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Homberg JR, Brivio P, Greven CU, Calabrese F. Individuals being high in their sensitivity to the environment: Are sensitive period changes in play? Neurosci Biobehav Rev 2024; 159:105605. [PMID: 38417743 DOI: 10.1016/j.neubiorev.2024.105605] [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: 10/11/2023] [Revised: 02/13/2024] [Accepted: 02/25/2024] [Indexed: 03/01/2024]
Abstract
All individuals on planet earth are sensitive to the environment, but some more than others. These individual differences in sensitivity to environments are seen across many animal species including humans, and can influence personalities as well as vulnerability and resilience to mental disorders. Yet, little is known about the underlying brain mechanisms. Key genes that contribute to individual differences in environmental sensitivity are the serotonin transporter, dopamine D4 receptor and brain-derived neurotrophic factor genes. By synthesizing neurodevelopmental findings of these genetic factors, and discussing them through the lens of mechanisms related to sensitive periods, which are phases of heightened neuronal plasticity during which a certain network is being finetuned by experiences, we propose that these genetic factors delay but extend postnatal sensitive periods. This may explain why sensitive individuals show behavioral features that are characteristic of a young brain state at the level of sensory information processing, such as reduced filtering or blockade of irrelevant information, resulting in a sensory processing system that 'keeps all options open'.
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Affiliation(s)
- Judith R Homberg
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Paola Brivio
- Department of Pharmacological and Biomolecular Sciences "Rodolfo Paoletti", Università degli Studi di Milano, Milan, Italy
| | - Corina U Greven
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands; Karakter Child and Adolescent Psychiatry University Center, Nijmegen, the Netherlands; King's College London, Institute of Psychiatry, Psychology and Neuroscience, Social, Genetic and Developmental Psychiatry Center, London, United Kingdom
| | - Francesca Calabrese
- Department of Pharmacological and Biomolecular Sciences "Rodolfo Paoletti", Università degli Studi di Milano, Milan, Italy
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Shan L, Linssen S, Harteman Z, den Dekker F, Shuker L, Balesar R, Breesuwsma N, Anink J, Zhou J, Lammers GJ, Swaab DF, Fronczek R. Activated Wake Systems in Narcolepsy Type 1. Ann Neurol 2023; 94:762-771. [PMID: 37395722 DOI: 10.1002/ana.26736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 06/27/2023] [Accepted: 06/29/2023] [Indexed: 07/04/2023]
Abstract
OBJECTIVE Narcolepsy type 1 (NT1) is assumed to be caused solely by a lack of hypocretin (orexin) neurotransmission. Recently, however, we found an 88% reduction in corticotropin-releasing hormone (CRH)-positive neurons in the paraventricular nucleus (PVN). We assessed the remaining CRH neurons in NT1 to determine whether they co-express vasopressin (AVP) to reflect upregulation. We also systematically assessed other wake-systems, since current NT1 treatments target histamine, dopamine, and norepinephrine pathways. METHODS In postmortem tissue of people with NT1 and matched controls, we immunohistochemically stained and quantified neuronal populations expressing: CRH and AVP in the PVN, and CRH in the Barrington nucleus; the key neuronal histamine-synthesizing enzyme, histidine decarboxylase (HDC) in the hypothalamic tuberomammillary nucleus (TMN); the rate-limited-synthesizing enzyme, tyrosine hydroxylase (TH), for dopamine in the mid-brain and for norepinephrine in the locus coeruleus (LC). RESULTS In NT1, there was: a 234% increase in the percentage of CRH cells co-expressing AVP, while there was an unchanged integrated optical density of CRH staining in the Barrington nucleus; a 36% increased number of histamine neurons expressing HDC, while the number of typical human TMN neuronal profiles was unchanged; a tendency toward an increased density of TH-positive neurons in the substantia nigra compacta; while the density of TH-positive LC neurons was unchanged. INTERPRETATION Our findings suggest an upregulation of activity by histamine neurons and remaining CRH neurons in NT1. This may explain earlier reports of normal basal plasma cortisol levels but lower levels after dexamethasone suppression. Alternatively, CRH neurons co-expressing AVP neurons are less vulnerable. ANN NEUROL 2023;94:762-771.
