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Gutiérrez-Vera B, Reyes-García SE, Escobar ML. Brief environmental enrichment elicits metaplasticity on the insular cortex in vivo and reduces the strength of conditioned taste aversion. Neurobiol Learn Mem 2023; 205:107840. [PMID: 37805119 DOI: 10.1016/j.nlm.2023.107840] [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: 03/16/2023] [Revised: 09/20/2023] [Accepted: 10/04/2023] [Indexed: 10/09/2023]
Abstract
Environmental enrichment (EE) is known to improve memory and cognition and modulate the impact of aversive stimuli in animals, promoting the development of resilience to stressful situations. Likewise, it is known that EE can modulate synaptic plasticity as is the case of long-term potentiation (LTP). These findings have been described initially in ex vivo preparations, suggesting that the effects of EE are the result of an early modification of the synaptic excitability and transmission. In this regard, it is known that metaplasticity refers to the persistent modification, by previous activity, in the ability to induce synaptic plasticity. Our previous studies have shown that prior training in conditioned taste aversion (CTA) prevents the subsequent induction of LTP in the projection from the basolateral nucleus of the amygdala (Bla) to the insular cortex (IC) in vivo. In addition, we have shown that CTA extinction allows the induction but not the maintenance of IC-LTP of the Bla-IC pathway. Recently, we also showed that prior exposure to environmental enrichment for three weeks reduces the strength of CTA, restoring the brain-derived neurotrophic factor (BDNF) levels in the IC. The present study aimed to analyze the effects of brief exposure to an enriched environment on the strength of aversive memory, as well as on the in vivo IC-LTP. To do so, adult rats were exposed for seven days to an EE, either before CTA training or LTP induction in the Bla-IC pathway. Our results demonstrate that a seven-day exposure to an enriched environment attenuates the aversive response to a strong CTA and allows the induction but not the maintenance of LTP in the insular cortex. These findings provide evidence that metaplastic regulation in a neocortical region takes part in the mechanisms through which brief exposure to enriched environments attenuates an aversive response.
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Affiliation(s)
- Beatriz Gutiérrez-Vera
- División de Investigación y Estudios de Posgrado, Facultad de Psicología, Universidad Nacional Autónoma de México, 04510, Mexico
| | - Salma E Reyes-García
- División de Investigación y Estudios de Posgrado, Facultad de Psicología, Universidad Nacional Autónoma de México, 04510, Mexico
| | - Martha L Escobar
- División de Investigación y Estudios de Posgrado, Facultad de Psicología, Universidad Nacional Autónoma de México, 04510, Mexico.
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2
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Ziółkowska M, Borczyk M, Cały A, Tomaszewski KF, Nowacka A, Nalberczak-Skóra M, Śliwińska MA, Łukasiewicz K, Skonieczna E, Wójtowicz T, Wlodarczyk J, Bernaś T, Salamian A, Radwanska K. Phosphorylation of PSD-95 at serine 73 in dCA1 is required for extinction of contextual fear. PLoS Biol 2023; 21:e3002106. [PMID: 37155709 DOI: 10.1371/journal.pbio.3002106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 05/18/2023] [Accepted: 04/04/2023] [Indexed: 05/10/2023] Open
Abstract
The updating of contextual memories is essential for survival in a changing environment. Accumulating data indicate that the dorsal CA1 area (dCA1) contributes to this process. However, the cellular and molecular mechanisms of contextual fear memory updating remain poorly understood. Postsynaptic density protein 95 (PSD-95) regulates the structure and function of glutamatergic synapses. Here, using dCA1-targeted genetic manipulations in vivo, combined with ex vivo 3D electron microscopy and electrophysiology, we identify a novel, synaptic mechanism that is induced during attenuation of contextual fear memories and involves phosphorylation of PSD-95 at Serine 73 in dCA1. Our data provide the proof that PSD-95-dependent synaptic plasticity in dCA1 is required for updating of contextual fear memory.
