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Olivier JDA, Vinkers CH, Olivier B. The role of the serotonergic and GABA system in translational approaches in drug discovery for anxiety disorders. Front Pharmacol 2013; 4:74. [PMID: 23781201 PMCID: PMC3677985 DOI: 10.3389/fphar.2013.00074] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 05/21/2013] [Indexed: 12/13/2022] Open
Abstract
There is ample evidence that genetic factors play an important role in anxiety disorders. In support, human genome-wide association studies have implicated several novel candidate genes. However, illumination of such genetic factors involved in anxiety disorders has not resulted in novel drugs over the past decades. A complicating factor is the heterogeneous classification of anxiety disorders in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) and diverging operationalization of anxiety used in preclinical and clinical studies. Currently, there is an increasing focus on the gene × environment (G × E) interaction in anxiety as genes do not operate in isolation and environmental factors have been found to significantly contribute to the development of anxiety disorders in at-risk individuals. Nevertheless, extensive research on G × E mechanisms in anxiety has not resulted in major breakthroughs in drug discovery. Modification of individual genes in rodent models has enabled the specific study of anxiety in preclinical studies. In this context, two extensively studied neurotransmitters involved in anxiety are the gamma-aminobutyric acid (GABA) and 5-HT (5-hydroxytryptamine) system. In this review, we illustrate the complex interplay between genes and environment in anxiety processes by reviewing preclinical and clinical studies on the serotonin transporter (5-HTT), 5-HT1A receptor, 5-HT2 receptor, and GABAA receptor. Even though targets from the serotonin and GABA system have yielded drugs with known anxiolytic efficacy, the relation between the genetic background of these targets and anxiety symptoms and development of anxiety disorders is largely unknown. The aim of this review is to show the vast complexity of genetic and environmental factors in anxiety disorders. In light of the difficulty with which common genetic variants are identified in anxiety disorders, animal models with translational validity may aid in elucidating the neurobiological background of these genes and their possible role in anxiety. We argue that, in addition to human genetic studies, translational models are essential to map anxiety-related genes and to enhance our understanding of anxiety disorders in order to develop potentially novel treatment strategies.
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Affiliation(s)
- Jocelien D A Olivier
- Department of, Women's and Children's Health, Uppsala University Uppsala, Sweden ; Center for Gender Medicine, Karolinska Institutet Stockholm, Sweden
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102
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Central nervous system effects of prenatal selective serotonin reuptake inhibitors: sensing the signal through the noise. Psychopharmacology (Berl) 2013; 227:567-82. [PMID: 23681158 PMCID: PMC3838633 DOI: 10.1007/s00213-013-3115-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 04/10/2013] [Indexed: 10/26/2022]
Abstract
RATIONALE Women are increasingly prescribed selective serotonin reuptake inhibitors (SSRIs) during pregnancy, with potential implications for neurodevelopment. Whether prenatal SSRI exposure has an effect on neurodevelopment and behavior in the offspring is an important area of investigation. OBJECTIVES The aim of this paper was to review the existing preclinical and clinical literature of prenatal SSRI exposure on serotonin-related behaviors and markers in the offspring. The goal is to determine if there is a signal in the literature that could guide clinical care and/or inform research. RESULTS Preclinical studies (n = 4) showed SSRI exposure during development enhanced depression-like behavior. Half of rodent studies examining anxiety-like behavior (n = 13) noted adverse effects with SSRI exposure. A majority of studies of social behavior (n = 4) noted a decrease in sociability in SSRI exposed offspring. Human studies (n = 4) examining anxiety in the offspring showed no adverse effects of prenatal SSRI exposure. The outcome of one study suggested that children with autism were more likely to have a mother who was prescribed an SSRI during pregnancy. CONCLUSIONS Preclinical findings in rodents exposed to SSRIs during development point to an increase in depression- and anxiety-like behavior and alteration in social behaviors in the offspring, though both the methods used and the findings were not uniform. These data are not robust enough to discourage use of SSRIs during human pregnancy, particularly given the known adverse effects of maternal mental illness on pregnancy outcomes and infant neurodevelopment. Future research should focus on consistent animal models and prospective human studies with larger samples.
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103
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Olivier JDA, Akerud H, Kaihola H, Pawluski JL, Skalkidou A, Högberg U, Sundström-Poromaa I. The effects of maternal depression and maternal selective serotonin reuptake inhibitor exposure on offspring. Front Cell Neurosci 2013; 7:73. [PMID: 23734100 PMCID: PMC3659337 DOI: 10.3389/fncel.2013.00073] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 05/01/2013] [Indexed: 01/05/2023] Open
Abstract
It has been estimated that 20% of pregnant women suffer from depression and it is well-documented that maternal depression can have long-lasting effects on the child. Currently, common treatment for maternal depression has been the selective serotonin reuptake inhibitor medications (SSRIs) which are used by 2–3% of pregnant women in the Nordic countries and by up to 10% of pregnant women in the United States. Antidepressants cross the placenta and are transferred to the fetus, thus, the question arises as to whether children of women taking antidepressants are at risk for altered neurodevelopmental outcomes and, if so, whether the risks are due to SSRI medication exposure or to the underlying maternal depression. This review considers the effects of maternal depression and SSRI exposure on offspring development in both clinical and preclinical populations. As it is impossible in humans to study the effects of SSRIs without taking into account the possible underlying effects of maternal depression (healthy pregnant women do not take SSRIs), animal models are of great value. For example, rodents can be used to determine the effects of maternal depression and/or perinatal SSRI exposure on offspring outcomes. Unraveling the joint (or separate) effects of maternal depression and SSRI exposure will provide more insights into the risks or benefits of SSRI exposure during gestation and will help women make informed decisions about using SSRIs during pregnancy.
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Affiliation(s)
- J D A Olivier
- Department of Women's and Children's Health, Uppsala University Uppsala, Sweden ; Center for Gender Medicine, Karolinska Institutet Stockholm, Sweden
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104
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Hoffman KL. Role of murine models in psychiatric illness drug discovery: a dimensional view. Expert Opin Drug Discov 2013; 8:865-77. [DOI: 10.1517/17460441.2013.797959] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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105
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Stewart AM, Cachat J, Gaikwad S, Robinson KS, Gebhardt M, Kalueff AV. Perspectives on experimental models of serotonin syndrome in zebrafish. Neurochem Int 2013; 62:893-902. [DOI: 10.1016/j.neuint.2013.02.018] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Revised: 02/10/2013] [Accepted: 02/14/2013] [Indexed: 01/07/2023]
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106
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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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107
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Gallagher JJ, Zhang X, Hall FS, Uhl GR, Bearer EL, Jacobs RE. Altered reward circuitry in the norepinephrine transporter knockout mouse. PLoS One 2013; 8:e57597. [PMID: 23469209 PMCID: PMC3587643 DOI: 10.1371/journal.pone.0057597] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 01/22/2013] [Indexed: 01/08/2023] Open
Abstract
Synaptic levels of the monoamine neurotransmitters dopamine, serotonin, and norepinephrine are modulated by their respective plasma membrane transporters, albeit with a few exceptions. Monoamine transporters remove monoamines from the synaptic cleft and thus influence the degree and duration of signaling. Abnormal concentrations of these neuronal transmitters are implicated in a number of neurological and psychiatric disorders, including addiction, depression, and attention deficit/hyperactivity disorder. This work concentrates on the norepinephrine transporter (NET), using a battery of in vivo magnetic resonance imaging techniques and histological correlates to probe the effects of genetic deletion of the norepinephrine transporter on brain metabolism, anatomy and functional connectivity. MRS recorded in the striatum of NET knockout mice indicated a lower concentration of NAA that correlates with histological observations of subtle dysmorphisms in the striatum and internal capsule. As with DAT and SERT knockout mice, we detected minimal structural alterations in NET knockout mice by tensor-based morphometric analysis. In contrast, longitudinal imaging after stereotaxic prefrontal cortical injection of manganese, an established neuronal circuitry tracer, revealed that the reward circuit in the NET knockout mouse is biased toward anterior portions of the brain. This is similar to previous results observed for the dopamine transporter (DAT) knockout mouse, but dissimilar from work with serotonin transporter (SERT) knockout mice where Mn2+ tracings extended to more posterior structures than in wildtype animals. These observations correlate with behavioral studies indicating that SERT knockout mice display anxiety-like phenotypes, while NET knockouts and to a lesser extent DAT knockout mice display antidepressant-like phenotypic features. Thus, the mainly anterior activity detected with manganese-enhanced MRI in the DAT and NET knockout mice is likely indicative of more robust connectivity in the frontal portion of the reward circuit of the DAT and NET knockout mice compared to the SERT knockout mice.