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Affiliation(s)
- Ling Shan
- Leiden University Medical Centre, Department of Neurology, Leiden, The Netherlands, and Sleep Wake Centre SEIN, Heemstede, The Netherlands
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Suzan Linssen
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Zoe Harteman
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Fleur den Dekker
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Lamis Shuker
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Rawien Balesar
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Nicole Breesuwsma
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Jasper Anink
- Department of (Neuro) Pathology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Jingru Zhou
- Leiden University Medical Centre, Department of Neurology, Leiden, The Netherlands, and Sleep Wake Centre SEIN, Heemstede, The Netherlands
| | - Gert Jan Lammers
- Leiden University Medical Centre, Department of Neurology, Leiden, The Netherlands, and Sleep Wake Centre SEIN, Heemstede, The Netherlands
| | - Dick F Swaab
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Rolf Fronczek
- Leiden University Medical Centre, Department of Neurology, Leiden, The Netherlands, and Sleep Wake Centre SEIN, Heemstede, The Netherlands
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Namkung H, Thomas KL, Hall J, Sawa A. Parsing neural circuits of fear learning and extinction across basic and clinical neuroscience: Towards better translation. Neurosci Biobehav Rev 2022; 134:104502. [PMID: 34921863 DOI: 10.1016/j.neubiorev.2021.12.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 12/13/2021] [Accepted: 12/14/2021] [Indexed: 12/22/2022]
Abstract
Over the past decades, studies of fear learning and extinction have advanced our understanding of the neurobiology of threat and safety learning. Animal studies can provide mechanistic/causal insights into human brain regions and their functional connectivity involved in fear learning and extinction. Findings in humans, conversely, may further enrich our understanding of neural circuits in animals by providing macroscopic insights at the level of brain-wide networks. Nevertheless, there is still much room for improvement in translation between basic and clinical research on fear learning and extinction. Through the lens of neural circuits, in this article, we aim to review the current knowledge of fear learning and extinction in both animals and humans, and to propose strategies to fill in the current knowledge gap for the purpose of enhancing clinical benefits.
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Affiliation(s)
- Ho Namkung
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA; Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA
| | - Kerrie L Thomas
- Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK; School of Biosciences, Cardiff University, Cardiff, UK
| | - Jeremy Hall
- Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, UK; School of Medicine, Cardiff University, Cardiff, UK
| | - Akira Sawa
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA; Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA; Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA; Department of Mental Health, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, 21287, USA.
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4
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Willadsen M, Uengoer M, Sługocka A, Schwarting RK, Homberg JR, Wöhr M. Fear Extinction and Predictive Trait-Like Inter-Individual Differences in Rats Lacking the Serotonin Transporter. Int J Mol Sci 2021; 22:ijms22137088. [PMID: 34209318 PMCID: PMC8268876 DOI: 10.3390/ijms22137088] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/24/2021] [Accepted: 06/28/2021] [Indexed: 11/28/2022] Open
Abstract
Anxiety disorders are associated with a failure to sufficiently extinguish fear memories. The serotonergic system (5-hydroxytryptamine, 5-HT) with the 5-HT transporter (5-HTT, SERT) is strongly implicated in the regulation of anxiety and fear. In the present study, we examined the effects of SERT deficiency on fear extinction in a differential fear conditioning paradigm in male and female rats. Fear-related behavior displayed during acquisition, extinction, and recovery, was measured through quantification of immobility and alarm 22-kHz ultrasonic vocalizations (USV). Trait-like inter-individual differences in novelty-seeking, anxiety-related behavior, habituation learning, cognitive performance, and pain sensitivity were examined for their predictive value in forecasting fear extinction. Our results show that SERT deficiency strongly affected the emission of 22-kHz USV during differential fear conditioning. During acquisition, extinction, and recovery, SERT deficiency consistently led to a reduction in 22-kHz USV emission. While SERT deficiency did not affect immobility during acquisition, genotype differences started to emerge during extinction, and during recovery rats lacking SERT showed higher levels of immobility than wildtype littermate controls. Recovery was reflected in increased levels of immobility but not 22-kHz USV emission. Prominent sex differences were evident. Among several measures for trait-like inter-individual differences, anxiety-related behavior had the best predictive quality.