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Affiliation(s)
- Magdalena Ziółkowska
- Laboratory of Molecular Basis of Behavior, the Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Malgorzata Borczyk
- Laboratory of Molecular Basis of Behavior, the Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
- Department Molecular Neuropharmacology, Maj Institute of Pharmacology of Polish Academy of Sciences, Krakow, Poland
| | - Anna Cały
- Laboratory of Molecular Basis of Behavior, the Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Kamil F Tomaszewski
- Laboratory of Molecular Basis of Behavior, the Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Agata Nowacka
- Laboratory of Molecular Basis of Behavior, the Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Maria Nalberczak-Skóra
- Laboratory of Molecular Basis of Behavior, the Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Małgorzata Alicja Śliwińska
- Laboratory of Molecular Basis of Behavior, the Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
- Laboratory of Imaging Tissue Structure and Function, the Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Kacper Łukasiewicz
- Laboratory of Molecular Basis of Behavior, the Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
- Psychiatry Clinic, Medical University of Bialystok, Białystok, Poland
| | - Edyta Skonieczna
- Laboratory of Molecular Basis of Behavior, the Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Tomasz Wójtowicz
- Laboratory of Cell Biophysics, the Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Jakub Wlodarczyk
- Laboratory of Cell Biophysics, the Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Tytus Bernaś
- Laboratory of Imaging Tissue Structure and Function, the Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
- Department of Anatomy and Neurology, VCU School of Medicine, Richmond, Virginia, United States of America
| | - Ahmad Salamian
- Laboratory of Molecular Basis of Behavior, the Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Kasia Radwanska
- Laboratory of Molecular Basis of Behavior, the Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
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3
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Luessen DJ, Conn PJ. Allosteric Modulators of Metabotropic Glutamate Receptors as Novel Therapeutics for Neuropsychiatric Disease. Pharmacol Rev 2022; 74:630-661. [PMID: 35710132 PMCID: PMC9553119 DOI: 10.1124/pharmrev.121.000540] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Metabotropic glutamate (mGlu) receptors, a family of G-protein-coupled receptors, have been identified as novel therapeutic targets based on extensive research supporting their diverse contributions to cell signaling and physiology throughout the nervous system and important roles in regulating complex behaviors, such as cognition, reward, and movement. Thus, targeting mGlu receptors may be a promising strategy for the treatment of several brain disorders. Ongoing advances in the discovery of subtype-selective allosteric modulators for mGlu receptors has provided an unprecedented opportunity for highly specific modulation of signaling by individual mGlu receptor subtypes in the brain by targeting sites distinct from orthosteric or endogenous ligand binding sites on mGlu receptors. These pharmacological agents provide the unparalleled opportunity to selectively regulate neuronal excitability, synaptic transmission, and subsequent behavioral output pertinent to many brain disorders. Here, we review preclinical and clinical evidence supporting the utility of mGlu receptor allosteric modulators as novel therapeutic approaches to treat neuropsychiatric diseases, such as schizophrenia, substance use disorders, and stress-related disorders.