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Affiliation(s)
- Joseph J. Gallagher
- Biological Imaging Center, Beckman Institute, California Institute of Technology, Pasadena, California, United States of America
| | - Xiaowei Zhang
- Biological Imaging Center, Beckman Institute, California Institute of Technology, Pasadena, California, United States of America
| | - F. Scott Hall
- Molecular Neurobiology Branch, National Institute on Drug Abuse, Intramural Research Program, Baltimore, Maryland, United States of America
| | - George R. Uhl
- Molecular Neurobiology Branch, National Institute on Drug Abuse, Intramural Research Program, Baltimore, Maryland, United States of America
| | - Elaine L. Bearer
- Biological Imaging Center, Beckman Institute, California Institute of Technology, Pasadena, California, United States of America
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States of America
| | - Russell E. Jacobs
- Biological Imaging Center, Beckman Institute, California Institute of Technology, Pasadena, California, United States of America
- * E-mail:
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108
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van der Marel K, Homberg JR, Otte WM, Dijkhuizen RM. Functional and structural neural network characterization of serotonin transporter knockout rats. PLoS One 2013; 8:e57780. [PMID: 23451267 PMCID: PMC3581479 DOI: 10.1371/journal.pone.0057780] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 01/29/2013] [Indexed: 12/20/2022] Open
Abstract
Brain serotonin homeostasis is crucially maintained by the serotonin transporter (5-HTT), and its down-regulation has been linked to increased vulnerability for anxiety- and depression-related behavior. Studies in 5-HTT knockout (5-HTT-/-) rodents have associated inherited reduced functional expression of 5-HTT with increased sensitivity to adverse as well as rewarding environmental stimuli, and in particular cocaine hyperresponsivity. 5-HTT down-regulation may affect normal neuronal wiring of implicated corticolimbic cerebral structures. To further our understanding of its contribution to potential alterations in basal functional and structural properties of neural network configurations, we applied resting-state functional MRI (fMRI), pharmacological MRI of cocaine-induced activation, and diffusion tensor imaging (DTI) in 5-HTT-/- rats and wild-type controls (5-HTT+/+). We found that baseline functional connectivity values and cocaine-induced neural activity within the corticolimbic network was not significantly altered in 5-HTT-/- versus 5-HTT+/+ rats. Similarly, DTI revealed mostly intact white matter structural integrity, except for a reduced fractional anisotropy in the genu of the corpus callosum of 5-HTT-/- rats. At the macroscopic level, analyses of complex graphs constructed from either functional connectivity values or structural DTI-based tractography results revealed that key properties of brain network organization were essentially similar between 5-HTT+/+ and 5-HTT-/- rats. The individual tests for differences between 5-HTT+/+ and 5-HTT-/- rats were capable of detecting significant effects ranging from 5.8% (fractional anisotropy) to 26.1% (pharmacological MRI) and 29.3% (functional connectivity). Tentatively, lower fractional anisotropy in the genu of the corpus callosum could indicate a reduced capacity for information integration across hemispheres in 5-HTT-/- rats. Overall, the comparison of 5-HTT-/- and wild-type rats suggests mostly limited effects of 5-HTT genotype on MRI-based measures of brain morphology and function.
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Affiliation(s)
- Kajo van der Marel
- Biomedical MR Imaging and Spectroscopy Group, Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands.
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109
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Altieri SC, Garcia-Garcia AL, Leonardo ED, Andrews AM. Rethinking 5-HT1A receptors: emerging modes of inhibitory feedback of relevance to emotion-related behavior. ACS Chem Neurosci 2013; 4:72-83. [PMID: 23336046 DOI: 10.1021/cn3002174] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 12/20/2012] [Indexed: 11/27/2022] Open
Abstract
The complexities of the involvement of the serotonin transmitter system in numerous biological processes and psychiatric disorders is, to a substantial degree, attributable to the large number of serotonin receptor families and subtypes that have been identified and characterized for over four decades. Of these, the 5-HT(1A) receptor subtype, which was the first to be cloned and characterized, has received considerable attention based on its purported role in the etiology and treatment of mood and anxiety disorders. 5-HT(1A) receptors function both at presynaptic (autoreceptor) and postsynaptic (heteroreceptor) sites. Recent research has implicated distinct roles for these two populations of receptors in mediating emotion-related behavior. New concepts as to how 5-HT(1A) receptors function to control serotonergic tone throughout life were highlights of the proceedings of the 2012 Serotonin Club Meeting in Montpellier, France. Here, we review recent findings and current perspectives on functional aspects of 5-HT(1A) auto- and heteroreceptors with particular regard to their involvement in altered anxiety and mood states.
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Affiliation(s)
| | - Alvaro L. Garcia-Garcia
- Department of Psychiatry, Division of Integrative Neuroscience, Columbia University and New York State Psychiatric Institute, New York, New York 10032, United States
| | - E. David Leonardo
- Department of Psychiatry, Division of Integrative Neuroscience, Columbia University and New York State Psychiatric Institute, New York, New York 10032, United States
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110
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Heiming RS, Mönning A, Jansen F, Kloke V, Lesch KP, Sachser N. To attack, or not to attack? The role of serotonin transporter genotype in the display of maternal aggression. Behav Brain Res 2013; 242:135-41. [PMID: 23291155 DOI: 10.1016/j.bbr.2012.12.045] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 12/20/2012] [Accepted: 12/24/2012] [Indexed: 11/26/2022]
Abstract
Aggressive behavior in males has been intensively investigated regarding the influence of the brain serotonergic system. Despite some inconsistencies, a general conclusion is that low levels of serotonin (5-HT) are associated with high levels of male aggression. The role of the serotonergic system for female aggression is less well researched. Female mice rarely show intraspecific aggressive behavior, except during lactation, when they may exhibit intense aggression towards intruders to protect their pups. The aim of the present study was to investigate the impact of 5-HT transporter (5-HTT) inactivation on maternal aggression in mice. Therefore, lactating homozygous and heterozygous 5-HTT knockout as well as wildtype mice were confronted with male intruders in their home cages. Homozygous 5-HTT knockout dams, which exhibit highest levels of extracellular 5-HT in the brain, were significantly less prone to initiate offensive aggression than wildtype controls. Moreover, they showed longer latencies to attack the intruder, attacked less often and displayed an overall lower frequency of offensive aggressive behavior patterns than wildtype dams. Heterozygous 5-HTT knockout mothers generally showed intermediate levels of aggressive behavior. Thus, our data indicate that higher extracellular including synaptic levels of 5-HT are associated with lower intensity of aggressive behavior in lactating mice, adding support to the inhibitory role of 5-HT in aggression also in females.
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Affiliation(s)
- Rebecca S Heiming
- Department of Behavioural Biology, University of Münster, Germany; Otto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, University of Münster, Germany.
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111
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Zoratto F, Fiore M, Ali SF, Laviola G, Macrì S. Neonatal tryptophan depletion and corticosterone supplementation modify emotional responses in adult male mice. Psychoneuroendocrinology 2013; 38:24-39. [PMID: 22613034 DOI: 10.1016/j.psyneuen.2012.04.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 04/26/2012] [Accepted: 04/29/2012] [Indexed: 11/15/2022]
Abstract
The serotonergic system and the hypothalamic-pituitary-adrenal (HPA) axis are crucially involved in the regulation of emotions. Specifically, spontaneous and/or environmentally mediated modulations of the functionality of these systems early in development may favour the onset of depressive- and anxiety-related phenotypes. While the independent contribution of each of these systems to the emergence of abnormal phenotypes has been detailed in clinical and experimental studies, only rarely has their interaction been systematically investigated. Here, we addressed the effects of reduced serotonin and environmental stress during the early stages of postnatal life on emotional regulations in mice. To this aim, we administered, to outbred CD1 mouse dams, during their first week of lactation, a tryptophan deficient diet (T) and corticosterone via drinking water (C; 80μg/ml). Four groups of dams (animal facility rearing, AFR; T treated, T; C treated, C; T and C treated, TC) and their male offspring were used in the study. Maternal care was scored throughout treatment and adult offspring were tested for: anhedonia (progressive ratio schedule); anxiety-related behaviour (approach-avoidance conflict paradigm); BDNF, dopamine and serotonin concentrations in selected brain areas. T, C and TC treatments reduced active maternal care compared to AFR. Adult TC offspring showed significantly increased anxiety- and anhedonia-related behaviours, reduced striatal and increased hypothalamic BDNF and reduced dopamine and serotonin in the prefrontal cortex and their turnover in the hippocampus. Thus, present findings support the view that neonatal variations in the functionality of the serotonergic system and of HPA axis may jointly contribute to induce emotional disturbances in adulthood.
