-caudally, (f) fibers traverse and distribute mostly within the gray matter, leaving the white fiber bundles uninnervated, and (g) most of the highly labeled nuclei and cortical areas have predominant anatomical connection to limbic structures. In conclusion, we provide novel, regionally specific insights on the distribution map of serotonergic fibers using transgenic mouse.
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Affiliation(s)
- Janak R Awasthi
- RIKEN Brain Science Institute, Wako, Japan.,Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | | | | | - Toru Takumi
- RIKEN Brain Science Institute, Wako, Japan.,Graduate School of Science and Engineering, Saitama University, Saitama, Japan.,Department of Physiology and Cell Biology, Kobe University School of Medicine, Kobe, Japan
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10
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Paul N, Raymond J, Lumbreras S, Bartsch D, Weber T, Lau T. Activation of the glucocorticoid receptor rapidly triggers calcium-dependent serotonin release in vitro. CNS Neurosci Ther 2021; 27:753-764. [PMID: 33715314 PMCID: PMC8193689 DOI: 10.1111/cns.13634] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 02/22/2021] [Accepted: 02/25/2021] [Indexed: 12/01/2022] Open
Abstract
Aims Glucocorticoids rapidly provoke serotonin (5‐HT) release in vivo. We aimed to investigate molecular mechanisms of glucocorticoid receptor (GR)‐triggered 5‐HT release. Methods Employing 1C11 cells to model 5‐HT neurotransmission, immunofluorescence and Pearson's Correlation Coefficient were used to analyze colocalization of GR, 5‐HT, vesicle membrane protein synaptotagmin 1 and vesicle dye FM4‐64FX. FFN511 and FM4‐64FX dyes as well as calcium imaging were used to visualize vesicular 5‐HT release upon application of GR agonist dexamethasone, GR antagonist mifepristone and voltage‐gated calcium channel (VGCC) inhibitors. Results GR, 5‐HT, synaptotagmin 1 and FM4‐64FX showed overlapping staining patterns, with Pearson's Correlation Coefficient indicating colocalization. Similarly to potassium chloride, dexamethasone caused a release of FFN511 and uptake of FM4‐64FX, indicating vesicular 5‐HT release. Mifepristone, calcium depletion and inhibition of L‐type VGCC significantly diminished dexamethasone‐induced vesicular 5‐HT release. Conclusions In close proximity to 5‐HT releasing sites, activated GR rapidly triggers L‐type VGCC‐dependent vesicular 5‐HT release. These findings provide a better understanding of the interrelationship between glucocorticoids and 5‐HT release.
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Affiliation(s)
- Nicolas Paul
- Department of Psychiatry and Psychotherapy, Biochemical Laboratory, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Justine Raymond
- Department of Psychiatry and Psychotherapy, Biochemical Laboratory, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Sara Lumbreras
- Department of Psychiatry and Psychotherapy, Biochemical Laboratory, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Dusan Bartsch
- Transgenic Models, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Tillmann Weber
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,MEDIAN Klinik Wilhelmsheim, Oppenweiler, Germany
| | - Thorsten Lau
- Department of Psychiatry and Psychotherapy, Biochemical Laboratory, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Department of Translational Brain Research, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Hector Institute for Translational Brain Research, Mannheim, Germany.,German Cancer Research Center, Heidelberg, Germany
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11
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Abstract
Inhibitors of Na+/Cl- dependent high affinity transporters for norepinephrine (NE), serotonin (5-HT), and/or dopamine (DA) represent frequently used drugs for treatment of psychological disorders such as depression, anxiety, obsessive-compulsive disorder, attention deficit hyperactivity disorder, and addiction. These transporters remove NE, 5-HT, and/or DA after neuronal excitation from the interstitial space close to the synapses. Thereby they terminate transmission and modulate neuronal behavioral circuits. Therapeutic failure and undesired central nervous system side effects of these drugs have been partially assigned to neurotransmitter removal by low affinity transport. Cloning and functional characterization of the polyspecific organic cation transporters OCT1 (SLC22A1), OCT2 (SLC22A2), OCT3 (SLC22A3) and the plasma membrane monoamine transporter PMAT (SLC29A4) revealed that every single transporter mediates low affinity uptake of NE, 5-HT, and DA. Whereas the organic transporters are all located in the blood brain barrier, OCT2, OCT3, and PMAT are expressed in neurons or in neurons and astrocytes within brain areas that are involved in behavioral regulation. Areas of expression include the dorsal raphe, medullary motoric nuclei, hypothalamic nuclei, and/or the nucleus accumbens. Current knowledge of the transport of monoamine neurotransmitters by the organic cation transporters, their interactions with psychotropic drugs, and their locations in the brain is reported in detail. In addition, animal experiments including behavior tests in wildtype and knockout animals are reported in which the impact of OCT2, OCT3, and/or PMAT on regulation of salt intake, depression, mood control, locomotion, and/or stress effect on addiction is suggested.
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Affiliation(s)
- Hermann Koepsell
- Institute of Anatomy and Cell Biology, University Würzburg, Würzburg, Germany.
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12
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Longley M, Ballard J, Andres-Alonso M, Varatharajah RC, Cuthbert H, Yeo CH. A Patterned Architecture of Monoaminergic Afferents in the Cerebellar Cortex: Noradrenergic and Serotonergic Fibre Distributions within Lobules and Parasagittal Zones. Neuroscience 2020; 462:106-121. [PMID: 32949672 DOI: 10.1016/j.neuroscience.2020.09.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/28/2020] [Accepted: 09/01/2020] [Indexed: 12/23/2022]
Abstract
The geometry of the glutamatergic mossy-parallel fibre and climbing fibre inputs to cerebellar cortical Purkinje cells has powerfully influenced thinking about cerebellar functions. The compartmentation of the cerebellum into parasagittal zones, identifiable in olivo-cortico-nuclear projections, and the trajectories of the parallel fibres, transverse to these zones and following the long axes of the cortical folia, are particularly important. Two monoaminergic afferent systems, the serotonergic and noradrenergic, are major inputs to the cerebellar cortex but their architecture and relationship with the cortical geometry are poorly understood. Immunohistochemistry for the serotonin transporter (SERT) and for the noradrenaline transporter (NET) revealed strong anisotropy of these afferent fibres in the molecular layer of rat cerebellar cortex. Individual serotonergic fibres travel predominantly medial-lateral, along the long axes of the cortical folia, similar to parallel fibres and Zebrin II immunohistochemistry revealed that they can influence multiple zones. In contrast, individual noradrenergic fibres run predominantly parasagittally with rostral-caudal extents significantly longer than their medial-lateral deviations. Their local area of influence has similarities in form and size to those of identified microzones. Within the molecular layer, the orthogonal trajectories of these two afferent systems suggest different information processing. An individual serotonergic fibre must influence all zones and microzones within its medial-lateral trajectory. In contrast, noradrenergic fibres can influence smaller cortical territories, potentially as limited as a microzone. Evidence is emerging that these monoaminergic systems may not supply a global signal to all of their targets and their potential for cerebellar cortical functions is discussed.
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Affiliation(s)
- Michael Longley
- Dept. Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom.
| | - John Ballard
- Dept. Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom.
| | - Maria Andres-Alonso
- Dept. Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom.
| | | | - Hadleigh Cuthbert
- Dept. Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom.
| | - Christopher H Yeo
- Dept. Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom.
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13
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Abstract
Neurons that synthesize and release 5-hydroxytryptamine (5-HT; serotonin) express a core set of genes that establish and maintain this neurotransmitter phenotype and distinguish these neurons from other brain cells. Beyond a shared 5-HTergic phenotype, these neurons display divergent cellular properties in relation to anatomy, morphology, hodology, electrophysiology and gene expression, including differential expression of molecules supporting co-transmission of additional neurotransmitters. This diversity suggests that functionally heterogeneous subtypes of 5-HT neurons exist, but linking subsets of these neurons to particular functions has been technically challenging. We discuss recent data from molecular genetic, genomic and functional methods that, when coupled with classical findings, yield a reframing of the 5-HT neuronal system as a conglomeration of diverse subsystems with potential to inspire novel, more targeted therapies for clinically distinct 5-HT-related disorders.