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Exploration of group II metabotropic glutamate receptor modulation in mouse models of Rett syndrome and MECP2 Duplication syndrome. Neuropharmacology 2022; 209:109022. [PMID: 35248529 PMCID: PMC8973998 DOI: 10.1016/j.neuropharm.2022.109022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 02/11/2022] [Accepted: 02/27/2022] [Indexed: 01/01/2023]
Abstract
Rett syndrome (RTT) and MECP2 Duplication syndrome (MDS) have opposing molecular origins in relation to expression and function of the transcriptional regulator Methyl-CpG-binding protein 2 (MeCP2). Several clinical and preclinical phenotypes, however, are shared between these disorders. Modulation of MeCP2 levels has recently emerged as a potential treatment option for both of these diseases. However, toxicity concerns remain with these approaches. Here, we focus on pharmacologically modulating the group II metabotropic glutamate receptors (mGlu), mGlu2 and mGlu3, which are two downstream targets of MeCP2 that are bidirectionally affected in expression in RTT patients and mice (Mecp2Null/+) versus an MDS mouse model (MECP2Tg1/o). Mecp2Null/+ and MECP2Tg1/o animals also exhibit contrasting phenotypes in trace fear acquisition, a form of temporal associative learning and memory, with trace fear deficiency observed in Mecp2Null/+ mice and abnormally enhanced trace fear acquisition in MECP2Tg1/o animals. In Mecp2Null/+ mice, treatment with the mGlu2/3 agonist LY379268 reverses the deficit in trace fear acquisition, and mGlu2/3 antagonism with LY341495 normalizes the abnormal trace fear learning and memory phenotype in MECP2Tg1/o mice. Altogether, these data highlight the role of group II mGlu receptors in RTT and MDS and demonstrate that both mGlu2 and mGlu3 may be potential therapeutic targets for these disorders.
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Sottile RJ, Vida T. A proposed mechanism for the MDMA-mediated extinction of traumatic memories in PTSD patients treated with MDMA-assisted therapy. Front Psychiatry 2022; 13:991753. [PMID: 36311515 PMCID: PMC9596814 DOI: 10.3389/fpsyt.2022.991753] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 08/29/2022] [Indexed: 11/29/2022] Open
Abstract
Post-traumatic stress disorder (PTSD) is a devastating psychiatric disorder afflicting millions of people around the world. Characterized by severe anxiety, intrusive thoughts, pervasive nightmares, an assortment of somatic symptoms, associations with severe long-term health problems, and an elevated risk of suicide, as much as 40-70% of patients suffer from refractory disease. 3,4-Methylenedioxy-methamphetamine (MDMA), like classic psychedelics such as psilocybin, have been used to enhance the efficacy of psychotherapy almost since their discovery, but due to their perceived potential for abuse and inclusion on USFDA (United States Food and Drug Administration) schedule 1, research into the mechanism by which they produce improvements in PTSD symptomology has been limited. Nevertheless, several compelling rationales have been explored, with the pro-social effects of MDMA thought to enhance therapeutic alliance and thus facilitate therapist-assisted trauma processing. This may be insufficient to fully explain the efficacy of MDMA in the treatment of psychiatric illness. Molecular mechanisms such as the MDMA mediated increase of brain-derived neurotrophic factor (BDNF) availability in the fear memory learning pathways combined with MDMA's pro-social effects may provide a more nuanced explanation for the therapeutic actions of MDMA.
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Affiliation(s)
- Robert J Sottile
- Department of Medical Education, Kirk Kerkorian School of Medicine at UNLV, University of Nevada Las Vegas, Las Vegas, NV, United States
| | - Thomas Vida
- Department of Medical Education, Kirk Kerkorian School of Medicine at UNLV, University of Nevada Las Vegas, Las Vegas, NV, United States
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Dogra S, Stansley BJ, Xiang Z, Qian W, Gogliotti RG, Nicoletti F, Lindsley CW, Niswender CM, Joffe ME, Conn PJ. Activating mGlu 3 Metabotropic Glutamate Receptors Rescues Schizophrenia-like Cognitive Deficits Through Metaplastic Adaptations Within the Hippocampus. Biol Psychiatry 2021; 90:385-398. [PMID: 33965197 PMCID: PMC8403106 DOI: 10.1016/j.biopsych.2021.02.970] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/08/2021] [Accepted: 02/08/2021] [Indexed: 12/26/2022]
Abstract