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Affiliation(s)
- Maria Willadsen
- Behavioral Neuroscience, Experimental and Biological Psychology, Faculty of Psychology, Philipps-University of Marburg, Gutenberg-Str. 18, D-35032 Marburg, Germany; (M.W.); (R.K.W.S.)
| | - Metin Uengoer
- Associative Learning, Experimental and Biological Psychology, Faculty of Psychology, Philipps-University of Marburg, Gutenberg-Str. 18, D-35032 Marburg, Germany;
| | - Anna Sługocka
- Department for Experimental Medicine, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 4, 40-752 Katowice, Poland;
- Department of Physiology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18, 40-752 Katowice, Poland
| | - Rainer K.W. Schwarting
- Behavioral Neuroscience, Experimental and Biological Psychology, Faculty of Psychology, Philipps-University of Marburg, Gutenberg-Str. 18, D-35032 Marburg, Germany; (M.W.); (R.K.W.S.)
- Center for Mind, Brain and Behavior, Philipps-University of Marburg, Hans-Meerwein-Str. 6, D-35032 Marburg, Germany
| | - Judith R. Homberg
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Kapittelweg 29, 6525 EN Nijmegen, The Netherlands;
| | - Markus Wöhr
- Behavioral Neuroscience, Experimental and Biological Psychology, Faculty of Psychology, Philipps-University of Marburg, Gutenberg-Str. 18, D-35032 Marburg, Germany; (M.W.); (R.K.W.S.)
- Center for Mind, Brain and Behavior, Philipps-University of Marburg, Hans-Meerwein-Str. 6, D-35032 Marburg, Germany
- KU Leuven, Faculty of Psychology and Educational Sciences, Research Unit Brain and Cognition, Laboratory of Biological Psychology, Social and Affective Neuroscience Research Group, B-3000 Leuven, Belgium
- KU Leuven, Leuven Brain Institute, B-3000 Leuven, Belgium
- Correspondence: ; Tel.: +32–16–19–45–57
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5
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Willadsen M, Uengoer M, Schwarting RKW, Homberg JR, Wöhr M. Reduced emission of alarm 22-kHz ultrasonic vocalizations during fear conditioning in rats lacking the serotonin transporter. Prog Neuropsychopharmacol Biol Psychiatry 2021; 108:110072. [PMID: 32800867 DOI: 10.1016/j.pnpbp.2020.110072] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 08/02/2020] [Accepted: 08/09/2020] [Indexed: 12/19/2022]
Abstract
Rats display a rich social behavioral repertoire. An important component of this repertoire is the emission of whistle-like calls in the ultrasonic range, so-called ultrasonic vocalizations (USV). Long low-frequency 22-kHz USV occur in aversive situations, including aggressive interactions, predator exposure, and electric shocks during fear conditioning. They are believed to reflect a negative affective state akin to anxiety and fear. A prominent theory suggests that 22-kHz USV function as alarm calls to warn conspecifics. Serotonin (5-hydroxytryptamine, 5-HT) is strongly implicated in the regulation of affective states, particularly anxiety and fear. A key component of the system is the 5-HT transporter (5-HTT, also known as SERT), regulating 5-HT availability in the synaptic cleft. In the present experiment, we studied the effects of SERT deficiency on overt fear-related behavior and alarm 22-kHz USV during fear conditioning in male and female rats. While overt fear-related behavior was not affected by SERT deficiency and sex, the emission of alarm 22-kHz USV was clearly reduced in homozygous SERT-/- but not heterozygous SERT+/- mutants, as compared to their wildtype SERT+/+ littermate controls. Genotype effects were particularly prominent in females. Females in general emitted fewer alarm 22-kHz USV than males. This supports the view that 22-kHz USV are, at least partly, independently regulated from anxiety or fear and as socially mediated alarm calls do not simply express a negative affective state. Reduced 22-kHz USV emission in rats lacking SERT might be due to social deficits in the use of 22-kHz USV as a socio-affective signal to warn conspecifics about threats.
