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Smith HC, Yu Z, Iyer L, Marvar PJ. Sex-Dependent Effects of Angiotensin Type 2 Receptor-Expressing Medial Prefrontal Cortex Interneurons in Fear Extinction Learning. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2024; 4:100340. [PMID: 39140003 PMCID: PMC11321323 DOI: 10.1016/j.bpsgos.2024.100340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 05/17/2024] [Accepted: 05/19/2024] [Indexed: 08/15/2024] Open
Abstract
Background The renin-angiotensin system has been identified as a potential therapeutic target for posttraumatic stress disorder, although its mechanisms are not well understood. Brain angiotensin type 2 receptors (AT2Rs) are a subtype of angiotensin II receptors located in stress and anxiety-related regions, including the medial prefrontal cortex (mPFC), but their function and mechanism in the mPFC remain unexplored. Therefore, we used a combination of imaging, cre/lox, and behavioral methods to investigate mPFC-AT2R-expressing neurons in fear and stess related behavior. Methods To characterize mPFC-AT2R-expressing neurons in the mPFC, AT2R-Cre/tdTomato male and female mice were used for immunohistochemistry. mPFC brain sections were stained with glutamatergic or interneuron markers, and density of AT2R+ cells and colocalization with each marker were quantified. To assess fear-related behaviors in AT2R-flox mice, we selectively deleted AT2R from mPFC neurons using a Cre-expressing adeno-associated virus. Mice then underwent Pavlovian auditory fear conditioning, elevated plus maze, and open field testing. Results Immunohistochemistry results revealed that AT2R was densely expressed throughout the mPFC and primarily expressed in somatostatin interneurons in a sex-dependent manner. Following fear conditioning, mPFC-AT2R Cre-lox deletion impaired extinction and increased exploratory behavior in female but not male mice, while locomotion was unaltered by mPFC-AT2R deletion in both sexes. Conclusions These results identify mPFC-AT2R+ neurons as a novel subgroup of somatostatin interneurons and reveal their role in regulating fear learning in a sex-dependent manner, potentially offering insights into novel therapeutic targets for posttraumatic stress disorder.
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Affiliation(s)
- Hannah C. Smith
- Department of Neuroscience, George Washington University, Washington, DC
| | - Zhe Yu
- Department of Pharmacology & Physiology, George Washington University, Washington, District of Columbia
| | - Laxmi Iyer
- Department of Pharmacology & Physiology, George Washington University, Washington, District of Columbia
| | - Paul J. Marvar
- Department of Neuroscience, George Washington University, Washington, DC
- Department of Pharmacology & Physiology, George Washington University, Washington, District of Columbia
- Department of Psychiatry and Behavioral Sciences, George Washington University, Washington, DC
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Merscher AS, Gamer M. Fear lies in the eyes of the beholder-Robust evidence for reduced gaze dispersion upon avoidable threat. Psychophysiology 2024; 61:e14421. [PMID: 37603439 DOI: 10.1111/psyp.14421] [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: 03/21/2023] [Revised: 07/28/2023] [Accepted: 07/28/2023] [Indexed: 08/23/2023]
Abstract
A rapid detection and processing of relevant information in our environment is crucial for survival. The human eyes are drawn to social or threatening stimuli as they may carry essential information on how to behave appropriately in a given context. Recent studies further showed a centralization of gaze that reminded of freezing behaviors in rodents. Probably constituting a component of an adaptive defense mode, centralized eye movements predicted the speed of motor actions. Here we conducted two experiments to examine if and how these presumably survival-relevant gaze patterns interact. Subjects viewed images including social, that is, faces (Experiment 1, N = 50) or threatening stimuli, that is, snakes or spiders (Experiment 2, N = 50) while awaiting an inevitable (shock), no (safety), or an avoidable shock (flight) they could escape from by a fast button press. The social and threatening cues within the scenes differed in their distance from the image center and we acquired eye-tracking and autonomic physiological data. Although we observed an initial orienting toward social and threatening stimulus aspects, this exploration pattern vanished towards the end of flight trials when a pronounced centralization of gaze emerged. Replicating previous findings, the amount of this center bias predicted the speed of motor reactions, and we observed a concurrent activation of the sympathetic and parasympathetic nervous system. Taken together, the exploration of potentially relevant cues seems to be part of a reflexive-orienting response regardless of contextual valence. However, centralization of gaze may be a threat-specific action-preparatory response that occurs across a wide range of stimulus contexts.
