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Rauhut AS, Tuladhar B, Tamvaka N, Warnick J. Differential effects of voluntary exercise and housing density on anxiety-like behavior in C57Bl/6 mice. Behav Processes 2024; 217:105023. [PMID: 38522795 DOI: 10.1016/j.beproc.2024.105023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 03/15/2024] [Accepted: 03/21/2024] [Indexed: 03/26/2024]
Abstract
The interaction of voluntary exercise and housing density on a) anxiety-like behavior and b) the stimulant effects of methamphetamine in C57Bl/6 mice were evaluated. Upon arrival, mice were housed singly or in pairs, and permitted access to home-cage running wheels or not for 4 weeks. Testing for anxiety-like behavior occurred over the next 3 weeks, one test per week [Elevated-Plus Maze (EPM) → Hyponeophagia (HNP) task → Open-Field (OF) task]. The final, OF task involved an 8-hour session in which mice were permitted to explore the chamber (drug free) during Hours 1-3; given an injection (s.c.) of methamphetamine (1.0 mg/kg) after Hour 3; followed by continued behavioral sampling during Hours 4-8. Several tasks (HNP and OF, but not EPM) consistently showed voluntary exercise induced anxiety-like behavior. In addition, two measures (time in center and time resting in the perimeter) in the OF task revealed that exercise mice compared to controls were more responsive to the anxiogenic effects of methamphetamine. Although pair housing was anxiolytic, it did not ameliorate the anxiogenic effects of voluntary exercise. Taken together, these results, when viewed in tandem with previous studies that utilized a less anxious mouse strain (Swiss Webster), may suggest that voluntary exercise is anxiogenic in an anxiety-prone mouse strain such as C57Bl/6 and highlight the importance of considering mouse strain when evaluating the impact of environmental manipulations on anxiety-like behavior in animal models.
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Affiliation(s)
- Anthony S Rauhut
- Psychology Department, Dickinson College, Carlisle 17013, PA; Neuroscience Program, Dickinson College, Carlisle 17013, PA.
| | | | - Nicole Tamvaka
- Neuroscience Program, Dickinson College, Carlisle 17013, PA
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2
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Falkai P, Rossner MJ, Raabe FJ, Wagner E, Keeser D, Maurus I, Roell L, Chang E, Seitz-Holland J, Schulze TG, Schmitt A. Disturbed Oligodendroglial Maturation Causes Cognitive Dysfunction in Schizophrenia: A New Hypothesis. Schizophr Bull 2023; 49:1614-1624. [PMID: 37163675 PMCID: PMC10686333 DOI: 10.1093/schbul/sbad065] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
BACKGROUND AND HYPOTHESIS Cognitive impairment is a hallmark of schizophrenia, but no effective treatment is available to date. The underlying pathophysiology includes disconnectivity between hippocampal and prefrontal brain regions. Supporting evidence comes from diffusion-weighted imaging studies that suggest abnormal organization of frontotemporal white matter pathways in schizophrenia. STUDY DESIGN Here, we hypothesize that in schizophrenia, deficient maturation of oligodendrocyte precursor cells (OPCs) into mature oligodendrocytes substantially contributes to abnormal frontotemporal macro- and micro-connectivity and subsequent cognitive deficits. STUDY RESULTS Our postmortem studies indicate a reduced oligodendrocyte number in the cornu ammonis 4 (CA4) subregion of the hippocampus, and others have reported the same histopathological finding in the dorsolateral prefrontal cortex. Our series of studies on aerobic exercise training showed a volume increase in the hippocampus, specifically in the CA4 region, and improved cognition in individuals with schizophrenia. The cognitive effects were subsequently confirmed by meta-analyses. Cell-specific schizophrenia polygenic risk scores showed that exercise-induced CA4 volume increase significantly correlates with OPCs. From animal models, it is evident that early life stress and oligodendrocyte-related gene variants lead to schizophrenia-related behavior, cognitive deficits, impaired oligodendrocyte maturation, and reduced myelin thickness. CONCLUSIONS Based on these findings, we propose that pro-myelinating drugs (e.g., the histamine blocker clemastine) combined with aerobic exercise training may foster the regeneration of myelin plasticity as a basis for restoring frontotemporal connectivity and cognition in schizophrenia.
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Affiliation(s)
- Peter Falkai
- Department of Psychiatry and Psychotherapy, University Hospital, Ludwig-Maximilian University, Munich, Germany
- Max-Planck-Institute of Psychiatry, Munich, Germany
| | - Moritz J Rossner
- Department of Psychiatry and Psychotherapy, University Hospital, Ludwig-Maximilian University, Munich, Germany
| | - Florian J Raabe
- Department of Psychiatry and Psychotherapy, University Hospital, Ludwig-Maximilian University, Munich, Germany
| | - Elias Wagner
- Department of Psychiatry and Psychotherapy, University Hospital, Ludwig-Maximilian University, Munich, Germany
| | - Daniel Keeser
- Department of Psychiatry and Psychotherapy, University Hospital, Ludwig-Maximilian University, Munich, Germany
- NeuroImaging Core Unit Munich (NICUM), University Hospital, Ludwig-Maximilian University, Munich, Germany
| | - Isabel Maurus
- Department of Psychiatry and Psychotherapy, University Hospital, Ludwig-Maximilian University, Munich, Germany
| | - Lukas Roell
- Department of Psychiatry and Psychotherapy, University Hospital, Ludwig-Maximilian University, Munich, Germany
- NeuroImaging Core Unit Munich (NICUM), University Hospital, Ludwig-Maximilian University, Munich, Germany
| | - Emily Chang
- Department of Psychiatry and Psychotherapy, University Hospital, Ludwig-Maximilian University, Munich, Germany
| | - Johanna Seitz-Holland
- Department of Psychiatry, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Thomas G Schulze
- Institute for Psychiatric Phenomic and Genomic (IPPG), Munich, Germany
| | - Andrea Schmitt
- Department of Psychiatry and Psychotherapy, University Hospital, Ludwig-Maximilian University, Munich, Germany
- Laboratory of Neuroscience (LIM27), Institute of Psychiatry, University of São Paulo (USP), São Paulo-SP, Brazil
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Bratzu J, Ciscato M, Pisanu A, Talani G, Frau R, Porcu P, Diana M, Fumagalli F, Romualdi P, Rullo L, Trezza V, Ciccocioppo R, Sanna F, Fattore L. Communal nesting differentially attenuates the impact of pre-weaning social isolation on behavior in male and female rats during adolescence and adulthood. Front Behav Neurosci 2023; 17:1257417. [PMID: 37915532 PMCID: PMC10616881 DOI: 10.3389/fnbeh.2023.1257417] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 10/02/2023] [Indexed: 11/03/2023] Open
Abstract
Introduction Early social isolation (ESI) disrupts neurodevelopmental processes, potentially leading to long-lasting emotional and cognitive changes in adulthood. Communal nesting (CN), i.e., the sharing of parental responsibilities between multiple individuals in a nest, creates a socially enriching environment known to impact social and anxiety-related behaviors. Methods This study examines the effects of (i) the CN condition and of (ii) ESI during the 3rd week of life (i.e., pre-weaning ESI) on motor, cognitive, and emotional domains during adolescence and adulthood in male and female rats reared in the two different housing conditions, as well as (iii) the potential of CN to mitigate the impact of ESI on offspring. Results We found that in a spontaneous locomotor activity test, females exhibited higher activity levels compared to males. In female groups, adolescents reared in standard housing (SH) condition spent less time in the center of the arena, suggestive of increased anxiety levels, while the CN condition increased the time spent in the center during adolescence, but not adulthood, independently from ESI. The prepulse inhibition (PPI) test showed a reduced PPI in ESI adolescent animals of both sexes and in adult males (but not in adult females), with CN restoring PPI in males, but not in adolescent females. Further, in the marble burying test SH-ESI adolescent males exhibited higher marble burying behavior than all other groups, suggestive of obsessive-compulsive traits. CN completely reversed this stress-induced effect. Interestingly, ESI and CN did not have a significant impact on burying behavior in adult animals of both sexes. Discussion Overall, our findings (i) assess the effects of ESI on locomotion, sensorimotor gating, and compulsive-like behaviors, (ii) reveal distinct vulnerabilities of males and females within these domains, and (iii) show how early-life social enrichment may successfully counteract some of the behavioral alterations induced by early-life social stress in a sex-dependent manner. This study strengthens the notion that social experiences during early-life can shape emotional and cognitive outcomes in adulthood, and points to the importance of social enrichment interventions for mitigating the negative effects of early social stress on neurodevelopment.
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Affiliation(s)
- Jessica Bratzu
- Neuroscience Institute, National Research Council of Italy (CNR), Cagliari, Italy
| | - Maria Ciscato
- Neuroscience Institute, National Research Council of Italy (CNR), Cagliari, Italy
| | - Augusta Pisanu
- Neuroscience Institute, National Research Council of Italy (CNR), Cagliari, Italy
| | - Giuseppe Talani
- Neuroscience Institute, National Research Council of Italy (CNR), Cagliari, Italy
| | - Roberto Frau
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Patrizia Porcu
- Neuroscience Institute, National Research Council of Italy (CNR), Cagliari, Italy
| | - Marco Diana
- G.Minardi’ Cognitive Neuroscience Laboratory, CPMB Science Department, University of Sassari, Sassari, Italy
| | - Fabio Fumagalli
- Department of Pharmacological and Biomolecular Sciences ‘Rodolfo Paoletti’, University of Milan, Milan, Italy
| | - Patrizia Romualdi
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Laura Rullo
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Viviana Trezza
- Department of Science, University “Roma Tre”, Rome, Italy
| | - Roberto Ciccocioppo
- School of Pharmacy, Center for Neuroscience, Pharmacology Unit, University of Camerino, Camerino, Italy
| | - Fabrizio Sanna
- Department of Biomedical Sciences, University of Cagliari, Monserrato, Italy
| | - Liana Fattore
- Neuroscience Institute, National Research Council of Italy (CNR), Cagliari, Italy
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Zhang C, Zhou X, Zhou X. Effect of Acute Brief Social Isolation on Visceral Pain. J Pain Res 2022; 15:3547-3553. [PMID: 36394056 PMCID: PMC9657267 DOI: 10.2147/jpr.s378244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 10/05/2022] [Indexed: 11/10/2022] Open
Abstract
Objective The sensitivity of somatic pain could be affected by social isolation; however, few studies have examined the impact of social isolation on visceral pain. In the present study, the effect of acute brief social isolation on visceral pain response was investigated. Methods Adult male rats were either reared individually or grouped for 2 hours or 24 hours. Colorectal distention (CRD)-induced abdominal withdrawal reflex (AWR) score and pain threshold were used to assess visceral pain sensitivity. The amount of fecal bolus was used to determine the stress level. Results Acute brief isolation rearing for 2 hours significantly increased AWR score and reduced visceral pain threshold in rats when compared to group rearing. Similarly, acute isolation for 24 hours resulted in visceral hypersensitivity, as indicated by an increase in the AWR score and a decrease in the visceral pain threshold. Furthermore, the amount of fecal bolus in acute isolation rearing (2 or 24 hours) rats was considerably higher than in the control group rearing rats. Conclusion Acute short-term social isolation enhances visceral pain sensitivity, which could be related to an increase in stress levels.
