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Clewett D, Huang R, Davachi L. Locus coeruleus activation "resets" hippocampal event representations and separates adjacent memories. Neuron 2025:S0896-6273(25)00360-5. [PMID: 40482639 DOI: 10.1016/j.neuron.2025.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2024] [Revised: 03/13/2025] [Accepted: 05/13/2025] [Indexed: 06/11/2025]
Abstract
Memories reflect the ebb and flow of experiences, capturing distinct events from our lives. Using a combination of functional magnetic resonance imaging (fMRI), neuromelanin imaging, and pupillometry, we show that arousal and locus coeruleus (LC) activation segment continuous experiences into discrete memories. As sequences unfold, encountering a context shift or event boundary triggers pupil-linked arousal and LC processes that predict later memory separation. Boundaries, furthermore, promote temporal pattern separation within the left hippocampal dentate gyrus, which correlates with heightened LC responses to those same transition points. Unlike transient LC effects, indirect structural and functional markers of elevated background LC activation correlate with reduced arousal-related LC and pupil responses at boundaries, suggesting that hyperarousal disrupts event segmentation. Our findings support the idea that arousal mechanisms initiate a neural and memory "reset" in response to significant changes, fundamentally shaping the episodes that define episodic memory.
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Affiliation(s)
- David Clewett
- Department of Psychology, UCLA, Los Angeles, CA 90095, USA.
| | - Ringo Huang
- Department of Psychology, UCLA, Los Angeles, CA 90095, USA
| | - Lila Davachi
- Department of Psychology, Columbia University, New York, NY 10027, USA; Nathan Kline Institute, Orangeburg, NY 10962, USA
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2
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Zhang ET, Saglimbeni GS, Feng J, Li Y, Bruchas MR. Dentate gyrus norepinephrine ramping facilitates aversive contextual processing. Nat Commun 2025; 16:454. [PMID: 39774642 PMCID: PMC11707070 DOI: 10.1038/s41467-025-55817-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Accepted: 12/31/2024] [Indexed: 01/11/2025] Open
Abstract
Dysregulation in aversive contextual processing is believed to affect several forms of psychopathology, including post-traumatic stress disorder (PTSD). The dentate gyrus (DG) is an important brain region in contextual discrimination and disambiguation of new experiences from prior memories. The DG also receives dense projections from the locus coeruleus (LC), the primary source of norepinephrine (NE) in the mammalian brain, which is active during stressful events. However, how noradrenergic dynamics impact DG-dependent function during contextual discrimination and pattern separation remains unclear. Here, we report that aversive contextual processing in mice is linked to linear elevations in tonic norepinephrine release dynamics within the DG and report that this engagement of prolonged norepinephrine release is sufficient to produce contextual disambiguation, even in the absence of a salient aversive stimulus. These findings suggest that spatiotemporal ramping characteristics of LC-NE release in the DG during stress likely serve an important role in driving contextual processing.
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Affiliation(s)
- Eric T Zhang
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA
| | - Grace S Saglimbeni
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA
| | - Jiesi Feng
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
| | - Michael R Bruchas
- Department of Bioengineering, University of Washington, Seattle, WA, USA.
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA.
- Department of Pharmacology, University of Washington, Seattle, WA, USA.
- Center for the Neurobiology of Addiction, Pain and Emotion, University of Washington, Seattle, WA, USA.
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3
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Zhang ET, Saglimbeni GS, Feng J, Li Y, Bruchas MR. Dentate Gyrus Norepinephrine Ramping Facilitates Aversive Contextual Processing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.10.31.621389. [PMID: 39554120 PMCID: PMC11565931 DOI: 10.1101/2024.10.31.621389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2024]
Abstract
Dysregulation in aversive contextual processing is believed to affect several forms of psychopathology, including post-traumatic stress disorder (PTSD). The dentate gyrus (DG) is an important brain region in contextual discrimination and disambiguation of new experiences from prior memories. The DG also receives dense projections from the locus coeruleus (LC), the primary source of norepinephrine (NE) in the mammalian brain, which is active during stressful events. However, how noradrenergic dynamics impact DG-dependent function during contextual discrimination and pattern separation remains unclear. Here, we report that aversive contextual processing in mice is linked to linear elevations in tonic norepinephrine release dynamics within the DG and report that this engagement of prolonged norepinephrine release is sufficient to produce contextual disambiguation, even in the absence of a salient aversive stimulus. These findings suggest that spatiotemporal ramping characteristics of LC-NE release in the DG during stress likely serve an important role in driving contextual processing.
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4
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Clewett D, Huang R, Davachi L. Locus coeruleus activation 'resets' hippocampal event representations and separates adjacent memories. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.15.608148. [PMID: 39185215 PMCID: PMC11343187 DOI: 10.1101/2024.08.15.608148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/27/2024]
Abstract
Memories reflect the ebb and flow of experiences, capturing unique and meaningful events from our lives. Using a combination of functional magnetic resonance imaging (fMRI), neuromelanin imaging, and pupillometry, we show that arousal and locus coeruleus (LC) activation transform otherwise continuous experiences into distinct episodic memories. As sequences unfold, encountering a context shift, or event boundary, triggers arousal and LC processes that predict later memory separation. Boundaries furthermore promote temporal pattern separation within left hippocampal dentate gyrus, which correlates with heightened LC responses to those same transition points. We also find that a neurochemical index of prolonged LC activation correlates with diminished arousal responses at boundaries, suggesting a connection between elevated LC output and impaired event processing. These findings align with the idea that arousal processes initiate a neural and memory 'reset' in response to significant changes, constructing the very episodes that define everyday memory.
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Affiliation(s)
| | | | - Lila Davachi
- Department of Psychology, Columbia University, USA
- Nathan Kline Institute, Orangeburg, New York, USA
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5
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Taherian N, Vaezi G, Neamati A, Hojjati V, Ghorbani-Taherdehi F, Sahebkar A, Gorji-Valokola M. The dose-dependent neuroprotective effect of norepinephrine in improving memory retrieval in an experimental model of multiple sclerosis, experimental autoimmune encephalomyelitis. Brain Res Bull 2024; 209:110907. [PMID: 38395110 DOI: 10.1016/j.brainresbull.2024.110907] [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: 11/23/2023] [Revised: 01/26/2024] [Accepted: 02/20/2024] [Indexed: 02/25/2024]
Abstract
Multiple sclerosis (MS) is considered an immune-mediated inflammatory disorder that causes cognitive impairments by damaging the hippocampal tissue. Conversely, norepinephrine (NEP) has anti-inflammatory and re-myelinating properties, which improve cognitive impairments. The aim of this study was to assess the neuroprotective effects of NEP on learning and memory disorders in an experimental animal model of MS. Two guide cannulas were bilaterally implanted in the rat hippocampal CA1 regions. After recovery, the animals received 3 μl of 0.01% ethidium bromide (EtB) in each of both hippocampal regions. After three days, the rats were randomly divided into 6 groups (8 rats/group), including control, sham 1, sham 2, and three groups of NEP 0.25, 0.5, and 1 mg/kg by intrahippocampal injection. Behavioral tests (e.g. shuttle box test and open-field test) were then performed. Finally, ROS, MDA, GSH, TNF-α, IL-6, and IL-1β concentrations in the left CA1 area, as well as using western-blot analysis, p-p38, p-JNK, p-AKT, p-ERK1/2, p-NMDA, p-AMPA, p-CREB, and BDNF proteins in the right CA1 region evaluated. The EtB injection increased ROS, MDA, TNF-α, IL-6, and IL-1β levels, as well as p-JNK and p-P38, except all other proteins, while decreasing GSH content, as well as step-through latency and locomotor activity in sham groups compared to the control group. Conversely, NEP (0.5 and 1 mg/kg, particularly at the dose of 1 mg/kg) counterbalanced all the alterations mentioned above in comparison to the sham groups. The EtB induced learning and memory impairment; however, NEP dose-dependently restored these impairments to normal levels.