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14
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Huang WS, Chen GJ, Tsai TH, Cheng CY, Shiue CY, Ma KH, Yeh SHH. In vivo long-lasting alterations of central serotonin transporter activity and associated dopamine synthesis after acute repeated administration of methamphetamine. EJNMMI Res 2019; 9:92. [PMID: 31535286 PMCID: PMC6751231 DOI: 10.1186/s13550-019-0557-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 08/23/2019] [Indexed: 11/22/2022] Open
Abstract
Background Methamphetamine (METH)-associated alterations in the striatal dopamine (DA) system or dopamine transport (DAT) have been identified in clinical and preclinical studies with positron emission tomography (PET) imaging but have not been well correlated with in vivo serotonin transporter (SERT) availability due to the lack of appropriate imaging agents to assess SERTs. N,N-dimethyl-2-(2-amino-4-[18F]-fluorophenylthio) benzylamine (4-[18F]-ADAM) has been developed by our group and validated for its high affinity and selectivity for SERTs, allowing the in vivo examination of SERT density, location, and binding function. The aims of this study were to investigate the potential of SERT imaging using 4-[18F]-ADAM PET to estimate the long-lasting effects of METH-induced serotonergic neurotoxicity, and further determine whether a correlative relationship exists between SERT availability/activity and tyrosine hydroxylase (TH) activity in various brain regions due to the long-lasting consequences of METH treatment. Results Male rats received four administrations of METH (5 or 10 mg/kg, s.c.) or saline (1 ml/kg, s.c.) at 1-h intervals. At 30 days post-administration, in vivo SERT availability and activity were measured by 4-[18F]ADAM PET imaging. In contrast to the controls, the uptake of 4-[18F]ADAM in METH-treated mice was significantly reduced in a dose-dependent manner in the midbrain, followed by the hypothalamus, thalamus, striatum, hippocampus, and frontal cortex. The regional effects of METH on TH activity were assessed by quantitative immunohistochemistry and presented as integrated optical density (IOD). A significant decrease in TH immunostaining and IOD ratios was seen in the caudate, putamen, nucleus accumbens, substantia nigra pars compacta, and substantia nigra pars reticulata in the METH-treated rats compared to controls. Conclusion The present results suggested that the long-lasting response to METH decreased the uptake of 4-[18F]-ADAM and varied regionally along with TH immunoreactivity. In addition, 4-[18F]ADAM PET could be used to detect serotonergic neuron loss and to evaluate the severity of serotonergic neurotoxicity of METH.
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Affiliation(s)
- Wen-Sheng Huang
- Department of Nuclear Medicine, Taipei Veterans General Hospital, No. 201, Sec. 2, Shipai Rd., Beitou District, Taipei City, 11217, Taiwan, Republic of China.,Nuclear Medicine Department, Tri-Service General Hospital, Taipei, Taiwan
| | - Guann-Juh Chen
- Department of Neurological Surgery, National Defense Medical Center, Tri-Service General Hospital, No. 325, Sec. 2, Chenggong Rd., Neihu District, Taipei City, 11490, Taiwan, Republic of China.,Department of Neurological Surgery, Chiayi Branch, Taichung Veterans General Hospital, No. 600, Sec. 2, Shixian Rd., West District, Chiayi City, 60090, Taiwan, Republic of China
| | - Tung-Han Tsai
- Department of Neurological Surgery, National Defense Medical Center, Tri-Service General Hospital, No. 325, Sec. 2, Chenggong Rd., Neihu District, Taipei City, 11490, Taiwan, Republic of China
| | - Chen-Yi Cheng
- Nuclear Medicine Department, Tri-Service General Hospital, Taipei, Taiwan
| | - Chyng-Yann Shiue
- Department of Nuclear Medicine, National Taiwan University Hospital, No. 1, Changde St., Zhongzheng District, Taipei City, 10048, Taiwan, Republic of China
| | - Kuo-Hsing Ma
- Department of Anatomy and Biology, National Defense Medical Center, No. 161, Sec. 6, Minquan E. Rd., Neihu District, Taipei City, 11490, Taiwan, Republic of China.
| | - Skye Hsin-Hsien Yeh
- Brain Research Center, National Yang-Ming University, No. 155, Sec. 2, Linong Street, Taipei City, 112, Taiwan, Republic of China.
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15
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Daut RA, Fonken LK. Circadian regulation of depression: A role for serotonin. Front Neuroendocrinol 2019; 54:100746. [PMID: 31002895 PMCID: PMC9826732 DOI: 10.1016/j.yfrne.2019.04.003] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 03/13/2019] [Accepted: 04/15/2019] [Indexed: 01/11/2023]
Abstract
Synchronizing circadian (24 h) rhythms in physiology and behavior with the environmental light-dark cycle is critical for maintaining optimal health. Dysregulation of the circadian system increases susceptibility to numerous pathological conditions including major depressive disorder. Stress is a common etiological factor in the development of depression and the circadian system is highly interconnected to stress-sensitive neurotransmitter systems such as the serotonin (5-hydroxytryptamine, 5-HT) system. Thus, here we propose that stress-induced perturbation of the 5-HT system disrupts circadian processes and increases susceptibility to depression. In this review, we first provide an overview of the basic components of the circadian system. Next, we discuss evidence that circadian dysfunction is associated with changes in mood in humans and rodent models. Finally, we provide evidence that 5-HT is a critical factor linking dysregulation of the circadian system and mood. Determining how these two systems interact may provide novel therapeutic targets for depression.
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Affiliation(s)
- Rachel A Daut
- Department of Psychology and Neuroscience, Center for Neuroscience, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Laura K Fonken
- University of Texas at Austin, Division of Pharmacology and Toxicology, Austin, TX 78712, USA.
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16
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Zhou X, Xiao Q, Xie L, Yang F, Wang L, Tu J. Astrocyte, a Promising Target for Mood Disorder Interventions. Front Mol Neurosci 2019; 12:136. [PMID: 31231189 PMCID: PMC6560156 DOI: 10.3389/fnmol.2019.00136] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 05/09/2019] [Indexed: 01/03/2023] Open
Abstract
Mood disorders have multiple phenotypes and complex underlying biological mechanisms and, as such, there are no effective therapeutic strategies. A review of recent work on the role of astrocytes in mood disorders is thus warranted, which we embark on here. We argue that there is tremendous potential for novel strategies for therapeutic interventions based on the role of astrocytes. Astrocytes are traditionally considered to have supporting roles within the brain, yet emerging evidence has shown that astrocytes have more direct roles in influencing brain function. Notably, evidence from postmortem human brain tissues has highlighted changes in glial cell morphology, density and astrocyte-related biomarkers and genes following mood disorders, indicating astrocyte involvement in mood disorders. Findings from animal models strongly imply that astrocytes not only change astrocyte morphology and physiological characteristics but also influence neural circuits via synapse structure and formation. This review pays particular attention to interactions between astrocytes and neurons and argues that astrocyte dysfunction affects the monoaminergic system, excitatory–inhibitory balance and neurotrophic states of local networks. Together, these studies provide a foundation of knowledge about the exact role of astrocytes in mood disorders. Importantly, we then change the focus from neurons to glial cells and the interactions between the two, so that we can understand newly proposed mechanisms underlying mood disorders, and to identify more diagnostic indicators or effective targets for treatment of these diseases.
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Affiliation(s)
- Xinyi Zhou
- Shenzhen Key Lab of Neuropsychiatric Modulation, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China.,Shenzhen College of Advanced Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Qian Xiao
- Shenzhen Key Lab of Neuropsychiatric Modulation, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China.,Shenzhen College of Advanced Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Li Xie
- Shenzhen Key Lab of Neuropsychiatric Modulation, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
| | - Fan Yang
- Shenzhen Key Lab of Neuropsychiatric Modulation, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
| | - Liping Wang
- Shenzhen Key Lab of Neuropsychiatric Modulation, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
| | - Jie Tu
- Shenzhen Key Lab of Neuropsychiatric Modulation, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China
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17
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Normann C, Frase S, Haug V, von Wolff G, Clark K, Münzer P, Dorner A, Scholliers J, Horn M, Vo Van T, Seifert G, Serchov T, Biber K, Nissen C, Klugbauer N, Bischofberger J. Antidepressants Rescue Stress-Induced Disruption of Synaptic Plasticity via Serotonin Transporter-Independent Inhibition of L-Type Calcium Channels. Biol Psychiatry 2018; 84:55-64. [PMID: 29174591 DOI: 10.1016/j.biopsych.2017.10.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 09/29/2017] [Accepted: 10/11/2017] [Indexed: 12/19/2022]
Abstract
BACKGROUND Long-term synaptic plasticity is a basic ability of the brain to dynamically adapt to external stimuli and regulate synaptic strength and ultimately network function. It is dysregulated by behavioral stress in animal models of depression and in humans with major depressive disorder. Antidepressants have been shown to restore disrupted synaptic plasticity in both animal models and humans; however, the underlying mechanism is unclear. METHODS We examined modulation of synaptic plasticity by selective serotonin reuptake inhibitors (SSRIs) in hippocampal brain slices from wild-type rats and serotonin transporter (SERT) knockout mice. Recombinant voltage-gated calcium (Ca2+) channels in heterologous expression systems were used to determine the modulation of Ca2+ channels by SSRIs. We tested the behavioral effects of SSRIs in the chronic behavioral despair model of depression both in the presence and in the absence of SERT. RESULTS SSRIs selectively inhibited hippocampal long-term depression. The inhibition of long-term depression by SSRIs was mediated by a direct block of voltage-activated L-type Ca2+ channels and was independent of SERT. Furthermore, SSRIs protected both wild-type and SERT knockout mice from behavioral despair induced by chronic stress. Finally, long-term depression was facilitated in animals subjected to the behavioral despair model, which was prevented by SSRI treatment. CONCLUSIONS These results showed that antidepressants protected synaptic plasticity and neuronal circuitry from the effects of stress via a modulation of Ca2+ channels and synaptic plasticity independent of SERT. Thus, L-type Ca2+ channels might constitute an important signaling hub for stress response and for pathophysiology and treatment of depression.