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Affiliation(s)
- Chenjing Zhang
- Department of Gastroenterology, Zhejiang Provincial People’s Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, 310014, People’s Republic of China
| | - Xiaolu Zhou
- Department of Gastroenterology, Zhejiang Provincial People’s Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, 310014, People’s Republic of China
| | - Xuelong Zhou
- Department of Anesthesiology and Perioperative Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, People’s Republic of China
- Correspondence: Xuelong Zhou, Department of Anesthesiology and Perioperative Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, People’s Republic of China, Tel +86-021-83714511, Email
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5
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Zhou X, Zhou X, Zhang C. Long-term social isolation increases visceral pain in rats. Heliyon 2022; 8:e11663. [DOI: 10.1016/j.heliyon.2022.e11663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 09/19/2022] [Accepted: 11/10/2022] [Indexed: 11/19/2022] Open
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Perrino PA, Chasse RY, Monaco AP, Molnár Z, Velayos‐Baeza A, Fitch RH. Rapid auditory processing and medial geniculate nucleus anomalies in Kiaa0319 knockout mice. GENES, BRAIN, AND BEHAVIOR 2022; 21:e12808. [PMID: 35419947 PMCID: PMC9744489 DOI: 10.1111/gbb.12808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 03/23/2022] [Accepted: 03/31/2022] [Indexed: 11/29/2022]
Abstract
Developmental dyslexia is a common neurodevelopmental disorder characterized by difficulties in reading and writing. Although underlying biological and genetic mechanisms remain unclear, anomalies in phonological processing and auditory processing have been associated with dyslexia. Several candidate risk genes have also been identified, with KIAA0319 as a main candidate. Animal models targeting the rodent homolog (Kiaa0319) have been used to explore putative behavioral and anatomic anomalies, with mixed results. For example after downregulation of Kiaa0319 expression in rats via shRNA, significant adult rapid auditory processing impairments were reported, along with cortical anomalies reflecting atypical neuronal migration. Conversely, Kiaa0319 knockout (KO) mice were reported to have typical adult auditory processing, and no visible cortical anomalies. To address these inconsistencies, we tested Kiaa0319 KO mice on auditory processing tasks similar to those used previously in rat shRNA knockdown studies. Subsequent neuroanatomic analyses on these same mice targeted medial geniculate nucleus (MGN), a receptive communication-related brain structure. Results confirm that Kiaa0319 KO mice exhibit significant auditory processing impairments specific to rapid/brief stimuli, and also show significant volumetric reductions and a shift toward fewer large and smaller neurons in the MGN. The latter finding is consistent with post mortem MGN data from human dyslexic brains. Combined evidence supports a role for KIAA0319 in the development of auditory CNS pathways subserving rapid auditory processing functions critical to the development of speech processing, language, and ultimately reading. Results affirm KIAA0319 variation as a possible risk factor for dyslexia specifically via anomalies in central acoustic processing pathways.
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Affiliation(s)
- Peter A. Perrino
- Department of Psychological Science/Behavioral NeuroscienceUniversity of ConnecticutStorrsConnecticutUSA
| | - Renee Y. Chasse
- Department of Psychological Science/Behavioral NeuroscienceUniversity of ConnecticutStorrsConnecticutUSA
| | | | - Zoltán Molnár
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK
| | - Antonio Velayos‐Baeza
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUK,Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUK
| | - R. Holly Fitch
- Department of Psychological Science/Behavioral NeuroscienceUniversity of ConnecticutStorrsConnecticutUSA
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Craeghs L, Callaerts-Vegh Z, Verslegers M, Van der Jeugd A, Govaerts K, Dresselaers T, Wogensen E, Verreet T, Moons L, Benotmane MA, Himmelreich U, D'Hooge R. Prenatal Radiation Exposure Leads to Higher-Order Telencephalic Dysfunctions in Adult Mice That Coincide with Reduced Synaptic Plasticity and Cerebral Hypersynchrony. Cereb Cortex 2021; 32:3525-3541. [PMID: 34902856 DOI: 10.1093/cercor/bhab431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 11/14/2022] Open
Abstract
Higher-order telencephalic circuitry has been suggested to be especially vulnerable to irradiation or other developmentally toxic impact. This report details the adult effects of prenatal irradiation at a sensitive time point on clinically relevant brain functions controlled by telencephalic regions, hippocampus (HPC), and prefrontal cortex (PFC). Pregnant C57Bl6/J mice were whole-body irradiated at embryonic day 11 (start of neurogenesis) with X-ray intensities of 0.0, 0.5, or 1.0 Gy. Female offspring completed a broad test battery of HPC-/PFC-controlled tasks that included cognitive performance, fear extinction, exploratory, and depression-like behaviors. We examined neural functions that are mechanistically related to these behavioral and cognitive changes, such as hippocampal field potentials and long-term potentiation, functional brain connectivity (by resting-state functional magnetic resonance imaging), and expression of HPC vesicular neurotransmitter transporters (by immunohistochemical quantification). Prenatally exposed mice displayed several higher-order dysfunctions, such as decreased nychthemeral activity, working memory defects, delayed extinction of threat-evoked response suppression as well as indications of perseverative behavior. Electrophysiological examination indicated impaired hippocampal synaptic plasticity. Prenatal irradiation also induced cerebral hypersynchrony and increased the number of glutamatergic HPC terminals. These changes in brain connectivity and plasticity could mechanistically underlie the irradiation-induced defects in higher telencephalic functions.
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Affiliation(s)
- Livine Craeghs
- Department of Brain & Cognition, Research Group Biological Psychology, University of Leuven (KU Leuven), Leuven 3000, Belgium
| | - Zsuzsanna Callaerts-Vegh
- Department of Brain & Cognition, Research Group Biological Psychology, University of Leuven (KU Leuven), Leuven 3000, Belgium
| | - Mieke Verslegers
- Department of Radiobiology, Institute for Environmental Health and Safety, Nuclear Research Center (SCK CEN), Mol 2400, Belgium
| | - Ann Van der Jeugd
- Department of Brain & Cognition, Research Group Biological Psychology, University of Leuven (KU Leuven), Leuven 3000, Belgium
| | - Kristof Govaerts
- Department of Imaging & Pathology, Research Group Biomedical MRI, University of Leuven (KU Leuven), Leuven 3000, Belgium
| | - Tom Dresselaers
- Department of Imaging & Pathology, Research Group Biomedical MRI, University of Leuven (KU Leuven), Leuven 3000, Belgium
| | - Elise Wogensen
- Department of Brain & Cognition, Research Group Biological Psychology, University of Leuven (KU Leuven), Leuven 3000, Belgium
| | - Tine Verreet
- Department of Radiobiology, Institute for Environmental Health and Safety, Nuclear Research Center (SCK CEN), Mol 2400, Belgium
| | - Lieve Moons
- Department of Biology, Research Group Neural Circuit Development and Regeneration, University of Leuven (KU Leuven), Leuven 3000, Belgium
| | - Mohammed A Benotmane
- Department of Radiobiology, Institute for Environmental Health and Safety, Nuclear Research Center (SCK CEN), Mol 2400, Belgium
| | - Uwe Himmelreich
- Department of Imaging & Pathology, Research Group Biomedical MRI, University of Leuven (KU Leuven), Leuven 3000, Belgium
| | - Rudi D'Hooge
- Department of Brain & Cognition, Research Group Biological Psychology, University of Leuven (KU Leuven), Leuven 3000, Belgium
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Sansoninto attenuates aggressive behavior and increases levels of homovanillic acid, a dopamine metabolite, in social isolation-reared mice. J Tradit Complement Med 2021; 12:243-249. [PMID: 35493307 PMCID: PMC9039115 DOI: 10.1016/j.jtcme.2021.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 07/20/2021] [Accepted: 08/09/2021] [Indexed: 11/29/2022] Open
Abstract
Background and aim Early-life stress is thought to affect aggressive behavior in humans and rodents. Laboratory experiments have demonstrated that Sansoninto (SST; 酸棗仁湯 suān zǎo rén tāng), a traditional herbal medicine, attenuates stress-induced abnormal behavior in rodents. However, it is unknown whether SST attenuates stress-induced aggressive behavior. The current study examined the effects of SST on aggressive behavior of mice who suffered from social isolation (SI) stress in adolescence. Experimental procedure Five-week old mice were socially isolated for 6 weeks, and SST administration was started at 4 weeks after starting SI. Aggressive behavior and locomotor activity were examined in SST-treated mice. The content of dopamine and its metabolites in the hypothalamus were examined using high-performance liquid chromatography analysis. Gene expression analyses of monoamine oxidase-B (MAO-B), catechol-O-methyltransferase (COMT), and tyrosine hydroxylase in the hypothalamus were performed using quantitative reverse transcription polymerase chain reaction. Results and conclusion SST attenuated SI-induced aggressive behavior and increased levels of homovanillic acid, a metabolite of dopamine. However, SST did not affect dopamine levels. SI enhanced locomotion in a novel environment and increased COMT mRNA levels. In contrast, SST-treated mice showed no significant enhancement of locomotion. SST attenuated the increase in COMT mRNA levels. Given that the dopaminergic system has been implicated in aggressive behavior, these findings suggest that SST toned down dopaminergic signaling, resulting in amelioration of aggression. SST may be useful for treatment of aggressive behavior in patients with neurotic symptoms. Sansoninto prevented increased aggressive behavior in social isolation-reared mice. Sansoninto attenuated increased COMT mRNA in social isolation-reared mice. Hypothalamic homovanillic acid level was increased by Sansoninto.
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Silva J, Shao AS, Shen Y, Davies DL, Olsen RW, Holschneider DP, Shao XM, Liang J. Modulation of Hippocampal GABAergic Neurotransmission and Gephyrin Levels by Dihydromyricetin Improves Anxiety. Front Pharmacol 2020; 11:1008. [PMID: 32742262 PMCID: PMC7364153 DOI: 10.3389/fphar.2020.01008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 06/22/2020] [Indexed: 12/11/2022] Open
Abstract
Anxiety disorders are the most common mental illness in the U.S. and are estimated to consume one-third of the country’s mental health spending. Although anxiolytic therapies are available, many patients exhibit treatment-resistance, relapse, or substantial side effects. An urgent need exists to explore the underlying mechanisms of chronic anxiety and to develop alternative therapies. Presently, we identified dihydromyricetin (DHM), a flavonoid that has anxiolytic properties in a mouse model of isolation-induced anxiety. Socially isolated mice demonstrated increased anxiety levels and reduced exploratory behavior measured by elevated plus-maze and open-field tests. Socially isolated mice showed impaired GABAergic neurotransmission, including reduction in GABAA receptor-mediated extrasynaptic tonic currents, as well as amplitude and frequency of miniature inhibitory postsynaptic currents measured by whole-cell patch-clamp recordings from hippocampal slices. Furthermore, intracellular ATP levels and gephyrin expression decreased in anxious animals. DHM treatment restored ATP and gephyrin expression, GABAergic transmission and synaptic function, as well as decreased anxiety-like behavior. Our findings indicate broader roles for DHM in anxiolysis, GABAergic neurotransmission, and synaptic function. Collectively, our data suggest that reduction in intracellular ATP and gephyrin contribute to the development of anxiety, and represent novel treatment targets. DHM is a potential candidate for pharmacotherapy for anxiety disorders.
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Affiliation(s)
- Joshua Silva
- Titus Family Department of Clinical Pharmacy, University of Southern California School of Pharmacy, Los Angeles, CA, United States
| | - Amy S Shao
- Molecular & Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Yi Shen
- Department of Neurobiology, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Daryl L Davies
- Titus Family Department of Clinical Pharmacy, University of Southern California School of Pharmacy, Los Angeles, CA, United States
| | - Richard W Olsen
- Molecular & Medical Pharmacology, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Daniel P Holschneider
- Psychiatry and The Behavioral Sciences, University of Southern California, Los Angeles, CA, United States
| | - Xuesi M Shao
- Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Jing Liang
- Titus Family Department of Clinical Pharmacy, University of Southern California School of Pharmacy, Los Angeles, CA, United States
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Glutamic acid decarboxylase 67 haplodeficiency in mice: consequences of postweaning social isolation on behavior and changes in brain neurochemical systems. Brain Struct Funct 2020; 225:1719-1742. [PMID: 32514634 PMCID: PMC7321906 DOI: 10.1007/s00429-020-02087-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 05/09/2020] [Indexed: 01/22/2023]
Abstract
Reductions of glutamate acid decarboxylase (GAD67) and subsequent GABA levels have been consistently observed in neuropsychiatric disorders like schizophrenia and depression, but it has remained unclear how GABAergic dysfunction contributes to different symptoms of the diseases. To address this issue, we investigated male mice haplodeficient for GAD67 (GAD67+/GFP mice), which showed a reduced social interaction, social dominance and increased immobility in the forced swim test. No differences were found in rotarod performance and sensorimotor gating. We also addressed potential effects of social deprivation, which is known, during early life, to affect GABAergic function and induces behavioral abnormalities similar to the symptoms found in psychiatric disorders. Indeed, social isolation of GAD67+/GFP mice provoked increased rearing activity in the social interaction test and hyperlocomotion on elevated plus maze. Since GABA closely interacts with the dopaminergic, serotonergic and cholinergic neurotransmitter systems, we investigated GAD67+/GFP and GAD67+/+ mice for morphological markers of the latter systems and found increased tyrosine hydroxylase (TH)-IR fiber densities in CA1 of dorsal hippocampus. By contrast, no differences in numbers and densities of TH-positive neurons of the midbrain dopamine regions, serotonin (5-HT) neurons of the raphe nuclei, or choline acetyltransferase (ChAT)-expressing neurons of basal forebrain and their respective terminal fields were observed. Our results indicate that GAD67 haplodeficiency impairs sociability and increases vulnerability to social stress, provokes depressive-like behavior and alters the catecholaminergic innervation in brain areas associated with schizophrenia. GAD67+/GFP mice may provide a useful model for studying the impact of GABAergic dysfunction as related to neuropsychiatric disorders.