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Affiliation(s)
- Narjes Taherian
- Department of Biology, Damghan Branch, Islamic Azad University, Damghan, Iran
| | - Gholamhassan Vaezi
- Department of Biology, Damghan Branch, Islamic Azad University, Damghan, Iran
| | - Ali Neamati
- Department of Biology, Mashhad Branch, Islamic Azad University, Mashhad, Iran
| | - Vida Hojjati
- Department of Biology, Damghan Branch, Islamic Azad University, Damghan, Iran
| | - Faezeh Ghorbani-Taherdehi
- Department of Anatomy and Cell Biology, School of Medicine, Esfahan University of Medical Sciences, Esfahan, Iran
| | - Amirhossein Sahebkar
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mahmoud Gorji-Valokola
- Department of Food and Drug Administration, Shahid Sadoughi University of Medical Sciences, Yazd, Iran; Department of Pharmacology, Brain and Spinal Injury Repair Research Center, Tehran University of Medical Science, Tehran, Iran.
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6
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Grella SL, Donaldson TN. Contextual memory engrams, and the neuromodulatory influence of the locus coeruleus. Front Mol Neurosci 2024; 17:1342622. [PMID: 38375501 PMCID: PMC10875109 DOI: 10.3389/fnmol.2024.1342622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 01/19/2024] [Indexed: 02/21/2024] Open
Abstract
Here, we review the basis of contextual memory at a conceptual and cellular level. We begin with an overview of the philosophical foundations of traversing space, followed by theories covering the material bases of contextual representations in the hippocampus (engrams), exploring functional characteristics of the cells and subfields within. Next, we explore various methodological approaches for investigating contextual memory engrams, emphasizing plasticity mechanisms. This leads us to discuss the role of neuromodulatory inputs in governing these dynamic changes. We then outline a recent hypothesis involving noradrenergic and dopaminergic projections from the locus coeruleus (LC) to different subregions of the hippocampus, in sculpting contextual representations, giving a brief description of the neuroanatomical and physiological properties of the LC. Finally, we examine how activity in the LC influences contextual memory processes through synaptic plasticity mechanisms to alter hippocampal engrams. Overall, we find that phasic activation of the LC plays an important role in promoting new learning and altering mnemonic processes at the behavioral and cellular level through the neuromodulatory influence of NE/DA in the hippocampus. These findings may provide insight into mechanisms of hippocampal remapping and memory updating, memory processes that are potentially dysregulated in certain psychiatric and neurodegenerative disorders.
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Affiliation(s)
- Stephanie L. Grella
- MNEME Lab, Department of Psychology, Program in Neuroscience, Loyola University Chicago, Chicago, IL, United States
| | - Tia N. Donaldson
- Systems Neuroscience and Behavior Lab, Department of Psychology, The University of New Mexico, Albuquerque, NM, United States
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Yoo HJ, Nashiro K, Dutt S, Min J, Cho C, Thayer JF, Lehrer P, Chang C, Mather M. Daily biofeedback to modulate heart rate oscillations affects structural volume in hippocampal subregions targeted by the locus coeruleus in older adults but not younger adults. Neurobiol Aging 2023; 132:85-99. [PMID: 37769491 PMCID: PMC10840698 DOI: 10.1016/j.neurobiolaging.2023.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 08/24/2023] [Accepted: 08/28/2023] [Indexed: 10/03/2023]
Abstract
Using data from a clinical trial, we tested the hypothesis that daily sessions modulating heart rate oscillations affect older adults' volume of a region-of-interest (ROI) comprised of adjacent hippocampal subregions with relatively strong locus coeruleus (LC) noradrenergic input. Younger and older adults were randomly assigned to one of two daily biofeedback practices for 5 weeks: (1) engage in slow-paced breathing to increase the amplitude of oscillations in heart rate at their breathing frequency (Osc+); (2) engage in self-selected strategies to decrease heart rate oscillations (Osc-). The interventions did not significantly affect younger adults' hippocampal volume. Among older adults, the two conditions affected volume in the LC-targeted hippocampal ROI differentially as reflected in a significant condition × time-point interaction on ROI volume. These condition differences were driven by opposing changes in the two conditions (increased volume in Osc+ and decreased volume in Osc-) and were mediated by the degree of heart rate oscillation during training sessions.
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Affiliation(s)
- Hyun Joo Yoo
- University of Southern California, Los Angeles, CA 90089, USA
| | - Kaoru Nashiro
- University of Southern California, Los Angeles, CA 90089, USA
| | - Shubir Dutt
- University of Southern California, Los Angeles, CA 90089, USA
| | - Jungwon Min
- University of Southern California, Los Angeles, CA 90089, USA
| | - Christine Cho
- University of Southern California, Los Angeles, CA 90089, USA
| | | | - Paul Lehrer
- Rutgers University, New Brunswick, NJ 08852, USA
| | - Catie Chang
- Vanderbilt University, Nashville, TN 37235, USA
| | - Mara Mather
- University of Southern California, Los Angeles, CA 90089, USA.
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8
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Dahl MJ, Kulesza A, Werkle-Bergner M, Mather M. Declining locus coeruleus-dopaminergic and noradrenergic modulation of long-term memory in aging and Alzheimer's disease. Neurosci Biobehav Rev 2023; 153:105358. [PMID: 37597700 PMCID: PMC10591841 DOI: 10.1016/j.neubiorev.2023.105358] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 08/05/2023] [Accepted: 08/10/2023] [Indexed: 08/21/2023]
Abstract
Memory is essential in defining our identity by guiding behavior based on past experiences. However, aging leads to declining memory, disrupting older adult's lives. Memories are encoded through experience-dependent modifications of synaptic strength, which are regulated by the catecholamines dopamine and noradrenaline. While cognitive aging research demonstrates how dopaminergic neuromodulation from the substantia nigra-ventral tegmental area regulates hippocampal synaptic plasticity and memory, recent findings indicate that the noradrenergic locus coeruleus sends denser inputs to the hippocampus. The locus coeruleus produces dopamine as biosynthetic precursor of noradrenaline, and releases both to modulate hippocampal plasticity and memory. Crucially, the locus coeruleus is also the first site to accumulate Alzheimer's-related abnormal tau and severely degenerates with disease development. New in-vivo assessments of locus coeruleus integrity reveal associations with Alzheimer's markers and late-life memory impairments, which likely stem from impaired dopaminergic and noradrenergic neurotransmission. Bridging research across species, the reviewed findings suggest that degeneration of the locus coeruleus results in deficient dopaminergic and noradrenergic modulation of hippocampal plasticity and thus memory decline.
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Affiliation(s)
- Martin J Dahl
- Center for Lifespan Psychology, Max Planck Institute for Human Development, 14195 Berlin, Germany; Leonard Davis School of Gerontology, University of Southern California, 90089 Los Angeles, CA, USA.
| | - Agnieszka Kulesza
- Center for Lifespan Psychology, Max Planck Institute for Human Development, 14195 Berlin, Germany
| | - Markus Werkle-Bergner
- Center for Lifespan Psychology, Max Planck Institute for Human Development, 14195 Berlin, Germany
| | - Mara Mather
- Leonard Davis School of Gerontology, University of Southern California, 90089 Los Angeles, CA, USA; Department of Psychology, University of Southern California, Los Angeles, California, USA; Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA
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9
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Yoo HJ, Nashiro K, Dutt S, Min J, Cho C, Thayer JF, Lehrer P, Chang C, Mather M. Daily biofeedback to modulate heart rate oscillations affects structural volume in hippocampal subregions targeted by the locus coeruleus in older adults but not younger adults. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.03.02.23286715. [PMID: 37745356 PMCID: PMC10516053 DOI: 10.1101/2023.03.02.23286715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Using data from a clinical trial, we tested the hypothesis that daily sessions modulating heart rate oscillations affect older adults' volume of a region-of-interest (ROI) comprised of adjacent hippocampal subregions with relatively strong locus coeruleus (LC) noradrenergic input. Younger and older adults were randomly assigned to one of two daily biofeedback practices for 5 weeks: 1) engage in slow-paced breathing to increase the amplitude of oscillations in heart rate at their breathing frequency (Osc+); 2) engage in self-selected strategies to decrease heart rate oscillations (Osc-). The interventions did not significantly affect younger adults' hippocampal volume. Among older adults, the two conditions affected volume in the LC-targeted hippocampal ROI differentially as reflected in a significant condition x time-point interaction on ROI volume. These condition differences were driven by opposing changes in the two conditions (increased volume in Osc+ and decreased volume in Osc-) and were mediated by the degree of heart rate oscillation during training sessions.