BACKGROUND Polymorphisms in GRM3, the gene encoding the mGlu3 metabotropic glutamate receptor, are associated with impaired cognition and neuropsychiatric disorders such as schizophrenia. Limited availability of selective genetic and molecular tools has hindered progress in developing a clear understanding of the mechanisms through which mGlu3 receptors regulate synaptic plasticity and cognition. METHODS We examined associative learning in mice with trace fear conditioning, a hippocampal-dependent learning task disrupted in patients with schizophrenia. Underlying cellular mechanisms were assessed using ex vivo hippocampal slice preparations with selective pharmacological tools and selective genetic deletion of mGlu3 receptor expression in specific neuronal subpopulations. RESULTS mGlu3 receptor activation enhanced trace fear conditioning and reversed deficits induced by subchronic phencyclidine. Mechanistic studies revealed that mGlu3 receptor activation induced metaplastic changes, biasing afferent stimulation to induce long-term potentiation through an mGlu5 receptor-dependent, endocannabinoid-mediated, disinhibitory mechanism. Selective genetic deletion of either mGlu3 or mGlu5 from hippocampal pyramidal cells eliminated effects of mGlu3 activation, revealing a novel mechanism by which mGlu3 and mGlu5 interact to enhance cognitive function. CONCLUSIONS These data demonstrate that activation of mGlu3 receptors in hippocampal pyramidal cells enhances hippocampal-dependent cognition in control and impaired mice by inducing a novel form of metaplasticity to regulate circuit function, providing a clear mechanism through which genetic variation in GRM3 can contribute to cognitive deficits. Developing approaches to positively modulate mGlu3 receptor function represents an encouraging new avenue for treating cognitive disruption in schizophrenia and other psychiatric diseases.
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Affiliation(s)
- Shalini Dogra
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Branden J. Stansley
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Zixiu Xiang
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Weilun Qian
- Vanderbilt University, Nashville, TN 37232, USA
| | - Rocco G. Gogliotti
- Molecular Pharmacology and Neuroscience Department, Loyola University Chicago, Maywood, IL, 60153, USA
| | - Ferdinando Nicoletti
- IRCCS Neuromed, Pozzilli, Italy,Department of Physiology and Pharmacology, University Sapienza of Roma, Roma, Italy
| | - Craig W. Lindsley
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA,Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN, 37232, USA,Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Colleen M. Niswender
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA,Vanderbilt Kennedy Center, Vanderbilt University, Nashville, TN 37232, USA
| | - Max E. Joffe
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA,Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN, 37232, USA,Correspondence to: Max E. Joffe, Ph.D., Research Instructor, Department of Pharmacology, Vanderbilt University, 12475E MRB4, Nashville, TN 37232-0697, Tel. (615) 322-6730, Fax. (615) 343-3088, , Twitter: @mejoffe; P. Jeffrey Conn, Ph.D., Lee E. Limbird Professor of Pharmacology, Warren Center for Neuroscience Drug Discovery, Vanderbilt University, 1205 Light Hall, Nashville, TN 37232-0697, Tel. (615) 936-2478, Fax. (615) 343-3088,
| | - P. Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA,Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN, 37232, USA,Vanderbilt Kennedy Center, Vanderbilt University, Nashville, TN 37232, USA,Correspondence to: Max E. Joffe, Ph.D., Research Instructor, Department of Pharmacology, Vanderbilt University, 12475E MRB4, Nashville, TN 37232-0697, Tel. (615) 322-6730, Fax. (615) 343-3088, , Twitter: @mejoffe; P. Jeffrey Conn, Ph.D., Lee E. Limbird Professor of Pharmacology, Warren Center for Neuroscience Drug Discovery, Vanderbilt University, 1205 Light Hall, Nashville, TN 37232-0697, Tel. (615) 936-2478, Fax. (615) 343-3088,
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7
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Reyes-García SE, Escobar ML. Calcineurin Participation in Hebbian and Homeostatic Plasticity Associated With Extinction. Front Cell Neurosci 2021; 15:685838. [PMID: 34220454 PMCID: PMC8242195 DOI: 10.3389/fncel.2021.685838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/25/2021] [Indexed: 12/21/2022] Open
Abstract