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Affiliation(s)
| | - Matthias Gamer
- Department of Psychology, University of Würzburg, Würzburg, Germany
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Yu Z, Iyer L, Swiercz AP, Paronett E, Ramadan M, Marvar PJ, Posnack NG. The Impact of Chronic Phthalate Exposure on Rodent Anxiety and Cognition. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2024; 4:203-212. [PMID: 38298799 PMCID: PMC10829632 DOI: 10.1016/j.bpsgos.2023.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 06/29/2023] [Accepted: 07/01/2023] [Indexed: 02/02/2024] Open
Abstract
Background There is a growing importance for environmental contributions to psychiatric disorders and understanding the impact of the exposome (i.e., pollutants and toxins). For example, increased biomonitoring and epidemiological studies suggest that daily phthalate chemical exposure contributes to neurological and behavioral abnormalities; however, these mechanisms remain poorly understood. Therefore, the current study was aimed at examining the effects of chronic phthalate exposure on rodent anxiety behaviors and cognition and the impact on hypothalamic-pituitary-adrenal axis function. Methods Adult male mice (C57BL6/J) were administered MEHP via drinking water (1 mg/mL), and anxiety-like behavior and cognition combined with hypothalamic-pituitary-adrenal axis and inflammatory assays were assessed after 3 weeks of MEHP exposure. Results MEHP-treated mice exhibited enhanced generalized anxiety-like behaviors, as demonstrated by reduced time spent in the open-arm of the elevated plus maze and center exploration in the open field. Tests of spatial memory and cognition were unchanged. Following MEHP administration, circulating levels of corticosterone and proinflammatory cytokines were significantly increased, while at the tissue level, there were MEHP-dependent reductions in glucocorticoid metabolism genes Hsd11b1 and Hsd11b2. Conclusions These data suggest that chronic MEHP exposure leads to enhanced generalized anxiety behaviors independent of rodent measures of cognition and memory, which may be driven by MEHP-dependent effects on hypothalamic-pituitary-adrenal axis and peripheral glucocorticoid metabolism function.
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Affiliation(s)
- Zhe Yu
- Department of Pharmacology and Physiology, George Washington University, Washington, DC
| | - Laxmi Iyer
- Department of Anatomy, Physiology and Genetics, Uniformed Services University Health Sciences, Bethesda, Maryland
| | - Adam P. Swiercz
- National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland
| | - Elizabeth Paronett
- Department of Pharmacology and Physiology, George Washington University, Washington, DC
| | - Manelle Ramadan
- Children’s National Heart Institute, Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Hospital, Washington, DC
| | - Paul J. Marvar
- Department of Pharmacology and Physiology, George Washington University, Washington, DC
- Department of Psychiatry and Behavioral Sciences, George Washington University, Washington, DC
| | - Nikki Gillum Posnack
- Department of Pharmacology and Physiology, George Washington University, Washington, DC
- Children’s National Heart Institute, Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Hospital, Washington, DC
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Smith HC, Yu Z, Iyer L, Marvar PJ. Sex-dependent effects of angiotensin type 2 receptor expressing medial prefrontal cortex (mPFC) interneurons in fear extinction learning. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.21.568156. [PMID: 38045293 PMCID: PMC10690250 DOI: 10.1101/2023.11.21.568156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Background The renin-angiotensin system (RAS) has been identified as a potential therapeutic target for PTSD, though its mechanisms are not well understood. Brain angiotensin type 2 receptors (AT2Rs) are a subtype of angiotensin II receptors located in stress and anxiety-related regions, including the medial prefrontal cortex (mPFC), but their function and mechanism in the mPFC remain unexplored. We therefore used a combination of imaging, cre/lox, and behavioral methods to investigate mPFC-AT2R-expressing neuron involvement in fear learning. Methods To characterize mPFC-AT2R-expressing neurons in the mPFC, AT2R-Cre/td-Tomato male and female mice were used for immunohistochemistry (IHC). mPFC brain sections were stained with glutamatergic or interneuron markers, and density of AT2R+ cells and colocalization with each marker was quantified. To assess fear-related behaviors in AT2R-flox mice, we selectively deleted AT2R from mPFC neurons using an AAV-Cre virus. Mice then underwent Pavlovian auditory fear conditioning, approach/avoidance, and locomotion testing. Results IHC results revealed that AT2R is densely expressed in the mPFC. Furthermore, AT2R is primarily expressed in somatostatin interneurons in females but not males. Following fear conditioning, mPFC-AT2R deletion impaired extinction in female but not male mice. Locomotion was unaltered by mPFC-AT2R deletion in males or females, while AT2R-deleted females had increased exploratory behavior. Conclusion These results lend support for mPFC-AT2R+ neurons as a novel subgroup of somatostatin interneurons that influence fear extinction in a sex-dependent manner. This furthers underscores the role of mPFC in top-down regulation and a unique role for peptidergic (ie., angiotensin) mPFC regulation of fear and sex differences.