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Affiliation(s)
- Hyun Joo Yoo
- University of Southern California, Los Angeles, CA 90089
| | - Kaoru Nashiro
- University of Southern California, Los Angeles, CA 90089
| | - Shubir Dutt
- University of Southern California, Los Angeles, CA 90089
| | - Jungwon Min
- University of Southern California, Los Angeles, CA 90089
| | - Christine Cho
- University of Southern California, Los Angeles, CA 90089
| | | | | | | | - Mara Mather
- University of Southern California, Los Angeles, CA 90089
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10
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Olsen LK, Solis E, McIntire LK, Hatcher-Solis CN. Vagus nerve stimulation: mechanisms and factors involved in memory enhancement. Front Hum Neurosci 2023; 17:1152064. [PMID: 37457500 PMCID: PMC10342206 DOI: 10.3389/fnhum.2023.1152064] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 03/21/2023] [Indexed: 07/18/2023] Open
Abstract
Vagus nerve stimulation (VNS) has been recognized as a useful neuromodulation tool to target the central nervous system by electrical stimulation of peripheral nerves. Activation of the nucleus of the solitary tract (NTS) in the brainstem by vagal afferent nerve fibers allows for modulation of various higher order brain regions, including limbic and cerebral cortex structures. Along with neurological and psychiatric indications, clinical and preclinical studies suggest that VNS can improve memory. While the underlying mechanisms to improve memory with VNS involve brain areas, such as the prefrontal cortex and processes including alertness and arousal, here we focus on VNS-induced memory improvements related to the hippocampus, the main area implicated in memory acquisition. In addition, we detail research demonstrating that a targeted approach to VNS can modify memory outcomes and delve into the molecular mechanisms associated with these changes. These findings indicate that a greater understanding of VNS mechanisms while also considering stimulation parameters, administration site, timing in relation to training, and sex-specific factors, may allow for optimal VNS application to enhance memory.
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Affiliation(s)
- Laura K. Olsen
- Air Force Research Laboratory, 711th Human Performance Wing, Cognitive Neuroscience, Wright-Patterson Air Force Base, OH, United States
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, United States
| | - Ernesto Solis
- Air Force Research Laboratory, 711th Human Performance Wing, Aerospace Physiology, Wright-Patterson Air Force Base, OH, United States
- Consortium of Universities of the Washington Metropolitan Area, Washington, DC, United States
| | - Lindsey K. McIntire
- Air Force Research Laboratory, 711th Human Performance Wing, Cognitive Neuroscience, Wright-Patterson Air Force Base, OH, United States
- Infoscitex Corporation, Dayton, OH, United States
| | - Candice N. Hatcher-Solis
- Air Force Research Laboratory, 711th Human Performance Wing, Cognitive Neuroscience, Wright-Patterson Air Force Base, OH, United States
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11
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Arcangeli G, Lulli LG, Traversini V, De Sio S, Cannizzaro E, Galea RP, Mucci N. Neurobehavioral Alterations from Noise Exposure in Animals: A Systematic Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 20:591. [PMID: 36612911 PMCID: PMC9819367 DOI: 10.3390/ijerph20010591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 12/18/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
Ecosystems are increasingly involved and influenced by human activities, which are ever-increasing. These activities are mainly due to vehicular, air and sea transportation, thus causing possible repercussions on the fauna that exists there. The aim of this systematic review is to investigate the possible consequences that these activities may have in the field of animal neurobehavior, with special emphasis on the species involved, the most common environment concerned, the noise source and the disturbance that is caused. This research includes articles published in the major databases (PubMed, Cochrane Library, Scopus, Embase, Web of Sciences); the online search yielded 1901 references. After selection, 49 articles (14 reviews and 35 original articles) were finally scrutinized. The main problems that were reported were in relation to movement, reproduction, offspring care and foraging. In live experiments carried out, the repercussions on the marine environment mainly concerned altered swimming, shallower descents, less foraging and an escape reaction for fear of cetaceans and fish. In birds, alterations in foraging, vocalizations and nests were noted; laboratory studies, on the other hand, carried out on small mammals, highlighted spatio-temporal cognitive alterations and memory loss. In conclusion, it appears that greater attention to all ecosystems should be given as soon as possible so as to try to achieve a balance between human activity and the well-being of terrestrial fauna.
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Affiliation(s)
- Giulio Arcangeli
- Department of Experimental and Clinical Medicine, University of Florence, 50139 Florence, Italy
| | | | - Veronica Traversini
- Department of Experimental and Clinical Medicine, University of Florence, 50139 Florence, Italy
| | - Simone De Sio
- R.U. of Occupational Medicine, “Sapienza” University of Rome, 00100 Rome, Italy
| | | | - Raymond Paul Galea
- Department of Obstetrics & Gynaecology, University of Malta, MSD 2080 Msida, Malta
| | - Nicola Mucci
- Department of Experimental and Clinical Medicine, University of Florence, 50139 Florence, Italy
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12
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Chai GS, Wu JJ, Gong J, Zhou JL, Jiang ZQ, Yi HY, Gu Y, Huang HH, Yao ZY, Zhang YQ, Zhao P, Nie YJ. Activation of β2-adrenergic Receptor Ameliorates Amyloid-β-induced Mitophagy Defects and Tau Pathology in Mice. Neuroscience 2022; 505:34-50. [DOI: 10.1016/j.neuroscience.2022.09.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 09/26/2022] [Accepted: 09/28/2022] [Indexed: 10/31/2022]
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13
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Maity S, Abbaspour R, Nahabedian D, Connor SA. Norepinephrine, beyond the Synapse: Coordinating Epigenetic Codes for Memory. Int J Mol Sci 2022; 23:ijms23179916. [PMID: 36077313 PMCID: PMC9456295 DOI: 10.3390/ijms23179916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/19/2022] [Accepted: 08/21/2022] [Indexed: 11/16/2022] Open
Abstract
The noradrenergic system is implicated in neuropathologies contributing to major disorders of the memory, including post-traumatic stress disorder and Alzheimer’s disease. Determining the impact of norepinephrine on cellular function and plasticity is thus essential for making inroads into our understanding of these brain conditions, while expanding our capacity for treating them. Norepinephrine is a neuromodulator within the mammalian central nervous system which plays important roles in cognition and associated synaptic plasticity. Specifically, norepinephrine regulates the formation of memory through the stimulation of β-ARs, increasing the dynamic range of synaptic modifiability. The mechanisms through which NE influences neural circuit function have been extended to the level of the epigenome. This review focuses on recent insights into how the noradrenergic recruitment of epigenetic modifications, including DNA methylation and post-translational modification of histones, contribute to homo- and heterosynaptic plasticity. These advances will be placed in the context of synaptic changes associated with memory formation and linked to brain disorders and neurotherapeutic applications.