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Affiliation(s)
- Claus Normann
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany.
| | - Sibylle Frase
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Verena Haug
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Gregor von Wolff
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Kristin Clark
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Patrick Münzer
- Institute of Biology, University of Freiburg, Freiburg, Germany
| | - Alexandra Dorner
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Jonas Scholliers
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Max Horn
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Tanja Vo Van
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Gabriel Seifert
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Tsvetan Serchov
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Knut Biber
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Christoph Nissen
- Department of Psychiatry, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany
| | - Norbert Klugbauer
- Institute of Experimental and Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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18
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Matsui A, Alvarez VA. Cocaine Inhibition of Synaptic Transmission in the Ventral Pallidum Is Pathway-Specific and Mediated by Serotonin. Cell Rep 2018; 23:3852-3863. [PMID: 29949769 PMCID: PMC6101978 DOI: 10.1016/j.celrep.2018.05.076] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 04/09/2018] [Accepted: 05/22/2018] [Indexed: 01/10/2023] Open
Abstract
The ventral pallidum (VP) is part of the basal ganglia circuitry and a target of both direct and indirect pathway projections from the nucleus accumbens. VP is important in cocaine reinforcement, and the firing of VP neurons is modulated in vivo during cocaine self-administration. This modulation of firing is thought to be indirect via cocaine actions on dopamine in the accumbens. Here, we show that cocaine directly inhibits synaptic transmission evoked by selective stimulation of indirect pathway projections to VP neurons. The inhibition is independent of dopamine receptor activation, absent in 5-HT1B knockout mice, and mimicked by a serotonin transporter (SERT) blocker. SERT-expressing neurons in dorsal raphe project to the VP. Optogenetic stimulation of these projections evokes serotonin transients and effectively inhibits GABAergic transmission to VP neurons. This study shows that cocaine increases endogenous serotonin in the VP to suppress synaptic transmission selectively from indirect pathway projections to VP neurons.
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Affiliation(s)
- Aya Matsui
- Laboratory on Neurobiology of Compulsive Behaviors, Intramural Research Program, National Institute on Alcohol Abuse and Alcoholism (NIAAA-IRP), NIH, Bethesda, MD 20892, USA
| | - Veronica A Alvarez
- Laboratory on Neurobiology of Compulsive Behaviors, Intramural Research Program, National Institute on Alcohol Abuse and Alcoholism (NIAAA-IRP), NIH, Bethesda, MD 20892, USA; Intramural Research Program, National Institute on Drug Abuse (NIDA-IRP), Baltimore, MD 21224, USA; Center on Compulsive Behaviors, Intramural Research Program, NIH, Bethesda, MD 20892, USA.
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19
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Fritze S, Spanagel R, Noori HR. Adaptive dynamics of the 5-HT systems following chronic administration of selective serotonin reuptake inhibitors: a meta-analysis. J Neurochem 2017; 142:747-755. [PMID: 28653748 DOI: 10.1111/jnc.14114] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 06/20/2017] [Accepted: 06/20/2017] [Indexed: 02/05/2023]
Abstract
Selective serotonin reuptake inhibitors (SSRIs) are the most frequently prescribed antidepressants. However, a major concern is their delayed onset of action, which is hypothesized to be associated with the time required for serotonin (5-HT) autoreceptors to desensitize, which should be reflected by actual neurochemical changes. Numerous in vivo microdialysis studies have been published that report on 5-HT levels in different brain sites following SSRI administration. Here, we performed a meta-analysis on dynamic changes of 5-HT neurotransmission during the course of chronic SSRI treatment. We conducted a meta-analysis on research articles of 5-HT neurotransmission measured by in vivo microdialysis in rat brain after subchronic and chronic SSRI administrations. In total, data from 42 microdialysis studies (798 rats) were analyzed. Within the first week of SSRI treatment, extracellular 5-HT concentrations drop in frontal cortex. Over the next 2 weeks of treatment, a linear increase in extracellular 5-HT levels up to 350% of prior treatment baseline is evident (n = 269). However, in hippocampus, prefrontal cortex, nucleus accumbens, and ventral tegmental area we found increased 5-HT levels within the first 3 days of SSRI administration. The time course of 5-HT dynamics in frontal cortex is in line with the hypothesis that 5-HT autoreceptors desensitize over 2-3 weeks of SSRI treatment and thereby enhanced extracellular 5-HT levels ensue. Yet, in other regions we did not find evidence supporting the traditional autoreceptor-mediated feedback loops hypothesis and thus other neurobiological adaptation mechanisms may also play a role in the delayed onset of SSRI action.
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Affiliation(s)
- Stefan Fritze
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Rainer Spanagel
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Hamid R Noori
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.,Neuronal Convergence Group, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
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20
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Waider J, Ziegler J, Lau T. Outside the brain: an inside view on transgenic animal and stem cell-based models to examine neuronal serotonin-dependent regulation of HPA axis-controlled events during development and adult stages. Stem Cell Investig 2017; 3:94. [PMID: 28078274 DOI: 10.21037/sci.2016.11.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 11/08/2016] [Indexed: 11/06/2022]
Abstract
Recently, Trista North and colleagues showed that neuronal synthesis of serotonin is an essential key process for embryonic hematopoietic stem (HPS) cell production in zebrafish. Using their experimental design, they were able to show that neuronal serotonin activates the stress-responsive hypothalamic-pituitary-adrenal (HPA) axis and glucocorticoid receptor activity which in turn induces HPS cell formation. In our perspective, we give a short overview on established experimental approaches for serotonergic neurotransmission in vivo and in vitro and their potential to address putative contributions of serotonergic neurotransmission to physiological processes beyond the central nervous systems (CNS). We briefly introduce common features of brain serotonin-depleted, tryptophan hydroxylase-2 knockout mice, which can be applied to investigate the contribution of brain-derived serotonin to developmental and adult physiological processes outside the CNS. These models allow to analyzing gender-specific, HPA axis-dependent processes in female and male knockout mice during developmental and adult stages. We also highlight the application of human and mouse stem cell-derived serotonergic neurons as an independent research model as well as complementary experimental approach to transgenic animal models. In case of human serotonergic neurotransmission, human in vitro-generated neurons present a very promising and highly valuable experimental approach to address characteristics of human neuronal serotonin signaling on a molecular and cellular level. The combination of transgenic animal models and newly established stem cell technologies will provide powerful research platforms, which will help to answer yet unsolved mysteries of serotonergic neurotransmission.