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Affiliation(s)
- Hannah C. Smith
- Department of Neuroscience, George Washington University, Washington, DC
| | - Zhe Yu
- Department of Pharmacology & Physiology, George Washington University, Washington, DC
| | - Laxmi Iyer
- Department of Pharmacology & Physiology, George Washington University, Washington, DC
| | - Paul J. Marvar
- Department of Neuroscience, George Washington University, Washington, DC
- Department of Pharmacology & Physiology, George Washington University, Washington, DC
- Department of Psychiatry and Behavioral Sciences, George Washington University, Washington DC
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Bordes J, Miranda L, Müller-Myhsok B, Schmidt MV. Advancing social behavioral neuroscience by integrating ethology and comparative psychology methods through machine learning. Neurosci Biobehav Rev 2023; 151:105243. [PMID: 37225062 DOI: 10.1016/j.neubiorev.2023.105243] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/21/2023] [Accepted: 05/20/2023] [Indexed: 05/26/2023]
Abstract
Social behavior is naturally occurring in vertebrate species, which holds a strong evolutionary component and is crucial for the normal development and survival of individuals throughout life. Behavioral neuroscience has seen different influential methods for social behavioral phenotyping. The ethological research approach has extensively investigated social behavior in natural habitats, while the comparative psychology approach was developed utilizing standardized and univariate social behavioral tests. The development of advanced and precise tracking tools, together with post-tracking analysis packages, has recently enabled a novel behavioral phenotyping method, that includes the strengths of both approaches. The implementation of such methods will be beneficial for fundamental social behavioral research but will also enable an increased understanding of the influences of many different factors that can influence social behavior, such as stress exposure. Furthermore, future research will increase the number of data modalities, such as sensory, physiological, and neuronal activity data, and will thereby significantly enhance our understanding of the biological basis of social behavior and guide intervention strategies for behavioral abnormalities in psychiatric disorders.
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Affiliation(s)
- Joeri Bordes
- Research Group Neurobiology of Stress Resilience, Max Planck Institute of Psychiatry, 80804 Munich, Germany
| | - Lucas Miranda
- Research Group Statistical Genetics, Max Planck Institute of Psychiatry, 80804 Munich, Germany; International Max Planck Research School for Translational Psychiatry (IMPRS-TP), 80804 Munich, Germany
| | - Bertram Müller-Myhsok
- Research Group Statistical Genetics, Max Planck Institute of Psychiatry, 80804 Munich, Germany
| | - Mathias V Schmidt
- Research Group Neurobiology of Stress Resilience, Max Planck Institute of Psychiatry, 80804 Munich, Germany
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Yu Z, Iyer L, Swiercz AP, Paronett E, Ramadan M, Marvar PJ, Posnack NG. The Impact of Chronic Phthalate Exposure on Rodent Anxiety and Cognition. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.13.536567. [PMID: 37886449 PMCID: PMC10602041 DOI: 10.1101/2023.04.13.536567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
There is a growing importance for environmental contributions to psychiatric disorders and understanding the impact of the exposome (i.e., pollutants and toxins). Increased biomonitoring and epidemiological studies, for example, suggest that daily phthalate chemical exposure contribute to neurological and behavioral abnormalities, however these mechanisms remain poorly understood. The current study therefore aimed to examine the effects of chronic phthalate exposure on rodent anxiety behaviors, cognition, and the impact on hypothalamic-pituitary- adrenal (HPA)-axis function. Adult male mice (C57BL6/J) were administered mono-2-ethylhexyl phthalate (MEHP) via drinking water (1 mg/ml), and anxiety-like behavior, cognition combined with HPA- axis and inflammatory assays were assessed after 3 weeks of MEHP exposure. MEHP-treated mice exhibited enhanced generalized anxiety-like behaviors, as demonstrated by reduced time spent in the open-arm of the elevated plus maze (EPM) and center exploration in the open field (OF). Tests of spatial, cognition and memory function were unchanged. Following MEHP administration, circulating levels of corticosterone and pro- inflammatory cytokines were significantly increased, while at the tissue level, MEHP-dependent reductions in glucocorticoid metabolism genes 11β-hydroxysteroid dehydrogenase (11β-HSD) 1 and 2. These data suggest that chronic MEHP exposure leads to enhanced generalized-anxiety behaviors independent of rodent measures of cognition and memory, which maybe driven by MEHP-dependent effects on HPA-axis and peripheral glucocorticoid metabolism function.