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Affiliation(s)
- Sabyasachi Maity
- Department of Physiology, Neuroscience, and Behavioral Sciences, St. George’s University School of Medicine, True Blue FZ818, Grenada
| | - Raman Abbaspour
- Department of Biology, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada
| | - David Nahabedian
- The Center for Biomedical Visualization, Department of Anatomical Sciences, St. George’s University School of Medicine, True Blue FZ818, Grenada
| | - Steven A. Connor
- Department of Biology, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada
- Correspondence: ; Tel.: +1-(416)-736-2100 (ext. 33803)
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14
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Jennen L, Mazereel V, Lecei A, Samaey C, Vancampfort D, van Winkel R. Exercise to spot the differences: a framework for the effect of exercise on hippocampal pattern separation in humans. Rev Neurosci 2022; 33:555-582. [PMID: 35172422 DOI: 10.1515/revneuro-2021-0156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/16/2022] [Indexed: 12/12/2022]
Abstract
Exercise has a beneficial effect on mental health and cognitive functioning, but the exact underlying mechanisms remain largely unknown. In this review, we focus on the effect of exercise on hippocampal pattern separation, which is a key component of episodic memory. Research has associated exercise with improvements in pattern separation. We propose an integrated framework mechanistically explaining this relationship. The framework is divided into three pathways, describing the pro-neuroplastic, anti-inflammatory and hormonal effects of exercise. The pathways are heavily intertwined and may result in functional and structural changes in the hippocampus. These changes can ultimately affect pattern separation through direct and indirect connections. The proposed framework might guide future research on the effect of exercise on pattern separation in the hippocampus.
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Affiliation(s)
- Lise Jennen
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium
| | - Victor Mazereel
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium.,University Psychiatric Center KU Leuven, Leuvensesteenweg 517, 3070 Leuven-Kortenberg, Belgium
| | - Aleksandra Lecei
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium
| | - Celine Samaey
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium
| | - Davy Vancampfort
- University Psychiatric Center KU Leuven, Leuvensesteenweg 517, 3070 Leuven-Kortenberg, Belgium.,KU Leuven Department of Rehabilitation Sciences, ON IV Herestraat 49, bus 1510, 3000, Leuven, Belgium
| | - Ruud van Winkel
- KU Leuven, Department of Neurosciences, Center for Clinical Psychiatry, ON V Herestraat 49, bus 1029, 3000 Leuven, Belgium.,University Psychiatric Center KU Leuven, Leuvensesteenweg 517, 3070 Leuven-Kortenberg, Belgium
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15
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Broncel A, Bocian R, Kłos-Wojtczak P, Konopacki J. Noradrenergic Profile of Hippocampal Formation Theta Rhythm in Anaesthetized Rats. Neuroscience 2021; 473:13-28. [PMID: 34418519 DOI: 10.1016/j.neuroscience.2021.08.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 08/11/2021] [Accepted: 08/12/2021] [Indexed: 10/20/2022]
Abstract
The present study was undertaken to identify the noradrenergic receptors underlying the production of hippocampal formation (HPC) type 2 theta rhythm. The experiments were performed on urethanized rats wherein type 2 theta is the only rhythm present. In three independent stages of experiments, the effects of noradrenaline (NE) and selective noradrenergic α and β agonists and antagonists were tested. We indicate that the selective activation of three HPC noradrenergic receptors, α1, α2 and β1, induced a similar effect (i.e., inhibition) on type 2 theta rhythm. The remaining HPC β2 and β3 noradrenergic receptors do not seem to be directly involved in the pharmacological mechanism responsible for the suppression of theta rhythm in anaesthetized rats. Obtained results provide evidence for the suppressant effect of exogenous NE on HPC type 2 theta rhythm and show the crucial role of α1, α2 and β1 noradrenergic receptors in the modulation of HPC mechanisms of oscillations and synchrony. This finding is in contrast to the effects of endogenous NE produced by electrical stimulation of the locus coeruleus (LC) and procaine injection into the LC (Broncel et al., 2020).
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Affiliation(s)
- A Broncel
- Neuromedical, Research Department, Natolin 15, 92-701 Lodz, Poland.
| | - R Bocian
- Department of Neurobiology, Faculty of Biology and Environmental Protection, The University of Lodz, Pomorska St. No 141/143, 90-236 Lodz, Poland.
| | - P Kłos-Wojtczak
- Neuromedical, Research Department, Natolin 15, 92-701 Lodz, Poland.
| | - J Konopacki
- Department of Neurobiology, Faculty of Biology and Environmental Protection, The University of Lodz, Pomorska St. No 141/143, 90-236 Lodz, Poland.
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16
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Grella SL, Gomes SM, Lackie RE, Renda B, Marrone DF. Norepinephrine as a spatial memory reset signal. Behav Pharmacol 2021; 32:531-548. [PMID: 34417358 DOI: 10.1097/fbp.0000000000000648] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Contextual information is represented in the hippocampus (HPC) partially through the recruitment of distinct neuronal ensembles. It is believed that reactivation of these ensembles underlies memory retrieval processes. Recently, we showed that norepinephrine input from phasic locus coeruleus activation induces hippocampal plasticity resulting in the recruitment of new neurons and disengagement from previously established representations. We hypothesize that norepinephrine may provide a neuromodulatory mnemonic switch signaling the HPC to move from a state of retrieval to encoding in the presence of novelty, and therefore, plays a role in memory updating. Here, we tested whether bilateral dorsal dentate gyrus (dDG) infusions of the β-adrenergic receptor (BAR) agonist isoproterenol (ISO), administered prior to encoding or retrieval, would impair spatial working and reference memory by reverting, the system to encoding (thereby recruiting new neurons) potentially interfering with the retrieval of the previously established spatial ensemble. We also investigated whether dDG infusions of ISO could promote cognitive flexibility by switching the system to encoding when it is adaptive (ie, when new information is presented, eg, reversal learning). We found that intra-dDG infusions of ISO given prior to retrieval caused deficits in working and reference memory which was blocked by pretreatment with the BAR-antagonist, propranolol (PRO). In contrast, ISO administered prior to reversal learning led to improved performance. These data support our hypothesis that norepinephrine serves as a novelty signal to update HPC contextual representations via BAR activation-facilitated recruitment of new neurons. This can be both maladaptive and adaptive depending on the situation.
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Affiliation(s)
- Stephanie L Grella
- Department of Psychology, Wilfrid Laurier University, Waterloo, Ontario, Canada
- Department of Psychological & Brain Sciences, Boston University, Boston, Massachusetts, USA
| | - Sarah M Gomes
- Department of Psychology, Wilfrid Laurier University, Waterloo, Ontario, Canada
- Faculty of Health Sciences, School of Medicine, Queen's University, Kingston
| | - Rachel E Lackie
- Department of Psychology, Wilfrid Laurier University, Waterloo, Ontario, Canada
- Program in Neuroscience, Robarts Research Institute, University of Western Ontario, London
| | - Briana Renda
- Department of Psychology, Wilfrid Laurier University, Waterloo, Ontario, Canada
- Department of Psychology, University of Guelph, Guelph, Ontario, Canada
| | - Diano F Marrone
- Department of Psychology, Wilfrid Laurier University, Waterloo, Ontario, Canada
- McKnight Brain Institute, University of Arizona, Tucson, Arizona, USA
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17
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Seo DO, Zhang ET, Piantadosi SC, Marcus DJ, Motard LE, Kan BK, Gomez AM, Nguyen TK, Xia L, Bruchas MR. A locus coeruleus to dentate gyrus noradrenergic circuit modulates aversive contextual processing. Neuron 2021; 109:2116-2130.e6. [PMID: 34081911 PMCID: PMC8754261 DOI: 10.1016/j.neuron.2021.05.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 01/19/2021] [Accepted: 05/07/2021] [Indexed: 12/26/2022]
Abstract
Dysregulation in contextual processing is believed to affect several forms of psychopathology, such as post-traumatic stress disorder (PTSD). The dentate gyrus (DG), a subregion of the hippocampus, is thought to be an important brain region for disambiguating new experiences from prior experiences. Noradrenergic (NE) neurons in the locus coeruleus (LC) are more tonically active during stressful events and send dense projections to the DG, yet an understanding of their function in DG-dependent contextual discrimination has not been established. Here, we isolate a key function of the LC-NE-DG circuit in contextual aversive generalization using selective manipulations and in vivo single-cell calcium imaging. We report that activation of LC-NE neurons and terminal activity results in contextual generalization. We found that these effects required β-adrenergic-mediated modulation of hilar interneurons to ultimately promote aversive generalization, suggesting that disruption of noradrenergic tone may serve as an important avenue for treating stress-induced disorders.
