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Matsuda S. Importance of home cage condition for contextual fear memory, fear extinction and spontaneous recovery: Cage size and bedding material. Neurosci Lett 2023; 804:137204. [PMID: 36966963 DOI: 10.1016/j.neulet.2023.137204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 03/06/2023] [Accepted: 03/22/2023] [Indexed: 03/29/2023]
Abstract
Home cage condition influences the central nervous system of experimental animals. However, little is known about the effect of home cage size and bedding material on fear-related behaviors. Thus, in this study, the effects of home cage size (large or small) and/or bedding material (paper or wood) on acquisition, retrieval, extinction, and spontaneous recovery of contextual fear memory were investigated in both male and female mice. The present study demonstrated that males housed in small cages with wood bedding showed a low fear response during fear extinction when compared to males housed in small or large cages with paper bedding. In females, mice housed in small cages with wood bedding showed low fear response during fear conditioning and extinction when compared to mice housed in large cages with paper bedding. Moreover, small cages with wood bedding, but not small or large cages with paper bedding, prevented the spontaneous recovery of fear memory in females. Thus, home cage conditions, and particularly bedding material, influence contextual fear extinction and spontaneous recovery. This finding may help to obtain reproducibility of results by researchers and explain discrepancies of results among research groups.
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de Oliveira Alves C, Reimer AE, de Oliveira AR. Involvement of D2-like dopaminergic receptors in contextual fear conditioning in female rats: influence of estrous cycle. Front Behav Neurosci 2022; 16:1033649. [PMID: 36518813 PMCID: PMC9742248 DOI: 10.3389/fnbeh.2022.1033649] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 11/08/2022] [Indexed: 10/19/2023] Open
Abstract
Introduction: Dopamine has been increasingly recognized as a key neurotransmitter regulating fear/anxiety states. Nevertheless, the influence of sex and estrous cycle differences on the role of dopamine in fear responses needs further investigation. We aimed to evaluate the effects of sulpiride (a dopaminergic D2-like receptor antagonist) on contextual fear conditioning in females while exploring the influence of the estrous cycle. Methods: First, using a contextual fear conditioning paradigm, we assessed potential differences in acquisition, expression, and extinction of the conditioned freezing response in male and female (split in proestrus/estrus and metestrus/diestrus) Wistar rats. In a second cohort, we evaluated the effects of sulpiride (20 and 40 mg/kg) on contextual conditioned fear in females during proestrus/estrus and metestrus/diestrus. Potential nonspecific effects were assessed in motor activity assays (catalepsy and open-field tests). Results: No sex differences nor estrous cycle effects on freezing behavior were observed during the fear conditioning phases. Sulpiride reduced freezing expression in female rats. Moreover, females during the proestrus/estrus phases of the estrous cycle were more sensitive to the effects of sulpiride than females in metestrus/diestrus. Sulpiride did not cause motor impairments. Discussion: Although no sex or estrous cycle differences were observed in basal conditioned fear expression and extinction, the estrous cycle seems to influence the effects of D2-like antagonists on contextual fear conditioning.