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Merscher AS, Tovote P, Pauli P, Gamer M. Centralized gaze as an adaptive component of defensive states in humans. Proc Biol Sci 2022; 289:20220405. [PMID: 35582796 PMCID: PMC9114933 DOI: 10.1098/rspb.2022.0405] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Adequate defensive responding is crucial for mental health but scientifically not well understood. Specifically, it seems difficult to dissociate defense and approach states based on autonomic response patterns. We thus explored the robustness and threat-specificity of recently described oculomotor dynamics upon threat in anticipation of either threatening or rewarding stimuli in humans. While visually exploring naturalistic images, participants (50 per experiment) expected an inevitable, no, or avoidable shock (Experiment 1) or a guaranteed, no, or achievable reward (Experiment 2) that could be averted or gained by a quick behavioural response. We observed reduced heart rate (bradycardia), increased skin conductance, pupil dilation and globally centralized gaze when shocks were inevitable but, more pronouncedly, when they were avoidable. Reward trials were not associated with globally narrowed visual exploration, but autonomic responses resembled characteristics of the threat condition. While bradycardia and concomitant sympathetic activation reflect not only threat-related but also action-preparatory states independent of valence, global centralization of gaze seems a robust phenomenon during the anticipation of avoidable threat. Thus, instead of relying on single readouts, translational research in animals and humans should consider the multi-dimensionality of states in aversive and rewarding contexts, especially when investigating ambivalent, conflicting situations.
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Affiliation(s)
- Alma-Sophia Merscher
- Department of Psychology, University of Würzburg, Marcusstr. 9-11, 97070 Würzburg, Germany
| | - Philip Tovote
- Systems Neurobiology, Institute of Clinical Neurobiology, University Hospital Würzburg, Versbacher Str. 5, 97078 Würzburg, Germany
| | - Paul Pauli
- Department of Psychology, University of Würzburg, Marcusstr. 9-11, 97070 Würzburg, Germany
| | - Matthias Gamer
- Department of Psychology, University of Würzburg, Marcusstr. 9-11, 97070 Würzburg, Germany
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Turley B, Swiercz AP, Iyer L, Marvar PJ. Internal state-dependent conditioned stimulus delivery using cardiovascular telemetry in mice. Physiol Behav 2021; 236:113414. [PMID: 33819454 DOI: 10.1016/j.physbeh.2021.113414] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/24/2021] [Accepted: 03/30/2021] [Indexed: 11/19/2022]
Abstract
To further understand mechanisms of neuropsychiatric disease(s) and their impact on physiological systems, improved pre-clinical models and innovative methodology are needed to assess the internal physiological state of the animal in real-time. To address this challenge we developed a customizable software-based program for Ponemah™ that takes into account the animals diurnal and resting cardiovascular state in a home-cage environment. Using an integrated Pavlovian fear conditioning and cardiovascular telemetry approach in mice, we demonstrate for the first time a novel software add-on application that can remotely trigger a conditioned stimulus (CS) (i.e., audible tone) based on the animals instantaneous cardiovascular state while in its home-cage environment. This new software tool extends the ability to quantify integrated physiological correlates of learned threat and defensive behavior and may aid in further understanding mechanisms related to enhanced cardiovascular and autonomic arousal in anxiety-based disorders.