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Affiliation(s)
- Maria Willadsen
- Behavioral Neuroscience, Experimental and Biological Psychology, Faculty of Psychology, Philipps-University of Marburg, Gutenberg-Str. 18, D-35032 Marburg, Germany
| | - Metin Uengoer
- Behavioral Neuroscience, Experimental and Biological Psychology, Faculty of Psychology, Philipps-University of Marburg, Gutenberg-Str. 18, D-35032 Marburg, Germany; Center for Mind, Brain and Behavior, Philipps-University of Marburg, Hans-Meerwein-Str. 6, D-35032 Marburg, Germany
| | - Rainer K W Schwarting
- Behavioral Neuroscience, Experimental and Biological Psychology, Faculty of Psychology, Philipps-University of Marburg, Gutenberg-Str. 18, D-35032 Marburg, Germany; Center for Mind, Brain and Behavior, Philipps-University of Marburg, Hans-Meerwein-Str. 6, D-35032 Marburg, Germany
| | - Judith R Homberg
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Markus Wöhr
- Behavioral Neuroscience, Experimental and Biological Psychology, Faculty of Psychology, Philipps-University of Marburg, Gutenberg-Str. 18, D-35032 Marburg, Germany; Center for Mind, Brain and Behavior, Philipps-University of Marburg, Hans-Meerwein-Str. 6, D-35032 Marburg, Germany; Laboratory for Behavioral Neuroscience, Department of Biology, Faculty of Science, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
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6
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Caffino L, Mottarlini F, Van Reijmersdal B, Telese F, Verheij MM, Fumagalli F, Homberg JR. The role of the serotonin transporter in prefrontal cortex glutamatergic signaling following short- and long-access cocaine self-administration. Addict Biol 2021; 26:e12896. [PMID: 32187792 PMCID: PMC7988536 DOI: 10.1111/adb.12896] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/28/2020] [Accepted: 03/06/2020] [Indexed: 12/14/2022]
Abstract
Vulnerability to drug addiction relies on substantial individual differences. We previously demonstrated that serotonin transporter knockout (SERT−/−) rats show increased cocaine intake and develop signs of compulsivity. However, the underlying neural mechanisms are not fully understood. Given the pivotal role of glutamate and prefrontal cortex in cocaine‐seeking behavior, we sought to investigate the expression of proteins implicated in glutamate neurotransmission in the prefrontal cortex of naïve and cocaine‐exposed rats lacking SERT. We focused on the infralimbic (ILc) and prelimbic (PLc) cortices, which are theorized to exert opposing effects on the control over subcortical brain areas. SERT−/− rats, which compared to wild‐type (SERT+/+) rats show increased ShA and LgA intake short‐access (ShA) and long‐access (LgA) cocaine intake, were sacrificed 24 h into withdrawal for ex vivo molecular analyses. In the ILc homogenate of SERT−/− rats, we observed a sharp increase in glial glutamate transporter 1 (GLT‐1) after ShA, but not LgA, cocaine intake. This was paralleled by ShA‐induced increases in GluN1, GluN2A, and GluN2B NMDA receptor subunits and their scaffolding protein SAP102 in the ILc homogenate, but not postsynaptic density, of these knockout animals. In the PLc, we found no major changes in the homogenate; conversely, the expression of GluN1 and GluN2A NMDA receptor subunits was increased in the postsynaptic density under ShA conditions and reduced under LgA conditions. These results point to SERT as a critical regulator of glutamate homeostasis in a way that differs between the subregions investigated, the duration of cocaine exposure as well as the cellular compartment analyzed.