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Affiliation(s)
- Francesca Zoratto
- Section of Behavioural Neuroscience, Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Rome, Italy
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112
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Homberg JR. Measuring behaviour in rodents: Towards translational neuropsychiatric research. Behav Brain Res 2013; 236:295-306. [DOI: 10.1016/j.bbr.2012.09.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 08/31/2012] [Accepted: 09/05/2012] [Indexed: 11/30/2022]
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113
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Homberg JR, van den Hove DL. The serotonin transporter gene and functional and pathological adaptation to environmental variation across the life span. Prog Neurobiol 2012; 99:117-27. [DOI: 10.1016/j.pneurobio.2012.08.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 08/03/2012] [Accepted: 08/07/2012] [Indexed: 11/24/2022]
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114
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Weikum WM, Oberlander TF, Hensch TK, Werker JF. Prenatal exposure to antidepressants and depressed maternal mood alter trajectory of infant speech perception. Proc Natl Acad Sci U S A 2012; 109 Suppl 2:17221-7. [PMID: 23045665 PMCID: PMC3477387 DOI: 10.1073/pnas.1121263109] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Language acquisition reflects a complex interplay between biology and early experience. Psychotropic medication exposure has been shown to alter neural plasticity and shift sensitive periods in perceptual development. Notably, serotonin reuptake inhibitors (SRIs) are antidepressant agents increasingly prescribed to manage antenatal mood disorders, and depressed maternal mood per se during pregnancy impacts infant behavior, also raising concerns about long-term consequences following such developmental exposure. We studied whether infants' language development is altered by prenatal exposure to SRIs and whether such effects differ from exposure to maternal mood disturbances. Infants from non-SRI-treated mothers with little or no depression (control), depressed but non-SRI-treated (depressed-only), and depressed and treated with an SRI (SRI-exposed) were studied at 36 wk gestation (while still in utero) on a consonant and vowel discrimination task and at 6 and 10 mo of age on a nonnative speech and visual language discrimination task. Whereas the control infants responded as expected (success at 6 mo and failure at 10 mo) the SRI-exposed infants failed to discriminate the language differences at either age and the depressed-only infants succeeded at 10 mo instead of 6 mo. Fetuses at 36 wk gestation in the control condition performed as expected, with a response on vowel but not consonant discrimination, whereas the SRI-exposed fetuses showed accelerated perceptual development by discriminating both vowels and consonants. Thus, prenatal depressed maternal mood and SRI exposure were found to shift developmental milestones bidirectionally on infant speech perception tasks.
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Affiliation(s)
- Whitney M. Weikum
- Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada V6H 3V4
| | - Tim F. Oberlander
- Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada V6H 3V4
| | - Takao K. Hensch
- Center for Brain Science, Harvard University, Cambridge, MA 02138; and
| | - Janet F. Werker
- Department of Psychology, University of British Columbia, Vancouver, BC, Canada V6T 1Z4
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115
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Homberg JR. Serotonergic modulation of conditioned fear. SCIENTIFICA 2012; 2012:821549. [PMID: 24278743 PMCID: PMC3820492 DOI: 10.6064/2012/821549] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 09/26/2012] [Indexed: 06/02/2023]
Abstract
Conditioned fear plays a key role in anxiety disorders as well as depression and other neuropsychiatric conditions. Understanding how neuromodulators drive the associated learning and memory processes, including memory consolidation, retrieval/expression, and extinction (recall), is essential in the understanding of (individual differences in vulnerability to) these disorders and their treatment. The human and rodent studies I review here together reveal, amongst others, that acute selective serotonin reuptake inhibitor (SSRI) treatment facilitates fear conditioning, reduces contextual fear, and increases cued fear, chronic SSRI treatment reduces both contextual and cued fear, 5-HT1A receptors inhibit the acquisition and expression of contextual fear, 5-HT2A receptors facilitates the consolidation of cued and contextual fear, inactivation of 5-HT2C receptors facilitate the retrieval of cued fear memory, the 5-HT3 receptor mediates contextual fear, genetically induced increases in serotonin levels are associated with increased fear conditioning, impaired cued fear extinction, or impaired extinction recall, and that genetically induced 5-HT depletion increases fear conditioning and contextual fear. Several explanations are presented to reconcile seemingly paradoxical relationships between serotonin levels and conditioned fear.
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Affiliation(s)
- Judith R. Homberg
- Donders Institute for Brain, Cognition and Behaviour, Department of Cognitive Neuroscience, Radboud University Medical Centre, Geert Grooteplein 21, Route 126, 6525 EZ Nijmegen, The Netherlands
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116
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Sciolino NR, Holmes PV. Exercise offers anxiolytic potential: a role for stress and brain noradrenergic-galaninergic mechanisms. Neurosci Biobehav Rev 2012; 36:1965-84. [PMID: 22771334 PMCID: PMC4815919 DOI: 10.1016/j.neubiorev.2012.06.005] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 05/01/2012] [Accepted: 06/10/2012] [Indexed: 12/15/2022]
Abstract
Although physical activity reduces anxiety in humans, the neural basis for this response is unclear. Rodent models are essential to understand the mechanisms that underlie the benefits of exercise. However, it is controversial whether exercise exerts anxiolytic-like potential in rodents. Evidence is reviewed to evaluate the effects of wheel running, an experimental mode of exercise in rodents, on behavior in tests of anxiety and on norepinephrine and galanin systems in neural circuits that regulate stress. Stress is proposed to account for mixed behavioral findings in this literature. Indeed, running promotes an adaptive response to stress and alters anxiety-like behaviors in a manner dependent on stress. Running amplifies galanin expression in noradrenergic locus coeruleus (LC) and suppresses stress-induced activity of the LC and norepinephrine output in LC-target regions. Thus, enhanced galanin-mediated suppression of brain norepinephrine in runners is supported by current literature as a mechanism that may contribute to the stress-protective effects of exercise. These data support the use of rodents to study the emotional and neurobiological consequences of exercise.
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Affiliation(s)
- Natale R. Sciolino
- Neuroscience Program, Biomedical and Health Sciences Institute, Department of Psychology, University of Georgia, Athens, GA 30602, United States
| | - Philip V. Holmes
- Neuroscience Program, Biomedical and Health Sciences Institute, Department of Psychology, University of Georgia, Athens, GA 30602, United States
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117
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Npas4: a neuronal transcription factor with a key role in social and cognitive functions relevant to developmental disorders. PLoS One 2012; 7:e46604. [PMID: 23029555 PMCID: PMC3460929 DOI: 10.1371/journal.pone.0046604] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 09/01/2012] [Indexed: 11/19/2022] Open
Abstract
Npas4 is a transcription factor, which is highly expressed in the brain and regulates the formation and maintenance of inhibitory synapses in response to excitatory synaptic activity. A deregulation of the inhibitory-excitatory balance has been associated with a variety of human developmental disorders such as schizophrenia and autism. However, not much is known about the role played by inhibitory synapses and inhibitory pathways in the development of nervous system disorders. We hypothesized that alterations in the inhibitory pathways induced by the absence of Npas4 play a major role in the expression of the symptoms observed in psychiatric disorders. To test this hypothesis we tested mice lacking the transcription factor (Npas4 knock-out mice (Npas4-KO)) in a battery of behavioral assays focusing on general activity, social behaviors, and cognitive functions. Npas4-KO mice are hyperactive in a novel environment, spend less time exploring an unfamiliar ovariectomized female, spend more time avoiding an unfamiliar male during a first encounter, show higher social dominance than their WT littermates, and display pre-pulse inhibition, working memory, long-term memory, and cognitive flexibility deficits. These behavioral deficits may replicate schizophrenia-related symptomatology such as social anxiety, hyperactivity, and cognitive and sensorimotor gating deficits. Immunohistochemistry analyses revealed that Npas4 expression is induced in the hippocampus after a social encounter and that Npas4 regulates the expression of c-Fos in the CA1 and CA3 regions of the hippocampus after a cognitive task. Our results suggest that Npas4 may play a major role in the regulation of cognitive and social functions in the brain with possible implications for developmental disorders such as schizophrenia and autism.
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118
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Kyzar EJ, Pham M, Roth A, Cachat J, Green J, Gaikwad S, Kalueff AV. Alterations in grooming activity and syntax in heterozygous SERT and BDNF knockout mice: the utility of behavior-recognition tools to characterize mutant mouse phenotypes. Brain Res Bull 2012; 89:168-76. [PMID: 22951260 DOI: 10.1016/j.brainresbull.2012.08.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 08/03/2012] [Accepted: 08/08/2012] [Indexed: 12/31/2022]
Abstract
Serotonin transporter (SERT) and brain-derived neurotrophic factor (BDNF) are key modulators of molecular signaling, cognition and behavior. Although SERT and BDNF mutant mouse phenotypes have been extensively characterized, little is known about their self-grooming behavior. Grooming represents an important behavioral domain sensitive to environmental stimuli and is increasingly used as a model for repetitive behavioral syndromes, such as autism and attention deficit/hyperactivity disorder. The present study used heterozygous ((+/-)) SERT and BDNF male mutant mice on a C57BL/6J background and assessed their spontaneous self-grooming behavior applying both manual and automated techniques. Overall, SERT(+/-) mice displayed a general increase in grooming behavior, as indicated by more grooming bouts and more transitions between specific grooming stages. SERT(+/-) mice also aborted more grooming bouts, but showed generally unaltered activity levels in the observation chamber. In contrast, BDNF(+/-) mice displayed a global reduction in grooming activity, with fewer bouts and transitions between specific grooming stages, altered grooming syntax, as well as hypolocomotion and increased turning behavior. Finally, grooming data collected by manual and automated methods (HomeCageScan) significantly correlated in our experiments, confirming the utility of automated high-throughput quantification of grooming behaviors in various genetic mouse models with increased or decreased grooming phenotypes. Taken together, these findings indicate that mouse self-grooming behavior is a reliable behavioral biomarker of genetic deficits in SERT and BDNF pathways, and can be reliably measured using automated behavior-recognition technology.