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Affiliation(s)
- Jonas Waider
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Würzburg, Germany
| | - Janina Ziegler
- Central Institute of Mental Health, Hector Institute for Translational Brain Research, Medical Faculty Mannheim, University Heidelberg, Heidelberg, Germany
| | - Thorsten Lau
- Central Institute of Mental Health, Hector Institute for Translational Brain Research, Medical Faculty Mannheim, University Heidelberg, Heidelberg, Germany
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21
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Abstract
Mood, cognition, and many other physiological functions are modulated by the midbrain raphe serotonin (5- HT) system. By directing the magnitude and duration of postsynaptic receptor-mediated signaling, the 5-HT transporter (5-HTT) plays a crucial role in the integration of 5-HT neurotransmission. Considerable progress has been made in the molecular characterization of the 5-HTT, and research is currently focusing on the organization of 5-HTT gene (SLC6A4, OMIM accession number 182138), on the regulation of 5-HTT ex pression, on alterations in expression because of allelic variation in gene transcription, on structure-activity relationships of the 5-HTT protein, and on mechanisms of 5-HT and ion translocation. In the psychobiological dimension, it is becoming increasingly evident that inadequate adaptive responses to environmental stress ors, in conjunction with predisposing genes like the 5-HTT, contribute to the etiopathogenesis of behavioral and psychiatric disorders. A polymorphism in the regulatory region of the 5-HTT gene is associated with anxiety- and depression-related personality traits, and preliminary studies suggest that it influences the risk to develop affective disorders, alcohol dependence, and late-onset dementias. Finally, transgenic strategies are gaining momentum for the validation of the concept of the 5-HTT gene as a susceptibility locus for emotional instability (neuroticism) and psychiatric disorders. This approach addresses the pertinent question: to what extent does targeted disruption of the 5-HTT gene affect biochemistry, electrophysiology, and phar macology of the 5-HT system and modulate neural development and synaptic plasticity? It may also provide a model system that facilitates the dissection of successive events that lead to disease states as well as to the testing of novel therapeutic concepts. NEUROSCIENTIST 4:25-34, 1998
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22
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Linley SB, Olucha-Bordonau F, Vertes RP. Pattern of distribution of serotonergic fibers to the amygdala and extended amygdala in the rat. J Comp Neurol 2016; 525:116-139. [PMID: 27213991 DOI: 10.1002/cne.24044] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 03/03/2016] [Accepted: 05/20/2016] [Indexed: 02/01/2023]
Abstract
As is well recognized, serotonergic (5-HT) fibers distribute widely throughout the forebrain, including the amygdala. Although a few reports have examined the 5-HT innervation of select nuclei of the amygdala in the rat, no previous report has described overall 5-HT projections to the amygdala in the rat. Using immunostaining for the serotonin transporter, SERT, we describe the complete pattern of distribution of 5-HT fibers to the amygdala (proper) and to the extended amygdala in the rat. Based on its ontogenetic origins, the amygdala was subdivided into two major parts, pallial and subpallial components, with the pallial component further divided into superficial and deep nuclei (Olucha-Bordonau et al. 2015). SERT+ fibers were shown to distributed moderately to densely to the deep and cortical pallial nuclei, but, by contrast, lightly to the subpallial nuclei. Specifically, 1) of the deep pallial nuclei, the lateral, basolateral, and basomedial nuclei contained a very dense concentration of 5-HT fibers; 2) of the cortical pallial nuclei, the anterior cortical and amygdala-cortical transition zone rostrally and the posteromedial and posterolateral nuclei caudally contained a moderate concentration of 5-HT fibers; and 3) of the subpallial nuclei, the anterior nuclei and the rostral part of the medial (Me) nuclei contained a moderate concentration of 5-HT fibers, whereas caudal regions of Me as well as the central nuclei and the intercalated nuclei contained a sparse/light concentration of 5-HT fibers. With regard to the extended amygdala (primarily the bed nucleus of stria terminalis; BST), on the whole, the BST contained moderate numbers of 5-HT fibers, spread fairly uniformly throughout BST. The findings are discussed with respect to a critical serotonergic influence on the amygdala, particularly on the basal complex, and on the extended amygdala in the control of states of fear and anxiety. J. Comp. Neurol. 525:116-139, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Stephanie B Linley
- Department of Psychology, Florida Atlantic University, Boca Raton, Florida, 33431.,Center for Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, Florida, 33431
| | - Francisco Olucha-Bordonau
- Departamento de Medicina, Facultad de Ciencias de la Salud, Universitat Jaume I, 12071, Castellón, Spain
| | - Robert P Vertes
- Center for Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, Florida, 33431
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Abe K, Shimada R, Okada Y, Kibayashi K. Traumatic brain injury decreases serotonin transporter expression in the rat cerebrum. Neurol Res 2016; 38:358-63. [PMID: 27082144 DOI: 10.1080/01616412.2015.1110402] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
OBJECTIVES An association has been postulated between traumatic brain injury (TBI) and depression. The serotonin transporter (SERT) regulates the concentration of serotonin in the synaptic cleft and represents a molecular target for antidepressants. We hypothesized that SERT expression in the brain changes following TBI. METHODS We performed immunohistochemistry, real-time polymerase chain reaction analysis for mRNA and western blot analysis for protein to examine the time-dependent changes in SERT expression in the cerebrum during the first 14 days after TBI, using a controlled cortical impact model in rats. RESULTS SERT immunoreactivity in neuronal fibres within the area adjacent to the cortical contusion decreased 1 to 14 days after injury. Significantly decreased SERT mRNA and protein expression were noted in the area adjacent to the cortical contusion 7 days after injury. There were no significant changes in SERT expression in the cingulum of the injured brain. DISCUSSION The findings of this study indicate that TBI decreases SERT expression in the cerebral cortex. The decreased levels of SERT expression after TBI may result in decreased serotonin neurotransmission in the brain and indicate a possible relationship with depression following TBI.
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Affiliation(s)
- Keiichi Abe
- a Department of Neurosurgery , School of Medicine, Tokyo Women's Medical University , Tokyo , Japan
| | - Ryo Shimada
- b Department of Legal Medicine , School of Medicine, Tokyo Women's Medical University , Tokyo , Japan
| | - Yoshikazu Okada
- a Department of Neurosurgery , School of Medicine, Tokyo Women's Medical University , Tokyo , Japan
| | - Kazuhiko Kibayashi
- b Department of Legal Medicine , School of Medicine, Tokyo Women's Medical University , Tokyo , Japan
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Bocchio M, McHugh SB, Bannerman DM, Sharp T, Capogna M. Serotonin, Amygdala and Fear: Assembling the Puzzle. Front Neural Circuits 2016; 10:24. [PMID: 27092057 PMCID: PMC4820447 DOI: 10.3389/fncir.2016.00024] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 03/21/2016] [Indexed: 11/13/2022] Open
Abstract
The fear circuitry orchestrates defense mechanisms in response to environmental threats. This circuitry is evolutionarily crucial for survival, but its dysregulation is thought to play a major role in the pathophysiology of psychiatric conditions in humans. The amygdala is a key player in the processing of fear. This brain area is prominently modulated by the neurotransmitter serotonin (5-hydroxytryptamine, 5-HT). The 5-HT input to the amygdala has drawn particular interest because genetic and pharmacological alterations of the 5-HT transporter (5-HTT) affect amygdala activation in response to emotional stimuli. Nonetheless, the impact of 5-HT on fear processing remains poorly understood.The aim of this review is to elucidate the physiological role of 5-HT in fear learning via its action on the neuronal circuits of the amygdala. Since 5-HT release increases in the basolateral amygdala (BLA) during both fear memory acquisition and expression, we examine whether and how 5-HT neurons encode aversive stimuli and aversive cues. Next, we describe pharmacological and genetic alterations of 5-HT neurotransmission that, in both rodents and humans, lead to altered fear learning. To explore the mechanisms through which 5-HT could modulate conditioned fear, we focus on the rodent BLA. We propose that a circuit-based approach taking into account the localization of specific 5-HT receptors on neurochemically-defined neurons in the BLA may be essential to decipher the role of 5-HT in emotional behavior. In keeping with a 5-HT control of fear learning, we review electrophysiological data suggesting that 5-HT regulates synaptic plasticity, spike synchrony and theta oscillations in the BLA via actions on different subcellular compartments of principal neurons and distinct GABAergic interneuron populations. Finally, we discuss how recently developed optogenetic tools combined with electrophysiological recordings and behavior could progress the knowledge of the mechanisms underlying 5-HT modulation of fear learning via action on amygdala circuits. Such advancement could pave the way for a deeper understanding of 5-HT in emotional behavior in both health and disease.