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Affiliation(s)
- Dong-Oh Seo
- Department of Anesthesiology, Division of Basic Research, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Eric T Zhang
- Department of Bioengineering, University of Washington, Seattle, WA 98105, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA; Center for the Neurobiology of Addiction, Pain and Emotion, University of Washington, Seattle, WA 98195, USA
| | - Sean C Piantadosi
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA; Center for the Neurobiology of Addiction, Pain and Emotion, University of Washington, Seattle, WA 98195, USA
| | - David J Marcus
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA; Center for the Neurobiology of Addiction, Pain and Emotion, University of Washington, Seattle, WA 98195, USA
| | - Laura E Motard
- Department of Anesthesiology, Division of Basic Research, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Bryce K Kan
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA; Center for the Neurobiology of Addiction, Pain and Emotion, University of Washington, Seattle, WA 98195, USA
| | - Adrian M Gomez
- Department of Anesthesiology, Division of Basic Research, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Tammy K Nguyen
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA; Center for the Neurobiology of Addiction, Pain and Emotion, University of Washington, Seattle, WA 98195, USA
| | - Li Xia
- Division of Biology and Biomedical Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael R Bruchas
- Department of Anesthesiology, Division of Basic Research, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Bioengineering, University of Washington, Seattle, WA 98105, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA; Center for the Neurobiology of Addiction, Pain and Emotion, University of Washington, Seattle, WA 98195, USA; Division of Biology and Biomedical Sciences, Washington University School of Medicine, St. Louis, MO 63110, USA; Departments of Anesthesiology and Pharmacology, University of Washington, Seattle, WA 98195, USA.
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18
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Ross JA, Van Bockstaele EJ. The Locus Coeruleus- Norepinephrine System in Stress and Arousal: Unraveling Historical, Current, and Future Perspectives. Front Psychiatry 2021; 11:601519. [PMID: 33584368 PMCID: PMC7873441 DOI: 10.3389/fpsyt.2020.601519] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 12/14/2020] [Indexed: 01/03/2023] Open
Abstract
Arousal may be understood on a spectrum, with excessive sleepiness, cognitive dysfunction, and inattention on one side, a wakeful state in the middle, and hypervigilance, panic, and psychosis on the other side. However, historically, the concepts of arousal and stress have been challenging to define as measurable experimental variables. Divergent efforts to study these subjects have given rise to several disciplines, including neurobiology, neuroendocrinology, and cognitive neuroscience. We discuss technological advancements that chronologically led to our current understanding of the arousal system, focusing on the multifaceted nucleus locus coeruleus. We share our contemporary perspective and the hypotheses of others in the context of our current technological capabilities and future developments that will be required to move forward in this area of research.
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Affiliation(s)
- Jennifer A. Ross
- Department of Pharmacology and Physiology, College of Medicine, Drexel University, Philadelphia, PA, United States
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19
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Perez DM. α 1-Adrenergic Receptors in Neurotransmission, Synaptic Plasticity, and Cognition. Front Pharmacol 2020; 11:581098. [PMID: 33117176 PMCID: PMC7553051 DOI: 10.3389/fphar.2020.581098] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 09/11/2020] [Indexed: 12/14/2022] Open
Abstract
α1-adrenergic receptors are G-Protein Coupled Receptors that are involved in neurotransmission and regulate the sympathetic nervous system through binding and activating the neurotransmitter, norepinephrine, and the neurohormone, epinephrine. There are three α1-adrenergic receptor subtypes (α1A, α1B, α1D) that are known to play various roles in neurotransmission and cognition. They are related to two other adrenergic receptor families that also bind norepinephrine and epinephrine, the β- and α2-, each with three subtypes (β1, β2, β3, α2A, α2B, α2C). Previous studies assessing the roles of α1-adrenergic receptors in neurotransmission and cognition have been inconsistent. This was due to the use of poorly-selective ligands and many of these studies were published before the characterization of the cloned receptor subtypes and the subsequent development of animal models. With the availability of more-selective ligands and the development of animal models, a clearer picture of their role in cognition and neurotransmission can be assessed. In this review, we highlight the significant role that the α1-adrenergic receptor plays in regulating synaptic efficacy, both short and long-term synaptic plasticity, and its regulation of different types of memory. We will also present evidence that the α1-adrenergic receptors, and particularly the α1A-adrenergic receptor subtype, are a potentially good target to treat a wide variety of neurological conditions with diminished cognition.
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Affiliation(s)
- Dianne M Perez
- The Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, OH, United States
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20
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Broncel A, Bocian R, Kłos-Wojtczak P, Konopacki J. Effects of locus coeruleus activation and inactivation on hippocampal formation theta rhythm in anesthetized rats. Brain Res Bull 2020; 162:180-190. [DOI: 10.1016/j.brainresbull.2020.05.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 04/23/2020] [Accepted: 05/12/2020] [Indexed: 02/05/2023]
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21
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Maity S, Chandanathil M, Millis RM, Connor SA. Norepinephrine stabilizes translation-dependent, homosynaptic long-term potentiation through mechanisms requiring the cAMP sensor Epac, mTOR and MAPK. Eur J Neurosci 2020; 52:3679-3688. [PMID: 32275785 DOI: 10.1111/ejn.14735] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 02/21/2020] [Accepted: 03/22/2020] [Indexed: 02/01/2023]
Abstract
Neuromodulators regulate higher-order cognitive processes including learning and memory through modulation of synaptic transmission and plasticity. Norepinephrine is a neuromodulator that is secreted throughout the brain in response to novelty or increased arousal, which alters neural circuits by increasing the modifiability of CNS synapses. Norepinephrine activates metabotropic receptors, initiating complex intracellular signalling cascades that can promote enduring changes in synaptic strength including long-term potentiation (LTP). In particular, activation of beta-adrenergic receptors (β-ARs) by norepinephrine enhances LTP through downstream engagement of signalling cascades which upregulate protein synthesis at synapses. Here, we sought to determine the select signalling pathways recruited by norepinephrine to promote homosynaptic LTP at hippocampal synapses in mice. Application of norepinephrine initiated a long-lasting form of homosynaptic LTP that requires protein synthesis. Norepinephrine-mediated enhancement of LTP was reduced by inhibition of mammalian target of rapamycin and exchange protein directly activated by cAMP (Epac) but not cAMP-dependent protein kinase A, suggesting that the endogenous β-AR ligand norepinephrine may preferentially recruit Epac signalling to promote enduring changes in synaptic strength. These findings advance our understanding of the mechanisms through which norepinephrine regulates synaptic plasticity associated with formation of new memories.