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11
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Raabe FJ, Slapakova L, Rossner MJ, Cantuti-Castelvetri L, Simons M, Falkai PG, Schmitt A. Oligodendrocytes as A New Therapeutic Target in Schizophrenia: From Histopathological Findings to Neuron-Oligodendrocyte Interaction. Cells 2019; 8:cells8121496. [PMID: 31771166 PMCID: PMC6952785 DOI: 10.3390/cells8121496] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/20/2019] [Accepted: 11/21/2019] [Indexed: 12/11/2022] Open
Abstract
Imaging and postmortem studies have revealed disturbed oligodendroglia-related processes in patients with schizophrenia and provided much evidence for disturbed myelination, irregular gene expression, and altered numbers of oligodendrocytes in the brains of schizophrenia patients. Oligodendrocyte deficits in schizophrenia might be a result of failed maturation and disturbed regeneration and may underlie the cognitive deficits of the disease, which are strongly associated with impaired long-term outcome. Cognition depends on the coordinated activity of neurons and interneurons and intact connectivity. Oligodendrocyte precursors form a synaptic network with parvalbuminergic interneurons, and disturbed crosstalk between these cells may be a cellular basis of pathology in schizophrenia. However, very little is known about the exact axon-glial cellular and molecular processes that may be disturbed in schizophrenia. Until now, investigations were restricted to peripheral tissues, such as blood, correlative imaging studies, genetics, and molecular and histological analyses of postmortem brain samples. The advent of human-induced pluripotent stem cells (hiPSCs) will enable functional analysis in patient-derived living cells and holds great potential for understanding the molecular mechanisms of disturbed oligodendroglial function in schizophrenia. Targeting such mechanisms may contribute to new treatment strategies for previously treatment-resistant cognitive symptoms.
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Affiliation(s)
- Florian J. Raabe
- Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Nussbaumstrasse 7, 80336 Munich, Germany; (F.J.R.); (L.S.); (P.G.F.)
- International Max Planck Research School for Translational Psychiatry (IMPRS-TP), Kraepelinstr, 2-10, 80804 Munich, Germany
- Molecular and Behavioural Neurobiology, Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, 80336 Munich, Germany;
| | - Lenka Slapakova
- Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Nussbaumstrasse 7, 80336 Munich, Germany; (F.J.R.); (L.S.); (P.G.F.)
- International Max Planck Research School for Translational Psychiatry (IMPRS-TP), Kraepelinstr, 2-10, 80804 Munich, Germany
| | - Moritz J. Rossner
- Molecular and Behavioural Neurobiology, Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, 80336 Munich, Germany;
| | - Ludovico Cantuti-Castelvetri
- German Center for Neurodegenerative Diseases (DZNE), Feodor-Lynen Str. 17, 81377 Munich, Germany; (L.C.-C.); (M.S.)
| | - Mikael Simons
- German Center for Neurodegenerative Diseases (DZNE), Feodor-Lynen Str. 17, 81377 Munich, Germany; (L.C.-C.); (M.S.)
- Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
- Institute of Neuronal Cell Biology, Technical University Munich, 80805 Munich, Germany
| | - Peter G. Falkai
- Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Nussbaumstrasse 7, 80336 Munich, Germany; (F.J.R.); (L.S.); (P.G.F.)
| | - Andrea Schmitt
- Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Nussbaumstrasse 7, 80336 Munich, Germany; (F.J.R.); (L.S.); (P.G.F.)
- Molecular and Behavioural Neurobiology, Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, 80336 Munich, Germany;
- Laboratory of Neuroscience (LIM27), Institute of Psychiatry, University of Sao Paulo, 05453-010 São Paulo, Brazil
- Correspondence: ; Tel.: +49-(0)89-4400-52761; Fax: +49-(0)89-4400-55530
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12
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Sichler ME, Löw MJ, Schleicher EM, Bayer TA, Bouter Y. Reduced Acoustic Startle Response and Prepulse Inhibition in the Tg4-42 Model of Alzheimer's Disease. J Alzheimers Dis Rep 2019; 3:269-278. [PMID: 31867566 PMCID: PMC6918877 DOI: 10.3233/adr-190132] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Sensorimotor deficits have been described in several neuropsychiatric disorders including Alzheimer’s disease. The aim of the present study was to evaluate possible sensorimotor gating deficits in the Tg4-42 mouse model of Alzheimer’s disease using the prepulse inhibition task (PPI). Previous studies indicated that the hippocampus is essentially involved in the regulation of PPI. We analyzed 7-month-old homozygous Tg4-42 mice as mice at this age display severe neuron loss especially in the CA1 region of the hippocampus. Our results revealed a reduced startle response and PPI in Tg4-42 mice. The observed deficits in startle response and PPI are likely due to altered sensory processing abilities rather than hearing deficits as Tg4-42 displayed intact hearing in the fear conditioning task. The present study demonstrates for the first time that sensorimotor gating is impaired in Tg4-42 mice. Analyzing startle response as well as the PPI may offer valuable measurements to assess the efficacy of therapeutic strategies in the future in this Alzheimer’s disease model.
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Affiliation(s)
- Marius E Sichler
- Division of Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Medical Center Goettingen (UMG), Georg-August-University, Goettingen, Germany
| | - Maximilian J Löw
- Division of Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Medical Center Goettingen (UMG), Georg-August-University, Goettingen, Germany
| | - Eva M Schleicher
- Division of Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Medical Center Goettingen (UMG), Georg-August-University, Goettingen, Germany
| | - Thomas A Bayer
- Division of Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Medical Center Goettingen (UMG), Georg-August-University, Goettingen, Germany
| | - Yvonne Bouter
- Division of Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Medical Center Goettingen (UMG), Georg-August-University, Goettingen, Germany
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13
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Gulinello M, Mitchell HA, Chang Q, Timothy O'Brien W, Zhou Z, Abel T, Wang L, Corbin JG, Veeraragavan S, Samaco RC, Andrews NA, Fagiolini M, Cole TB, Burbacher TM, Crawley JN. Rigor and reproducibility in rodent behavioral research. Neurobiol Learn Mem 2019; 165:106780. [PMID: 29307548 PMCID: PMC6034984 DOI: 10.1016/j.nlm.2018.01.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 12/22/2017] [Accepted: 01/03/2018] [Indexed: 01/08/2023]
Abstract
Behavioral neuroscience research incorporates the identical high level of meticulous methodologies and exacting attention to detail as all other scientific disciplines. To achieve maximal rigor and reproducibility of findings, well-trained investigators employ a variety of established best practices. Here we explicate some of the requirements for rigorous experimental design and accurate data analysis in conducting mouse and rat behavioral tests. Novel object recognition is used as an example of a cognitive assay which has been conducted successfully with a range of methods, all based on common principles of appropriate procedures, controls, and statistics. Directors of Rodent Core facilities within Intellectual and Developmental Disabilities Research Centers contribute key aspects of their own novel object recognition protocols, offering insights into essential similarities and less-critical differences. Literature cited in this review article will lead the interested reader to source papers that provide step-by-step protocols which illustrate optimized methods for many standard rodent behavioral assays. Adhering to best practices in behavioral neuroscience will enhance the value of animal models for the multiple goals of understanding biological mechanisms, evaluating consequences of genetic mutations, and discovering efficacious therapeutics.
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Affiliation(s)
- Maria Gulinello
- IDDRC Behavioral Core Facility, Neuroscience Department, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Heather A Mitchell
- IDD Models Core, Waisman Center, University of Wisconsin Madison, Madison, WI 53705, USA
| | - Qiang Chang
- IDD Models Core, Waisman Center, University of Wisconsin Madison, Madison, WI 53705, USA
| | - W Timothy O'Brien
- IDDRC Preclinical Models Core, Children's Hospital of Philadelphia and University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Zhaolan Zhou
- IDDRC Preclinical Models Core, Children's Hospital of Philadelphia and University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Ted Abel
- IDDRC Preclinical Models Core, Children's Hospital of Philadelphia and University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Current affiliation: Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, USA
| | - Li Wang
- IDDRC Neurobehavioral Core, Center for Neuroscience Research, Children's National Health System, Washington, DC 20010, USA
| | - Joshua G Corbin
- IDDRC Neurobehavioral Core, Center for Neuroscience Research, Children's National Health System, Washington, DC 20010, USA
| | - Surabi Veeraragavan
- IDDRC Neurobehavioral Core, Baylor College of Medicine, Houston, TX 77030, USA
| | - Rodney C Samaco
- IDDRC Neurobehavioral Core, Baylor College of Medicine, Houston, TX 77030, USA
| | - Nick A Andrews
- IDDRC Neurodevelopmental Behavior Core, Boston Children's Hospital, Boston, MA 02115, USA
| | - Michela Fagiolini
- IDDRC Neurodevelopmental Behavior Core, Boston Children's Hospital, Boston, MA 02115, USA
| | - Toby B Cole
- IDDRC Rodent Behavior Laboratory, Center on Human Development and Disability, University of Washington, Seattle, WA 98195, USA
| | - Thomas M Burbacher
- IDDRC Rodent Behavior Laboratory, Center on Human Development and Disability, University of Washington, Seattle, WA 98195, USA
| | - Jacqueline N Crawley
- IDDRC Rodent Behavior Core, MIND Institute, University of California Davis School of Medicine, Sacramento, CA 95817, USA.
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14
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Fulford AJ, Keskes S. Limbic circuit connectivity and the stress response: New insights into the mammalian nociceptin peptide system. VITAMINS AND HORMONES 2019; 111:131-145. [PMID: 31421698 DOI: 10.1016/bs.vh.2019.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
Considerable progress has been made in understanding the neurobehavioral effects of nociceptin peptide (N/OFQ) and its NOP receptor. Recent interest has focused on its role in stress and cognition, with consideration of therapeutic potential in regard to anxiety and mood disorders. Research has interrogated the mechanisms of action of N/OFQ peptide in the context of stress-related behavior. We are interested in the endogenous role of N/OFQ and NOP receptor in terms of adaptation to chronic stress. Our research has highlighted the importance of associated limbic regions including the bed nucleus, extended amygdala, in addition to thalamic reticular nucleus as important sites for long-term adaptations in endogenous N/OFQ function in chronic stress. Such research raises interest in appreciation of extended limbic connections and novel pathways which allow us to reevaluate current understanding of stress neurocircuitry. Examination of endogenous N/OFQ-NOP receptor modulation of monoaminergic and amino acid transmitter systems in this extended limbic architecture will facilitate deeper understanding of the tonic control of behavior. Application of in vivo experimental approaches to models of abnormal neurodevelopment and heightened stress vulnerability in adulthood will enable the role of N/OFQ in complex neuropsychiatric disorders including schizophrenia and post-traumatic stress disorder to be defined.