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Affiliation(s)
- Evan J Kyzar
- Department of Pharmacology and Neuroscience Program, Tulane University Medical School, New Orleans, LA 70112, USA
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Farook MF, DeCuypere M, Hyland K, Takumi T, LeDoux MS, Reiter LT. Altered serotonin, dopamine and norepinepherine levels in 15q duplication and Angelman syndrome mouse models. PLoS One 2012; 7:e43030. [PMID: 22916201 PMCID: PMC3420863 DOI: 10.1371/journal.pone.0043030] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 07/16/2012] [Indexed: 01/18/2023] Open
Abstract
Childhood neurodevelopmental disorders like Angelman syndrome and autism may be the result of underlying defects in neuronal plasticity and ongoing problems with synaptic signaling. Some of these defects may be due to abnormal monoamine levels in different regions of the brain. Ube3a, a gene that causes Angelman syndrome (AS) when maternally deleted and is associated with autism when maternally duplicated has recently been shown to regulate monoamine synthesis in the Drosophila brain. Therefore, we examined monoamine levels in striatum, ventral midbrain, frontal cerebral cortex, cerebellar cortex and hippocampus in Ube3a deficient and Ube3a duplication animals. We found that serotonin (5HT), a monoamine affected in autism, was elevated in the striatum and cortex of AS mice. Dopamine levels were almost uniformly elevated compared to control littermates in the striatum, midbrain and frontal cortex regardless of genotype in Ube3a deficient and Ube3a duplication animals. In the duplication 15q autism mouse model, paternal but not maternal duplication animals showed a decrease in 5HT levels when compared to their wild type littermates, in accordance with previously published data. However, maternal duplication animals show no significant changes in 5HT levels throughout the brain. These abnormal monoamine levels could be responsible for many of the behavioral abnormalities observed in both AS and autism, but further investigation is required to determine if any of these changes are purely dependent on Ube3a levels in the brain.
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Affiliation(s)
- M. Febin Farook
- Department of Neurology, UTHSC, Memphis, Tennessee, United States of America
| | - Michael DeCuypere
- Department of Neurosurgery, UTHSC, Memphis, Tennessee, United States of America
| | - Keith Hyland
- Medical Neurogenetics, LCC, Atlanta, Georgia, United States of America
| | - Toru Takumi
- Hiroshima University, School of Medicine, Hiroshima, Japan
| | - Mark S. LeDoux
- Department of Neurology, UTHSC, Memphis, Tennessee, United States of America
- Department of Anatomy and Neurobiology, UTHSC, Memphis, Tennessee, United States of America
| | - Lawrence T. Reiter
- Department of Neurology, UTHSC, Memphis, Tennessee, United States of America
- Department of Anatomy and Neurobiology, UTHSC, Memphis, Tennessee, United States of America
- Department of Pediatrics, UTHSC, Memphis, Tennessee, United States of America
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120
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Oberlander TF. Fetal serotonin signaling: setting pathways for early childhood development and behavior. J Adolesc Health 2012; 51:S9-16. [PMID: 22794534 DOI: 10.1016/j.jadohealth.2012.04.009] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 04/20/2012] [Accepted: 04/23/2012] [Indexed: 02/07/2023]
Abstract
Finely tuning levels of the key neurotransmitter serotonin (5-hydroxytryptamine [5-HT]) during early life is essential for brain development and setting pathways for health and disorder across the early life span. Given the central role of 5-HT in brain development, regulation of mood, stress reactivity, and risk for psychiatric disorders, alterations in 5-HT signaling early in life have critical implications for behavior and mental health in childhood and adolescence. This article reviews the developmental consequences of two key influences that alter fetal 5-HT signaling: (1) in utero exposure to 5-HT reuptake inhibitor antidepressants, and (2) genetic variations in the 5-HT transporter gene (SLC6A4). The consequences of altered prenatal 5-HT signaling vary greatly, and developmental outcomes depend on an ongoing interplay between biological (genetic/epigenetic variations), experiential (prenatal drug or maternal mood exposure), and contextual (postnatal social environment) variables. Emerging evidence suggests both exposure to 5-HT reuptake inhibitors and genetic variations that affect 5-HT signaling may increase sensitivity to negative social contexts for some individuals, whereas for others, they may confer sensitivity to positive life circumstances. In this sense, factors that change central 5-HT levels may function less like influences that predict "vulnerability," but rather act like "plasticity factors." Understanding the impact of early changes in serotonergic programming offers critical insights that might explain patterns of individual differences in developmental risk and resilience.
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Affiliation(s)
- Tim F Oberlander
- Department of Pediatrics, Child and Family Research Institute, Vancouver, British Columbia, Canada.
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121
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Berger SM, Weber T, Perreau-Lenz S, Vogt MA, Gartside SE, Maser-Gluth C, Lanfumey L, Gass P, Spanagel R, Bartsch D. A functional Tph2 C1473G polymorphism causes an anxiety phenotype via compensatory changes in the serotonergic system. Neuropsychopharmacology 2012; 37:1986-98. [PMID: 22491354 PMCID: PMC3398728 DOI: 10.1038/npp.2012.46] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The association of single-nucleotide polymorphisms (SNPs) in the human tryptophan hydroxylase 2 (TPH2) gene with anxiety traits and depression has been inconclusive. Observed inconsistencies might result from the fact that TPH2 polymorphisms have been studied in a genetically heterogeneous human population. A defined genetic background, control over environmental factors, and the ability to analyze the molecular and neurochemical consequences of introduced genetic alterations constitute major advantages of investigating SNPs in inbred laboratory mouse strains. To investigate the behavioral and neurochemical consequences of a functional C1473G SNP in the mouse Tph2 gene, we generated congenic C57BL/6N mice homozygous for the Tph2 1473G allele. The Arg(447) substitution in the TPH2 enzyme resulted in a significant reduction of the brain serotonin (5-HT) in vivo synthesis rate. Despite decreased 5-HT synthesis, we could detect neither a reduction of brain region-specific 5-HT concentrations nor changes in baseline and stress-induced 5-HT release using a microdialysis approach. However, using a [(35)S]GTP-γ-S binding assay and 5-HT(1A) receptor autoradiography, a functional desensitization of 5-HT(1A) autoreceptors could be identified. Furthermore, behavioral analysis revealed a distinct anxiety phenotype in homozygous Tph2 1473G mice, which could be reversed with chronic escitalopram treatment. Alterations in depressive-like behavior could not be detected under baseline conditions or after chronic mild stress. These findings provide evidence for an involvement of functional Tph2 polymorphisms in anxiety-related behaviors, which are likely not caused directly by alterations in 5-HT content or release but are rather due to compensatory changes during development involving functional desensitization of 5-HT(1A) autoreceptors.
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Affiliation(s)
- Stefan M Berger
- Department of Molecular Biology, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Tillmann Weber
- Department of Molecular Biology, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany,Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany,Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Stephanie Perreau-Lenz
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Miriam A Vogt
- Department of Psychiatry and Psychotherapy, Research Group Animal Models in Psychiatry, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany
| | - Sarah E Gartside
- Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Christiane Maser-Gluth
- Steroid Laboratory, Department of Pharmacology, University of Heidelberg, Heidelberg, Germany
| | - Laurence Lanfumey
- INSERM UMRS894, CPN, Université Pierre and Marie Curie, Paris, France
| | - Peter Gass
- Department of Psychiatry and Psychotherapy, Research Group Animal Models in Psychiatry, 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
| | - Dusan Bartsch
- Department of Molecular Biology, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany,Department of Molecular Biology, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, J-5, 68159 Mannheim, Germany, Tel: +49 621 1703 6202, Fax: +49 621 1703 6205, E-mail:
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122
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Hanley GE, Oberlander TF. Neurodevelopmental outcomes following prenatal exposure to serotonin reuptake inhibitor antidepressants: A “social teratogen” or moderator of developmental risk? ACTA ACUST UNITED AC 2012; 94:651-9. [DOI: 10.1002/bdra.23032] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 03/28/2012] [Accepted: 04/19/2012] [Indexed: 11/10/2022]
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123
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Nonkes LJP, van de Vondervoort IIGM, de Leeuw MJC, Wijlaars LP, Maes JHR, Homberg JR. Serotonin transporter knockout rats show improved strategy set-shifting and reduced latent inhibition. Learn Mem 2012; 19:190-3. [PMID: 22505721 DOI: 10.1101/lm.025908.112] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Behavioral flexibility is a cognitive process depending on prefrontal areas allowing adaptive responses to environmental changes. Serotonin transporter knockout (5-HTT(-/-)) rodents show improved reversal learning in addition to orbitofrontal cortex changes. Another form of behavioral flexibility, extradimensional strategy set-shifting (EDSS), heavily depends on the medial prefrontal cortex. This region shows functional changes in 5-HTT(-/-) rodents as well. Here we subjected 5-HTT(-/-) rats and their wild-type counterparts to an EDSS paradigm and a supplementary latent inhibition task. Results indicate that 5-HTT(-/-) rats also show improved EDSS, and indicate that reduced latent inhibition may contribute as an underlying mechanism.