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Affiliation(s)
- Camila de Oliveira Alves
- Department of Psychology, Center of Education and Human Sciences, Federal University of São Carlos (UFSCar), São Carlos, Brazil
- Institute of Neuroscience and Behavior (INeC), Ribeirão Preto, Brazil
| | - Adriano Edgar Reimer
- Department of Psychology, Center of Education and Human Sciences, Federal University of São Carlos (UFSCar), São Carlos, Brazil
- Institute of Neuroscience and Behavior (INeC), Ribeirão Preto, Brazil
| | - Amanda Ribeiro de Oliveira
- Department of Psychology, Center of Education and Human Sciences, Federal University of São Carlos (UFSCar), São Carlos, Brazil
- Institute of Neuroscience and Behavior (INeC), Ribeirão Preto, Brazil
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3
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Emtyazi D, Rabelo TK, Katzman H, Campos AC, Diwan M, Gidyk D, Rabelo Dos Santos P, Giacobbe P, Lipsman N, Aubert I, Hamani C. Sex differences in long-term fear and anxiety-like responses in a preclinical model of PTSD. J Psychiatr Res 2022; 151:619-625. [PMID: 35640386 DOI: 10.1016/j.jpsychires.2022.05.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 05/14/2022] [Accepted: 05/19/2022] [Indexed: 10/18/2022]
Abstract
With a high prevalence of posttraumatic stress disorder (PTSD) in females, studying sex differences in preclinical models is of substantial importance. We have previously employed behavioural criteria to identify and characterize a subpopulation of rats that presented impaired fear extinction and long-term fear and anxiety responses following fear conditioning. We now exposed male and female rats to fear conditioning and extinction and segregated the animals into weak- (WE) and strong-extinction (SE) groups based on behavioural scores during extinction. Animals were subsequently tested for tone and context recall, as well as anxiety-like responses in the marble burying and novelty suppression of feeding (NSF) tests. Vaginal lavages were collected to characterize the phase of the estrous cycle during fear extinction. We found that females had reduced freezing during tone recall and a lower latency to feed in the NSF test. No differences were found in females undergoing extinction during high and low estrogen phases of the cycle in any of the performed tests. Overall, the percentage of animals that presented WE and SE phenotypes was similar in males and females. Both, WE males and females had increased freezing during tone and context recall. Along with our previous reports, WE males presented anxiety-like responses, particularly in the NSF compared to SE animals. In contrast, WE females buried less marbles than their SE mates. Future investigation including a larger number of behavioural tests are certainly required to corroborate our findings and ascertain potential mechanisms to explain the differences observed in our study.
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Affiliation(s)
- Delara Emtyazi
- Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, Toronto, ON, M4N 3M5, Canada
| | - Thallita Kelly Rabelo
- Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, Toronto, ON, M4N 3M5, Canada
| | - Hailey Katzman
- Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, Toronto, ON, M4N 3M5, Canada
| | - Ana Carolina Campos
- Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, Toronto, ON, M4N 3M5, Canada
| | - Mustansir Diwan
- Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, Toronto, ON, M4N 3M5, Canada
| | - Darryl Gidyk
- Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, Toronto, ON, M4N 3M5, Canada
| | | | - Peter Giacobbe
- Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, Toronto, ON, M4N 3M5, Canada; Hurvitz Brain Sciences Centre, Sunnybrook Research Institute, Toronto, ON, M4N 3M5, Canada; Department of Psychiatry, Sunnybrook Health Sciences Centre, Toronto, ON, M4N 3M5, Canada
| | - Nir Lipsman
- Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, Toronto, ON, M4N 3M5, Canada; Hurvitz Brain Sciences Centre, Sunnybrook Research Institute, Toronto, ON, M4N 3M5, Canada; Division of Neurosurgery, Department of Medicine, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, M4N 3M5, Canada
| | - Isabelle Aubert
- Hurvitz Brain Sciences Centre, Sunnybrook Research Institute, Toronto, ON, M4N 3M5, Canada; Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, University of Toronto, ON, M5S 1A8, Canada
| | - Clement Hamani
- Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, Toronto, ON, M4N 3M5, Canada; Hurvitz Brain Sciences Centre, Sunnybrook Research Institute, Toronto, ON, M4N 3M5, Canada; Division of Neurosurgery, Department of Medicine, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, M4N 3M5, Canada.
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4
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Florido A, Velasco ER, Soto-Faguás CM, Gomez-Gomez A, Perez-Caballero L, Molina P, Nadal R, Pozo OJ, Saura CA, Andero R. Sex differences in fear memory consolidation via Tac2 signaling in mice. Nat Commun 2021; 12:2496. [PMID: 33941789 PMCID: PMC8093426 DOI: 10.1038/s41467-021-22911-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 03/25/2021] [Indexed: 11/08/2022] Open
Abstract
Memory formation is key for brain functioning. Uncovering the memory mechanisms is helping us to better understand neural processes in health and disease. Moreover, more specific treatments for fear-related disorders such as posttraumatic stress disorder and phobias may help to decrease their negative impact on mental health. In this line, the Tachykinin 2 (Tac2) pathway in the central amygdala (CeA) has been shown to be sufficient and necessary for the modulation of fear memory consolidation. CeA-Tac2 antagonism and its pharmacogenetic temporal inhibition impair fear memory in male mice. Surprisingly, we demonstrate here the opposite effect of Tac2 blockade on enhancing fear memory consolidation in females. Furthermore, we show that CeA-testosterone in males, CeA-estradiol in females and Akt/GSK3β/β-Catenin signaling both mediate the opposite-sex differential Tac2 pathway regulation of fear memory.