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Affiliation(s)
| | - Sarah Keskes
- Centre for Applied Anatomy, University of Bristol, Bristol, United Kingdom; Keele University Medical School, Keele, United Kingdom
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15
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Popovic D, Schmitt A, Kaurani L, Senner F, Papiol S, Malchow B, Fischer A, Schulze TG, Koutsouleris N, Falkai P. Childhood Trauma in Schizophrenia: Current Findings and Research Perspectives. Front Neurosci 2019; 13:274. [PMID: 30983960 PMCID: PMC6448042 DOI: 10.3389/fnins.2019.00274] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 03/07/2019] [Indexed: 01/09/2023] Open
Abstract
Schizophrenia is a severe neuropsychiatric disorder with persistence of symptoms throughout adult life in most of the affected patients. This unfavorable course is associated with multiple episodes and residual symptoms, mainly negative symptoms and cognitive deficits. The neural diathesis-stress model proposes that psychosocial stress acts on a pre-existing vulnerability and thus triggers the symptoms of schizophrenia. Childhood trauma is a severe form of stress that renders individuals more vulnerable to developing schizophrenia; neurobiological effects of such trauma on the endocrine system and epigenetic mechanisms are discussed. Childhood trauma is associated with impaired working memory, executive function, verbal learning, and attention in schizophrenia patients, including those at ultra-high risk to develop psychosis. In these patients, higher levels of childhood trauma were correlated with higher levels of attenuated positive symptoms, general symptoms, and depressive symptoms; lower levels of global functioning; and poorer cognitive performance in visual episodic memory end executive functions. In this review, we discuss effects of specific gene variants that interact with childhood trauma in patients with schizophrenia and describe new findings on the brain structural and functional level. Additive effects between childhood trauma and brain-derived neurotrophic factor methionine carriers on volume loss of the hippocampal subregions cornu ammonis (CA)4/dentate gyrus and CA2/3 have been reported in schizophrenia patients. A functional magnetic resonance imaging study showed that childhood trauma exposure resulted in aberrant function of parietal areas involved in working memory and of visual cortical areas involved in attention. In a theory of mind task reflecting social cognition, childhood trauma was associated with activation of the posterior cingulate gyrus, precuneus, and dorsomedial prefrontal cortex in patients with schizophrenia. In addition, decreased connectivity was shown between the posterior cingulate/precuneus region and the amygdala in patients with high levels of physical neglect and sexual abuse during childhood, suggesting that disturbances in specific brain networks underlie cognitive abilities. Finally, we discuss some of the questionnaires that are commonly used to assess childhood trauma and outline possibilities to use recent biostatistical methods, such as machine learning, to analyze the resulting datasets.
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Affiliation(s)
- David Popovic
- Department of Psychiatry and Psychotherapy, University Hospital, Ludwig Maximilian University of Munich, Munich, Germany.,International Max Planck Research School for Translational Psychiatry (IMPRS-TP), Munich, Germany
| | - Andrea Schmitt
- Department of Psychiatry and Psychotherapy, University Hospital, Ludwig Maximilian University of Munich, Munich, Germany.,Laboratory of Neuroscience (LIM27), Institute of Psychiatry, University of São Paulo, São Paulo, Brazil
| | - Lalit Kaurani
- German Center of Neurodegenerative Diseases, University of Göttingen, Göttingen, Germany
| | - Fanny Senner
- Department of Psychiatry and Psychotherapy, University Hospital, Ludwig Maximilian University of Munich, Munich, Germany.,Institute of Psychiatric Phenomics and Genomics, University Hospital, Ludwig Maximilian University of Munich, Munich, Germany
| | - Sergi Papiol
- Department of Psychiatry and Psychotherapy, University Hospital, Ludwig Maximilian University of Munich, Munich, Germany.,Institute of Psychiatric Phenomics and Genomics, University Hospital, Ludwig Maximilian University of Munich, Munich, Germany
| | - Berend Malchow
- Department of Psychiatry and Psychotherapy, University Hospital of Jena, Jena, Germany
| | - Andre Fischer
- German Center of Neurodegenerative Diseases, University of Göttingen, Göttingen, Germany
| | - Thomas G Schulze
- Institute of Psychiatric Phenomics and Genomics, University Hospital, Ludwig Maximilian University of Munich, Munich, Germany
| | - Nikolaos Koutsouleris
- Department of Psychiatry and Psychotherapy, University Hospital, Ludwig Maximilian University of Munich, Munich, Germany
| | - Peter Falkai
- Department of Psychiatry and Psychotherapy, University Hospital, Ludwig Maximilian University of Munich, Munich, Germany
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16
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Shoji H, Miyakawa T. Relationships between the acoustic startle response and prepulse inhibition in C57BL/6J mice: a large-scale meta-analytic study. Mol Brain 2018; 11:42. [PMID: 30001725 PMCID: PMC6044095 DOI: 10.1186/s13041-018-0382-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 06/25/2018] [Indexed: 11/10/2022] Open
Abstract
Prepulse inhibition (PPI) is the suppression of a startle reflex response to a startle stimulus that occurs when a weak prepulse stimulus precedes the startle stimulus. PPI is measured to assess sensorimotor gating across species, including humans and rodents. Reduced PPI, which is thought to reflect dysfunction of sensorimotor gating, is reported in patients with psychiatric disorders, such as schizophrenia, bipolar disorder, and post-traumatic stress disorder (PTSD), and in animal models of these disorders. Individual differences in basal startle reactivity occur even in a genetically homogenous group of animals; however, there is limited information regarding whether basal levels of the startle response are associated with variations in PPI levels. Here, to explore the relationship between an acoustic startle response (ASR) and PPI, we performed a meta-analysis of data obtained from more than 1300 C57BL/6J male mice on the influence of an ASR to 110- and 120-dB startle stimuli on the PPI levels of the ASR at 74- and 78-dB prepulse intensities. Examination of scatter plots of the ASR amplitudes and PPI levels followed by correlation analyses indicated that there is no simple linear relationship between the two measures; when mice were divided into three groups on the basis of their startle amplitudes, there were positive correlations between the amplitude of the ASR to the 110-dB stimulus and PPI levels in a group of mice that showed lower ASR amplitudes among the genetically homogenous group, whereas no significant correlations were identified in groups of mice that showed intermediate and higher ASR amplitudes. As indicated by the correlation analysis, the lowest responders to the 110-dB stimulus exhibited lower levels of PPI than the intermediate or higher responders. In contrast, for the 120-dB stimulus, a negative correlation was identified between the amplitude of the ASR to the 120-dB stimulus and the PPI levels in the groups of mice that showed intermediate or higher ASR amplitudes. Lower and intermediate responders showed higher levels of PPI than higher responders to the 120-dB stimulus. These findings suggest that basal startle reactivity may affect PPI levels in male C57BL/6J mice, thus representing one potential confounding factor that may confuse the interpretation of PPI results. These findings emphasize the importance of careful examination of startle reactivity to ensure a reliable assessment of PPI.
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Affiliation(s)
- Hirotaka Shoji
- Division of Systems Medical Science, Institute for Comprehensive Medical Science, Fujita Health University, 1-98 Dengakugakubo Kutsukake-cho, Toyoake, Aichi, 470-1192, Japan
| | - Tsuyoshi Miyakawa
- Division of Systems Medical Science, Institute for Comprehensive Medical Science, Fujita Health University, 1-98 Dengakugakubo Kutsukake-cho, Toyoake, Aichi, 470-1192, Japan.
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17
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Arakawa H. Ethological approach to social isolation effects in behavioral studies of laboratory rodents. Behav Brain Res 2018; 341:98-108. [DOI: 10.1016/j.bbr.2017.12.022] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 12/15/2017] [Accepted: 12/17/2017] [Indexed: 12/31/2022]
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18
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Lauer AM, Behrens D, Klump G. Acoustic startle modification as a tool for evaluating auditory function of the mouse: Progress, pitfalls, and potential. Neurosci Biobehav Rev 2017; 77:194-208. [PMID: 28327385 PMCID: PMC5446932 DOI: 10.1016/j.neubiorev.2017.03.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 02/23/2017] [Accepted: 03/13/2017] [Indexed: 12/16/2022]
Abstract
Acoustic startle response (ASR) modification procedures, especially prepulse inhibition (PPI), are increasingly used as behavioral measures of auditory processing and sensorimotor gating in rodents due to their perceived ease of implementation and short testing times. In practice, ASR and PPI procedures are extremely variable across animals, experimental setups, and studies, and the interpretation of results is subject to numerous caveats and confounding influences. We review considerations for modification of the ASR using acoustic stimuli, and we compare the sensitivity of PPI procedures to more traditional operant psychoacoustic techniques. We also discuss non-auditory variables that must be considered. We conclude that ASR and PPI measures cannot substitute for traditional operant techniques due to their low sensitivity. Additionally, a substantial amount of pilot testing must be performed to properly optimize an ASR modification experiment, negating any time benefit over operant conditioning. Nevertheless, there are some circumstances where ASR measures may be the only option for assessing auditory behavior, such as when testing mouse strains with early-onset hearing loss or learning impairments.
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Affiliation(s)
- Amanda M Lauer
- Department of Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins University, 515 Traylor Building, 720 Rutland Ave., Baltimore, MD 21205, USA.
| | - Derik Behrens
- Cluster of Excellence Hearing4all, Animal Physiology & Behavior Group, Department for Neuroscience, School of Medicine and Health Sciences, Carl Von Ossietzky University Oldenburg, Carl Von Ossietzky Str. 9-11, 26111 Oldenburg, Germany
| | - Georg Klump
- Cluster of Excellence Hearing4all, Animal Physiology & Behavior Group, Department for Neuroscience, School of Medicine and Health Sciences, Carl Von Ossietzky University Oldenburg, Carl Von Ossietzky Str. 9-11, 26111 Oldenburg, Germany
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19
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Lander SS, Linder-Shacham D, Gaisler-Salomon I. Differential effects of social isolation in adolescent and adult mice on behavior and cortical gene expression. Behav Brain Res 2016; 316:245-254. [PMID: 27618762 DOI: 10.1016/j.bbr.2016.09.005] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 08/07/2016] [Accepted: 09/02/2016] [Indexed: 12/15/2022]
Abstract
Intact function of the medial prefrontal cortex (mPFC) function relies on proper development of excitatory and inhibitory neuronal populations and on integral myelination processes. Social isolation (SI) affects behavior and brain circuitry in adulthood, but previous rodent studies typically induced prolonged (post-weaning) exposure and failed to directly compare between the effects of SI in adolescent and adulthood. Here, we assessed the impact of a 3-week SI period, starting in mid-adolescence (around the onset of puberty) or adulthood, on a wide range of behaviors in adult male mice. Additionally, we asked whether adolescent SI would differentially affect the expression of excitatory and inhibitory neuronal markers and myelin-related genes in mPFC. Our findings indicate that mid-adolescent or adult SI increase anxiogenic behavior and locomotor activity. However, SI in adolescence uniquely affects the response to the psychotomimetic drug amphetamine, social and novelty exploration and performance in reversal and attentional set shifting tasks. Furthermore, adolescent but not adult SI increased the expression of glutamate markers in the adult mPFC. Our results imply that adolescent social deprivation is detrimental for normal development and may be particularly relevant to the investigation of developmental psychopathology.
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Affiliation(s)
- Sharon S Lander
- Haifa University, Psychology Dept., 199 Aba Khoushy Ave., Mount Carmel, Haifa 3498838, Israel
| | - Donna Linder-Shacham
- Haifa University, Psychology Dept., 199 Aba Khoushy Ave., Mount Carmel, Haifa 3498838, Israel
| | - Inna Gaisler-Salomon
- Haifa University, Psychology Dept., 199 Aba Khoushy Ave., Mount Carmel, Haifa 3498838, Israel; Columbia University, Neuroscience Dept., 1051 Riverside Drive 10032, USA.
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20
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Powell SB, Swerdlow NR. Social Isolation Rearing and Sensorimotor Gating in Rat Models of Relevance to Schizophrenia. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2016. [DOI: 10.1016/b978-0-12-800981-9.00009-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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21
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Müller I, Obata K, Richter-Levin G, Stork O. GAD65 haplodeficiency conveys resilience in animal models of stress-induced psychopathology. Front Behav Neurosci 2014; 8:265. [PMID: 25147515 PMCID: PMC4124590 DOI: 10.3389/fnbeh.2014.00265] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 07/17/2014] [Indexed: 12/19/2022] Open
Abstract
GABAergic mechanisms are critically involved in the control of fear and anxiety, but their role in the development of stress-induced psychopathologies, including post-traumatic stress disorder (PTSD) and mood disorders is not sufficiently understood. We studied these functions in two established mouse models of risk factors for stress-induced psychopathologies employing variable juvenile stress and/or social isolation. A battery of emotional tests in adulthood revealed the induction of contextually generalized fear, anxiety, hyperarousal and depression-like symptoms in these paradigms. These reflect the multitude and complexity of stress effects in human PTSD patients. With factor analysis we were able to identify parameters that reflect these different behavioral domains in stressed animals and thus provide a basis for an integrated scoring of affectedness more closely resembling the clinical situation than isolated parameters. To test the applicability of these models to genetic approaches we further tested the role of GABA using heterozygous mice with targeted mutation of the GABA synthesizing enzyme GAD65 [GAD65(+/−) mice], which show a delayed postnatal increase in tissue GABA content in limbic and cortical brain areas. Unexpectedly, GAD65(+/−) mice did not show changes in exploratory activity regardless of the stressor type and were after the variable juvenile stress procedure protected from the development of contextual generalization in an auditory fear conditioning experiment. Our data demonstrate the complex nature of behavioral alterations in rodent models of stress-related psychopathologies and suggest that GAD65 haplodeficiency, likely through its effect on the postnatal maturation of GABAergic transmission, conveys resilience to some of these stress-induced effects.