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Affiliation(s)
- Sabyasachi Maity
- Department of Physiology, Neuroscience and Behavioral Sciences, St. George's University School of Medicine, St. George, Grenada.,Department of Physiology, University of Alberta, Edmonton, AB, Canada
| | - Merin Chandanathil
- Department of Physiology, American University of Antigua College of Medicine, St. John's, Antigua
| | - Richard M Millis
- Department of Physiology, American University of Antigua College of Medicine, St. John's, Antigua
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22
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Nguyen PV, Connor SA. Noradrenergic Regulation of Hippocampus-Dependent Memory. Cent Nerv Syst Agents Med Chem 2020; 19:187-196. [PMID: 31749419 DOI: 10.2174/1871524919666190719163632] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 06/24/2019] [Accepted: 06/28/2019] [Indexed: 12/24/2022]
Abstract
Neuromodulation regulates critical functions of CNS synapses, ranging from neural circuit development to high-order cognitive processes, including learning and memory. This broad scope of action is generally mediated through alterations of the strength of synaptic transmission (i.e. synaptic plasticity). Changes in synaptic strength are widely considered to be a cellular representation of learned information. Noradrenaline is a neuromodulator that is secreted throughout the brain in response to novelty or increased arousal. Once released, noradrenaline activates metabotropic receptors, initiating intracellular signaling cascades that promote enduring changes in synaptic strength and facilitate memory storage. Here, we provide an overview of noradrenergic modulation of synaptic plasticity and memory formation within mammalian neural circuits, which has broad applicability within the neurotherapeutics community. Advances in our understanding of noradrenaline in the context of these processes may provide a foundation for refining treatment strategies for multiple brain diseases, ranging from post-traumatic stress disorder to Alzheimer's Disease.
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Affiliation(s)
- Peter V Nguyen
- Department of Physiology, University of Alberta School of Medicine, Edmonton, AB, T6G 2H7, Canada
| | - Steven A Connor
- Department of Biology, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada
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23
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Stevens L, Vonck K, Larsen LE, Van Lysebettens W, Germonpré C, Baekelandt V, Van den Haute C, Carrette E, Wadman WJ, Boon P, Raedt R. A Feasibility Study to Investigate Chemogenetic Modulation of the Locus Coeruleus by Means of Single Unit Activity. Front Neurosci 2020; 14:162. [PMID: 32210746 PMCID: PMC7067893 DOI: 10.3389/fnins.2020.00162] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 02/12/2020] [Indexed: 11/13/2022] Open
Abstract
Aim Selective chemogenetic modulation of locus coeruleus (LC) neurons would allow dedicated investigation of the role of the LC-NA pathway in brain excitability and disorders such as epilepsy. This study investigated the feasibility of an experimental set-up where chemogenetic modification of the brainstem locus coeruleus NA neurons is aimed at and followed by LC unit activity recording in response to clozapine. Methods The LC of male Sprague-Dawley rats was injected with 10 nl of adeno-associated viral vector AAV2/7-PRSx8-hM3Dq-mCherry (n = 19, DREADD group) or AAV2/7-PRSx8-eGFP (n = 13, Controls). Three weeks later, LC unit recordings were performed in anesthetized rats. We investigated whether clozapine, a drug known to bind to modified neurons expressing hM3Dq receptors, was able to increase the LC firing rate. Baseline unit activity was recorded followed by subsequent administration of 0.01 and 0.1 mg/kg of clozapine in all rats. hM3Dq-mcherry expression levels were investigated using immunofluorescence staining of brainstem slices at the end of the experiment. Results Unit recordings could be performed in 12 rats and in a total of 12 neurons (DREADDs: n = 7, controls: n = 5). Clozapine 0.01 mg/kg did not affect the mean firing rate of recorded LC-neurons; 0.1 mg/kg induced an increased firing rate, irrespective whether neurons were recorded from DREADD or control rats (p = 0.006). Co-labeling of LC neurons and mCherry-tag showed that 20.6 ± 2.3% LC neurons expressed the hM3Dq receptor. Aspecific expression of hM3Dq-mCherry was also observed in non-LC neurons (26.0 ± 4.1%). Conclusion LC unit recording is feasible in an experimental set-up following manipulations for DREADD induction. A relatively low transduction efficiency of the used AAV was found. In view of this finding, the effect of injected clozapine on LC-NA could not be investigated as a reliable outcome parameter for activation of chemogenetically modified LC neurons. The use of AAV2/7, a vector previously applied successfully to target dopaminergic neurons in the substantia nigra, leads to insufficient chemogenetic modification of the LC compared to transduction with AAV2/9.
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Affiliation(s)
- Latoya Stevens
- 4BRAIN, Institute for Neuroscience, Department of Neurology, Ghent University, Ghent, Belgium
| | - Kristl Vonck
- 4BRAIN, Institute for Neuroscience, Department of Neurology, Ghent University, Ghent, Belgium
| | - Lars Emil Larsen
- 4BRAIN, Institute for Neuroscience, Department of Neurology, Ghent University, Ghent, Belgium
| | - Wouter Van Lysebettens
- 4BRAIN, Institute for Neuroscience, Department of Neurology, Ghent University, Ghent, Belgium
| | - Charlotte Germonpré
- 4BRAIN, Institute for Neuroscience, Department of Neurology, Ghent University, Ghent, Belgium
| | - Veerle Baekelandt
- Laboratory for Neurobiology and Gene Therapy, Center for Molecular Medicine, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Chris Van den Haute
- Laboratory for Neurobiology and Gene Therapy, Center for Molecular Medicine, Leuven Brain Institute, KU Leuven, Leuven, Belgium.,Leuven Viral Vector Core, Centre for Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Evelien Carrette
- 4BRAIN, Institute for Neuroscience, Department of Neurology, Ghent University, Ghent, Belgium
| | - Wytse Jan Wadman
- 4BRAIN, Institute for Neuroscience, Department of Neurology, Ghent University, Ghent, Belgium
| | - Paul Boon
- 4BRAIN, Institute for Neuroscience, Department of Neurology, Ghent University, Ghent, Belgium
| | - Robrecht Raedt
- 4BRAIN, Institute for Neuroscience, Department of Neurology, Ghent University, Ghent, Belgium
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24
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Brandwein NJ, Nguyen PV. A requirement for epigenetic modifications during noradrenergic stabilization of heterosynaptic LTP in the hippocampus. Neurobiol Learn Mem 2019; 161:72-82. [PMID: 30930287 DOI: 10.1016/j.nlm.2019.03.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 03/22/2019] [Accepted: 03/27/2019] [Indexed: 12/31/2022]
Abstract
Beta-adrenergic receptor (b-AR) activation by noradrenaline (NA) enhances memory formation and long-term potentiation (LTP), a form of synaptic plasticity characterized by an activity-dependent increase in synaptic strength. LTP is believed to be a cellular mechanism for contextual learning and memory. In the mammalian hippocampus, LTP can be observed at multiple synaptic pathways after strong stimulation of a single synaptic pathway. This heterosynaptic LTP is believed to involve synaptic tagging of active synapses and capture of plasticity-related proteins that enable heterosynaptic transfer of persistent potentiation. These processes may permit distinct neural pathways to associate information transmitted by separate, but convergent, synaptic inputs. We had previously shown that transcription and epigenetic modifications were necessary for stabilization of homosynaptic LTP. However, it is unclear whether transfer of LTP to a second, heterosynaptic pathway involves b-ARs signalling to the nucleus. Using electrophysiologic recordings in area CA1 of murine hippocampal slices, we show here that pharmacologically inhibiting b-AR activation, transcription, DNA methyltransferase or histone acetyltransferase activation, prevents stabilization of heterosynaptic LTP. Our data suggest that noradrenergic stabilization of heterosynaptic ("tagged") LTP requires not only transcription, but specifically, DNA methylation and histone acetylation. NA promotes stable heterosynaptic plasticity through engagement of nuclear processes that may contribute to prompt consolidation of short-term memories into resilient long-term memories under conditions when the brain's noradrenergic system is recruited.
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Affiliation(s)
- N J Brandwein
- Department of Physiology, University of Alberta School of Medicine, Edmonton, Alberta T6G 2H7, Canada
| | - P V Nguyen
- Department of Physiology, University of Alberta School of Medicine, Edmonton, Alberta T6G 2H7, Canada.