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Affiliation(s)
- Marco Bocchio
- MRC Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford Oxford, UK
| | - Stephen B McHugh
- Department of Experimental Psychology, University of Oxford Oxford, UK
| | - David M Bannerman
- Department of Experimental Psychology, University of Oxford Oxford, UK
| | - Trevor Sharp
- Department of Pharmacology, University of Oxford Oxford, UK
| | - Marco Capogna
- MRC Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford Oxford, UK
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25
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Harding KM, Lonstein JS. Extensive juvenile “babysitting” facilitates later adult maternal responsiveness, decreases anxiety, and increases dorsal raphe tryptophan hydroxylase-2 expression in female laboratory rats. Dev Psychobiol 2016; 58:492-508. [DOI: 10.1002/dev.21392] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 12/03/2015] [Indexed: 12/26/2022]
Affiliation(s)
- Kaitlyn M. Harding
- Behavioral Neuroscience Program, Department of Psychology; Michigan State University; East Lansing MI 48824
| | - Joseph S. Lonstein
- Behavioral Neuroscience Program, Department of Psychology; Michigan State University; East Lansing MI 48824
- Neuroscience Program; Michigan State University; East Lansing MI 48824
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26
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Schloss P, Matthäus F, Lau T. Shine bright: considerations on the use of fluorescent substrates in living monoaminergic neurons in vitro. Neural Regen Res 2015; 10:1383-5. [PMID: 26604887 PMCID: PMC4625492 DOI: 10.4103/1673-5374.165223] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Affiliation(s)
- Patrick Schloss
- Biochemical Laboratory, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Germany
| | - Friederike Matthäus
- Biochemical Laboratory, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Germany
| | - Thorsten Lau
- Biochemical Laboratory, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Germany
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27
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Li IH, Ma KH, Kao TJ, Lin YY, Weng SJ, Yen TY, Chen LC, Huang YS. Involvement of autophagy upregulation in 3,4-methylenedioxymethamphetamine ('ecstasy')-induced serotonergic neurotoxicity. Neurotoxicology 2015; 52:114-26. [PMID: 26610922 DOI: 10.1016/j.neuro.2015.11.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 11/16/2015] [Accepted: 11/16/2015] [Indexed: 12/20/2022]
Abstract
It has been suggested that autophagy plays pathogenetic roles in cerebral ischemia, brain trauma, and neurodegenerative disorders. 3,4-Methylenedioxymethamphetamine (MDMA or ecstasy) is an illicit drug that causes long-term serotonergic neurotoxicity in the brain. Apoptosis and necrosis have been implicated in MDMA-induced neurotoxicity, but the role of autophagy in MDMA-elicited serotonergic toxicity has not been investigated. The present study aimed to examine the contribution of autophagy to neurotoxicity in serotonergic neurons in in vitro and in vivo animal models challenged with MDMA. Here, we demonstrated that in cultured rat serotonergic neurons, MDMA exposure induced LC3B-densely stained autophagosome formation, accompanying by a decrease in neurite outgrowth. Autophagy inhibitor 3-methyladenine (3-MA) significantly attenuated MDMA-induced autophagosome accumulation, and ameliorated MDMA-triggered serotonergic neurite damage and neuron death. In contrast, enhanced autophagy flux by rapamycin or impaired autophagosome clearance by bafilomycin A1 led to more autophagosome accumulation in serotonergic neurons and aggravated neurite degeneration. In addition, MDMA-induced autophagy activation in cultured serotonergic neurons might be mediated by serotonin transporter (SERT). In an in vivo animal model administered MDMA, neuroimaging showed that 3-MA protected the serotonin system against MDMA-induced downregulation of SERT evaluated by animal-PET with 4-[(18)F]-ADAM, a SERT radioligand. Taken together, our results demonstrated that MDMA triggers upregulation of autophagy in serotonergic neurons, which appears to be detrimental to neuronal growth.
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Affiliation(s)
- I-Hsun Li
- Department of Pharmacy Practice, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Kuo-Hsing Ma
- Department of Biology and Anatomy, National Defense Medical Center, Taipei, Taiwan
| | - Tzu-Jen Kao
- Graduate Institute of Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan; Center for Neurotrauma and Neuroregeneration, Taipei Medical University, Taipei, Taiwan
| | - Yang-Yi Lin
- Department of Biology and Anatomy, National Defense Medical Center, Taipei, Taiwan
| | - Shao-Ju Weng
- Department of Biology and Anatomy, National Defense Medical Center, Taipei, Taiwan
| | - Ting-Yin Yen
- Department of Biology and Anatomy, National Defense Medical Center, Taipei, Taiwan
| | - Lih-Chi Chen
- Department of Pharmacy, Taipei City Hospital, Taipei, Taiwan
| | - Yuahn-Sieh Huang
- Department of Biology and Anatomy, National Defense Medical Center, Taipei, Taiwan.
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28
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Stimpson CD, Barger N, Taglialatela JP, Gendron-Fitzpatrick A, Hof PR, Hopkins WD, Sherwood CC. Differential serotonergic innervation of the amygdala in bonobos and chimpanzees. Soc Cogn Affect Neurosci 2015; 11:413-22. [PMID: 26475872 DOI: 10.1093/scan/nsv128] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 10/07/2015] [Indexed: 01/18/2023] Open
Abstract
Humans' closest living relatives are bonobos (Pan paniscus) and chimpanzees (Pan troglodytes), yet these great ape species differ considerably from each other in terms of social behavior. Bonobos are more tolerant of conspecifics in competitive contexts and often use sexual behavior to mediate social interactions. Chimpanzees more frequently employ aggression during conflicts and actively patrol territories between communities. Regulation of emotional responses is facilitated by the amygdala, which also modulates social decision-making, memory and attention. Amygdala responsiveness is further regulated by the neurotransmitter serotonin. We hypothesized that the amygdala of bonobos and chimpanzees would differ in its neuroanatomical organization and serotonergic innervation. We measured volumes of regions and the length density of serotonin transporter-containing axons in the whole amygdala and its lateral, basal, accessory basal and central nuclei. Results showed that accessory basal nucleus volume was larger in chimpanzees than in bonobos. Of particular note, the amygdala of bonobos had more than twice the density of serotonergic axons than chimpanzees, with the most pronounced differences in the basal and central nuclei. These findings suggest that variation in serotonergic innervation of the amygdala may contribute to mediating the remarkable differences in social behavior exhibited by bonobos and chimpanzees.
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Affiliation(s)
- Cheryl D Stimpson
- Department of Anthropology, Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC 20052,
| | - Nicole Barger
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, CA 95616
| | - Jared P Taglialatela
- Department of Ecology, Evolution and Organismal Biology, Kennesaw State University, Kennesaw, GA 30144
| | | | - Patrick R Hof
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - William D Hopkins
- Neuroscience Institute and Language Research Center, Georgia State University, Atlanta, GA 30302, and Department of Developmental and Cognitive Neuroscience, Yerkes National Primate Research Center, Atlanta, GA 30322
| | - Chet C Sherwood
- Department of Anthropology, Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC 20052
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29
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Root DH, Melendez RI, Zaborszky L, Napier TC. The ventral pallidum: Subregion-specific functional anatomy and roles in motivated behaviors. Prog Neurobiol 2015; 130:29-70. [PMID: 25857550 PMCID: PMC4687907 DOI: 10.1016/j.pneurobio.2015.03.005] [Citation(s) in RCA: 229] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 03/19/2015] [Accepted: 03/29/2015] [Indexed: 12/17/2022]
Abstract
The ventral pallidum (VP) plays a critical role in the processing and execution of motivated behaviors. Yet this brain region is often overlooked in published discussions of the neurobiology of mental health (e.g., addiction, depression). This contributes to a gap in understanding the neurobiological mechanisms of psychiatric disorders. This review is presented to help bridge the gap by providing a resource for current knowledge of VP anatomy, projection patterns and subregional circuits, and how this organization relates to the function of VP neurons and ultimately behavior. For example, ventromedial (VPvm) and dorsolateral (VPdl) VP subregions receive projections from nucleus accumbens shell and core, respectively. Inhibitory GABAergic neurons of the VPvm project to mediodorsal thalamus, lateral hypothalamus, and ventral tegmental area, and this VP subregion helps discriminate the appropriate conditions to acquire natural rewards or drugs of abuse, consume preferred foods, and perform working memory tasks. GABAergic neurons of the VPdl project to subthalamic nucleus and substantia nigra pars reticulata, and this VP subregion is modulated by, and is necessary for, drug-seeking behavior. Additional circuits arise from nonGABAergic neuronal phenotypes that are likely to excite rather than inhibit their targets. These subregional and neuronal phenotypic circuits place the VP in a unique position to process motivationally relevant stimuli and coherent adaptive behaviors.
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Affiliation(s)
- David H Root
- Department of Psychology, Rutgers University, 152 Frelinghuysen Road, New Brunswick, NJ 08854, United States.
| | - Roberto I Melendez
- Department of Anatomy and Neurobiology, University of Puerto Rico School of Medicine, San Juan, PR 00936, United States.
| | - Laszlo Zaborszky
- Center for Molecular and Behavioral Neuroscience, Rutgers, The State University of New Jersey, 197 University Avenue, Newark, NJ 07102, United States.
| | - T Celeste Napier
- Departments of Pharmacology and Psychiatry, Center for Compulsive Behavior and Addiction, Rush University Medical Center, Chicago, IL 60612, United States.