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Affiliation(s)
- Iris Müller
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University Magdeburg, Germany
| | - Kunihiko Obata
- National Institute for Physiological Sciences Okazaki, Aichi, Japan
| | - Gal Richter-Levin
- Department of Neurobiology and Ethology and Department of Psychology, Institute for the Study of Affective Neuroscience, University of Haifa Haifa, Israel
| | - Oliver Stork
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke University Magdeburg, Germany ; Center for Behavioural Brain Sciences Magdeburg, Germany
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22
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Henry BL, Geyer MA, Buell MR, Perry W, Young JW, Minassian A. Prepulse inhibition in HIV-1 gp120 transgenic mice after withdrawal from chronic methamphetamine. Behav Pharmacol 2014; 25:12-22. [PMID: 24281153 PMCID: PMC3926694 DOI: 10.1097/fbp.0000000000000012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
HIV infection is frequently comorbid with methamphetamine (METH) dependence. Both factors are associated with impairment in inhibitory function that continues even after abstinence from the drug. Deficits in prepulse inhibition (PPI), a measure of sensorimotor gating, are induced by acute stimulant administration, but the combined effect of HIV and chronic METH exposure on PPI is not well characterized. We quantified baseline acoustic startle and PPI in mice expressing the HIV-1 gp120 envelope protein (gp120tg) and in wild-type (WT) littermates; thereafter, we administered a chronic regimen of METH or vehicle and tested startle and PPI after 7 days of drug withdrawal. We hypothesized that METH-treated gp120tg mice would exhibit PPI deficits compared with vehicle-treated WT or gp120tg animals. Before METH administration, drug-naive female gp120tg mice exhibited decreased PPI compared with female WT mice, whereas male gp120tg mice exhibited increased startle compared with other groups. After drug withdrawal, no consistent genotype effect was observed, but METH-treated mice exhibited increased PPI compared with vehicle, in contrast to previous reports of acute METH-induced PPI deficits. In summary, PPI impairment in HIV could depend on factors such as sex, whereas changes in PPI following METH withdrawal may depend on the quantity and duration of drug exposure.
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Affiliation(s)
- Brook L. Henry
- Department of Psychiatry, University of California, San Diego
| | - Mark A. Geyer
- Department of Psychiatry, University of California, San Diego
- Research Service, VA San Diego Healthcare System, San Diego, California, USA
| | | | - William Perry
- Department of Psychiatry, University of California, San Diego
| | - Jared W. Young
- Department of Psychiatry, University of California, San Diego
- Research Service, VA San Diego Healthcare System, San Diego, California, USA
| | - Arpi Minassian
- Department of Psychiatry, University of California, San Diego
- Center of Excellence for Stress and Mental Health, (CESAMH), Veteran’s Administration, San Diego, California, USA
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23
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Ago Y, Araki R, Tanaka T, Sasaga A, Nishiyama S, Takuma K, Matsuda T. Role of social encounter-induced activation of prefrontal serotonergic systems in the abnormal behaviors of isolation-reared mice. Neuropsychopharmacology 2013; 38:1535-47. [PMID: 23426384 PMCID: PMC3682148 DOI: 10.1038/npp.2013.52] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Isolation-reared male rodents show abnormal behaviors such as hyperlocomotion, aggressive behaviors, deficits of prepulse inhibition, and depression- and anxiety-like behaviors, but the neurochemical mechanism for the effects of psychological stress in these animals is not fully understood. This study examined the effects of social interactions between isolation-reared mice and intruder mice on brain monoaminergic systems. A cage was divided into two compartments by a mesh partition to prevent direct physical interactions. The 20-min encounter with an intruder elicited a restless and hyperexcitable state (hyperactivity) in male, but not in female, isolation-reared mice, whereas encounters with a sleeping intruder or a novel object did not. Although the encounter did not affect prefrontal neuronal-activity-marker c-Fos expression, dopamine (DA) levels, or serotonin (5-HT) levels in male group-reared mice or female isolation-reared mice, it increased prefrontal c-Fos expression, DA levels, and 5-HT levels in male isolation-reared mice. Furthermore, encounter-induced increases in c-Fos expression in the dorsal raphe nucleus and ventral tegmental area, but not in the nucleus accumbens shell, were much greater in isolation-reared than group-reared male mice. A 5-HT1A receptor agonist, a metabotropic glutamate 2/3 receptor agonist, and a gamma-aminobutyric acid A receptor agonist attenuated isolation-induced aggressive behaviors and encounter-induced hyperactivity, c-Fos expression in the prefrontal cortex and dorsal raphe nucleus, and increases in prefrontal 5-HT levels. These findings suggest that the prefrontal DA and 5-HT systems are activated by encounter stimulation in male isolation-reared mice, and the encounter-induced activation of 5-HT system triggers the induction of some abnormal behaviors in male isolation-reared mice. Furthermore, this study implies that the encounter stimulation-induced signal has a pharmacological significance.
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Affiliation(s)
- Yukio Ago
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Ryota Araki
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Tatsunori Tanaka
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Asuka Sasaga
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Saki Nishiyama
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Kazuhiro Takuma
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
| | - Toshio Matsuda
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan,United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, Suita, Osaka, Japan,Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan, Tel: +81 6 6879 8161, Fax: +81 6 6879 8159, E-mail:
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Petrovszki Z, Adam G, Tuboly G, Kekesi G, Benedek G, Keri S, Horvath G. Characterization of gene–environment interactions by behavioral profiling of selectively bred rats: The effect of NMDA receptor inhibition and social isolation. Behav Brain Res 2013. [DOI: 10.1016/j.bbr.2012.11.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Coudereau JP, Sreng L, Palme R, Touma C, Pratte M. Do social statuses affect the startle reflex in male mice? Behav Brain Res 2012; 234:117-20. [PMID: 22728306 DOI: 10.1016/j.bbr.2012.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 06/07/2012] [Accepted: 06/12/2012] [Indexed: 11/30/2022]
Abstract
Usual housing conditions lead to dominance hierarchy forming between male mice. The situation produces physiological and behavioural differences between dominants and subordinates. The goal of the present study was to assess stress responses, and possible changes in prepulse inhibition (PPI) of the startle reflex in dominant and subordinate male mice. Three weeks of daily social interactions led to stable aggressive dominance in 11 pairs of male NMRI mice. Stress levels were assessed by measuring faecal corticosterone metabolites (FCM), a non-invasive technique for monitoring hormonal changes in response to specific situations, with repeated sampling of each animal. The analysis of FCM levels showed greater stress in subordinate males at the beginning of the experiment, as the hierarchy was being established, but by the end of the experiment, FCM levels were reduced and similar in both dominants and subordinates. No significant differences were found in the startle response or PPI.
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Affiliation(s)
- J-P Coudereau
- Genetique Medicale et Genomique Fonctionnelle, Inserm UMR 910, Faculte de Medecine de Timone, 27 boulevard Jean Moulin, 13385 Marseille Cedex 05, France
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Powell SB, Sejnowski TJ, Behrens MM. Behavioral and neurochemical consequences of cortical oxidative stress on parvalbumin-interneuron maturation in rodent models of schizophrenia. Neuropharmacology 2012; 62:1322-31. [PMID: 21315745 PMCID: PMC3106123 DOI: 10.1016/j.neuropharm.2011.01.049] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 01/26/2011] [Accepted: 01/28/2011] [Indexed: 11/26/2022]
Abstract
Oxidative stress, in response to the activation of the superoxide-producing enzyme Nox2, has been implicated in the schizophrenia-like behavioral dysfunction that develops in animals that were subject to either neonatal NMDA receptor-antagonist treatment or social isolation. In both of these animal models of schizophrenia, an environmental insult occurring during the period of active maturation of the fast-spiking parvalbumin-positive (PV+) interneuronal circuit leads to a diminished expression of parvalbumin in GABA-inhibitory neurons when animals reach adulthood. The loss of PV+ interneurons in animal models had been tentatively attributed to the death of these neurons. However, present results show that for the perinatal NMDA-R antagonist model these interneurons are still alive when animals are 5-6 weeks of age even though they have lost their phenotype and no longer express parvalbumin. Alterations in parvalbumin expression and sensory-evoked gamma-oscillatory activity, regulated by PV+ interneurons, are consistently observed in schizophrenia. We propose that cortical networks consisting of faulty PV+ interneurons interacting with pyramidal neurons may be responsible for the aberrant oscillatory activity observed in schizophrenia. Thus, oxidative stress during the maturation window for PV+ interneurons by alteration of normal brain development, leads to the emergence of schizophrenia-like behavioral dysfunctions when subjects reach early adulthood.
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Affiliation(s)
- Susan B. Powell
- Department of Psychiatry, University of California, San Diego, MC0804, La Jolla, CA 92093-0804
| | - Terrence J. Sejnowski
- Howard Hughes Medical Institute. The Salk Institute for Biological Studies, La Jolla, CA 92037
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA, 92093
| | - M. Margarita Behrens
- Howard Hughes Medical Institute. The Salk Institute for Biological Studies, La Jolla, CA 92037
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Evaluation of social and physical enrichment in modulation of behavioural phenotype in C57BL/6J female mice. PLoS One 2011; 6:e24755. [PMID: 21931844 PMCID: PMC3169619 DOI: 10.1371/journal.pone.0024755] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 08/17/2011] [Indexed: 12/18/2022] Open
Abstract
Housing conditions represent an important environmental variable playing a critical role in the assessment of mouse behaviour. In the present study the effects of isolation and nesting material on the behaviour of female C57BL/6J mice were evaluated. The mice were subjected to different rearing conditions from weaning (at the age of 3 weeks). The study groups were group- and single-housed mice, divided further into groups with or without nesting material (species-specific enrichment). After 8 weeks spent in respective conditions the behavioural testing began. Both factors (social conditions and nesting material) appeared to have a significant impact on the behavioural phenotype. However, it is important to stress that the interaction between the factors was virtually absent. We established that isolation increased locomotor activity and reduced anxiety-like behaviour in several tests of exploration. In contrast, absence of nesting material increased anxiety-like behaviour. Neither factor affected rota-rod performance, nociception and prepulse inhibition. Contextual fear memory was significantly reduced in single-housed mice, and interestingly, in mice with nesting material. Cued fear memory was reduced by single-housing, but not affected by enrichment. Mice from enriched cages displayed faster and better learning and spatial search strategy in the water maze. In contrast, isolation caused significant impairment in the water maze. In conclusion, both isolation and species-specific enrichment have profound effects on mouse behaviour and should be considered in design of the experiments and in assessment of animal welfare issues.
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Koda K, Ago Y, Yano K, Nishimura M, Kobayashi H, Fukada A, Takuma K, Matsuda T. Involvement of decreased muscarinic receptor function in prepulse inhibition deficits in mice reared in social isolation. Br J Pharmacol 2011; 162:763-72. [PMID: 20958289 DOI: 10.1111/j.1476-5381.2010.01080.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND PURPOSE We have previously reported that galantamine, a weak acetylcholinesterase inhibitor, improves prepulse inhibition (PPI) deficits in mice reared in social isolation. ACh receptors are involved in the underlying mechanism of PPI, but whether rearing in social isolation causes dysfunction of the cholinergic system is unknown. In this study, we examined the involvement of muscarinic receptors in the improvement of PPI deficits induced by galantamine, and whether the cholinergic system is altered in mice reared in isolation. EXPERIMENTAL APPROACH Three-week-old male ddY mice were housed in isolated cages for 6 weeks before the initiation of experiments to create PPI deficits. Cholinergic functions were determined by measuring the behavioural and neurochemical responses to nicotinic and muscarinic receptor agonists. KEY RESULTS The improvement by galantamine of social isolation-induced PPI deficits was blocked by scopolamine, a non-selective muscarinic antagonist, and telenzepine, a preferential M₁ receptor antagonist. Activation of M₁ receptors improved social isolation-induced PPI deficits. Social isolation did not affect choline acetyltransferase and acetylcholinesterase activities in the prefrontal cortex and hippocampus, but it reduced the locomotor-suppressive response to muscarinic agonist oxotremorine, but not to nicotine. The isolation also attenuated the M₁ receptor agonist N-desmethylclozapine-induced increase in prefrontal dopamine release. CONCLUSIONS AND IMPLICATIONS Galantamine improves PPI deficits of mice reared in social isolation via activation of M₁ receptors. Social isolation reduces the muscarinic, especially M₁, receptor function and this is involved in PPI deficits.