In nature, animals need to adapt to constant changes in their environment. Learning and memory are cognitive capabilities that allow this to happen. Extinction, the reduction of a certain behavior or learning previously established, refers to a very particular and interesting type of learning that has been the basis of a series of therapies to diminish non-adaptive behaviors. In recent years, the exploration of the cellular and molecular mechanisms underlying this type of learning has received increasing attention. Hebbian plasticity (the activity-dependent modification of the strength or efficacy of synaptic transmission), and homeostatic plasticity (the homeostatic regulation of plasticity) constitute processes intimately associated with memory formation and maintenance. Particularly, long-term depression (LTD) has been proposed as the underlying mechanism of extinction, while the protein phosphatase calcineurin (CaN) has been widely related to both the extinction process and LTD. In this review, we focus on the available evidence that sustains CaN modulation of LTD and its association with extinction. Beyond the classic view, we also examine the interconnection among extinction, Hebbian and homeostatic plasticity, as well as emergent evidence of the participation of kinases and long-term potentiation (LTP) on extinction learning, highlighting the importance of the balance between kinases and phosphatases in the expression of extinction. Finally, we also integrate data that shows the association between extinction and less-studied phenomena, such as synaptic silencing and engram formation that open new perspectives in the field.
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Affiliation(s)
- Salma E Reyes-García
- Laboratorio de Neurobiología del Aprendizaje y la Memoria, División de Investigación y Estudios de Posgrado, Facultad de Psicología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Martha L Escobar
- Laboratorio de Neurobiología del Aprendizaje y la Memoria, División de Investigación y Estudios de Posgrado, Facultad de Psicología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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Urrieta E, Escobar ML. Metaplastic regulation of neocortical long-term depression in vivo is sensitive to distinct phases of conditioned taste aversion. Neurobiol Learn Mem 2021; 182:107449. [PMID: 33915300 DOI: 10.1016/j.nlm.2021.107449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 04/12/2021] [Accepted: 04/22/2021] [Indexed: 10/21/2022]
Abstract
Metaplasticity refers to the persistent modification, by previous activity, in the ability to induce synaptic plasticity. Accumulated evidence has proposed that metaplasticity contributes to network function and cognitive processes such as learning and memory. In this regard, it has been observed that training in several behavioral tasks modifies the possibility to induce subsequent synaptic plasticity, such as long-term potentiation (LTP) and long-term depression (LTD). For instance, our previous studies have shown that conditioned taste aversion (CTA) training prevents the induction of in vivo LTP in the projection from the basolateral nucleus of the amygdala to the insular cortex (BLA-IC). Likewise, we reported that extinction of CTA allows induction but not maintenance of LTP in the same pathway. Besides, we showed that it is possible to express in vivo low-frequency stimulation LTD in the BLA-IC projection and that its induction prior to CTA training facilitates the extinction of this task. However, until now, little is known about the participation of LTD on metaplastic processes. The present study aimed to analyze whether CTA training modifies the expression of in vivo LTD in the BLA-IC projection. To do so, animals received low-frequency stimulation to induce IC-LTD 48 h after CTA training. Our results show that CTA training occludes the subsequent induction of LTD in the BLA-IC pathway in a retrieval-dependent manner. These findings reveal that CTA elicits a metaplastic regulation of long-lasting changes in the IC synaptic strength, as well as that specific phases of learning differentially take part in adjusting the expression of synaptic plasticity in neocortical regions.
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Affiliation(s)
- Esteban Urrieta
- División de Investigación y Estudios de Posgrado, Facultad de Psicología, Universidad Nacional Autónoma de México, 04510, Mexico
| | - Martha L Escobar
- División de Investigación y Estudios de Posgrado, Facultad de Psicología, Universidad Nacional Autónoma de México, 04510, Mexico.