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30
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Visualization of neurotransmitter uptake and release in serotonergic neurons. J Neurosci Methods 2015; 241:10-7. [DOI: 10.1016/j.jneumeth.2014.12.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 11/20/2014] [Accepted: 12/10/2014] [Indexed: 11/18/2022]
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31
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Gilbert ME, Ramos RL, McCloskey DP, Goodman JH. Subcortical band heterotopia in rat offspring following maternal hypothyroxinaemia: structural and functional characteristics. J Neuroendocrinol 2014; 26:528-41. [PMID: 24889016 DOI: 10.1111/jne.12169] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 05/19/2014] [Accepted: 05/28/2014] [Indexed: 01/22/2023]
Abstract
Thyroid hormones (TH) play crucial roles in brain maturation and are important for neuronal migration and neocortical lamination. Subcortical band heterotopia (SBH) represent a class of neuronal migration errors in humans that are often associated with childhood epilepsy. We have previously reported the presence of SBH in a rodent model of low level hypothyroidism induced by maternal exposure to the goitrogen, propylthiouracil (PTU). In the present study, we report the dose-response characteristics of this developmental malformation and the connectivity of heterotopic neurones with other brain regions, as well as their functionality. Pregnant rats were exposed to varying concentrations of PTU through the drinking water (0-10 p.p.m.) beginning on gestational day 6 to produce graded levels of TH insufficiency. Dose-dependent increases in the volume of the SBH present in the corpus callosum were documented in the adult offspring, with a clear presence at concentrations of PTU that resulted in minor (< 15%) reductions in maternal serum thyroxine as measured when pups were weaned. SBH contain neurones, oligodendrocytes, astrocytes and microglia. Monoaminergic and cholinergic processes were prevalent and many of the axons were myelinated. Anatomical connectivity of SBH neurones to cortical neurones and the synaptic functionality of these anatomical connections was verified by ex vivo field potential recordings. SBH persisted in adult offspring despite a return to euthyroid status on termination of exposure and these offspring displayed an increased sensitivity to seizures. Features of this model are attractive with respect to the investigation of the molecular mechanisms of cortical development, the effectiveness of therapeutic intervention in hypothyroxinaemia during pregnancy and the impact of the very modest TH imbalance that accompanies exposure to environmental contaminants.
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Affiliation(s)
- M E Gilbert
- Toxicity Assessment Division, Neurotoxicology Branch, US Environmental Protection Agency, Research Triangle Park, NC, USA
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32
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Brain SERT Expression of Male Rats Is Reduced by Aging and Increased by Testosterone Restitution. NEUROSCIENCE JOURNAL 2013; 2013:201909. [PMID: 26317087 PMCID: PMC4437264 DOI: 10.1155/2013/201909] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 11/23/2013] [Indexed: 11/28/2022]
Abstract
In preclinical and clinical studies aging has been associated with a deteriorated response to antidepressant treatment. We hypothesize that such impairment is explained by an age-related decrease in brain serotonin transporter (SERT) expression associated with low testosterone (T) levels. The objectives of this study were to establish (1) if brain SERT expression is reduced by aging and (2) if the SERT expression in middle-aged rats is increased by T-restitution. Intact young rats (3–5 months) and gonad-intact middle-aged rats with or without T-restitution were used. The identification of the brain SERT expression was done by immunofluorescence in prefrontal cortex, lateral septum, hippocampus, and raphe nuclei. An age-dependent reduction of SERT expression was observed in all brain regions examined, while T-restitution recovered the SERT expression only in the dorsal raphe of middle-aged rats. This last action seems relevant since dorsal raphe plays an important role in the antidepressant action of selective serotonin reuptake inhibitors. All data suggest that this mechanism accounts for the T-replacement usefulness to improve the response to antidepressants in the aged population.
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Wang H, Chen XY, Chen WF, Xue Y, Wei L, Chen L. Anticataleptic effects of 5-HT(1B) receptors in the globus pallidus. Neurosci Res 2013; 77:162-9. [PMID: 24045116 DOI: 10.1016/j.neures.2013.09.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Revised: 08/09/2013] [Accepted: 09/03/2013] [Indexed: 11/18/2022]
Abstract
The globus pallidus occupies an important position in the indirect pathway of the basal ganglia. Being a monoamine neurotransmitter, 5-HT is involved in mediating many physiological functions and pathophysiological processes in several movement disorders. Morphological studies have revealed that the globus pallidus receives serotonergic innervation arising from the raphe nuclei, mainly the dorsal raphe nucleus. A high level of 5-HT and 5-HT(1B) receptors were detected in the globus pallidus. In the present study, bilateral microinjection of 5-HT or 5-HT(1B) receptor agonist, CP-93129, into the globus pallidus significantly alleviated the symptoms of rigidity caused by haloperidol. To further elucidate 5-HT(1B) receptor-induced anticatalepsy, in vivo extracellular recordings were performed to examine the effects of 5-HT(1B) receptor activation on the firing activity of the globus pallidus neurons under the presence of haloperidol. Micro-pressure ejection of 5-HT or CP-93129 increased the spontaneous firing rate of the pallidal neurons. Furthermore, by using immunohistochemistry, positive staining of 5-HT(1B) receptor was observed in the globus pallidus neurons. Taken together, the present findings provide evidence that activation of 5-HT(1B) receptor may exert anticataleptic effects by increasing the activity of pallidal neurons.
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Affiliation(s)
- Hua Wang
- Department of Physiology, Qingdao University, Qingdao 266071, China; Department of Physiology, Binzhou Medical University, Yantai 264003, China
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Dam H, Mellerup ET, Plenge P, Winther R, Wörtwein G. The serotonin transporter and 5HT2A receptor in rat brain after localized lesions. Neurol Res 2013; 29:717-22. [PMID: 17711618 DOI: 10.1179/016164107x208059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES Post-stroke depression and depression after traumatic brain lesion are most often seen when the lesion includes frontal areas. The development of depression may include the serotonergic system because selective serotonin reuptake inhibitors (SSRIs) can be used to treat the depression. The purpose of the present study was to examine whether serotonin transporter density or 5HT2A serotonin receptor density is changed in specific brain areas following anterior or posterior lesions in the two hemispheres. METHODS Localized heat-induced brain lesions were induced in rats, and the densities of the serotonin transporter and 5HT2A receptor were measured by quantitative autoradiography in eight and 15 different brain areas, respectively. RESULTS A decrease in serotonin transporter density was detected in some frontal rat brain areas, and an increase in serotonin transporter density was detected in the right median raphe nucleus. No change was detected for 5HT2A receptor density.
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Affiliation(s)
- Henrik Dam
- Department of Psychiatry, H:S Rigshospitalet, Copenhagen, Denmark.
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35
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Kang HH, Wang CH, Chen HC, Li IH, Cheng CY, Liu RS, Huang WS, Shiue CY, Ma KH. Investigating the effects of noise-induced hearing loss on serotonin transporters in rat brain using 4-[18F]-ADAM/small animal PET. Neuroimage 2013; 75:262-269. [DOI: 10.1016/j.neuroimage.2012.06.049] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 06/08/2012] [Accepted: 06/26/2012] [Indexed: 01/10/2023] Open
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Ma S, Pawlak AP, Cho J, Root DH, Barker DJ, West MO. Amphetamine's dose-dependent effects on dorsolateral striatum sensorimotor neuron firing. Behav Brain Res 2013; 244:152-61. [PMID: 23396149 PMCID: PMC3603143 DOI: 10.1016/j.bbr.2013.01.044] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 01/25/2013] [Accepted: 01/29/2013] [Indexed: 11/18/2022]
Abstract
Amphetamine elicits motoric changes by increasing the activity of central neurotransmitters such as dopamine and serotonin, but how these neurochemical signals are transduced into motor commands is unclear. The dorsolateral striatum (DLS), a component of the cortico-subcortical reentrant motor loop, contains abundant neurotransmitter transporters that amphetamine could affect. It has been hypothesized that DLS medium spiny neurons contribute to amphetamine's motor effects. To study striatal activity contributing to amphetamine-induced movements, activity of DLS neurons related to vertical head movement was recorded while tracking head movements before and after acute amphetamine injection. Relative to saline, all amphetamine doses induced head movements above pre-injection levels, revealing an inverted U-shaped dose-response function. Lower doses (1 mg/kg and 2 mg/kg, intraperitoneal) induced a greater number of long (distance and duration) movements than the high dose (4 mg/kg), which induced stereotypy. Firing rates (FR) of individual head movement neurons were compared before and after injection during similar head movements, defined by direction, distance, duration, and apex. Changes in FR induced by amphetamine were co-determined by dose and pre-injection FR of the neuron. Specifically, all doses increased the FRs of slower firing neurons but decreased the FRs of faster firing neurons. The magnitudes of elevation or reduction were greater at lower doses, but less pronounced at the high dose, forming an inverted U function. Modulation of DLS firing may interfere with sensorimotor processing. Furthermore, pervasive elevation of slow firing neurons' FRs may feed-forward and increase excitability in thalamocortical premotor areas, contributing to the increased movement initiation rate.