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Affiliation(s)
- Lucia Caffino
- Department of Pharmacological and Biomolecular Sciences Università degli Studi di Milano Milan Italy
| | - Francesca Mottarlini
- Department of Pharmacological and Biomolecular Sciences Università degli Studi di Milano Milan Italy
| | - Boyd Van Reijmersdal
- Department of Cognitive Neuroscience, Division of Molecular Neurogenetics, Donders Institute for Brain, Cognition and Behaviour Radboud University Nijmegen Medical Centre Nijmegen The Netherlands
| | - Francesca Telese
- Department of Pharmacological and Biomolecular Sciences Università degli Studi di Milano Milan Italy
| | - Michel M.M. Verheij
- Department of Cognitive Neuroscience, Division of Molecular Neurogenetics, Donders Institute for Brain, Cognition and Behaviour Radboud University Nijmegen Medical Centre Nijmegen The Netherlands
| | - Fabio Fumagalli
- Department of Pharmacological and Biomolecular Sciences Università degli Studi di Milano Milan Italy
| | - Judith R. Homberg
- Department of Cognitive Neuroscience, Division of Molecular Neurogenetics, Donders Institute for Brain, Cognition and Behaviour Radboud University Nijmegen Medical Centre Nijmegen The Netherlands
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7
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Histamine-4 receptor antagonist ameliorates Parkinson-like pathology in the striatum. Brain Behav Immun 2021; 92:127-138. [PMID: 33249171 DOI: 10.1016/j.bbi.2020.11.036] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 11/22/2020] [Accepted: 11/23/2020] [Indexed: 12/21/2022] Open
Abstract
Growing evidence indicates that microglia activation and a neuroinflammatory trigger contribute to dopaminergic cell loss in Parkinson's disease (PD). Furthermore, increased density of histaminergic fibers and enhanced histamine levels have been observed in the substantia nigra of PD-postmortem brains. Histamine-induced microglial activation is mediated by the histamine-4 receptor (H4R). In the current study, gene set enrichment and pathway analyses of a PD basal ganglia RNA-sequencing dataset revealed that upregulation of H4R was in the top functional category for PD treatment targets. Interestingly, the H4R antagonist JNJ7777120 normalized the number of nigrostriatal dopaminergic fibers and striatal dopamine levels in a rotenone-induced PD rat model. These improvements were accompanied by a reduction of α-synuclein-positive inclusions in the striatum. In addition, intracerebroventricular infusion of JNJ7777120 alleviated the morphological changes in Iba-1-positive microglia and resulted in a lower tumor necrosis factor-α release from this brain region, as well as in ameliorated apomorphine-induced rotation behaviour. Finally, JNJ7777120 also restored basal ganglia function by decreasing the levels of γ-aminobutyric acid (GABA) and the 5-hydroxyindoleactic acid to serotonin (5-HIAA/5-HT) concentration ratios in the striatum of the PD model. Our results highlight H4R inhibition in microglia as a promising and specific therapeutic target to reduce or prevent neuroinflammation, and as such the development of PD pathology.
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8
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SKF83959, an agonist of phosphatidylinositol-linked dopamine receptors, prevents renewal of extinguished conditioned fear and facilitates extinction. Brain Res 2020; 1749:147136. [PMID: 32980332 DOI: 10.1016/j.brainres.2020.147136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 09/19/2020] [Accepted: 09/21/2020] [Indexed: 12/11/2022]
Abstract
Fear-related anxiety disorders, such as social phobia and post-traumatic stress disorder, are partly explained by an uncontrollable state of fear. An emerging literature suggests dopamine receptor-1 (D1 receptor) in the amygdala is involved in the regulation of fear memory. An early study has reported that amygdaloid D1 receptor (D1R) is not coupled to the classic cAMP-dependent signal transduction. Here, we investigated whether SKF83959, a typical D1R agonist that mainly activates a D1-like receptor-dependent phosphatidylinositol (PI) signal pathway, facilitates fear extinction and reduces the return of extinguished fear. Interestingly, long-term loss of fearful memories can be induced through a combination of SKF83959 (1 mg/kg/day, i.p., once daily for one week) pharmacotherapy and extinction training. Furthermore, sub-chronic administration of SKF83959 after fear conditioning reduced fear renewal and reinstatement in the mice. We found that the activation D1R and PI signaling in the amygdala was responsible for the effect of SKF83959 on fear extinction. Additionally, SKF83959 significantly promoted the elevation of brain-derived neurotrophic factor (BDNF) expression, possibly by the cAMP response element binding protein (CREB) -directed gene transcription. Given the beneficial effects on extinction, SKF83959 may emerge as a candidate pharmacological approach for improving cognitive-behavioral therapy on fear-related anxiety disorders.