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Affiliation(s)
- Lourens J P Nonkes
- Donders Institute for Brain, Cognition, and Behaviour, Centre for Neuroscience, Department of Cognitive Neuroscience, Radboud University Nijmegen Medical Centre, 6525 EZ, The Netherlands
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124
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Yamakado H, Moriwaki Y, Yamasaki N, Miyakawa T, Kurisu J, Uemura K, Inoue H, Takahashi M, Takahashi R. α-Synuclein BAC transgenic mice as a model for Parkinson's disease manifested decreased anxiety-like behavior and hyperlocomotion. Neurosci Res 2012; 73:173-7. [PMID: 22475625 DOI: 10.1016/j.neures.2012.03.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 03/03/2012] [Accepted: 03/19/2012] [Indexed: 12/31/2022]
Abstract
α-Synuclein (α-syn), the main component of Lewy bodies, was identified as a genetic risk factor for idiopathic Parkinson's disease (PD). As a model for PD, we generated human α-syn bacterial artificial chromosome transgenic mice (BAC tg mice) harboring the entire human α-syn gene and its gene expression regulatory regions. The α-syn BAC tg mice manifested decreased anxiety-like behaviors which may reflect non-motor symptoms of early PD, and they exhibited increased SERT expression that may be responsible for decreased anxiety-like behaviors. Our α-syn BAC tg mice could be a valuable tool to evaluate α-syn gene dosage effects in vivo.
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Affiliation(s)
- Hodaka Yamakado
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
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125
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Guidotti G, Calabrese F, Auletta F, Olivier J, Racagni G, Homberg J, Riva MA. Developmental influence of the serotonin transporter on the expression of npas4 and GABAergic markers: modulation by antidepressant treatment. Neuropsychopharmacology 2012; 37:746-58. [PMID: 22012473 PMCID: PMC3260971 DOI: 10.1038/npp.2011.252] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Alterations of the serotonergic system are involved in the pathophysiology of mood disorders and represent an important target for its pharmacological treatment. Genetic deletion of the serotonin transporter (SERT) in rodents leads to an anxious and depressive phenotype, and is associated with reduced neuronal plasticity as indicated by decreased brain-derived neurotrophic factor (Bdnf) expression levels. One of the transcription factors regulating Bdnf is the neuronal PAS domain protein 4 (Npas4), which regulates activity-dependent genes and neuroprotection, and has a critical role in the development of GABA synapses. On the basis of these premises, we investigated the expression of Npas4 and GABAergic markers in the hippocampus and prefrontal cortex of homozygous (SERT(-/-)) and heterozygous (SERT(+/-)) knockout rats, and analyzed the effect of long-term duloxetine treatment on the expression of these targets. We found that Npas4 expression was reduced in both the brain structures of adult SERT(+/-) and SERT(-/-) animals. This effect was already present in adolescent SERT(-/-), and could be mimicked by prenatal exposure to the antidepressant fluoxetine. Moreover, SERT(-/-) rats showed a strong impairment of the GABAergic system, as indicated by the reduction of several markers, including the vesicular transporter (Vgat), glutamic acid decarboxylase-67 (Gad67), the receptor subunit GABA A receptor, gamma 2 (GABA(A)-γ2), and calcium-binding proteins that label subgroups of the GABAergic neurons. Interestingly, chronic treatment with the antidepressant duloxetine was able to restore the physiological levels of Npas4 and GABAergic markers in SERT(-/-) rats, although some differences in the modulation of GABAergic genes exist between hippocampus and prefrontal cortex. Our results demonstrate that SERT knockout rats, an animal model of mood disorders, have reduced Npas4 expression that correlates with decreased expression of Bdnf exon I and IV. These changes lead to an impairment of the GABAergic system that may contribute to the anxious and depressive phenotype associated with inherited SERT downregulation.
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Affiliation(s)
- Gianluigi Guidotti
- Center of Neuropharmacology, Department of Pharmacological Sciences, Universita' degli Studi di Milano, Milan, Italy
| | - Francesca Calabrese
- Center of Neuropharmacology, Department of Pharmacological Sciences, Universita' degli Studi di Milano, Milan, Italy
| | - Francesca Auletta
- Center of Neuropharmacology, Department of Pharmacological Sciences, Universita' degli Studi di Milano, Milan, Italy
| | - Jocelien Olivier
- Department of Clinical Neuroscience, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Giorgio Racagni
- Center of Neuropharmacology, Department of Pharmacological Sciences, Universita' degli Studi di Milano, Milan, Italy,Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Milan, Italy
| | - Judith Homberg
- Donders Institute for Brain, Cognition, and Behaviour, Department of Cognitive Neuroscience, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | - Marco A Riva
- Center of Neuropharmacology, Department of Pharmacological Sciences, Universita' degli Studi di Milano, Milan, Italy,Center of Excellence on Neurodegenerative Diseases, Università degli Studi di Milano, Milan, Italy,Center of Neuropharmacology, Department of Pharmacological Sciences, University of Milan, Via Balzaretti 9, 20133 Milan, Italy, Tel: +39 02 50318334, Fax: +39 02 50318278, E-mail:
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Kiser D, SteemerS B, Branchi I, Homberg JR. The reciprocal interaction between serotonin and social behaviour. Neurosci Biobehav Rev 2012; 36:786-98. [DOI: 10.1016/j.neubiorev.2011.12.009] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Revised: 11/23/2011] [Accepted: 12/14/2011] [Indexed: 11/27/2022]
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127
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Fournet V, Schweitzer A, Chevarin C, Deloulme JC, Hamon M, Giros B, Andrieux A, Martres MP. The deletion of STOP/MAP6 protein in mice triggers highly altered mood and impaired cognitive performances. J Neurochem 2012; 121:99-114. [PMID: 22146001 DOI: 10.1111/j.1471-4159.2011.07615.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The microtubule-associated Stable Tubulie Only Polypeptide (STOP; also known as MAP6) protein plays a key role in neuron architecture and synaptic plasticity, the dysfunctions of which are thought to be implicated in the pathophysiology of psychiatric diseases. The deletion of STOP in mice leads to severe disorders reminiscent of several schizophrenia-like symptoms, which are also associated with differential alterations of the serotonergic tone in somas versus terminals. In STOP knockout (KO) compared with wild-type mice, serotonin (5-HT) markers are found to be markedly accumulated in the raphe nuclei and, in contrast, deeply depleted in all serotonergic projection areas. In the present study, we carefully examined whether the 5-HT imbalance would lead to behavioral consequences evocative of mood and/or cognitive disorders. We showed that STOP KO mice exhibited depression-like behavior, associated with a decreased anxiety-status in validated paradigms. In addition, although STOP KO mice had a preserved very short-term memory, they failed to perform well in all other learning and memory tasks. We also showed that STOP KO mice exhibited regional imbalance of the norepinephrine tone as observed for 5-HT. As a consequence, mutant mice were hypersensitive to acute antidepressants with different selectivity. Altogether, these data indicate that the deletion of STOP protein in mice caused deep alterations in mood and cognitive performances and that STOP protein might have a crucial role in the 5-HT and norepinephrine networks development.
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Affiliation(s)
- Vincent Fournet
- INSERM UMRS 952, CNRS UMR 7224, Université Pierre et Marie Curie, Paris, France
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128
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Homberg JR. Serotonin and decision making processes. Neurosci Biobehav Rev 2012; 36:218-36. [DOI: 10.1016/j.neubiorev.2011.06.001] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2011] [Revised: 05/27/2011] [Accepted: 06/02/2011] [Indexed: 10/18/2022]
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129
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The stress-coping (mis)match hypothesis for nature×nurture interactions. Brain Res 2012; 1432:114-21. [DOI: 10.1016/j.brainres.2011.11.037] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 11/17/2011] [Indexed: 01/18/2023]
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131
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de Visser L, Homberg JR, Mitsogiannis M, Zeeb FD, Rivalan M, Fitoussi A, Galhardo V, van den Bos R, Winstanley CA, Dellu-Hagedorn F. Rodent versions of the iowa gambling task: opportunities and challenges for the understanding of decision-making. Front Neurosci 2011; 5:109. [PMID: 22013406 PMCID: PMC3189637 DOI: 10.3389/fnins.2011.00109] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 08/29/2011] [Indexed: 01/21/2023] Open
Abstract
Impaired decision-making is a core problem in several psychiatric disorders including attention-deficit/hyperactivity disorder, schizophrenia, obsessive–compulsive disorder, mania, drug addiction, eating disorders, and substance abuse as well as in chronic pain. To ensure progress in the understanding of the neuropathophysiology of these disorders, animal models with good construct and predictive validity are indispensable. Many human studies aimed at measuring decision-making capacities use the Iowa gambling task (IGT), a task designed to model everyday life choices through a conflict between immediate gratification and long-term outcomes. Recently, new rodent models based on the same principle have been developed to investigate the neurobiological mechanisms underlying IGT-like decision-making on behavioral, neural, and pharmacological levels. The comparative strengths, as well as the similarities and differences between these paradigms are discussed. The contribution of these models to elucidate the neurobehavioral factors that lead to poor decision-making and to the development of better treatments for psychiatric illness is considered, along with important future directions and potential limitations.