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Affiliation(s)
- Sisi Ma
- Department of Psychology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, 08854, USA
| | - Anthony P. Pawlak
- Department of Psychology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, 08854, USA
| | - Jeiwon Cho
- Department of Psychology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, 08854, USA
| | - David H. Root
- Department of Psychology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, 08854, USA
| | - David J. Barker
- Department of Psychology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, 08854, USA
| | - Mark O. West
- Department of Psychology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, 08854, USA
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37
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Tuominen L, Salo J, Hirvonen J, Någren K, Laine P, Melartin T, Isometsä E, Viikari J, Cloninger CR, Raitakari O, Hietala J, Keltikangas-Järvinen L. Temperament, character and serotonin activity in the human brain: a positron emission tomography study based on a general population cohort. Psychol Med 2013; 43:881-894. [PMID: 22850434 DOI: 10.1017/s003329171200164x] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND The psychobiological model of personality by Cloninger and colleagues originally hypothesized that interindividual variability in the temperament dimension 'harm avoidance' (HA) is explained by differences in the activity of the brain serotonin system. We assessed brain serotonin transporter (5-HTT) density in vivo with positron emission tomography (PET) in healthy individuals with high or low HA scores using an 'oversampling' study design. Method Subjects consistently in either upper or lower quartiles for the HA trait were selected from a population-based cohort in Finland (n = 2075) with pre-existing Temperament and Character Inventory (TCI) scores. A total of 22 subjects free of psychiatric and somatic disorders were included in the matched high- and low-HA groups. The main outcome measure was regional 5-HTT binding potential (BPND) in high- and low-HA groups estimated with PET and [11C]N,N-dimethyl-2-(2-amino-4-methylphenylthio)benzylamine ([11C]MADAM). In secondary analyses, 5-HTT BPND was correlated with other TCI dimensions. RESULTS 5-HTT BPND did not differ between high- and low-HA groups in the midbrain or any other brain region. This result remained the same even after adjusting for other relevant TCI dimensions. Higher 5-HTT BPND in the raphe nucleus predicted higher scores in 'self-directedness'. CONCLUSIONS This study does not support an association between the temperament dimension HA and serotonin transporter density in healthy subjects. However, we found a link between high serotonin transporter density and high 'self-directedness' (ability to adapt and control one's behaviour to fit situations in accord with chosen goals and values). We suggest that biological factors are more important in explaining variability in character than previously thought.
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Affiliation(s)
- L Tuominen
- Department of Psychiatry, University of Turku, Turku, Finland
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Asan E, Steinke M, Lesch KP. Serotonergic innervation of the amygdala: targets, receptors, and implications for stress and anxiety. Histochem Cell Biol 2013; 139:785-813. [DOI: 10.1007/s00418-013-1081-1] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2013] [Indexed: 01/09/2023]
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Arrant AE, Jemal H, Kuhn CM. Adolescent male rats are less sensitive than adults to the anxiogenic and serotonin-releasing effects of fenfluramine. Neuropharmacology 2012; 65:213-22. [PMID: 23103347 DOI: 10.1016/j.neuropharm.2012.10.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 10/14/2012] [Accepted: 10/18/2012] [Indexed: 11/30/2022]
Abstract
Risk taking behavior increases during adolescence, which is also a critical period for the onset of drug abuse. The central serotonergic system matures during the adolescent period, and its immaturity during early adolescence may contribute to adolescent risk taking, as deficits in central serotonergic function have been associated with impulsivity, aggression, and risk taking. We investigated serotonergic modulation of behavior and presynaptic serotonergic function in adult (67-74 days old) and adolescent (28-34 days old) male rats. Fenfluramine (2 mg/kg, i.p.) produced greater anxiogenic effects in adult rats in both the light/dark and elevated plus maze tests for anxiety-like behavior, and stimulated greater increases in extracellular serotonin in the adult medial prefrontal cortex (mPFC) (1, 2.5, and 10 mg/kg, i.p.). Local infusion of 100 mM potassium chloride into the mPFC also stimulated greater serotonin efflux in adult rats. Adult rats had higher tissue serotonin content than adolescents in the prefrontal cortex, amygdala, and hippocampus, but the rate of serotonin synthesis was similar between age groups. Serotonin transporter (SERT) immunoreactivity and SERT radioligand binding were comparable between age groups in all three brain regions. These data suggest that lower tissue serotonin stores in adolescents limit fenfluramine-stimulated serotonin release and so contribute to the lesser anxiogenic effects of fenfluramine.
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Affiliation(s)
- Andrew E Arrant
- Department of Pharmacology & Cancer Biology, Duke University, Room 100B Research Park Building 2, Box 3813, Duke University Medical Center, Durham, NC 27710, USA
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Quelch DR, Parker CA, Nutt DJ, Tyacke RJ, Erritzoe D. Influence of different cellular environments on [(3)H]DASB radioligand binding. Synapse 2012; 66:1035-9. [PMID: 22927261 DOI: 10.1002/syn.21605] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 08/16/2012] [Indexed: 11/06/2022]
Affiliation(s)
- D R Quelch
- Neuropsychopharmacology Unit, Division of Experimental Medicine, Imperial College London, London W120NN, United Kingdom.
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41
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Wixey JA, Reinebrant HE, Buller KM. Evidence that the serotonin transporter does not shift into the cytosol of remaining neurons after neonatal brain injury. Neurosci Res 2012; 73:252-6. [DOI: 10.1016/j.neures.2012.04.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 04/03/2012] [Accepted: 04/05/2012] [Indexed: 10/28/2022]
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Lau T, Schloss P. Differential regulation of serotonin transporter cell surface expression. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/wmts.10] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Shinozaki G. The integrated model of serotonin transporter gene variation (5HTTLPR) and the glial cell transporter in stress vulnerability and depression. Med Hypotheses 2012; 78:410-4. [PMID: 22236459 DOI: 10.1016/j.mehy.2011.10.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 07/08/2011] [Accepted: 10/27/2011] [Indexed: 10/14/2022]
Abstract
The serotonin transporter gene (SLC6A4) promoter polymorphism (5HTTLPR) has been associated with individual stress responses such that individuals with childhood abuse history have higher rates of depression in later life if they are homozygous short (s/s) of the gene. It is hypothesized that these findings could be explained by an integrated model of a role of the glial cell transporter and a functional difference of 5HTTLPR in the capacity of absorbing serotonin from the synapse. A hypothetical integrated model of the SLC6A4 function and the role of glial cells are put forward to explain accumulating results of recent investigations exploring the relationship between the gene and the diverse mental activities including depression and stress response. A model based on SLC6A4 variation is proposed to explain individual differences in stress vulnerability/resilience. The role of the glial cell transporter surrounding the synapse is integrated in the model to understand the modulation of the neurotransmission. It is hypothesized that a synapse with less serotonin transporter contributes to unstable processing in neurotransmission as compared to a synapse with more serotonin transporter. As such, based on functional differences of 5HTTLPR in the expression of the serotonin transporter, it is asserted that individuals with the s/s genotype process neurotransmission differently and in a reactive way. This integrated model of 5HTTLPR and glial cells suggests that the efficacy of serotonin reuptake in the synapse may play a crucial role in variability of neurotransmission, which can lead to differences in the stress response and the pathophysiology of depression.
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Affiliation(s)
- Gen Shinozaki
- Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN, United States.
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Sager JJ, Torres GE. Proteins interacting with monoamine transporters: current state and future challenges. Biochemistry 2011; 50:7295-310. [PMID: 21797260 DOI: 10.1021/bi200405c] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Plasma membrane and vesicular transporters for the biogenic amines, dopamine, norepinephrine, and serotonin, represent a group of proteins that play a crucial role in the regulation of neurotransmission. Clinically, mono amine transporters are the primary targets for the actions of many therapeutic agents used to treat mood disorders, as well as the site of action for highly addictive psychostimulants such as cocaine, amphetamine, methamphetamine, and 3,4-methylenedioxymethamphetamine. Over the past decade, the use of approaches such as yeast two-hybrid and proteomics has identified a multitude of transporter interacting proteins, suggesting that the function and regulation of these transporters are more complex than previously anticipated. With the increasing number of interacting proteins, the rules dictating transporter synthesis, assembly, targeting, trafficking, and function are beginning to be deciphered. Although many of these protein interactions have yet to be fully characterized, current knowledge is beginning to shed light on novel transporter mechanisms involved in monoamine homeostasis, the molecular actions of psychostimulants, and potential disease mechanisms. While future studies resolving the spatial and temporal resolution of these, and yet unknown, interactions will be needed, the realization that monoamine transporters do not work alone opens the path to a plethora of possible pharmacological interventions.