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Affiliation(s)
- Ben Turley
- Columbian College of Arts and Sciences, George Washington University, Washington DC, United States
| | - Adam P Swiercz
- Department of Pharmacology and Physiology, George Washington University, Washington DC, United States
| | - Laxmi Iyer
- Department of Pharmacology and Physiology, George Washington University, Washington DC, United States
| | - Paul J Marvar
- Department of Pharmacology and Physiology, George Washington University, Washington DC, United States; Department of Psychiatry and Behavioral Sciences, George Washington University, Washington DC, United States.
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Reyes KAE, Kudva PS, Heckler B, Gonzalez AE, Sorg BA. Rat ultrasonic vocalizations as an index of memory. Neurosci Lett 2021; 741:135458. [PMID: 33166637 PMCID: PMC7750257 DOI: 10.1016/j.neulet.2020.135458] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/28/2020] [Accepted: 10/04/2020] [Indexed: 11/16/2022]
Abstract
The emission of 50 kHz frequency-modulated ultrasonic vocalizations (FM USVs) in rats has been associated with positive affective states, while a decrease in FM USVs has been associated with anxiety-like states. We tested the hypothesis in male Sprague-Dawley rats that FM USVs would complement measures of aversive memories (decrease in FM USVs) in a conditioned fear task in which we examined extinction or reconsolidation disruption. In Experiment 1, rats were fear conditioned using low-level footshock followed by extinction while monitoring freezing and FM USVs. In Experiment 2, rats were fear conditioned, the alpha-1 antagonist prazosin was used to disrupt reconsolidation of memory, and freezing and FM USVs were measured. Rats fear conditioned with low-level shock showed minimal freezing that rapidly extinguished, despite a persistent decrease in FM USVs throughout extinction. Prazosin reduced freezing in a memory reactivation-dependent manner as expected, but the reduction in FM USVs after fear conditioning remained decreased, suggesting that an affective component of memory was not impacted by prazosin. These findings indicate that FM USVs may be used as an index of fear- or anxiety-like memory, and their measurement could benefit pre-clinical animal models for assessing reduction of aversive memories.
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Affiliation(s)
- Kyrie-Anne E Reyes
- Department of Integrative Physiology and Neuroscience, Translational Addiction Research Center, Washington State University, Vancouver, WA 98686, United States
| | - Priya S Kudva
- Department of Integrative Physiology and Neuroscience, Translational Addiction Research Center, Washington State University, Vancouver, WA 98686, United States
| | - Benjamin Heckler
- Department of Integrative Physiology and Neuroscience, Translational Addiction Research Center, Washington State University, Vancouver, WA 98686, United States
| | - Angela E Gonzalez
- Department of Integrative Physiology and Neuroscience, Translational Addiction Research Center, Washington State University, Vancouver, WA 98686, United States
| | - Barbara A Sorg
- Department of Integrative Physiology and Neuroscience, Translational Addiction Research Center, Washington State University, Vancouver, WA 98686, United States.
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Swiercz AP, Iyer L, Yu Z, Edwards A, Prashant NM, Nguyen BN, Horvath A, Marvar PJ. Evaluation of an angiotensin Type 1 receptor blocker on the reconsolidation of fear memory. Transl Psychiatry 2020; 10:363. [PMID: 33110066 PMCID: PMC7591922 DOI: 10.1038/s41398-020-01043-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 09/11/2020] [Accepted: 10/07/2020] [Indexed: 12/30/2022] Open
Abstract
Inhibition of the angiotensin type 1 receptor (AT1R) has been shown to decrease fear responses in both humans and rodents. These effects are attributed to modulation of extinction learning, however the contribution of AT1R to alternative memory processes remains unclear. Using classic Pavlovian conditioning combined with radiotelemetry and whole-genome RNA sequencing, we evaluated the effects of the AT1R antagonist losartan on fear memory reconsolidation. Following the retrieval of conditioned auditory fear memory, animals were given a single intraperitoneal injection of losartan or saline. In response to the conditioned stimulus (CS), losartan-treated animals exhibited significantly less freezing at 24 h and 1 week; an effect that was dependent upon memory reactivation and independent of conditioned cardiovascular reactivity. Using an unbiased whole-genome RNA sequencing approach, transcriptomic analysis of the basolateral amygdala (BLA) identified losartan-dependent differences in gene expression during the reconsolidation phase. These findings demonstrate that post-retrieval losartan modifies behavioral and transcriptomic markers of conditioned fear memory, supporting an important regulatory role for this receptor in reconsolidation and as a potential pharmacotherapeutic target for maladaptive fear disorders such as PTSD.