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25
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Quinlan MAL, Strong VM, Skinner DM, Martin GM, Harley CW, Walling SG. Locus Coeruleus Optogenetic Light Activation Induces Long-Term Potentiation of Perforant Path Population Spike Amplitude in Rat Dentate Gyrus. Front Syst Neurosci 2019; 12:67. [PMID: 30687027 PMCID: PMC6333706 DOI: 10.3389/fnsys.2018.00067] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 12/12/2018] [Indexed: 12/16/2022] Open
Abstract
Norepinephrine (NE) in dentate gyrus (DG) produces NE-dependent long-term potentiation (NE-LTP) of the perforant path-evoked potential population spike both in vitro and in vivo. Chemical activators infused near locus coeruleus (LC), the source of DG NE, produce a NE-LTP that is associative, i.e., requires concurrent pairing with perforant path (PP) input. Here, we ask if LC optogenetic stimulation that allows us to activate only LC neurons can induce NE-LTP in DG. We use an adeno-associated viral vector containing a depolarizing channel (AAV8-Ef1a-DIO-eChR2(h134r)-EYFP-WPRE) infused stereotaxically into the LC of TH:Cre rats to produce light-sensitive LC neurons. A co-localization of ~62% in LC neurons was observed for these channels. Under urethane anesthesia, we demonstrated that 5-10 s 10 Hz trains of 30 ms light pulses in LC reliably activated neurons near an LC optoprobe. Ten minutes of the same train paired with 0.1 Hz PP electrical stimulation produced a delayed NE-LTP of population spike amplitude, but not EPSP slope. A leftward shift in the population spike input/output curve at the end of the experiment was also consistent with long-term population spike potentiation. LC neuron activity during the 10 min light train was unexpectedly transient. Increased LC neuronal firing was seen only for the first 2 min of the light train. NE-LTP was more delayed and less robust than reported with LC chemo-activation. Previous estimates of LC axonal conduction times suggest acute release of NE occurs 40-70 ms after an LC neuron action potential. We used single LC light pulses to examine acute effects of NE release and found potentiated population spike amplitude when a light pulse in LC occurred 40-50 ms, but not 20-30 ms, prior to a PP pulse, consistent with conduction estimates. These effects of LC optogenetic activation reinforce evidence for a continuum of NE potentiation effects in DG. The single pulse effects mirror an earlier report using LC electrical stimulation. These acute effects support an attentional role of LC activation. The LTP of PP responses induced by optogenetic LC activation is consistent with the role of LC in long-term learning and memory.
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Affiliation(s)
| | | | | | | | - Carolyn W. Harley
- Behavioural Neuroscience Group, Department of Psychology, Memorial University of Newfoundland, St. John’s, NL, Canada
| | - Susan G. Walling
- Behavioural Neuroscience Group, Department of Psychology, Memorial University of Newfoundland, St. John’s, NL, Canada
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26
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Locus Coeruleus Phasic, But Not Tonic, Activation Initiates Global Remapping in a Familiar Environment. J Neurosci 2018; 39:445-455. [PMID: 30478033 DOI: 10.1523/jneurosci.1956-18.2018] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 11/13/2018] [Accepted: 11/16/2018] [Indexed: 12/16/2022] Open
Abstract
Locus coeruleus (LC) neurons, the source of hippocampal norepinephrine (NE), are activated by novelty and changes in environmental contingencies. Based on the role of monoamines in reconfiguring invertebrate networks, and data from mammalian systems, a network reset hypothesis for the effects of LC activation has been proposed. We used the cellular compartmental analysis of temporal FISH technique based on the cellular distribution of immediate early genes to examine the effect of LC activation and inactivation, on regional hippocampal maps in male rats, when LC activity was manipulated just before placement in a second familiar (A/A) and/or novel environment (A/B). We found that bilateral phasic, but not tonic, activation of LC reset hippocampal maps in the A/A condition, whereas silencing the LC with clonidine before placement in the A/B condition blocked map reset and a familiar map emerged in the dentate gyrus, proximal and distal CA1, and CA3c. However, CA3a and CA3b encoded the novel environment. These results support a role for phasic LC responses in generating novel hippocampal sequences during memory encoding and, potentially, memory updating. The silencing experiments suggest that novel environments may not be recognized as different by dentate gyrus and CA1 without LC input. The functional distinction between phasic and tonic LC activity argues that these parameters are critical for determining network changes. These data are consistent with the hippocampus activating internal network representations to encode novel experiential episodes and suggest LC input is critical for this role.SIGNIFICANCE STATEMENT Burst activation of the broadly projecting novelty signaling system of the locus coeruleus initiates new network representations throughout the hippocampus despite unchanged external environments. Tonic activation does not alter network representations in the same condition. This suggests differences in the temporal parameters of neuromodulator network activation are critical for neuromodulator function. Silencing this novelty signaling system prevented the appearance of new network representations in a novel environment. Instead, familiar representations were expressed in a subset of hippocampal areas, with another subset encoding the novel environment. This "being in two places at once" argues for independent functional regions within the hippocampus. These experiments strengthen the view that internal states are major determinants of the brain's construction of environmental representations.
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Xiao LY, Wang XR, Yang JW, Ye Y, Zhu W, Cao Y, Ma SM, Liu CZ. Acupuncture Prevents the Impairment of Hippocampal LTP Through β1-AR in Vascular Dementia Rats. Mol Neurobiol 2018; 55:7677-7690. [PMID: 29435917 DOI: 10.1007/s12035-018-0943-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Accepted: 01/29/2018] [Indexed: 02/06/2023]
Abstract
It is widely accepted that the synaptic dysfunction and synapse loss contribute to the cognitive deficits of vascular dementia (VD) patients. We have previously reported that acupuncture improved cognitive function in rats with VD. However, the mechanisms involved in acupuncture improving cognitive ability remain to be elucidated. The present study aims to investigate the pathways and molecules involved in the neuroprotective effect of acupuncture. We assessed the effects of acupuncture on hippocampal long-term potentiation (LTP), the most prominent cellular model of memory formation. Acupuncture enhanced LTP and norepinephrine (NE) levels in the hippocampus. Inhibition of the β-adrenergic receptor (AR), but not the α-AR, was able to block the effects of acupuncture on hippocampal LTP. Furthermore, inhibition of β1-AR, not β2-AR, abolished the enhanced LTP induced by acupuncture. The expression analysis revealed a significant upregulation of β1-AR and unchanged β2-AR with acupuncture, which supported the above findings. Specifically, increased β1-ARs in the dentate gyrus were expressed on neurons exclusively. Taken together, the present data supports a beneficial role of acupuncture in synaptic plasticity challenged with VD. A likely mechanism is the increase of NE and activation of β1-AR in the hippocampus.
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Affiliation(s)
- Ling-Yong Xiao
- Department of Acupuncture and Moxibustion, Beijing Hospital of Traditional Chinese Medicine affiliated to Capital Medical University, 23 Meishuguanhou Street, Dongcheng District, Beijing, China
- Department of Acupuncture and Moxibustion, Dongfang Hospital, Beijing University of Chinese Medicine, No. 6 Fangxingyuan 1st Block, Fengtai District, Beijing, 100078, China
| | - Xue-Rui Wang
- Beijing Institute of Traditional Chinese Medicine, Beijing Hospital of Traditional Chinese Medicine affiliated to Capital Medical University, 23 Meishuguanhou Street, Dongcheng District, Beijing, China
| | - Jing-Wen Yang
- Department of Acupuncture and Moxibustion, Beijing Hospital of Traditional Chinese Medicine affiliated to Capital Medical University, 23 Meishuguanhou Street, Dongcheng District, Beijing, China
| | - Yang Ye
- Department of Acupuncture and Moxibustion, Dongfang Hospital, Beijing University of Chinese Medicine, No. 6 Fangxingyuan 1st Block, Fengtai District, Beijing, 100078, China
| | - Wen Zhu
- Department of Acupuncture and Moxibustion, Beijing Hospital of Traditional Chinese Medicine affiliated to Capital Medical University, 23 Meishuguanhou Street, Dongcheng District, Beijing, China
| | - Yan Cao
- Department of Acupuncture and Moxibustion, Beijing Hospital of Traditional Chinese Medicine affiliated to Capital Medical University, 23 Meishuguanhou Street, Dongcheng District, Beijing, China
| | - Si-Ming Ma
- Department of Acupuncture and Moxibustion, Beijing Hospital of Traditional Chinese Medicine affiliated to Capital Medical University, 23 Meishuguanhou Street, Dongcheng District, Beijing, China
| | - Cun-Zhi Liu
- Department of Acupuncture and Moxibustion, Dongfang Hospital, Beijing University of Chinese Medicine, No. 6 Fangxingyuan 1st Block, Fengtai District, Beijing, 100078, China.