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Affiliation(s)
- Leonie de Visser
- Department of Neuroscience and Pharmacology, Rudolf Magnus Institute of Neuroscience, University Medical Centre Utrecht, Netherlands
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Olivier JDA, Vallès A, van Heesch F, Afrasiab-Middelman A, Roelofs JJPM, Jonkers M, Peeters EJ, Korte-Bouws GAH, Dederen JP, Kiliaan AJ, Martens GJ, Schubert D, Homberg JR. Fluoxetine administration to pregnant rats increases anxiety-related behavior in the offspring. Psychopharmacology (Berl) 2011; 217:419-32. [PMID: 21487650 DOI: 10.1007/s00213-011-2299-z] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 03/30/2011] [Indexed: 01/14/2023]
Abstract
RATIONALE Fluoxetine (Prozac®) is the most frequently prescribed drug to battle depression in pregnant women, but its safety in the unborn child has not yet been established. Fluoxetine, a selective serotonin reuptake inhibitor, crosses the placenta, leading to increased extracellular serotonin levels and potentially neurodevelopmental changes in the fetus. OBJECTIVES The purpose of this study was to elucidate the long-term consequences of prenatal fluoxetine in rats. METHODS Pregnant rats were injected daily with 12 mg/kg fluoxetine or vehicle from gestational day 11 until birth, and the behavior of the offspring was monitored. RESULTS Plasma fluoxetine transfer from mother to pup was 83%, and high levels of fluoxetine (13.0 μg/g) were detected in the pup brain 5 h after the last injection. Fluoxetine-treated dams gave birth to litters 15% smaller than usual and to pups of reduced weight (until postnatal day 7). Furthermore, prenatal fluoxetine exposure significantly increased anxiety in the novelty-suppressed feeding test, the footshock-induced conditioned place aversion test, and the elevated plus maze test (following footshock pre-exposure) during adulthood, and also significantly decreased components of social play behavior at 4 weeks of age, and a strong tendency for increased self-grooming and making less contact in adults. Behavioral despair, anhedonia, and sexual behavior were not different between treatment groups. Finally, the hypothermic response to the 5-HT(1A) agonist flesinoxan was observed at a lower dose in prenatally fluoxetine-exposed rats than in controls. CONCLUSIONS Prenatal fluoxetine exposure in rats leads to detrimental behavioral outcomes in later life, which may partly be due to altered 5-HT(1A) receptor signaling.
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Affiliation(s)
- Jocelien D A Olivier
- Donders Institute for Brain, Cognition, and Behaviour, Centre for Neuroscience, Department of Cognitive Neuroscience, Radboud University Nijmegen Medical Centre, Geert Grooteplein 21 (route 126), 6525, EZ, Nijmegen, The Netherlands
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Petrik D, Lagace DC, Eisch AJ. The neurogenesis hypothesis of affective and anxiety disorders: are we mistaking the scaffolding for the building? Neuropharmacology 2011; 62:21-34. [PMID: 21945290 DOI: 10.1016/j.neuropharm.2011.09.003] [Citation(s) in RCA: 179] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 09/03/2011] [Accepted: 09/06/2011] [Indexed: 01/22/2023]
Abstract
Hypotheses are scaffoldings erected in front of a building and then dismantled when the building is finished. They are indispensable for the workman; but you mustn't mistake the scaffolding for the building. Johann Wolfgang von Goethe. The neurogenesis hypothesis of affective disorders - in its simplest form - postulates that the generation of neurons in the postnatal hippocampal dentate gyrus is involved in the etiology and treatment efficacy of major depressive disorder (MDD). The hypothesis was established in the 1990s but was built on a broad foundation of earlier research on the hippocampus, serotonin and MDD. It has gone through several growth phases fueled by discoveries both correlative and causative in nature. Recently, the hypothesis has also been broadened to also include potential relevance for anxiety disorders, like post-traumatic stress disorder (PTSD). As any hypothesis should be, it has been tested and challenged, sometimes vigorously. Here we review the current standing of the neurogenesis hypothesis of affective and anxiety disorders, noting in particular how a central postulate - that decreased neurogenesis results in depression or anxiety - has, in general, been rejected. We also review the controversies on whether treatments for these disorders, like antidepressants, rely on intact neurogenesis for their efficacy, and the existence of neurogenesis-dependent and -independent effects of antidepressants. In addition, we review the implications that the hypothesis has for the response to stress, PTSD, and the neurobiology of resilience, and highlight our own work showing that adult-generated neurons are functionally important for the behavioral response to social stress. We conclude by emphasizing how advancements in transgenic mouse technology, rodent behavioral analyses, and our understanding of the neurogenesis process will allow us to refine our conclusions and perform ever more specific experiments. Such scrutiny is critical, since if we "mistake the scaffolding for the building" we could overlook opportunities for translational impact in the clinic. This article is part of a special Issue entitled 'Anxiety and Depression'.
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Affiliation(s)
- David Petrik
- Department of Psychiatry, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9070, USA
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134
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Compton DM, Dietrich KL, Selinger MC, Testa EK. 5-Methoxy-N,N-di(iso)propyltryptamine hydrochloride (Foxy)-induced cognitive deficits in rat after exposure in adolescence. Physiol Behav 2011; 103:203-9. [DOI: 10.1016/j.physbeh.2011.01.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 01/14/2011] [Accepted: 01/24/2011] [Indexed: 10/18/2022]
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135
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Kloke V, Jansen F, Heiming RS, Palme R, Lesch KP, Sachser N. The winner and loser effect, serotonin transporter genotype, and the display of offensive aggression. Physiol Behav 2011; 103:565-74. [PMID: 21549735 DOI: 10.1016/j.physbeh.2011.04.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 04/18/2011] [Accepted: 04/19/2011] [Indexed: 10/18/2022]
Abstract
Aggressive behaviour results from a complex interplay between genetic and environmental factors. Key modulators of aggression include the serotonergic system on the molecular level and experience in prior aggressive contests as an environmental factor. The aim of this study was to elucidate the effects of fighting experience on the display of offensive aggressive behaviour in adult male mice varying in serotonin transporter (5-HTT) genotype. 5-HTT +/+, 5-HTT +/- and 5-HTT -/- mice were given either a winning or a losing experience on each of three consecutive days and were subsequently observed for their offensive aggressive behaviour as residents against a docile intruder from the C3H strain in a resident-intruder paradigm. The main findings were: There was no significant difference between the amount of offensive aggressive behaviour displayed by the genotypes. Winners showed more engagement with the intruder, attacked him faster and exhibited overall higher aggression scores than losers. There was no significant genotype × social experience interaction: winning and losing had a similar effect on offensive aggressive behaviour in all three 5-HTT genotypes. We conclude that social experience in terms of having been a winner or having been a loser rather than the 5-HTT genotype determines the behaviour towards a docile intruder.
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Affiliation(s)
- Vanessa Kloke
- Department of Behavioural Biology, University of Münster, Badestr. 13, 48149 Münster, Germany.
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136
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Schipper P, Nonkes LJP, Karel P, Kiliaan AJ, Homberg JR. Serotonin transporter genotype x construction stress interaction in rats. Behav Brain Res 2011; 223:169-75. [PMID: 21549766 DOI: 10.1016/j.bbr.2011.04.037] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 04/13/2011] [Accepted: 04/20/2011] [Indexed: 12/20/2022]
Abstract
A well-known example for gene x environment interactions in psychiatry is the one involving the low activity (s) allelic variant of the serotonin transporter (5-HTT) promoter polymorphism (5-HTTLPR) that in the context of stress increases risk for depression. In analogy, 5-HTT knockout rodents are highly responsive to early life, but also adult external stressors, albeit conflicting data have been obtained. In our study on emotion and cognition using homozygous 5-HTT knockout (5-HTT(-/-)) and wild-type (5-HTT(+/+)) rats we have been confronted with animal facility construction, which were associated with severe lifetime stress (noise and vibrations). To assess the impact of construction stress on well-established 5-HTT(-/-) rat phenotypes we conducted ad hoc analyses of 5-HTT(-/-) and 5-HTT(+/+) rats that grew up before and during the construction. The reproductive capacity of the parents of the experimental 5-HTT(+/-) rats was significantly decreased. Further, 5-HTT(-/-) anxiety-related phenotypes in the elevated plus maze and social interaction tests were abolished after construction noise exposure, due to increased anxiety in 5-HTT(+/+) rats and decreased anxiety in 5-HTT(-/-) rats (social interaction test only). In addition, reversal learning was improved in 5-HTT(+/+) and, to a milder extent, decreased in 5-HTT(-/-) rats. Finally, construction stress genotype-independently increased behavioural despair in the forced swim test. In conclusion, severe construction stress induces 5-HTT genotype-dependent 'for-better-and-for-worse' effects. These data importantly contribute to the understanding of 5-HTT gene x environment interactions and show the risk of losing genotype effects by construction stress.
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Affiliation(s)
- Pieter Schipper
- Department of Anatomy, Donders Institute for Brain, Cognition, and Behavior, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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137
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Daws LC, Gould GG. Ontogeny and regulation of the serotonin transporter: providing insights into human disorders. Pharmacol Ther 2011; 131:61-79. [PMID: 21447358 DOI: 10.1016/j.pharmthera.2011.03.013] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 03/11/2011] [Indexed: 12/17/2022]
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) was one of the first neurotransmitters for which a role in development was identified. Pharmacological and gene knockout studies have revealed a critical role for 5-HT in numerous processes, including cell division, neuronal migration, differentiation and synaptogenesis. An excess in brain 5-HT appears to be mechanistically linked to abnormal brain development, which in turn is associated with neurological disorders. Ambient levels of 5-HT are controlled by a vast orchestra of proteins, including a multiplicity of pre- and post-synaptic 5-HT receptors, heteroreceptors, enzymes and transporters. The 5-HT transporter (SERT, 5-HTT) is arguably the most powerful regulator of ambient extracellular 5-HT. SERT is the high-affinity uptake mechanism for 5-HT and exerts tight control over the strength and duration of serotonergic neurotransmission. Perturbation of its expression level or function has been implicated in many diseases, prominent among them are psychiatric disorders. This review synthesizes existing information on the ontogeny of SERT during embryonic and early postnatal development though adolescence, along with factors that influence its expression and function during these critical developmental windows. We integrate this knowledge to emphasize how inappropriate SERT expression or its dysregulation may be linked to the pathophysiology of psychiatric, cardiovascular and gastrointestinal diseases.