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9
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The association between serotonin transporter availability and the neural correlates of fear bradycardia. Proc Natl Acad Sci U S A 2019; 116:25941-25947. [PMID: 31772023 PMCID: PMC6925990 DOI: 10.1073/pnas.1904843116] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Reduced expression of the serotonin transporter (5-HTT) is associated with susceptibility to stress-related psychopathology, but the underlying mechanisms remain elusive. We investigated whether an aberrant physiological and neural response to threat underlies this increased vulnerability. In a cross-species approach, we investigated the association between genetically encoded differences in 5-HTT expression and the neural correlates of fear bradycardia, a defensive response linked to vigilance. In both humans and rats, reduced 5-HTT expression was associated with exaggerated bradycardia or bradycardia-associated freezing, reduced activity of the medial prefrontal cortex, and increased threat-induced amygdala-periaqueductal grey connectivity and central amygdala somatostatin neuron activity. We have delineated a previously unknown neurogenetic mechanism underlying individual differences in the expression of anticipatory threat responses, contributing to stress sensitivity. Susceptibility to stress-related psychopathology is associated with reduced expression of the serotonin transporter (5-HTT), particularly in combination with stress exposure. Aberrant physiological and neuronal responses to threat may underlie this increased vulnerability. Here, implementing a cross-species approach, we investigated the association between 5-HTT expression and the neural correlates of fear bradycardia, a defensive response linked to vigilance and action preparation. We tested this during threat anticipation induced by a well-established fear conditioning paradigm applied in both humans and rodents. In humans, we studied the effect of the common 5-HTT-linked polymorphic region (5-HTTLPR) on bradycardia and neural responses to anticipatory threat during functional magnetic resonance imaging scanning in healthy volunteers (n = 104). Compared with homozygous long-allele carriers, the 5-HTTLPR short-allele carriers displayed an exaggerated bradycardic response to threat, overall reduced activation of the medial prefrontal cortex (mPFC), and increased threat-induced connectivity between the amygdala and periaqueductal gray (PAG), which statistically mediated the effect of the 5-HTTLPR genotype on bradycardia. In parallel, 5-HTT knockout (KO) rats also showed exaggerated threat-related bradycardia and behavioral freezing. Immunohistochemistry indicated overall reduced activity of glutamatergic neurons in the mPFC of KO rats and increased activity of central amygdala somatostatin-positive neurons, putatively projecting to the PAG, which—similarly to the human population—mediated the 5-HTT genotype’s effect on freezing. Moreover, the ventrolateral PAG of KO rats displayed elevated overall activity and increased relative activation of CaMKII-expressing projection neurons. Our results provide a mechanistic explanation for previously reported associations between 5-HTT gene variance and a stress-sensitive phenotype.
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Schipper P, Brivio P, de Leest D, Madder L, Asrar B, Rebuglio F, Verheij MMM, Kozicz T, Riva MA, Calabrese F, Henckens MJAG, Homberg JR. Impaired Fear Extinction Recall in Serotonin Transporter Knockout Rats Is Transiently Alleviated during Adolescence. Brain Sci 2019; 9:brainsci9050118. [PMID: 31121975 PMCID: PMC6562656 DOI: 10.3390/brainsci9050118] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/21/2019] [Accepted: 05/21/2019] [Indexed: 11/16/2022] Open
Abstract
Adolescence is a developmental phase characterized by emotional turmoil and coincides with the emergence of affective disorders. Inherited serotonin transporter (5-HTT) downregulation in humans increases sensitivity to these disorders. To reveal whether and how 5-HTT gene variance affects fear-driven behavior in adolescence, we tested wildtype and serotonin transporter knockout (5-HTT-/-) rats of preadolescent, adolescent, and adult age for cued fear extinction and extinction recall. To analyze neural circuit function, we quantified inhibitory synaptic contacts and, through RT-PCR, the expression of c-Fos, brain-derived neurotrophic factor (BDNF), and NDMA receptor subunits, in the medial prefrontal cortex (mPFC) and amygdala. Remarkably, the impaired recall of conditioned fear that characterizes preadolescent and adult 5-HTT-/- rats was transiently normalized during adolescence. This did not relate to altered inhibitory neurotransmission, since mPFC inhibitory immunoreactivity was reduced in 5-HTT-/- rats across all ages and unaffected in the amygdala. Rather, since mPFC (but not amygdala) c-Fos expression and NMDA receptor subunit 1 expression were reduced in 5-HTT-/- rats during adolescence, and since PFC c-Fos correlated negatively with fear extinction recall, the temporary normalization of fear extinction during adolescence could relate to altered plasticity in the developing mPFC.