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Affiliation(s)
- A Florido
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - E R Velasco
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - C M Soto-Faguás
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Department de Bioquímica i Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - A Gomez-Gomez
- Integrative Pharmacology and Systems Neuroscience Research Group, Neurosciences Research Program, IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain
| | - L Perez-Caballero
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - P Molina
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Unitat de Fisiologia Animal, Departament de Biologia Cel·lular, Fisiologia i Immunologia. Facultat de Biociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - R Nadal
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Centro de Investigación Biomédica En Red en Salud Mental (CIBERSAM), Instituto de Salud Carlos III, Madrid, Spain
- Unitat de Neurociència Traslacional, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc Taulí (I3PT), Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - O J Pozo
- Integrative Pharmacology and Systems Neuroscience Research Group, Neurosciences Research Program, IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain
| | - C A Saura
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Department de Bioquímica i Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Centro de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - R Andero
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain.
- Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain.
- Centro de Investigación Biomédica En Red en Salud Mental (CIBERSAM), Instituto de Salud Carlos III, Madrid, Spain.
- Unitat de Neurociència Traslacional, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc Taulí (I3PT), Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain.
- ICREA, Pg. Lluís Companys 23, Barcelona, Spain.
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5
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Florido A, Perez-Caballero L, Velasco ER, Molina P, Marin-Blasco I, Andero R. Direct and Indirect Measurements of Sex Hormones in Rodents During Fear Conditioning. Curr Protoc 2021; 1:e102. [PMID: 33950571 DOI: 10.1002/cpz1.102] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Fear conditioning (FC) is a widely accepted tool for the assessment of learning and memory processes in rodents related to normal and dysregulated acquired fear. The study of sex differences in fear learning and memory is vast and currently increasing. Sex hormones have proven to be crucial for fear memory formation in males and females, and several methods have been developed to assess this hormonal state in rats and mice. Herein, we explain a routine FC and extinction protocol, together with the evaluation of sex hormonal state in male and female rodents. We explain three protocols for the evaluation of this hormonal state directly from blood samples extracted during the procedure or indirectly through histological verification of the estrous cycle for females or behavioral assessment of social hierarchies in males. Although females have typically been considered to present great variability in sex hormones, it is highlighted that sex hormone assessment in males is as variable as in females and equally important for fear memory formation. The readout of these protocols has had a great impact on different fields of fear learning and memory study and appears essential when studying FC. The proven interaction with drugs involved in the modulation of these processes makes sex hormone assessment during FC a valuable tool for the development of effective treatments for fear-related disorders in men and women. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Fear conditioning and fear extinction Basic Protocol 2: Blood collection for direct measurement of sex hormone levels in fear conditioning Basic Protocol 3: Indirect measurement of sex hormones in females during fear conditioning Basic Protocol 4: Assessment of dominance status in males before a fear conditioning protocol Support Protocol: Construction of a confrontation tube.