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Affiliation(s)
- Adam P. Swiercz
- grid.253615.60000 0004 1936 9510Department of Pharmacology and Physiology, George Washington University, Washington, DC 20052 USA
| | - Laxmi Iyer
- grid.253615.60000 0004 1936 9510Department of Pharmacology and Physiology, George Washington University, Washington, DC 20052 USA
| | - Zhe Yu
- grid.253615.60000 0004 1936 9510Department of Pharmacology and Physiology, George Washington University, Washington, DC 20052 USA
| | - Allison Edwards
- grid.253615.60000 0004 1936 9510Department of Pharmacology and Physiology, George Washington University, Washington, DC 20052 USA
| | - N. M. Prashant
- grid.253615.60000 0004 1936 9510Department of Pharmacology and Physiology, George Washington University, Washington, DC 20052 USA
| | - Bryan N. Nguyen
- grid.253615.60000 0004 1936 9510Computational Biology Institute, George Washington University, Washington, DC 20052 USA
| | - Anelia Horvath
- grid.253615.60000 0004 1936 9510Department of Pharmacology and Physiology, George Washington University, Washington, DC 20052 USA
| | - Paul J. Marvar
- grid.253615.60000 0004 1936 9510Department of Pharmacology and Physiology, George Washington University, Washington, DC 20052 USA ,grid.253615.60000 0004 1936 9510Department of Psychiatry and Behavioral Sciences, George Washington University, Washington, DC 20052 USA
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Seligowski AV, Merker JB, Swiercz AP, Park J, Marvar PJ, Ressler KJ, Jovanovic T. Examining the cardiovascular response to fear extinction in a trauma-exposed sample. J Psychiatr Res 2020; 124:85-90. [PMID: 32126364 PMCID: PMC7097830 DOI: 10.1016/j.jpsychires.2020.02.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 02/24/2020] [Indexed: 01/22/2023]
Abstract
BACKGROUND Trauma and symptoms of posttraumatic stress disorder (PTSD) have repeatedly been linked to impaired cardiovascular functioning. Poor fear extinction is a well-established biomarker of PTSD that may provide insight into mechanisms underlying cardiovascular risk. The current study probed the cardiovascular response to extinction in a sample of trauma-exposed individuals. METHODS Participants were 51 trauma-exposed women who underwent a fear conditioning paradigm. Heart rate (HR) during extinction was examined in response to a conditioned stimulus that was previously paired with an aversive unconditioned stimulus (CS+) and one that was never paired (CS-). Heart rate variability (HRV) was calculated at baseline and during the extinction session. RESULTS Consistent with fear bradycardia, initial HR deceleration (.5-2s) after CS + onset occurred during early extinction and appeared to extinguish over time. Higher baseline HRV was significantly associated with greater fear bradycardia during early extinction. CONCLUSIONS This is the first study to demonstrate a pattern of fear bradycardia in early extinction, which was associated with higher HRV levels and decreased over the course of the extinction phase. These results suggest that increased fear bradycardia may be indicative of greater vagal control (i.e., HRV), both of which are psychophysiological biomarkers that may influence cardiovascular and autonomic disease risk in trauma-exposed individuals.