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Affiliation(s)
- Jonathan J Sager
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, United States
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Larsen MB, Sonders MS, Mortensen OV, Larson GA, Zahniser NR, Amara SG. Dopamine transport by the serotonin transporter: a mechanistically distinct mode of substrate translocation. J Neurosci 2011; 31:6605-15. [PMID: 21525301 PMCID: PMC3107525 DOI: 10.1523/jneurosci.0576-11.2011] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 03/04/2011] [Accepted: 03/10/2011] [Indexed: 01/23/2023] Open
Abstract
The serotonin transporter (SERT) is the principal mechanism for terminating serotonin (5-HT) signals in the nervous system and is a site of action for a variety of psychoactive drugs including antidepressants, amphetamines, and cocaine. Here we show that human SERTs (hSERTs) and rat SERTs are capable of robust dopamine (DA) uptake through a process that differs mechanistically from 5-HT transport in several unanticipated ways. DA transport by hSERT has a higher maximum velocity than 5-HT transport, requires significantly higher Na(+) and Cl(-) concentrations to sustain transport, is inhibited noncompetitively by 5-HT, and is more sensitive to SERT inhibitors, including selective serotonin reuptake inhibitors. We use a thiol-reactive methane thiosulfonate (MTS) reagent to modify a conformationally sensitive cysteine residue to demonstrate that hSERT spends more time in an outward facing conformation when transporting DA than when transporting 5-HT. Cotransfection of an inactive or an MTS-sensitive SERT with wild-type SERT subunits reveals an absence of cooperative interactions between subunits during DA but not 5-HT transport. To establish the physiological relevance of this mechanism for DA clearance, we show using in vivo high-speed chronoamperometry that SERT has the capacity to clear extracellularly applied DA in the hippocampal CA3 region of anesthetized rats. Together, these observations suggest the possibility that SERT serves as a DA transporter in vivo and highlight the idea that there can be distinct modes of transport of alternative physiological substrates by SERT.
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Affiliation(s)
- Mads Breum Larsen
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
| | - Mark S. Sonders
- Center for Molecular Recognition, Columbia University and New York State Psychiatric Institute, New York, New York 10032, and
| | - Ole Valente Mortensen
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
| | - Gaynor A. Larson
- Department of Pharmacology, University of Colorado Denver, Aurora, Colorado 80045
| | - Nancy R. Zahniser
- Department of Pharmacology, University of Colorado Denver, Aurora, Colorado 80045
| | - Susan G. Amara
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
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Inhibition of Neuroinflammation Prevents Injury to the Serotonergic Network After Hypoxia-Ischemia in the Immature Rat Brain. J Neuropathol Exp Neurol 2011; 70:23-35. [DOI: 10.1097/nen.0b013e3182020b7b] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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47
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Hagan CE, Neumaier JF, Schenk JO. Rotating disk electrode voltammetric measurements of serotonin transporter kinetics in synaptosomes. J Neurosci Methods 2010; 193:29-38. [PMID: 20713085 PMCID: PMC2952731 DOI: 10.1016/j.jneumeth.2010.08.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 08/06/2010] [Accepted: 08/06/2010] [Indexed: 12/13/2022]
Abstract
Altered serotonin (5-HT) signaling is implicated in several neuropsychiatric disorders, including depression, anxiety, obsessive-compulsive disorder, and autism. The 5-HT transporter (SERT) modulates 5-HT neurotransmission strength and duration. This is the first study using rotating disk electrode voltammetry (RDEV) to measure 5-HT clearance. SERT kinetics were measured in whole brain synaptosomes. Uptake kinetics of exogenous 5-HT were measured using glassy carbon electrodes rotated in 500 μL glass chambers containing synaptosomes from SERT-knockout (-/-), heterozygous (+/-), or wild-type (+/+) mice. RDEV detected 5-HT concentrations of 5nM and higher. Initial velocities were kinetically resolved with K(m) and V(max) values of 99±35 standard error of regression (SER) nM and 181±11 SER fmol/(s×mg protein), respectively in wild-type synaptosomes. The method enables control over drug and chemical concentrations, facilitating interpretation of results. Results are compared in detail to other techniques used to measure SERT kinetics, including tritium labeled assays, chronoamperometry, and fast scan cyclic voltammetry. RDEV exhibits decreased 5-HT detection limits, decreased vulnerability to 5-HT oxidation products that reduce electrode sensitivity, and also overcomes diffusion limitations via forced convection by providing a continuous, kinetically resolved signal. Finally, RDEV distinguishes functional differences between genotypes, notably, between wild-type and heterozygous mice, an experimental problem with other experimental approaches.
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Affiliation(s)
- Catherine E Hagan
- Department of Comparative Medicine, University of Washington, Seattle, WA 98195, USA.
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48
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Vertes RP, Linley SB, Hoover WB. Pattern of distribution of serotonergic fibers to the thalamus of the rat. Brain Struct Funct 2010; 215:1-28. [PMID: 20390296 DOI: 10.1007/s00429-010-0249-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2009] [Accepted: 03/16/2010] [Indexed: 11/26/2022]
Abstract
It is well established that serotonergic (5-hydroxytryptamine, 5-HT) fibers, mainly originating from the dorsal and median raphe nuclei of the brainstem, distribute throughout the forebrain, most heavily to 'limbic' forebrain structures. Few reports have examined the distribution of 5-HT fibers to the thalamus and none to our knowledge using immunoprocedures for the detection of the serotonin transporter (SERT)-a very sensitive marker for 5-HT fibers. Using immunohistochemical methods for SERT, we examined the pattern of distribution of 5-HT fibers to the thalamus in the rat. We show that serotonergic fibers are heavily concentrated in midline, intralaminar and association nuclei of the thalamus, and with the exception of the lateral geniculate complex, weakly distributed to principal nuclei of thalamus. Specifically, we demonstrate that 5-HT fibers are densely concentrated in the anteroventral, anteromedial and interanteromedial nuclei of the anterior thalamus, the paraventricular, rhomboid and reuniens nuclei of the midline thalamus, the central medial and central lateral nuclei of the intralaminar thalamus, the intermediodorsal nucleus, the lateral dorsal nucleus, and the dorsal and ventral lateral geniculate nuclei and intergeniculate leaflet of the LGN complex. Less densely innervated sites include the mediodorsal, paracentral, parafascicular, lateral posterior and submedial nuclei of thalamus. Remaining regions of the thalamus, largely consisting of principal nuclei, contained few 5-HT fibers. This pattern of 5-HT innervation indicates that serotonin/ serotonergic fibers mainly affect thalamic nuclei with connections to 'non-principal' or limbic regions of the cortex (or forebrain). This suggests that serotonergic fibers to the thalamus may exert a significant influence on affective and cognitive functions, possibly complementing the actions of 5-HT fibers to other parts of the brain involved in emotional and cognitive behaviors.
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Affiliation(s)
- Robert P Vertes
- Center for Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA.
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50
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Kittler K, Lau T, Schloss P. Antagonists and substrates differentially regulate serotonin transporter cell surface expression in serotonergic neurons. Eur J Pharmacol 2009; 629:63-7. [PMID: 20006597 DOI: 10.1016/j.ejphar.2009.12.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 11/19/2009] [Accepted: 12/07/2009] [Indexed: 10/20/2022]
Abstract
The serotonin transporter (SERT) terminates serotonergic neurotransmission by the rapid removal of serotonin (5-hydroxytryptamine, 5-HT) from the extracellular space back into serotonergic neurons. SERT therefore controls the concentration of extracellular 5-HT, and thus one mechanism to regulate the efficacy of serotonergic neurotransmission is via modulation of the density of SERT molecules on the cell membrane. We have studied the effects of prolonged exposure to various selective serotonin re-uptake inhibitors (SSRIs), as well as cocaine and the transport substrates 5-HT and 3,4-methylenedioxy-methamphetamine (MDMA), on SERT cell surface expression in cultured serotonergic neurons. This was achieved via quantification of the amount of cell surface-expressed SERT molecules using antibody detection combined with confocal laser scanning microscopy. Our results show that exposure to the SSRIs citalopram, fluoxetine, sertraline and paroxetine all induced SERT internalization, but with different efficacies. The substrates 5-HT and MDMA also induced SERT internalization, while cocaine elevated SERT cell surface expression.
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Affiliation(s)
- Katharina Kittler
- Biochemical Laboratory, Central Institute of Mental Health, J5, 68159 Mannheim, Germany
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