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Affiliation(s)
- Antonio Florido
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Laura Perez-Caballero
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Eric Raúl Velasco
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Patricia Molina
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Unitat de Fisiologia Animal (Departament de Biologia Cel·lular, Fisiologia i Immunologia), Facultat de Biociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Ignacio Marin-Blasco
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Raül Andero
- Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Departament de Psicobiologia i de Metodologia de les Ciències de la Salut, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Instituto de Salud Carlos III, Madrid, Spain
- Unitat de Neurociència Traslacional, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc Taulí (I3PT), Institut de Neurociències, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
- ICREA, Barcelona, Spain
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6
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Kolter JF, Hildenbrand MF, Popp S, Nauroth S, Bankmann J, Rother L, Waider J, Deckert J, Asan E, Jakob PM, Lesch KP, Schmitt-Böhrer A. Serotonin transporter genotype modulates resting state and predator stress-induced amygdala perfusion in mice in a sex-dependent manner. PLoS One 2021; 16:e0247311. [PMID: 33606835 PMCID: PMC7895400 DOI: 10.1371/journal.pone.0247311] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 02/04/2021] [Indexed: 12/16/2022] Open
Abstract
The serotonin transporter (5-HTT) is a key molecule of serotoninergic neurotransmission and target of many anxiolytics and antidepressants. In humans, 5-HTT gene variants resulting in lower expression levels are associated with behavioral traits of anxiety. Furthermore, functional magnetic resonance imaging (fMRI) studies reported increased cerebral blood flow (CBF) during resting state (RS) and amygdala hyperreactivity. 5-HTT deficient mice as an established animal model for anxiety disorders seem to be well suited for investigating amygdala (re-)activity in an fMRI study. We investigated wildtype (5-HTT+/+), heterozygous (5-HTT+/-), and homozygous 5-HTT-knockout mice (5-HTT-/-) of both sexes in an ultra-high-field 17.6 Tesla magnetic resonance scanner. CBF was measured with continuous arterial spin labeling during RS, stimulation state (SS; with odor of rats as aversive stimulus), and post-stimulation state (PS). Subsequently, post mortem c-Fos immunohistochemistry elucidated neural activation on cellular level. The results showed that in reaction to the aversive odor CBF in total brain and amygdala of all mice significantly increased. In male 5-HTT+/+ mice amygdala RS CBF levels were found to be significantly lower than in 5-HTT+/- mice. From RS to SS 5-HTT+/+ amygdala perfusion significantly increased compared to both 5-HTT+/- and 5-HTT-/- mice. Perfusion level changes of male mice correlated with the density of c-Fos-immunoreactive cells in the amygdaloid nuclei. In female mice the perfusion was not modulated by the 5-Htt-genotype, but by estrous cycle stages. We conclude that amygdala reactivity is modulated by the 5-Htt genotype in males. In females, gonadal hormones have an impact which might have obscured genotype effects. Furthermore, our results demonstrate experimental support for the tonic model of 5-HTTLPR function.
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Affiliation(s)
- Jann F. Kolter
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany
- Division of Molecular Psychiatry, Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany
| | - Markus F. Hildenbrand
- Department of Magnetic Resonance and X-Ray Imaging, Fraunhofer Development Center X-Ray Technology, Wuerzburg, Germany
| | - Sandy Popp
- Division of Molecular Psychiatry, Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany
| | - Stephan Nauroth
- Division of Molecular Psychiatry, Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany
| | - Julian Bankmann
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany
| | - Lisa Rother
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany
| | - Jonas Waider
- Division of Molecular Psychiatry, Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany
| | - Jürgen Deckert
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany
| | - Esther Asan
- Institute of Anatomy and Cell Biology, University of Wuerzburg, Wuerzburg, Germany
| | - Peter M. Jakob
- Department of Experimental Physics 5, University of Wuerzburg, Wuerzburg, Germany
| | - Klaus-Peter Lesch
- Division of Molecular Psychiatry, Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany
| | - Angelika Schmitt-Böhrer
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany
- * E-mail:
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7
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The infralimbic cortex and mGlu5 mediate the effects of chronic intermittent ethanol exposure on fear learning and memory. Psychopharmacology (Berl) 2020; 237:3417-3433. [PMID: 32767063 PMCID: PMC7572878 DOI: 10.1007/s00213-020-05622-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 07/27/2020] [Indexed: 01/19/2023]
Abstract
RATIONALE AND OBJECTIVES Alcohol use disorder (AUD) and post-traumatic stress disorder (PTSD) often occur comorbidly. While the incidence of these disorders is increasing, there is little investigation into the interacting neural mechanisms between these disorders. These studies aim to identify cognitive deficits that occur as a consequence of fear and ethanol exposure, implement a novel pharmaceutical intervention, and determine relevant underlying neurocircuitry. Additionally, due to clinical sex differences in PTSD prevalence and alcohol abuse, these studies examine the nature of this relationship in rodent models. METHODS Animals were exposed to a model of PTSD+AUD using auditory fear conditioning followed by chronic intermittent ethanol exposure (CIE). Then, rats received extinction training consisting of multiple conditioned stimulus presentations in absence of the shock. Extinction recall and context-induced freezing were measured in subsequent tests. CDPPB, a metabotropic glutamate receptor 5 (mGlu5) positive allosteric modulator, was used to treat these deficits, and region-specific effects were determined using microinjections. RESULTS These studies determined that CIE exposure led to deficits in fear extinction learning and heightened context-induced freezing while sex differences emerged in fear conditioning and extinction cue recall tests. Furthermore, using CDPPB, these studies found that enhancement of infralimbic (IfL) mGlu5 activity was able to recover CIE-induced deficits in both males and females. CONCLUSIONS These studies show that CIE induces deficits in fear-related behaviors and that enhancement of IfL glutamatergic activity can facilitate learning during extinction. Additionally, we identify novel pharmacological targets for the treatment of individuals who suffer from PTSD and AUD.