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9
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Piva A, Caffino L, Padovani L, Pintori N, Mottarlini F, Sferrazza G, Paolone G, Fumagalli F, Chiamulera C. The metaplastic effects of ketamine on sucrose renewal and contextual memory reconsolidation in rats. Behav Brain Res 2020; 379:112347. [DOI: 10.1016/j.bbr.2019.112347] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 11/06/2019] [Accepted: 11/06/2019] [Indexed: 12/15/2022]
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10
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Maksymetz J, Joffe ME, Moran SP, Stansley BJ, Li B, Temple K, Engers DW, Lawrence JJ, Lindsley CW, Conn PJ. M 1 Muscarinic Receptors Modulate Fear-Related Inputs to the Prefrontal Cortex: Implications for Novel Treatments of Posttraumatic Stress Disorder. Biol Psychiatry 2019; 85:989-1000. [PMID: 31003787 PMCID: PMC6555658 DOI: 10.1016/j.biopsych.2019.02.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/15/2019] [Accepted: 02/18/2019] [Indexed: 12/20/2022]
Abstract
BACKGROUND The prefrontal cortex (PFC) integrates information from multiple inputs to exert top-down control allowing for appropriate responses in a given context. In psychiatric disorders such as posttraumatic stress disorder, PFC hyperactivity is associated with inappropriate fear in safe situations. We previously reported a form of muscarinic acetylcholine receptor (mAChR)-dependent long-term depression in the PFC that we hypothesize is involved in appropriate fear responding and could serve to reduce cortical hyperactivity following stress. However, it is unknown whether this long-term depression occurs at fear-related inputs. METHODS Using optogenetics with extracellular and whole-cell electrophysiology, we assessed the effect of mAChR activation on the synaptic strength of specific PFC inputs. We used selective pharmacological tools to assess the involvement of M1 mAChRs in conditioned fear extinction in control mice and in the stress-enhanced fear-learning model. RESULTS M1 mAChR activation induced long-term depression at inputs from the ventral hippocampus and basolateral amygdala but not from the mediodorsal nucleus of the thalamus. We found that systemic M1 mAChR antagonism impaired contextual fear extinction. Treatment with an M1 positive allosteric modulator enhanced contextual fear extinction consolidation in stress-enhanced fear learning-conditioned mice. CONCLUSIONS M1 mAChRs dynamically modulate synaptic transmission at two PFC inputs whose activity is necessary for fear extinction, and M1 mAChR function is required for proper contextual fear extinction. Furthermore, an M1 positive allosteric modulator enhanced the consolidation of fear extinction in the stress-enhanced fear-learning model, suggesting that M1 positive allosteric modulators may provide a novel treatment strategy to facilitate exposure therapy in the clinic for the treatment of posttraumatic stress disorder.
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Affiliation(s)
- James Maksymetz
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee
| | - Max E Joffe
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee
| | - Sean P Moran
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee; Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee
| | - Branden J Stansley
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee
| | - Brianna Li
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee
| | - Kayla Temple
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee
| | - Darren W Engers
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee
| | - J Josh Lawrence
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Craig W Lindsley
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee; Department of Chemistry, Vanderbilt University, Nashville, Tennessee
| | - P Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee; Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Vanderbilt University, Nashville, Tennessee; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee.
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11
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Stansley BJ, Conn PJ. Neuropharmacological Insight from Allosteric Modulation of mGlu Receptors. Trends Pharmacol Sci 2019; 40:240-252. [PMID: 30824180 PMCID: PMC6445545 DOI: 10.1016/j.tips.2019.02.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 02/06/2019] [Accepted: 02/06/2019] [Indexed: 12/11/2022]
Abstract
The metabotropic glutamate (mGlu) receptors are a family of G-protein-coupled receptors (GPCRs) that regulate cell physiology throughout the nervous system. The potential of mGlu receptors as therapeutic targets has been bolstered by current research that has provided insight into the diverse modes of mGlu activation and signaling. In particular, the allosteric modulation of mGlu receptors represents a major area of focus in studies of basic pharmacology as well as drug development, largely due to the high subtype specificity achievable by targeting allosteric sites on mGlu receptors. These provide sophisticated regulation of neuronal excitability and synaptic transmission to influence behavioral output. Here, we review how these allosteric mechanisms have been leveraged preclinically to demonstrate the therapeutic potential of allosteric modulators for neurological and neuropsychiatric disorders, such as autism, cognitive impairment, Parkinson's disease (PD), stress, and schizophrenia.