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Affiliation(s)
- Lynette C Daws
- Department of Physiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MC 7756, San Antonio, TX 78229-3900, USA.
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138
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Hayes DJ, Greenshaw AJ. 5-HT receptors and reward-related behaviour: a review. Neurosci Biobehav Rev 2011; 35:1419-49. [PMID: 21402098 DOI: 10.1016/j.neubiorev.2011.03.005] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Revised: 03/03/2011] [Accepted: 03/04/2011] [Indexed: 01/07/2023]
Abstract
The brain's serotonin (5-HT) system is key in the regulation of reward-related behaviours, from eating and drinking to sexual activity. The complexity of studying this system is due, in part, to the fact that 5-HT acts at many receptor subtypes throughout the brain. The recent development of drugs with greater selectivity for individual receptor subtypes has allowed for rapid advancements in our understanding of this system. Use of these drugs in combination with animal models entailing selective reward measures (i.e. intracranial self-stimulation, drug self-administration, conditioned place preference) have resulted in a greater understanding of the pharmacology of reward-related processing and behaviour (particularly regarding drugs of abuse). The putative roles of each 5-HT receptor subtype in the pharmacology of reward are outlined and discussed here. It is concluded that the actions of 5-HT in reward are receptor subtype-dependent (and thus should not be generalized) and that all studied subtypes appear to have a unique profile which is determined by content (e.g. receptor function, localization - both throughout the brain and within the synapse) and context (e.g. type of behavioural paradigm, type of drug). Given evidence of altered reward-related processing and serotonergic function in numerous neuropsychiatric disorders, such as depression, schizophrenia, and addiction, a clearer understanding of the role of 5-HT receptor subtypes in this context may lead to improved drug development and therapeutic approaches.
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Affiliation(s)
- Dave J Hayes
- Centre for Neuroscience, 513 HMRC, University of Alberta, Edmonton, AB, T6G 2S2, Canada.
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139
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Homberg JR, Lesch KP. Looking on the bright side of serotonin transporter gene variation. Biol Psychiatry 2011; 69:513-9. [PMID: 21047622 DOI: 10.1016/j.biopsych.2010.09.024] [Citation(s) in RCA: 322] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Revised: 09/17/2010] [Accepted: 09/18/2010] [Indexed: 12/19/2022]
Abstract
Converging evidence indicates an association of the short (s), low-expressing variant of the repeat length polymorphism, serotonin transporter-linked polymorphic region (5-HTTLPR), in the human serotonin transporter gene (5-HTT, SERT, SLC6A4) with anxiety-related traits and increased risk for depression in interaction with psychosocial adversity across the life span. However, genetically driven deficient serotonin transporter (5-HTT) function would not have been maintained throughout evolution if it only exerted negative effects without conveying any gain of function. Here, we review recent findings that humans and nonhuman primates carrying the s variant of the 5-HTTLPR outperform subjects carrying the long allele in an array of cognitive tasks and show increased social conformity. In addition, studies in 5-HTT knockout rodents are included that provide complementary insights in the beneficial effects of the 5-HTTLPR s-allele. We postulate that hypervigilance, mediated by hyperactivity in corticolimbic structures, may be the common denominator in the anxiety-related traits and (social) cognitive superiority of s-allele carriers and that environmental conditions determine whether a response will turn out to be negative (emotional) or positive (cognitive, in conformity with the social group). Taken together, these findings urge for a conceptual change in the current deficit-oriented connotation of the 5-HTTLPR variants. In fact, these factors may counterbalance or completely offset the negative consequences of the anxiety-related traits. This notion may not only explain the modest effect size of the 5-HTTLPR and inconsistent reports but may also lead to a more refined appreciation of allelic variation in 5-HTT function.
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Affiliation(s)
- Judith R Homberg
- Donders Institute for Brain, Cognition, and Behaviour, Centre for Neuroscience, Department of Cognitive Neuroscience, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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140
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Thompson BJ, Jessen T, Henry LK, Field JR, Gamble KL, Gresch PJ, Carneiro AM, Horton RE, Chisnell PJ, Belova Y, McMahon DG, Daws LC, Blakely RD. Transgenic elimination of high-affinity antidepressant and cocaine sensitivity in the presynaptic serotonin transporter. Proc Natl Acad Sci U S A 2011; 108:3785-90. [PMID: 21282638 PMCID: PMC3048100 DOI: 10.1073/pnas.1011920108] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Serotonin [i.e., 5-hydroxytryptamine (5-HT)]-targeted antidepressants are in wide use for the treatment of mood disorders, although many patients do not show a response or experience unpleasant side effects. Psychostimulants, such as cocaine and 3,4-methylenedioxymethamphetamine (i.e., "ecstasy"), also impact 5-HT signaling. To help dissect the contribution of 5-HT signaling to the actions of these and other agents, we developed transgenic mice in which high-affinity recognition of multiple antidepressants and cocaine is eliminated. Our animals possess a modified copy of the 5-HT transporter (i.e., SERT, slc6a4) that bears a single amino acid substitution, I172M, proximal to the 5-HT binding site. Although the M172 substitution does not impact the recognition of 5-HT, this mutation disrupts high-affinity binding of many competitive antagonists in transfected cells. Here, we demonstrate that, in M172 knock-in mice, basal SERT protein levels, 5-HT transport rates, and 5-HT levels are normal. However, SERT M172 mice display a substantial loss of sensitivity to the selective 5-HT reuptake inhibitors fluoxetine and citalopram, as well as to cocaine. Through a series of biochemical, electrophysiological, and behavioral assays, we demonstrate the unique properties of this model and establish directly that SERT is the sole protein responsible for selective 5-HT reuptake inhibitor-mediated alterations in 5-HT clearance, in 5-HT1A autoreceptor modulation of raphe neuron firing, and in behaviors used to predict the utility of antidepressants.
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Affiliation(s)
| | | | | | | | - Karen L. Gamble
- Biological Sciences, Vanderbilt University School of Medicine, Nashville, TN 37232
| | | | | | - Rebecca E. Horton
- Department of Physiology, University of Texas Health Sciences Center, San Antonio, TX 78229
| | | | | | - Douglas G. McMahon
- Biological Sciences, Vanderbilt University School of Medicine, Nashville, TN 37232
- Center for Molecular Neuroscience, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Lynette C. Daws
- Department of Physiology, University of Texas Health Sciences Center, San Antonio, TX 78229
- Department of Pharmacology, University of Texas Health Sciences Center, San Antonio, TX 78229; and
| | - Randy D. Blakely
- Departments of Pharmacology and
- Center for Molecular Neuroscience, Vanderbilt University School of Medicine, Nashville, TN 37232
- Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37232
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141
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Haenisch B, Bönisch H. Depression and antidepressants: Insights from knockout of dopamine, serotonin or noradrenaline re-uptake transporters. Pharmacol Ther 2011; 129:352-68. [DOI: 10.1016/j.pharmthera.2010.12.002] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 11/29/2010] [Indexed: 12/15/2022]
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142
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143
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Meneses A, Perez-Garcia G, Ponce-Lopez T, Tellez R, Castillo C. Serotonin transporter and memory. Neuropharmacology 2011; 61:355-63. [PMID: 21276807 DOI: 10.1016/j.neuropharm.2011.01.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 12/15/2010] [Accepted: 01/10/2011] [Indexed: 10/18/2022]
Abstract
The serotonin transporter (SERT) has been associated to diverse functions and diseases, though seldom to memory. Therefore, we made an attempt to summarize and discuss the available publications implicating the involvement of the SERT in memory, amnesia and anti-amnesic effects. Evidence indicates that Alzheimer's disease and drugs of abuse like d-methamphetamine (METH) and (+/-)3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") have been associated to decrements in the SERT expression and memory deficits. Several reports have indicated that memory formation and amnesia affected the SERT expression. The SERT expression seems to be a reliable neural marker related to memory mechanisms, its alterations and potential treatment. The pharmacological, neural and molecular mechanisms associated to these changes are of great importance for investigation.
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Affiliation(s)
- Alfredo Meneses
- Depto. de Farmacobiología, CINVESTAV-IPN, Tenorios 235, Granjas Coapa, Mexico City 14330, Mexico.