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Affiliation(s)
- K Koda
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Yamada-oka, Suita, Osaka, Japan
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Long-lasting, distinct changes in central opioid receptor and urinary bladder functions in models of schizophrenia in rats. Eur J Pharmacol 2011; 661:35-41. [DOI: 10.1016/j.ejphar.2011.04.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 04/04/2011] [Accepted: 04/14/2011] [Indexed: 11/23/2022]
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Naert A, Callaerts-Vegh Z, D'Hooge R. Nocturnal hyperactivity, increased social novelty preference and delayed extinction of fear responses in post-weaning socially isolated mice. Brain Res Bull 2011; 85:354-62. [PMID: 21501666 DOI: 10.1016/j.brainresbull.2011.03.027] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 03/28/2011] [Accepted: 03/31/2011] [Indexed: 12/28/2022]
Abstract
When rodents are reared in isolation from young age onwards, they manifest a number of behavioural alterations in adulthood. Since some of these alterations resemble symptoms of psychiatric disorders, the post-weaning social isolation (ISO) manipulation is often applied to create rodent models of these disorders. In rats, ISO effects have been thoroughly characterised, but in mice they are less well documented. Therefore, we further evaluated behaviour of adult ISO mice with a test battery that focussed on abnormalities relevant to schizophrenia. We found that ISO mice were hyperactive during the dark phase. Also, ISO mice showed alterations in magnitude, habituation and prepulse-inhibition of the acoustic startle reflex, increased anxiety, increased social preference and changes in extinction of fear responses. We did not observe increased sensitivity to locomotor-activating effects of amphetamine. It is concluded that ISO of mice might serve as a useful model to test further hypotheses regarding pathogenesis occurring at specific developmental timeframes.
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Affiliation(s)
- Arne Naert
- Laboratory of Biological Psychology, Faculty of Psychology and Educational Sciences, KULeuven, Tiensestraat 102, B-3000 Leuven, Belgium.
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Serotonin1A receptor deletion does not interact with maternal separation-induced increases in startle reactivity and prepulse inhibition deficits. Psychopharmacology (Berl) 2011; 214:353-65. [PMID: 20811879 PMCID: PMC3045511 DOI: 10.1007/s00213-010-1998-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2010] [Accepted: 08/10/2010] [Indexed: 02/01/2023]
Abstract
RATIONALE Early life stress is a risk factor for the development of psychopathology in later life. Consequences of adverse life events, however, may depend on the genetic makeup of an individual. Reduced serotonin(1A) receptor function may predispose to the development of anxiety disorders. OBJECTIVE Determine susceptibility of serotonin(1A) receptor knockout (1AKO) mice on different background strains to the effects of maternal separation (MS) by assessing startle plasticity in adulthood. METHODS 1AKO mice on a 129S6 and a Swiss Webster (SW) background were used. MS groups were separated daily from their mother for 180 min/day from postnatal days 2 to 14. Control groups underwent normal animal facility rearing. In adulthood, effects on acoustic startle response, habituation, prepulse inhibition (PPI), and foot shock sensitization were determined. RESULTS MS increased startle reactivity and reduced PPI in 129S6 mice. These effects of MS were independent of genotype. MS had no effect on the other readouts. In SW mice, MS had no consistent effect on startle reactivity and did not alter startle plasticity in wild type or in 1AKO mice. 1AKO mice did not differ from wild-type mice in startle plasticity. CONCLUSION Serotonin(1A) receptor deletion does not enhance vulnerability to the effects of MS on startle plasticity. The life-long increase in startle reactivity and PPI deficit induced by MS are strain-dependent. Further, the use of startle reactivity and plasticity may have added value in translational studies relating to early life stress.
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Prolonged Social Isolation and Social Instability in Adolescence in Rats: Immediate and Long-Term Physiological and Behavioral Effects. ACTA ACUST UNITED AC 2010. [DOI: 10.1007/s11055-010-9352-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Gresack J, Powell S, Geyer M, Poore MS, Coste S, Risbrough V. CRF2 null mutation increases sensitivity to isolation rearing effects on locomotor activity in mice. Neuropeptides 2010; 44:349-53. [PMID: 20466421 PMCID: PMC2888500 DOI: 10.1016/j.npep.2010.04.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 04/15/2010] [Accepted: 04/17/2010] [Indexed: 01/05/2023]
Abstract
BACKGROUND Developmental stressors are consistently reported to increase risk for certain neuropsychiatric disorders including schizophrenia, depression, and post-traumatic stress disorder. Recent clinical evidence supports a "double-hit" hypothesis of genetic vulnerability interacting with developmental challenges to modulate this risk. Early life stressor effects on behavior may be modulated in part by alterations in corticotropin releasing factor (CRF) signaling via two known receptors, CRF(1) and CRF(2). One extant hypothesis is that CRF(2) activation may modulate long-term adaptive responses after homeostatic challenge. As such, loss of CRF(2) activity via genetic variance may increase sensitivity to the long-term effects of developmental stress. METHODS We tested the hypothesis that CRF(2) function may mitigate the behavioral effects of isolation rearing, predicting that loss of CRF(2) function increases sensitivity to this developmental challenge. Using the behavioral pattern monitor (BPM), we examined exploratory behavior and locomotor patterns in adult CRF(2) wild-type (WT) and gene knockout (KO) mice reared socially or in isolation. RESULTS Isolation housing produced robust increases in the amount of locomotor activity and investigatory holepoking, and altered the temporal distribution of activity in CRF(2) KO but not CRF(2) WT mice. Isolation housing significantly increased rearing behavior and altered spatial patterns of locomotor activity regardless of genotype. CONCLUSIONS Loss of CRF(2) function increased sensitivity to the effects of chronic social isolation on exploratory locomotor behavior. Thus, CRF(2) activation appears to mitigate isolation rearing effects on exploratory behavior. Further research assessing the interaction between CRF(2) function and developmental challenges is warranted.
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Affiliation(s)
- Jodi Gresack
- Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093-0804, USA
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Neonatal infection with neurotropic influenza A virus induces the kynurenine pathway in early life and disrupts sensorimotor gating in adult Tap1-/- mice. Int J Neuropsychopharmacol 2010; 13:475-85. [PMID: 19607757 PMCID: PMC2857580 DOI: 10.1017/s1461145709990253] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Epidemiological studies suggest that early life infections may contribute to the development of neuropsychiatric disorders later in life. Experimental studies employing infections during neonatal life support this notion by reporting persistent changes in the behaviour of adult animals, including deficits in sensorimotor gating. We have previously described an induction of the kynurenine pathway in neonatal wild-type (WT) mice following a systemic infection with neurotropic influenza A/WSN/33 virus. Here, we use the same model of infection in both WT and Tap1-/- mice (expressing reduced levels of MHC class I) and study long-term effects of the infection on sensorimotor gating, as determined by measuring prepulse inhibition (PPI). Moreover, transcription of genes encoding enzymes in the kynurenine pathway and levels of kynurenic acid (KYNA), in the brain of Tap1-/- mice were investigated. In mice infected on postnatal day (P)3 or P4, the levels of several transcripts in the kynurenine pathway were altered at P7, P13 and P24. Transcripts encoding indoleamine-pyrrole 2,3-dioxygenase (IDO), degrading tryptophan in the first step of the kynurenine pathway were consistently up-regulated at all time-points investigated. The changes in transcript levels were accompanied by a transient elevation of KYNA in the brain of infected mice at P13. At age 5-6 months, neonatally infected Tap1-/-, but not WT, mice exhibited a reduction in PPI. The present data show that a neonatal infection targeting the brain can induce the kynurenine pathway and that such an infection can disrupt sensorimotor gating in adulthood in genetically vulnerable mice.
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van den Buuse M. Modeling the positive symptoms of schizophrenia in genetically modified mice: pharmacology and methodology aspects. Schizophr Bull 2010; 36:246-70. [PMID: 19900963 PMCID: PMC2833124 DOI: 10.1093/schbul/sbp132] [Citation(s) in RCA: 275] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In recent years, there have been huge advances in the use of genetically modified mice to study pathophysiological mechanisms involved in schizophrenia. This has allowed rapid progress in our understanding of the role of several proposed gene mechanisms in schizophrenia, and yet this research has also revealed how much still remains unresolved. Behavioral studies in genetically modified mice are reviewed with special emphasis on modeling psychotic-like behavior. I will particularly focus on observations on locomotor hyperactivity and disruptions of prepulse inhibition (PPI). Recommendations are included to address pharmacological and methodological aspects in future studies. Mouse models of dopaminergic and glutamatergic dysfunction are then discussed, reflecting the most important and widely studied neurotransmitter systems in schizophrenia. Subsequently, psychosis-like behavior in mice with modifications in the most widely studied schizophrenia susceptibility genes is reviewed. Taken together, the available studies reveal a wealth of available data which have already provided crucial new insight and mechanistic clues which could lead to new treatments or even prevention strategies for schizophrenia.
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Affiliation(s)
- Maarten van den Buuse
- Mental Health Research Institute of Victoria, Parkville, Melbourne, Victoria 3052, Australia.
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Gresack JE, Risbrough VB, Scott CN, Coste S, Stenzel-Poore M, Geyer MA, Powell SB. Isolation rearing-induced deficits in contextual fear learning do not require CRF(2) receptors. Behav Brain Res 2010; 209:80-4. [PMID: 20097235 DOI: 10.1016/j.bbr.2010.01.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2009] [Revised: 01/11/2010] [Accepted: 01/15/2010] [Indexed: 12/29/2022]
Abstract
Post-weaning social isolation of rodents is used to model developmental stressors linked to neuropsychiatric disorders including schizophrenia as well as anxiety and mood disorders. Isolation rearing produces alterations in emotional memory and hippocampal neuropathology. Corticotropin releasing factor (CRF) signaling has recently been shown to be involved in behavioral effects of isolation rearing. Activation of the CRF(2) receptor is linked to stress-induced alterations in fear learning and may also be involved in long-term adaptation to stress. Here we tested the hypothesis that CRF(2) contributes to isolation rearing effects on emotional memory. At weaning, mice were housed either in groups of three or individually in standard mouse cages. In adulthood, isolation-reared mice exhibited significant reductions in context-specific, but not cue-specific, freezing. Isolation-reared mice exhibited no significant changes in locomotor exploration during brief exposure to a novel environment, suggesting that the reduced freezing in response to context cues was not due to activity confounds. Isolation rearing also disrupted context fear memory in mice with a CRF(2) gene null mutation, indicating that the CRF(2) receptor is not required for isolation effects on fear memory. Thus, isolation rearing disrupts hippocampal-dependent fear learning as indicated by consistent reductions in context-conditioned freezing in two separate cohorts of mice, and these effects are via a CRF(2)-independent mechanism. These findings may be clinically relevant because they suggest that isolation rearing in mice may be a useful model of developmental perturbations linked to disruptions in emotional memory in a variety of neuropsychiatric disorders.
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Affiliation(s)
- Jodi E Gresack
- Department of Psychiatry, University of California, San Diego, MC0804, La Jolla, CA 92093-0804, USA
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Abstract
The neurodevelopmental hypothesis of schizophrenia asserts that the underlying pathology of schizophrenia has its roots in brain development and that these brain abnormalities do not manifest themselves until adolescence or early adulthood. Animal models based on developmental manipulations have provided insight into the vulnerability of the developing fetus and the importance of the early environment for normal maturation. These models have provided a wide range of validated approaches to answer questions regarding environmental influences on both neural and behavioral development. In an effort to better understand the developmental hypothesis of schizophrenia, animal models have been developed, which seek to model the etiology and/or the pathophysiology of schizophrenia or specific behaviors associated with the disease. Developmental models specific to schizophrenia have focused on epidemiological risk factors (e.g., prenatal viral insult, birth complications) or more heuristic models aimed at understanding the developmental neuropathology of the disease (e.g., ventral hippocampal lesions). The combined approach of behavioral and neuroanatomical evaluation of these models strengthens their utility in improving our understanding of the pathophysiology of schizophrenia and developing new treatment strategies.
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Affiliation(s)
- Susan B Powell
- University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0804, USA.