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8
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Velasco ER, Florido A, Milad MR, Andero R. Sex differences in fear extinction. Neurosci Biobehav Rev 2019; 103:81-108. [PMID: 31129235 DOI: 10.1016/j.neubiorev.2019.05.020] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 03/08/2019] [Accepted: 05/19/2019] [Indexed: 12/18/2022]
Abstract
Despite the exponential increase in fear research during the last years, few studies have included female subjects in their design. The need to include females arises from the knowledge gap of mechanistic processes underlying the behavioral and neural differences observed in fear extinction. Moreover, the exact contribution of sex and hormones in relation to learning and behavior is still largely unknown. Insights from this field could be beneficial as fear-related disorders are twice as prevalent in women compared to men. Here, we review an up-to-date summary of animal and human studies in adulthood that report sex differences in fear extinction from a structural and functional approach. Furthermore, we describe how these factors could contribute to the observed sex differences in fear extinction during normal and pathological conditions.
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Affiliation(s)
- E R Velasco
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain
| | - A Florido
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain
| | - M R Milad
- Department of Psychiatry, University of Illinois at Chicago, USA
| | - R Andero
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain; CIBERSAM, Corporació Sanitaria Parc Taulí, Sabadell, Spain; Department of Psychobiology and Methodology of Health Sciences, Universitat Autònoma de Barcelona, Spain.
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9
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Maeng LY, Cover KK, Taha MB, Landau AJ, Milad MR, Lebrón-Milad K. Estradiol shifts interactions between the infralimbic cortex and central amygdala to enhance fear extinction memory in female rats. J Neurosci Res 2017; 95:163-175. [PMID: 27870439 DOI: 10.1002/jnr.23826] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/27/2016] [Accepted: 06/20/2016] [Indexed: 01/01/2023]
Abstract
There is growing evidence that estradiol (E2) enhances fear extinction memory consolidation. However, it is unclear how E2 influences the nodes of the fear extinction network to enhance extinction memory. This study begins to delineate the neural circuits underlying the influence of E2 on fear extinction acquisition and consolidation in female rats. After fear conditioning (day 1), naturally cycling female rats underwent extinction learning (day 2) in a low-E2 state, receiving a systemic administration of either E2 or vehicle prior to extinction training. Extinction memory recall was then tested 24 hr later (day 3). We measured immediate early gene c-fos expression within the extinction network during fear extinction learning and extinction recall. During extinction learning, E2 treatment increased centrolateral amygdala c-fos activity and reduced lateral amygdala activity relative to vehicle. During extinction recall, E2-treated rats exhibited reduced c-fos expression in the centromedial amygdala. There were no group differences in c-fos expression within the medial prefrontal cortex or dorsal hippocampus. Examining c-fos ratios with the infralimbic cortex (IL) revealed that, despite the lack of group differences within the IL, E2 treatment induced greater IL activity relative to both prelimbic cortex and central amygdala (CeA) activity during extinction memory recall. Only the relationship between IL and CeA activity positively correlated with extinction retention. In conclusion, E2 appears to modify interactions between the IL and the CeA in females, shifting from stronger amygdalar modulation of fear during extinction learning to stronger IL control during extinction recall. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Lisa Y Maeng
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, Massachusetts.,Department of Psychiatry, Harvard Medical School, Boston, Massachusetts
| | - Kara K Cover
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, Massachusetts
| | - Mohamad B Taha
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, Massachusetts.,Department of Psychiatry, Harvard Medical School, Boston, Massachusetts
| | - Aaron J Landau
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, Massachusetts
| | - Mohammed R Milad
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, Massachusetts.,Department of Psychiatry, Harvard Medical School, Boston, Massachusetts
| | - Kelimer Lebrón-Milad
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, Massachusetts.,Department of Psychiatry, Harvard Medical School, Boston, Massachusetts
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