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Affiliation(s)
- Pieter Schipper
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Kapittelweg 29, 6525 EN Nijmegen, The Netherlands.
| | - Paola Brivio
- Department of Pharmacological and Biomolecular Sciences, Universita' degli Studi di Milano, 20133 Milan, Italy.
| | - David de Leest
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Kapittelweg 29, 6525 EN Nijmegen, The Netherlands.
| | - Leonie Madder
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Kapittelweg 29, 6525 EN Nijmegen, The Netherlands.
| | - Beenish Asrar
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Kapittelweg 29, 6525 EN Nijmegen, The Netherlands.
| | - Federica Rebuglio
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Kapittelweg 29, 6525 EN Nijmegen, The Netherlands.
| | - Michel M M Verheij
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Kapittelweg 29, 6525 EN Nijmegen, The Netherlands.
| | - Tamas Kozicz
- Department of Clinical Genomics, Mayp Clinic, Rochester, MN 55905, USA.
| | - Marco A Riva
- Department of Pharmacological and Biomolecular Sciences, Universita' degli Studi di Milano, 20133 Milan, Italy.
| | - Francesca Calabrese
- Department of Pharmacological and Biomolecular Sciences, Universita' degli Studi di Milano, 20133 Milan, Italy.
| | - Marloes J A G Henckens
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Kapittelweg 29, 6525 EN Nijmegen, The Netherlands.
| | - Judith R Homberg
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Kapittelweg 29, 6525 EN Nijmegen, The Netherlands.
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Kroes MCW, Henckens MJAG, Homberg JR. How serotonin transporter gene variance affects defensive behaviours along the threat imminence continuum. Curr Opin Behav Sci 2019. [DOI: 10.1016/j.cobeha.2018.09.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Zhou P, Homberg JR, Fang Q, Wang J, Li W, Meng X, Shen J, Luan Y, Liao P, Swaab DF, Shan L, Liu C. Histamine-4 receptor antagonist JNJ7777120 inhibits pro-inflammatory microglia and prevents the progression of Parkinson-like pathology and behaviour in a rat model. Brain Behav Immun 2019; 76:61-73. [PMID: 30408497 DOI: 10.1016/j.bbi.2018.11.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 11/02/2018] [Accepted: 11/03/2018] [Indexed: 12/20/2022] Open
Abstract
The activation of microglial cells is presumed to play a key role in the pathogenesis of Parkinson's disease (PD). The activity of microglia is regulated by the histamine-4 receptor (H4R), thus providing a novel target that may prevent the progression of PD. However, this putative mechanism has so far not been validated. In our previous study, we found that mRNA expression of H4R was upregulated in PD patients. In the present study, we validated this possible mechanism using the rotenone-induced PD rat model, in which mRNA expression levels of H4R-, and microglial markers were significantly increased in the ventral midbrain. Inhibition of H4R in rotenone-induced PD rat model by infusion of the specific H4R antagonist JNJ7777120 into the lateral ventricle resulted in blockade of microglial activation. In addition, pharmacological targeting of H4R in rotenone-lesioned rats resulted in reduced apomorphine-induced rotational behaviour, prevention of dopaminergic neuron degeneration and associated decreases in striatal dopamine levels. These changes were accompanied by a reduction of Lewy body-like neuropathology. Our results provide first proof of the efficacy of an H4R antagonist in a commonly used PD rat model, and proposes the H4R as a promising target to clinically tackle microglial activation and thereby the progression of PD.