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144
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Meneses A, Pérez-García G, Ponce-Lopez T, Castillo C. 5-HT6 Receptor Memory and Amnesia: Behavioral Pharmacology – Learning and Memory Processes. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2011; 96:27-47. [DOI: 10.1016/b978-0-12-385902-0.00002-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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145
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Tamada K, Tomonaga S, Hatanaka F, Nakai N, Takao K, Miyakawa T, Nakatani J, Takumi T. Decreased exploratory activity in a mouse model of 15q duplication syndrome; implications for disturbance of serotonin signaling. PLoS One 2010; 5:e15126. [PMID: 21179543 PMCID: PMC3002297 DOI: 10.1371/journal.pone.0015126] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 10/27/2010] [Indexed: 11/24/2022] Open
Abstract
Autism spectrum disorders (ASDs) have garnered significant attention as an important grouping of developmental brain disorders. Recent genomic studies have revealed that inherited or de novo copy number variations (CNVs) are significantly involved in the pathophysiology of ASDs. In a previous report from our laboratory, we generated mice with CNVs as a model of ASDs, with a duplicated mouse chromosome 7C that is orthologous to human chromosome 15q11-13. Behavioral analyses revealed paternally duplicated (patDp/+) mice displayed abnormal behaviors resembling the symptoms of ASDs. In the present study, we extended these findings by performing various behavioral tests with C57BL/6J patDp/+ mice, and comprehensively measuring brain monoamine levels with ex vivo high performance liquid chromatography. Compared with wild-type controls, patDp/+ mice exhibited decreased locomotor and exploratory activities in the open field test, Y-maze test, and fear-conditioning test. Furthermore, their decreased activity levels overcame increased appetite induced by 24 hours of food deprivation in the novelty suppressed feeding test. Serotonin levels in several brain regions of adult patDp/+ mice were lower than those of wild-type control, with no concurrent changes in brain levels of dopamine or norepinephrine. Moreover, analysis of monoamines in postnatal developmental stages demonstrated reduced brain levels of serotonin in young patDp/+ mice. These findings suggest that a disrupted brain serotonergic system, especially during postnatal development, may generate the phenotypes of patDp/+ mice.
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Affiliation(s)
- Kota Tamada
- Osaka Bioscience Institute, Suita, Japan
- Kyoto University Graduate School of Biostudies, Kyoto, Japan
- Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | | | - Fumiyuki Hatanaka
- Osaka Bioscience Institute, Suita, Japan
- Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
- Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Nobuhiro Nakai
- Osaka Bioscience Institute, Suita, Japan
- Kyoto University Graduate School of Biostudies, Kyoto, Japan
- Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Keizo Takao
- Frontier Technology Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- Division of Systems Medicine, Institute for Comprehensive Medical Science, Fujita Health University, Aichi, Japan
- Section of Behavior Patterns, Center for Genetic Analysis of Behavior, National Institute for Physiological Sciences, Okazaki, Japan
| | - Tsuyoshi Miyakawa
- Frontier Technology Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- Division of Systems Medicine, Institute for Comprehensive Medical Science, Fujita Health University, Aichi, Japan
- Section of Behavior Patterns, Center for Genetic Analysis of Behavior, National Institute for Physiological Sciences, Okazaki, Japan
- Japan Science and Technology Agent (JST), Core Research for Evolutional Science and Technology (CREST), Saitama, Japan
| | | | - Toru Takumi
- Osaka Bioscience Institute, Suita, Japan
- Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
- Kyoto University Graduate School of Medicine, Kyoto, Japan
- Japan Science and Technology Agent (JST), Core Research for Evolutional Science and Technology (CREST), Saitama, Japan
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146
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Heiming RS, Sachser N. Consequences of serotonin transporter genotype and early adversity on behavioral profile - pathology or adaptation? Front Neurosci 2010; 4:187. [PMID: 21151780 PMCID: PMC2999984 DOI: 10.3389/fnins.2010.00187] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 10/17/2010] [Indexed: 11/13/2022] Open
Abstract
This review focuses on how behavioral profile is shaped by early adversity in individuals with varying serotonin transporter (5-HTT) genotype. In a recent study on 5-HTT knockout mice Heiming et al. (2009) simulated a 'dangerous environment' by confronting pregnant and lactating females with odor cues of unfamiliar males, indicating the risk of infant killing. Growing up in a dangerous environment induced increased anxiety-related behavior and decreased exploratory locomotion in the offspring, the effects being most pronounced in mice lacking 5-HTT expression. We argue that these alterations in behavioral profile represent adaptive maternal effects that help the individuals to cope with adversity. In principle, such effects of adversity on behavioral profile should not automatically be regarded as pathological. Rather and in accordance with modern evolutionary theory they may represent adaptations, although individuals with 5-HTT genotype induced susceptibility to adversity may be at risk of developing pathologies.
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Affiliation(s)
- Rebecca S Heiming
- Department of Behavioural Biology, University of Muenster Muenster, Germany
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147
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Nonkes LJ, Tomson K, Mærtin A, Dederen J, Roald Maes J, Homberg J. Orbitofrontal cortex and amygdalar over-activity is associated with an inability to use the value of expected outcomes to guide behaviour in serotonin transporter knockout rats. Neurobiol Learn Mem 2010; 94:65-72. [DOI: 10.1016/j.nlm.2010.04.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 03/29/2010] [Accepted: 04/07/2010] [Indexed: 11/29/2022]
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148
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Bordukalo-Niksic T, Mokrovic G, Stefulj J, Zivin M, Jernej B, Cicin-Sain L. 5HT-1A receptors and anxiety-like behaviours: studies in rats with constitutionally upregulated/downregulated serotonin transporter. Behav Brain Res 2010; 213:238-45. [PMID: 20457184 DOI: 10.1016/j.bbr.2010.05.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Revised: 04/29/2010] [Accepted: 05/04/2010] [Indexed: 12/30/2022]
Abstract
Altered activity of brain serotonergic (5HT) system has been implicated in a wide range of behaviours and behavioural disorders, including anxiety. Functioning of 5HT-1A receptor has been suggested as a modulator of emotional balance in both, normal and pathological forms of anxiety. Here, we studied serotonergic modulation of anxiety-like behaviour using a genetic rat model with constitutional differences in 5HT homeostasis, named Wistar-Zagreb 5HT (WZ-5HT) rats. The model, consisting of high-5HT and low-5HT sublines, was developed by selective breeding of animals for extreme activities of peripheral (platelet) 5HT transporter, but selection process had affected also central 5HT homeostasis, as evidenced from neurochemical and behavioural studies. Anxiety-like behaviour in WZ-5HT rats was evaluated by two commonly used paradigms: open field and elevated-plus maze. The involvement of 5HT-1A receptors in behavioural response was assessed by measuring mRNA expression in cell bodies (raphe nuclei) and projection regions (frontal cortex, hippocampus) by use of RT-PCR and in situ hybridization, and by measuring functionality of cortical 5HT-1A receptors by use of [(3)H]8-OH-DPAT radioligand binding. Animals from the high-5HT subline exhibit increased anxiety-like behaviour and decreased exploratory activity when exposed to novel environment. No measurable differences in constitutional (baseline) functionality or expression of 5HT-1A receptors between sublines were found. The results support contribution of increased serotonergic functioning to the anxiety-like behaviour. They also validate the high-5HT subline of WZ-5HT rats as a potential model to study mechanisms of anxiety, especially of its nonpathological form, while the low-5HT subline may be useful to model sensation seeking phenotype.
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Affiliation(s)
- Tatjana Bordukalo-Niksic
- Laboratory of Neurochemistry and Molecular Neurobiology, Department of Molecular Biology, Rudjer Boskovic Institute, Bijenicka 54, Zagreb, Croatia
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149
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Autoradiographic study of serotonin transporter during memory formation. Behav Brain Res 2010; 212:12-26. [PMID: 20226815 DOI: 10.1016/j.bbr.2010.03.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Accepted: 03/05/2010] [Indexed: 12/15/2022]
Abstract
Serotonin transporter (SERT) has been associated with drugs of abuse like d-methamphetamine (METH). METH is well known to produce effects on the monoamine systems but it is unclear how METH affects SERT and memory. Here the effects of METH and the serotonin reuptake inhibitor fluoxetine (FLX) on autoshaping and novel object recognition (NOR) were investigated. Notably, both memory tasks recruit different behavioral, neural and cognitive demand. In autoshaping task a dose-response curve for METH was determined. METH (1.0mg/kg) impaired short-term memory (STM; lasting less of 90min) in NOR and impaired both STM and long-term memory (LTM; lasting 24 and 48h) in autoshaping, indicating that METH had long-lasting effects in the latter task. A comparative autoradiography study of the relationship between the binding pattern of SERT in autoshaping new untrained vs. trained treated (METH, FLX, or both) animals was made. Considering that hemispheric dominance is important for LTM, hence right vs. left hemisphere of the brain was compared. Results showed that trained animals decreased cortical SERT binding relative to untrained ones. In untrained and trained treated animals with the amnesic dose (1.0mg/kg) of METH SERT binding in several areas including hippocampus and cortex decreased, more remarkably in the trained animals. In contrast, FLX improved memory, increased SERT binding, prevented the METH amnesic effect and re-established the SERT binding. In general, memory and amnesia seemed to make SERT more vulnerable to drugs effects.
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150
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Calabrese F, Molteni R, Cattaneo A, Macchi F, Racagni G, Gennarelli M, Ellenbroek BA, Riva MA. Long-Term Duloxetine Treatment Normalizes Altered Brain-Derived Neurotrophic Factor Expression in Serotonin Transporter Knockout Rats through the Modulation of Specific Neurotrophin Isoforms. Mol Pharmacol 2010; 77:846-53. [DOI: 10.1124/mol.109.063081] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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