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Oliver PL, Davies KE. Interaction between environmental and genetic factors modulates schizophrenic endophenotypes in the Snap-25 mouse mutant blind-drunk. Hum Mol Genet 2009; 18:4576-89. [PMID: 19729413 PMCID: PMC2773274 DOI: 10.1093/hmg/ddp425] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
To understand the pathophysiology of neuropsychiatric disorders such as schizophrenia requires consideration of multiple genetic and non-genetic factors. However, very little is known about the consequences of combining models of synaptic dysfunction with controlled environmental manipulations. Therefore, to generate new insights into gene–environment interactions and complex behaviour, we examined the influence of variable prenatal stress (PNS) on two mouse lines with mutations in synaptosomal-associated protein of 25 kDa (Snap-25): the blind-drunk (Bdr) point mutant and heterozygous Snap-25 knockout mice. Neonatal development was analysed in addition to an assessment of adult behavioural phenotypes relevant to the psychotic, cognitive and negative aspects of schizophrenia. These data show that PNS influenced specific anxiety-related behaviour in all animals. In addition, sensorimotor gating deficits previously noted in Bdr mutants were markedly enhanced by PNS; significantly, these effects could be reversed with the application of anti-psychotic drugs. Moreover, social interaction abnormalities were observed only in Bdr animals from stressed dams but not in wild-type littermates or mutants from non-stressed mothers. These results show for the first time that combining a synaptic mouse point mutant with a controlled prenatal stressor paradigm produces both modified and previously unseen phenotypes, generating new insights into the interactions between genetics and the environment relevant to the study of psychiatric disease.
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Affiliation(s)
- Peter L Oliver
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK.
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Ebstein RP, Israel S, Lerer E, Uzefovsky F, Shalev I, Gritsenko I, Riebold M, Salomon S, Yirmiya N. Arginine vasopressin and oxytocin modulate human social behavior. Ann N Y Acad Sci 2009; 1167:87-102. [PMID: 19580556 DOI: 10.1111/j.1749-6632.2009.04541.x] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Increasing evidence suggests that two nonapeptides, arginine vasopressin and oxytocin, shape human social behavior in both nonclinical and clinical subjects. Evidence is discussed that in autism spectrum disorders genetic polymorphisms in the vasopressin-oxytocin pathway, notably the arginine vasopressin receptor 1a (AVPR1a), the oxytocin receptor (OXTR), neurophysin I and II, and CD38 (recently shown to be critical for social behavior by mediating oxytocin secretion) contribute to deficits in socialization skills in this group of patients. We also present first evidence that CD38 expression in lymphoblastoid cells derived from subjects diagnosed with autism is correlated with social skill phenotype inventoried by the Vineland Adaptive Behavioral Scales. Additionally, we discuss molecular genetic evidence that in nonclinical subjects both AVPR1a and OXTR genes contribute to prosocial or altruistic behavior inventoried by two experimental paradigms, the dictator game and social values orientation. The role of the AVPR1a is also analyzed in prepulse inhibition. Prepulse inhibition of the startle response to auditory stimuli is a largely autonomic response that resonates with social cognition in both animal models and humans. First results are presented showing that intranasal administration of arginine vasopressin increases salivary cortisol levels in the Trier Social Stress test. To summarize, accumulating studies employing a broad array of cutting-edge tools in psychology, neuroeconomics, molecular genetics, pharmacology, electrophysiology, and brain imaging are beginning to elaborate the intriguing role of oxytocin and arginine vasopressin in human social behavior. We expect that future studies will continue this advance and deepen our understanding of these complex events.
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Affiliation(s)
- Richard P Ebstein
- Department of Psychology, The Hebrew University of Jerusalem, Herzog Memorial Hospital, Givat Shaul, Jerusalem, Israel.
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Levin R, Heresco-Levy U, Bachner-Melman R, Israel S, Shalev I, Ebstein RP. Association between arginine vasopressin 1a receptor (AVPR1a) promoter region polymorphisms and prepulse inhibition. Psychoneuroendocrinology 2009; 34:901-8. [PMID: 19195791 DOI: 10.1016/j.psyneuen.2008.12.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Revised: 12/25/2008] [Accepted: 12/26/2008] [Indexed: 01/22/2023]
Abstract
Arginine vasopressin and the arginine vasopressin 1a (AVPR1a) gene contribute to a range of social behaviors both in lower vertebrates and in humans. Human promoter-region microsatellite repeat regions (RS1 and RS3) in the AVPR1a gene region have been associated with autism spectrum disorders, prosocial behavior and social cognition. Prepulse inhibition (PPI) of the startle response to auditory stimuli is a largely autonomic response that resonates with social cognition in both animal models and humans. Reduced PPI has been observed in disorders including schizophrenia that are distinguished by deficits in social skills. In the current investigation association was examined between PPI and the AVPR1a RS1 and RS repeat regions and PPI in a group of 113 nonclinical subjects. Using a robust family-based strategy, association was observed between AVPR1a promoter-region repeat length, especially RS3) and PPI (30 ms: global p=0.04; 60 ms p=0.006; 120 ms p=0.008). Notably, longer RS3 alleles were associated with greater levels of prepulse inhibition. Using a short/long classification scheme for the repeat regions, significant association was also observed between all three PPI intervals (30, 60 and 120 ms) and both RS1 and RS3 polymorphisms (PBAT: FBAT-PC(2) statistic p=0.047). Tests of within-subject effects (SPSS GLM) showed significant sexxRS3 interactions at 30 ms (p=0.045) and 60 ms (p=0.01). Longer alleles, especially in male subjects, are associated with significantly higher PPI response, consistent with a role for the promoter repeat region in partially molding social behavior in both animals and humans. This is the first report in humans demonstrating a role of the AVPR1a gene in contributing to the PPI response to auditory stimuli.
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Affiliation(s)
- Raz Levin
- Neurobiology, Hebrew University, Jerusalem, Israel
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Ayhan Y, Sawa A, Ross CA, Pletnikov MV. Animal models of gene-environment interactions in schizophrenia. Behav Brain Res 2009; 204:274-81. [PMID: 19379776 DOI: 10.1016/j.bbr.2009.04.010] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2009] [Revised: 04/09/2009] [Accepted: 04/10/2009] [Indexed: 12/12/2022]
Abstract
The pathogenesis of schizophrenia and related mental illnesses likely involves multiple interactions between susceptibility genes of small effects and environmental factors. Gene-environment interactions occur across different stages of neurodevelopment to produce heterogeneous clinical and pathological manifestations of the disease. The main obstacle for mechanistic studies of gene-environment interplay has been the paucity of appropriate experimental systems for elucidating the molecular pathways that mediate gene-environment interactions relevant to schizophrenia. Recent advances in psychiatric genetics and a plethora of experimental data from animal studies allow us to suggest a new approach to gene-environment interactions in schizophrenia. We propose that animal models based on identified genetic mutations and measurable environment factors will help advance studies of the molecular mechanisms of gene-environment interplay.
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Affiliation(s)
- Yavuz Ayhan
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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Ferraguti F, Crepaldi L, Nicoletti F. Metabotropic glutamate 1 receptor: current concepts and perspectives. Pharmacol Rev 2009; 60:536-81. [PMID: 19112153 DOI: 10.1124/pr.108.000166] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Almost 25 years after the first report that glutamate can activate receptors coupled to heterotrimeric G-proteins, tremendous progress has been made in the field of metabotropic glutamate receptors. Now, eight members of this family of glutamate receptors, encoded by eight different genes that share distinctive structural features have been identified. The first cloned receptor, the metabotropic glutamate (mGlu) receptor mGlu1 has probably been the most extensively studied mGlu receptor, and in many respects it represents a prototypical subtype for this family of receptors. Its biochemical, anatomical, physiological, and pharmacological characteristics have been intensely investigated. Together with subtype 5, mGlu1 receptors constitute a subgroup of receptors that couple to phospholipase C and mobilize Ca(2+) from intracellular stores. Several alternatively spliced variants of mGlu1 receptors, which differ primarily in the length of their C-terminal domain and anatomical localization, have been reported. Use of a number of genetic approaches and the recent development of selective antagonists have provided a means for clarifying the role played by this receptor in a number of neuronal systems. In this article we discuss recent advancements in the pharmacology and concepts about the intracellular transduction and pathophysiological role of mGlu1 receptors and review earlier data in view of these novel findings. The impact that this new and better understanding of the specific role of these receptors may have on novel treatment strategies for a variety of neurological and psychiatric disorders is considered.
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Affiliation(s)
- Francesco Ferraguti
- Department of Pharmacology, Innsbruck Medical University, Peter-Mayr Strasse 1a, Innsbruck A-6020, Austria.
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Tuboly G, Benedek G, Horvath G. Selective disturbance of pain sensitivity after social isolation. Physiol Behav 2009; 96:18-22. [DOI: 10.1016/j.physbeh.2008.07.030] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2007] [Revised: 07/22/2008] [Accepted: 07/30/2008] [Indexed: 11/29/2022]
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Schubert MI, Porkess MV, Dashdorj N, Fone KCF, Auer DP. Effects of social isolation rearing on the limbic brain: a combined behavioral and magnetic resonance imaging volumetry study in rats. Neuroscience 2008; 159:21-30. [PMID: 19141315 DOI: 10.1016/j.neuroscience.2008.12.019] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Revised: 12/08/2008] [Accepted: 12/12/2008] [Indexed: 01/26/2023]
Abstract
Rearing rats in social isolation from weaning induces robust behavioral and neurobiological alterations resembling some of the core symptoms of schizophrenia, such as reduction in prepulse inhibition of acoustic startle (PPI) and locomotor hyperactivity in a novel arena. The aim of this study was to investigate whether social isolation rearing induces volumetric remodeling of the limbic system, and to probe for anatomical structure-behavioral interrelations. Isolation- (n=8) and group-reared (n=8) rats were examined by magnetic resonance (MR) volumetry using high-resolution T2-weighted imaging at 7 T. Volumes of medial prefrontal cortex (mPFC), anterior cingulate cortex (ACC), retrosplenial cortex (RSC) and hippocampal formation were compared between groups and with behavioral measures, i.e. PPI and locomotor activity in a novel arena. Isolation rearing induced locomotor hyperactivity and impaired PPI compared with group-housed rats. The right mPFC was significantly reduced (5.4%) in isolation-reared compared with group-reared rats, with a similar trend on the left side (5.2%). mPFC volumes changes were unrelated to behavioral abnormalities. No significant volume changes were observed in ACC, RSC or hippocampal formation. Hippocampal volumes were associated with the magnitude of PPI response in control but not in isolation-reared rats. Rearing rats in social isolation induced remodeling of the limbic brain with selective prefrontal cortex volume loss. In addition, a dissociation of the interrelation between hippocampal volume and PPI was noted in the isolation-reared rats. Taken together, limbic morphometry is sensitive to the effects of social isolation rearing but did not reveal direct brain-behavior interrelations, calling for more detailed circuitry analysis.
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Affiliation(s)
- M I Schubert
- Division of Academic Radiology, School of Clinical Sciences, University of Nottingham, Queen's Medical Centre, West Block, B Floor, Nottingham NG7 2UH, UK.
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Swerdlow NR, Weber M, Qu Y, Light GA, Braff DL. Realistic expectations of prepulse inhibition in translational models for schizophrenia research. Psychopharmacology (Berl) 2008; 199:331-88. [PMID: 18568339 PMCID: PMC2771731 DOI: 10.1007/s00213-008-1072-4] [Citation(s) in RCA: 421] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2007] [Accepted: 01/03/2008] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Under specific conditions, a weak lead stimulus, or "prepulse", can inhibit the startling effects of a subsequent intense abrupt stimulus. This startle-inhibiting effect of the prepulse, termed "prepulse inhibition" (PPI), is widely used in translational models to understand the biology of brainbased inhibitory mechanisms and their deficiency in neuropsychiatric disorders. In 1981, four published reports with "prepulse inhibition" as an index term were listed on Medline; over the past 5 years, new published Medline reports with "prepulse inhibition" as an index term have appeared at a rate exceeding once every 2.7 days (n=678). Most of these reports focus on the use of PPI in translational models of impaired sensorimotor gating in schizophrenia. This rapid expansion and broad application of PPI as a tool for understanding schizophrenia has, at times, outpaced critical thinking and falsifiable hypotheses about the relative strengths vs. limitations of this measure. OBJECTIVES This review enumerates the realistic expectations for PPI in translational models for schizophrenia research, and provides cautionary notes for the future applications of this important research tool. CONCLUSION In humans, PPI is not "diagnostic"; levels of PPI do not predict clinical course, specific symptoms, or individual medication responses. In preclinical studies, PPI is valuable for evaluating models or model organisms relevant to schizophrenia, "mapping" neural substrates of deficient PPI in schizophrenia, and advancing the discovery and development of novel therapeutics. Across species, PPI is a reliable, robust quantitative phenotype that is useful for probing the neurobiology and genetics of gating deficits in schizophrenia.