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Affiliation(s)
- Pei Zhou
- College of Medical Laboratory, Dalian Medical University, Dalian, Liaoning 116044, China; Department of Clinical Laboratory, The First College of Clinical Medical Science, China Three Gorges University, Yichang, Hubei 443003, China
| | - Judith R Homberg
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Qiuyuan Fang
- College of Medical Laboratory, Dalian Medical University, Dalian, Liaoning 116044, China
| | - Jiaqi Wang
- College of Medical Laboratory, Dalian Medical University, Dalian, Liaoning 116044, China
| | - Weizhuo Li
- College of Medical Laboratory, Dalian Medical University, Dalian, Liaoning 116044, China
| | - Xianzong Meng
- College of Medical Laboratory, Dalian Medical University, Dalian, Liaoning 116044, China
| | - Junqing Shen
- College of Medical Laboratory, Dalian Medical University, Dalian, Liaoning 116044, China
| | - Yi Luan
- College of Medical Laboratory, Dalian Medical University, Dalian, Liaoning 116044, China; Department of Clinical Laboratory, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510120, China
| | - Peng Liao
- College of Medical Laboratory, Dalian Medical University, Dalian, Liaoning 116044, China
| | - Dick F Swaab
- Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, the Netherlands
| | - Ling Shan
- Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, the Netherlands.
| | - Chunqing Liu
- College of Medical Laboratory, Dalian Medical University, Dalian, Liaoning 116044, China.
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Shan L, Guo HY, van den Heuvel CNAM, van Heerikhuize J, Homberg JR. Impaired fear extinction in serotonin transporter knockout rats is associated with increased 5-hydroxymethylcytosine in the amygdala. CNS Neurosci Ther 2018; 24:810-819. [PMID: 29427306 PMCID: PMC6120487 DOI: 10.1111/cns.12822] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 01/16/2018] [Accepted: 01/17/2018] [Indexed: 01/07/2023] Open
Abstract
Aims One potential risk factor for posttraumatic stress disorder (PTSD) involves the low activity (short; s) allelic variant of the serotonin transporter‐linked polymorphic region (5‐HTTLPR), possibly due to reduced prefrontal control over the amygdala. Evidence shows that DNA methylation/demethylation is crucial for fear extinction in these brain areas and is associated with neuronal activation marker c‐Fos expression. We hypothesized that impaired fear extinction in serotonin transporter knockout (5‐HTT−/−) rats is related to changes in DNA (de) methylation and c‐Fos expression in the prefrontal cortex (PFC) and/or amygdala. Methods 5‐HTT−/− and 5‐HTT+/+ rats were subjected to fear extinction. 2 hours after the extinction session, the overall levels of DNA methylation (5‐mC), demethylation (5‐hmC), and c‐Fos in fear extinction and nonfear extinction rats were measured by immunohistochemistry. Results 5‐HTT−/− rats displayed decreased fear extinction. This was associated with reduced c‐Fos activity in the infralimbic PFC. In the central nucleus of the amygdala, c‐Fos immunoreactivity was increased in the fear extinction group compared to the no‐fear extinction group, regardless of genotype. 5‐hmC levels were unaltered in the PFC, but reduced in the amygdala of nonextinction 5‐HTT−/− rats compared to nonextinction wild‐type rats, which caught up to wild‐type levels during fear extinction. 5‐mC levels were stable in central amygdala in both wild‐type and 5‐HTT−/− extinction rats. Finally, c‐Fos and 5‐mC levels were correlated with the prelimbic PFC, but not amygdala. Conclusions In the amygdala, DNA demethylation, independent from c‐Fos activation, may contribute to individual differences in risk for PTSD, as conferred by the 5‐HTTLPR s‐allele.
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Affiliation(s)
- Ling Shan
- Donders Institute for Brain, Cognition, and Behaviour, Centre for Neuroscience, Department of Cognitive Neuroscience, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Hang-Yuan Guo
- Shaoxing People's Hospital, Shaoxing Hospital of Zhejiang University, Shaoxing, China
| | - Corina N A M van den Heuvel
- Donders Institute for Brain, Cognition, and Behaviour, Centre for Neuroscience, Department of Cognitive Neuroscience, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Joop van Heerikhuize
- Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Science, Amsterdam, The Netherlands
| | - Judith R Homberg
- Donders Institute for Brain, Cognition, and Behaviour, Centre for Neuroscience, Department of Cognitive Neuroscience, Radboud University Medical Centre, Nijmegen, The Netherlands
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