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Affiliation(s)
- Branden J Stansley
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - P Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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12
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Fisher NM, Gogliotti RG, Vermudez SAD, Stansley BJ, Conn PJ, Niswender CM. Genetic Reduction or Negative Modulation of mGlu 7 Does Not Impact Anxiety and Fear Learning Phenotypes in a Mouse Model of MECP2 Duplication Syndrome. ACS Chem Neurosci 2018; 9:2210-2217. [PMID: 29227625 DOI: 10.1021/acschemneuro.7b00414] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Rett syndrome and MECP2 Duplication syndrome are neurodevelopmental disorders attributed to loss-of-function mutations in, or duplication of, the gene encoding methyl-CpG-binding protein 2 (MeCP2), respectively. We recently reported decreased expression and function of the metabotropic glutamate receptor 7 (mGlu7) in a mouse model of Rett syndrome. Positive allosteric modulation of mGlu7 activity was sufficient to improve several disease phenotypes including cognition. Here, we tested the hypothesis that mGlu7 expression would be reciprocally regulated in a mouse model of MECP2 Duplication syndrome, such that negative modulation of mGlu7 activity would exert therapeutic benefit. To the contrary, we report that mGlu7 is not functionally increased in mice overexpressing MeCP2 and that neither genetic nor pharmacological reduction of mGlu7 activity impacts phenotypes that are antiparallel to those observed in Rett syndrome model mice. These data expand our understanding of how mGlu7 expression and function is affected by changes in MeCP2 dosage and have important implications for the therapeutic development of mGlu7 modulators.
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Affiliation(s)
- Nicole M. Fisher
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Rocco G. Gogliotti
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Sheryl Anne D. Vermudez
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Branden J. Stansley
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - P. Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Colleen M. Niswender
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
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Joffe ME, Centanni SW, Jaramillo AA, Winder DG, Conn PJ. Metabotropic Glutamate Receptors in Alcohol Use Disorder: Physiology, Plasticity, and Promising Pharmacotherapies. ACS Chem Neurosci 2018; 9:2188-2204. [PMID: 29792024 PMCID: PMC6192262 DOI: 10.1021/acschemneuro.8b00200] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Developing efficacious treatments for alcohol use disorder (AUD) has proven difficult. The insidious nature of the disease necessitates a deep understanding of its underlying biology as well as innovative approaches to ameliorate ethanol-related pathophysiology. Excessive ethanol seeking and relapse are generated by long-term changes to membrane properties, synaptic physiology, and plasticity throughout the limbic system and associated brain structures. Each of these factors can be modulated by metabotropic glutamate (mGlu) receptors, a diverse set of G protein-coupled receptors highly expressed throughout the central nervous system. Here, we discuss how different components of the mGlu receptor family modulate neurotransmission in the limbic system and other brain regions involved in AUD etiology. We then describe how these processes are dysregulated following ethanol exposure and speculate about how mGlu receptor modulation might restore such pathophysiological changes. To that end, we detail the current understanding of the behavioral pharmacology of mGlu receptor-directed drug-like molecules in animal models of AUD. Together, this review highlights the prominent position of the mGlu receptor system in the pathophysiology of AUD and provides encouragement that several classes of mGlu receptor modulators may be translated as viable treatment options.
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Affiliation(s)
- Max E. Joffe
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
| | - Samuel W. Centanni
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Anel A. Jaramillo
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Danny G. Winder
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - P. Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37232-0697, United States
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