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Affiliation(s)
- Neal R Swerdlow
- Department of Psychiatry, UCSD School of Medicine, La Jolla, CA, 92093-0804, USA,
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Chester JA, Barrenha GD, Hughes ML, Keuneke KJ. Age- and sex-dependent effects of footshock stress on subsequent alcohol drinking and acoustic startle behavior in mice selectively bred for high-alcohol preference. Alcohol Clin Exp Res 2008; 32:1782-94. [PMID: 18652593 DOI: 10.1111/j.1530-0277.2008.00763.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Exposure to stress during adolescence is known to be a risk factor for alcohol-use and anxiety disorders. This study examined the effects of footshock stress during adolescence on subsequent alcohol drinking in male and female mice selectively bred for high-alcohol preference (HAP1 lines). Acoustic startle responses and prepulse inhibition (PPI) were also assessed in the absence of, and immediately following, subsequent footshock stress exposures to determine whether a prior history of footshock stress during adolescence would produce enduring effects on anxiety-related behavior and sensorimotor gating. METHODS Alcohol-naïve, adolescent (male, n = 27; female, n = 23) and adult (male, n = 30; female, n = 30) HAP1 mice were randomly assigned to a stress or no stress group. The study consisted of 5 phases: (1) 10 consecutive days of exposure to a 30-minute footshock session, (2) 1 startle test, (3) one 30-minute footshock session immediately followed by 1 startle test, (4) 30 days of free-choice alcohol consumption, and (5) one 30-minute footshock session immediately followed by 1 startle test. RESULTS Footshock stress exposure during adolescence, but not adulthood, robustly increased alcohol drinking behavior in both male and female HAP1 mice. Before alcohol drinking, females in both the adolescent and adult stress groups showed greater startle in phases 2 and 3; whereas males in the adolescent stress group showed greater startle only in phase 3. After alcohol drinking, in phase 5, enhanced startle was no longer apparent in any stress group. Males in the adult stress group showed reduced startle in phases 2 and 5. PPI was generally unchanged, except that males in the adolescent stress group showed increased PPI in phase 3 and females in the adolescent stress group showed decreased PPI in phase 5. CONCLUSIONS Adolescent HAP1 mice appear to be more vulnerable to the effects of footshock stress than adult mice, as manifested by increased alcohol drinking and anxiety-related behavior in adulthood. These results in mice suggest that stress exposure during adolescence may increase the risk for developing an alcohol-use and/or anxiety disorder in individuals with a genetic predisposition toward high alcohol consumption.
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Affiliation(s)
- Julia A Chester
- Department of Psychological Sciences, Purdue University, West Lafayette, Indiana 47907-2081, USA.
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Viggiano D. The hyperactive syndrome: metanalysis of genetic alterations, pharmacological treatments and brain lesions which increase locomotor activity. Behav Brain Res 2008; 194:1-14. [PMID: 18656502 DOI: 10.1016/j.bbr.2008.06.033] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Revised: 06/26/2008] [Accepted: 06/29/2008] [Indexed: 01/01/2023]
Abstract
The large number of transgenic mice realized thus far with different purposes allows addressing new questions, such as which animals, over the entire set of transgenic animals, show a specific behavioural abnormality. In the present study, we have used a metanalytical approach to organize a database of genetic modifications, brain lesions and pharmacological interventions that increase locomotor activity in animal models. To further understand the resulting data set, we have organized a second database of the alterations (genetic, pharmacological or brain lesions) that reduce locomotor activity. Using this approach, we estimated that 1.56% of the genes in the genome yield to hyperactivity and 0.75% of genes produce hypoactivity when altered. These genes have been classified into genes for neurotransmitter systems, hormonal, metabolic systems, ion channels, structural proteins, transcription factors, second messengers and growth factors. Finally, two additional classes included animals with neurodegeneration and inner ear abnormalities. The analysis of the database revealed several unexpected findings. First, the genes that, when mutated, induce hyperactive behaviour do not pertain to a single neurotransmitter system. In fact, alterations in most neurotransmitter systems can give rise to a hyperactive phenotype. In contrast, fewer changes can decrease locomotor activity. Specifically, genetic and pharmacological alterations that enhance the dopamine, orexin, histamine, cannabinoids systems or that antagonize the cholinergic system induce an increase in locomotor activity. Similarly, imbalances in the two main neurotransmitters of the nervous system, GABA and glutamate usually result in hyperactive behaviour. It is remarkable that no genetic alterations pertaining to the GABA system have been reported to reduce locomotor behaviour. Other neurotransmitters, such as norepinephrine and serotonin, have a more complex influence. For instance, a decrease in norepinephrine synthesis usually results in hypoactive behaviour. However, a chronic increase in norepinephrine may result in hypoactivity too. Similarly, changes in both directions of serotonin levels may reduce locomotor activity, whereas alterations in specific serotonin receptors can induce hyperactivity. The lesion of at least 12 different brain regions can increase locomotor activity too. Comparatively, few focal lesions decrease locomotor activity. Finally, a large number of toxic events can increase locomotor activity, particularly if delivered during the prepuberal time window. These data show that there is a net imbalance in the number of altered genes/brain lesions/toxics that induce hyperactivity versus hypoactive behaviour. Although some of these data may be explained in terms of the activating role of subcortical systems (such as catecholamines), the larger number of alterations that induce hyperactivity suggests a different scenario. Specifically, we hypothesize (i) the existence of a control system that continuously inhibit a basally hyperactive locomotor tone and (ii) that this control system is highly vulnerable (intrinsic fragility) to any change in the genetic asset or to any toxic/drug delivered during prepuberal stages. Brain lesion studies suggest that the putative control system is located along an axis that connects the olfactory bulb and the enthorhinal cortex (enthorhinal-hippocampal-septal-prefrontal cortex-olfactory bulb axis). We suggest that the increased locomotor activity in many psychiatric diseases may derive from the interference with the development of this brain axis during a specific postnatal time window.
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Affiliation(s)
- Davide Viggiano
- Department of Health Sciences, Faculty of Scienze del Benessere, University of Molise, Via De Sanctis III Edificio Polifunzionale, 86100 Campobasso, Italy.
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Pietropaolo S, Singer P, Feldon J, Yee BK. The postweaning social isolation in C57BL/6 mice: preferential vulnerability in the male sex. Psychopharmacology (Berl) 2008; 197:613-28. [PMID: 18317735 DOI: 10.1007/s00213-008-1081-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Accepted: 01/10/2008] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Social deprivation during early life can severely affect mental health later in adulthood, leading to the development of behavioural traits associated with several major psychiatric disorders including schizophrenia. This has led to the application of social isolation in laboratory animals to model the impact of environmental factors on the aetiopathology of schizophrenia. However, controversy exists over the precise behavioural profile and the robustness of some of the reported effects of social isolation rearing. MATERIALS AND METHODS Here, we evaluated the efficacy of postweaning social isolation to induce schizophrenia-related behavioural deficits in C57BL/6 mice of both sexes. RESULTS The effects of social isolation clearly differed between sexes: isolated male but not female mice exhibited multiple habituation deficits and enhanced locomotor reaction to amphetamine. DISCUSSION The preferential vulnerability in the male sex corresponds well with the earlier disease onset and poorer prognosis in male relative to female schizophrenic patients. In contrast, we observed no evidence for a disruption of sensorimotor gating in the prepulse inhibition paradigm despite the efficacy of social isolation to alter startle reactivity. With both success and failure in the induction of schizophrenia-related endophenotypes, the present study thus provides important characterizations and qualifications to the application of the social isolation model in mice. CONCLUSIONS We conclude that social isolation in mice represents a valuable tool for the examination of candidate genes within the context of the "two-hit" hypothesis of the aetiological processes in schizophrenia.
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Affiliation(s)
- Susanna Pietropaolo
- Laboratory of Behavioural Neurobiology, Swiss Federal Institute of Technology Zurich, Schorenstrasse 16, CH-8603 Schwerzenbach, Switzerland
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Fone KCF, Porkess MV. Behavioural and neurochemical effects of post-weaning social isolation in rodents-relevance to developmental neuropsychiatric disorders. Neurosci Biobehav Rev 2008; 32:1087-102. [PMID: 18423591 DOI: 10.1016/j.neubiorev.2008.03.003] [Citation(s) in RCA: 634] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Revised: 02/06/2008] [Accepted: 02/08/2008] [Indexed: 10/22/2022]
Abstract
Exposing mammals to early-life adverse events, including maternal separation or social isolation, profoundly affects brain development and adult behaviour and may contribute to the occurrence of psychiatric disorders, such as depression and schizophrenia in genetically predisposed humans. The molecular mechanisms underlying these environmentally induced developmental adaptations are unclear and best evaluated in animal paradigms with translational salience. Rearing rat pups from weaning in isolation, to prevent social contact with conspecifics, produces reproducible, long-term changes including; neophobia, impaired sensorimotor gating, aggression, cognitive rigidity, reduced prefrontal cortical volume and decreased cortical and hippocampal synaptic plasticity. These alterations are associated with hyperfunction of mesolimbic dopaminergic systems, enhanced presynaptic dopamine (DA) and serotonergic (5-HT) function in the nucleus accumbens (NAcc), hypofunction of mesocortical DA and attenuated 5-HT function in the prefrontal cortex and hippocampus. These behavioural, morphological and neurochemical abnormalities, as reviewed herein, strongly resemble core features of schizophrenia. Therefore unravelling the mechanisms that trigger these sequelae will improve our knowledge of the aetiology of neurodevelopmental psychiatric disorders, enable identification of longitudinal biomarkers of dysfunction and permit predictive screening for novel compounds with potential antipsychotic efficacy.
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Affiliation(s)
- Kevin C F Fone
- Institute of Neuroscience, School of Biomedical Sciences, Medical School, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK.
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Karl T, Duffy L, Scimone A, Harvey RP, Schofield PR. Altered motor activity, exploration and anxiety in heterozygous neuregulin 1 mutant mice: implications for understanding schizophrenia. GENES BRAIN AND BEHAVIOR 2007; 6:677-87. [PMID: 17309661 DOI: 10.1111/j.1601-183x.2006.00298.x] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Human genetic studies have shown that neuregulin 1 (NRG1) is a potential susceptibility gene for schizophrenia. Nrg1 influences various neurodevelopmental processes, which are potentially related to schizophrenia. The neurodevelopmental theory of schizophrenia suggests that interactions between genetic and environmental factors are responsible for biochemical alterations leading to schizophrenia. To investigate these interactions and to match experimental design with the pathophysiology of schizophrenia, we applied a comprehensive behavioural phenotyping strategy for motor activity, exploration and anxiety in a heterozygous Nrg1 transmembrane domain mutant mouse model (Nrg1 HET) using different housing conditions and age groups. We observed a locomotion- and exploration-related hyperactive phenotype in Nrg1 HETs. Increased age had a locomotion- and exploration-inhibiting effect, which was significantly attenuated in mutant mice. Environmental enrichment (EE) had a stimulating influence on locomotion and exploration. The impact of EE was more pronounced in Nrg1 hypomorphs. Our study also showed a moderate task-specific anxiolytic-like phenotype for Nrg1 HETs, which was influenced by external factors. The behavioural phenotype detected in heterozygous Nrg1 mutant mice is not specific to schizophrenia per se, but the increased sensitivity of mutant mice to exogenous factors is consistent with the pathophysiology of schizophrenia and the neurodevelopmental theory. Our findings reinforce the importance of carefully controlling experimental designs for external factors and of comprehensive, integrative phenotyping strategies. Thus, Nrg1 HETs may, in combination with other genetic and drug models, help to clarify pathophysiological mechanisms behind schizophrenia.
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Affiliation(s)
- T Karl
- Neuroscience Institute of Schizophrenia and Allied Disorders, Sydney, NSW, Australia.
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