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Affiliation(s)
- Antonia V Seligowski
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA; McLean Hospital, Belmont, MA, USA.
| | | | - Adam P Swiercz
- Department of Pharmacology and Physiology, George Washington University, Washington, DC, USA
| | - Jeanie Park
- Emory University School of Medicine Renal Division and the Atlanta Veterans Administration Hospital, Atlanta, GA, USA
| | - Paul J Marvar
- Department of Pharmacology and Physiology, George Washington University, Washington, DC, USA; Department of Psychiatry and Behavioral Sciences, George Washington University, Washington, DC, USA
| | - Kerry J Ressler
- Department of Psychiatry, Harvard Medical School, Boston, MA, USA; McLean Hospital, Belmont, MA, USA
| | - Tanja Jovanovic
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, USA
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Angiotensin II Type 2 Receptor-Expressing Neurons in the Central Amygdala Influence Fear-Related Behavior. Biol Psychiatry 2019; 86:899-909. [PMID: 31420088 DOI: 10.1016/j.biopsych.2019.05.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 05/29/2019] [Accepted: 05/30/2019] [Indexed: 12/29/2022]
Abstract
BACKGROUND The renin-angiotensin system has been implicated in posttraumatic stress disorder; however, the mechanisms responsible for this connection and the therapeutic potential of targeting the renin-angiotensin system in posttraumatic stress disorder remain unknown. Using an angiotensin receptor bacterial artificial chromosome (BAC) and enhanced green fluorescent protein (eGFP) reporter mouse, combined with neuroanatomical, pharmacological, and behavioral approaches, we examined the role of angiotensin II type 2 receptor (AT2R) in fear-related behavior. METHODS Dual immunohistochemistry with retrograde labeling was used to characterize AT2R-eGFP+ cells in the amygdala of the AT2R-eGFP-BAC reporter mouse. Pavlovian fear conditioning and behavioral pharmacological analyses were used to demonstrate the effects of AT2R activation on fear memory in male C57BL/6 mice. RESULTS AT2R-eGFP+ neurons in the amygdala were predominantly expressed in the medial amygdala and the medial division of the central amygdala (CeM), with little AT2R-eGFP expression in the basolateral amygdala or lateral division of the central amygdala. Characterization of AT2R-eGFP+ neurons in the CeM demonstrated distinct localization to gamma-aminobutyric acidergic projection neurons. Mice receiving acute intra-central amygdala injections of the selective AT2R agonist compound 21 prior to tests for cued or contextual fear expression displayed less freezing. Retrograde labeling of AT2R-eGFP+ neurons projecting to the periaqueductal gray revealed AT2R-eGFP+ neuronal projections from the CeM to the periaqueductal gray, a key brain structure mediating fear-related freezing. CONCLUSIONS These findings suggest that CeM AT2R-expressing neurons can modulate central amygdala outputs that play a role in fear expression, providing new evidence for a novel angiotensinergic circuit in the regulation of fear.
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Maddox SA, Hartmann J, Ross RA, Ressler KJ. Deconstructing the Gestalt: Mechanisms of Fear, Threat, and Trauma Memory Encoding. Neuron 2019; 102:60-74. [PMID: 30946827 DOI: 10.1016/j.neuron.2019.03.017] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 03/03/2019] [Accepted: 03/12/2019] [Indexed: 01/14/2023]
Abstract
Threat processing is central to understanding debilitating fear- and trauma-related disorders such as posttraumatic stress disorder (PTSD). Progress has been made in understanding the neural circuits underlying the "engram" of threat or fear memory formation that complements a decades-old appreciation of the neurobiology of fear and threat involving hub structures such as the amygdala. In this review, we examine key recent findings, as well as integrate the importance of hormonal and physiological approaches, to provide a broader perspective of how bodily systems engaged in threat responses may interact with amygdala-based circuits in the encoding and updating of threat-related memory. Understanding how trauma-related memories are encoded and updated throughout the brain and the body will ultimately lead to novel biologically-driven approaches for treatment and prevention.
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Affiliation(s)
- Stephanie A Maddox
- Neurobiology of Fear Laboratory, Division of Depression and Anxiety Disorders, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA; Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA
| | - Jakob Hartmann
- Neurobiology of Fear Laboratory, Division of Depression and Anxiety Disorders, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA; Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA
| | - Rachel A Ross
- Neurobiology of Fear Laboratory, Division of Depression and Anxiety Disorders, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA; Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA
| | - Kerry J Ressler
- Neurobiology of Fear Laboratory, Division of Depression and Anxiety Disorders, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA; Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA.
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