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Cellular Receptors of Amyloid β Oligomers (AβOs) in Alzheimer's Disease. Int J Mol Sci 2018; 19:ijms19071884. [PMID: 29954063 PMCID: PMC6073792 DOI: 10.3390/ijms19071884] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 06/19/2018] [Accepted: 06/22/2018] [Indexed: 12/15/2022] Open
Abstract
It is estimated that Alzheimer’s disease (AD) affects tens of millions of people, comprising not only suffering patients, but also their relatives and caregivers. AD is one of age-related neurodegenerative diseases (NDs) characterized by progressive synaptic damage and neuronal loss, which result in gradual cognitive impairment leading to dementia. The cause of AD remains still unresolved, despite being studied for more than a century. The hallmark pathological features of this disease are senile plaques within patients’ brain composed of amyloid beta (Aβ) and neurofibrillary tangles (NFTs) of Tau protein. However, the roles of Aβ and Tau in AD pathology are being questioned and other causes of AD are postulated. One of the most interesting theories proposed is the causative role of amyloid β oligomers (AβOs) aggregation in the pathogenesis of AD. Moreover, binding of AβOs to cell membranes is probably mediated by certain proteins on the neuronal cell surface acting as AβO receptors. The aim of our paper is to describe alternative hypotheses of AD etiology, including genetic alterations and the role of misfolded proteins, especially Aβ oligomers, in Alzheimer’s disease. Furthermore, in this review we present various putative cellular AβO receptors related to toxic activity of oligomers.
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Activation of β-adrenoceptor facilitates active avoidance learning through enhancement of glutamate levels in the hippocampal dentate gyrus. Neuroreport 2017; 28:973-979. [DOI: 10.1097/wnr.0000000000000868] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Prince LY, Bacon TJ, Tigaret CM, Mellor JR. Neuromodulation of the Feedforward Dentate Gyrus-CA3 Microcircuit. Front Synaptic Neurosci 2016; 8:32. [PMID: 27799909 PMCID: PMC5065980 DOI: 10.3389/fnsyn.2016.00032] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 09/20/2016] [Indexed: 12/16/2022] Open
Abstract
The feedforward dentate gyrus-CA3 microcircuit in the hippocampus is thought to activate ensembles of CA3 pyramidal cells and interneurons to encode and retrieve episodic memories. The creation of these CA3 ensembles depends on neuromodulatory input and synaptic plasticity within this microcircuit. Here we review the mechanisms by which the neuromodulators aceylcholine, noradrenaline, dopamine, and serotonin reconfigure this microcircuit and thereby infer the net effect of these modulators on the processes of episodic memory encoding and retrieval.
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Affiliation(s)
- Luke Y Prince
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol Bristol, UK
| | - Travis J Bacon
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol Bristol, UK
| | - Cezar M Tigaret
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol Bristol, UK
| | - Jack R Mellor
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol Bristol, UK
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Daulatzai MA. Dysfunctional Sensory Modalities, Locus Coeruleus, and Basal Forebrain: Early Determinants that Promote Neuropathogenesis of Cognitive and Memory Decline and Alzheimer’s Disease. Neurotox Res 2016; 30:295-337. [DOI: 10.1007/s12640-016-9643-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 06/08/2016] [Accepted: 06/10/2016] [Indexed: 12/22/2022]
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Davoudi M, Azizi H, Mirnajafi-Zadeh J, Semnanian S. The blockade of GABAA receptors attenuates the inhibitory effect of orexin type 1 receptors antagonist on morphine withdrawal syndrome in rats. Neurosci Lett 2016; 617:201-6. [DOI: 10.1016/j.neulet.2016.02.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 02/09/2016] [Accepted: 02/10/2016] [Indexed: 11/25/2022]
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Robinson AM, Buttolph T, Green JT, Bucci DJ. Physical exercise affects attentional orienting behavior through noradrenergic mechanisms. Behav Neurosci 2016; 129:361-7. [PMID: 26030434 DOI: 10.1037/bne0000054] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Spontaneously hypertensive rats (SHRs), a commonly used animal model of attention-deficit/hyperactivity disorder, exhibit little habituation of the orienting response to repeated presentations of a nonreinforced visual stimulus. However, SHRs that have access to a running wheel for 5, 10, or 21 days exhibit robust habituation that is indistinguishable from normo-active rats. Two days of exercise, in comparison, is not sufficient to affect habituation. Here we tested the hypothesis that the effect of exercise on orienting behavior in SHRs is mediated by changes in noradrenergic function. In Experiment 1, we found that 5, 10, or 21 days of access to a running wheel, but not 2 days, significantly reduced levels of the norepinephrine transporter in medial prefrontal cortex. In Experiment 2, we tested for a causal relationship between changes in noradrenergic function and orienting behavior by blocking noradrenergic receptors during exercise. Rats that received propranolol (beta adrenergic/noradrenergic receptor blocker) during 10 days of exercise failed to exhibit an exercise-induced reduction in orienting behavior. The results inform a growing literature regarding the effects of exercise on behavior and the potential use of exercise as a treatment for mental disorders.
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Affiliation(s)
| | - Thomas Buttolph
- Department of Neurological Sciences, College of Medicine, University of Vermont
| | - John T Green
- Department of Neurological Sciences, College of Medicine, University of Vermont
| | - David J Bucci
- Department of Psychological and Brain Sciences, Dartmouth College
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Hagena H, Hansen N, Manahan-Vaughan D. β-Adrenergic Control of Hippocampal Function: Subserving the Choreography of Synaptic Information Storage and Memory. Cereb Cortex 2016; 26:1349-64. [PMID: 26804338 PMCID: PMC4785955 DOI: 10.1093/cercor/bhv330] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Noradrenaline (NA) is a key neuromodulator for the regulation of behavioral state and cognition. It supports learning by increasing arousal and vigilance, whereby new experiences are “earmarked” for encoding. Within the hippocampus, experience-dependent information storage occurs by means of synaptic plasticity. Furthermore, novel spatial, contextual, or associative learning drives changes in synaptic strength, reflected by the strengthening of long-term potentiation (LTP) or long-term depression (LTD). NA acting on β-adrenergic receptors (β-AR) is a key determinant as to whether new experiences result in persistent hippocampal synaptic plasticity. This can even dictate the direction of change of synaptic strength. The different hippocampal subfields play different roles in encoding components of a spatial representation through LTP and LTD. Strikingly, the sensitivity of synaptic plasticity in these subfields to β-adrenergic control is very distinct (dentate gyrus > CA3 > CA1). Moreover, NA released from the locus coeruleus that acts on β-AR leads to hippocampal LTD and an enhancement of LTD-related memory processing. We propose that NA acting on hippocampal β-AR, that is graded according to the novelty or saliency of the experience, determines the content and persistency of synaptic information storage in the hippocampal subfields and therefore of spatial memories.
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Affiliation(s)
- Hardy Hagena
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Niels Hansen
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
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The effects of prolonged administration of norepinephrine reuptake inhibitors on long-term potentiation in dentate gyrus, and on tests of spatial and object recognition memory in rats. Neurobiol Learn Mem 2016; 128:92-102. [PMID: 26774023 DOI: 10.1016/j.nlm.2015.12.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 12/16/2015] [Accepted: 12/30/2015] [Indexed: 11/23/2022]
Abstract
Phasic norepinephrine (NE) release events are involved in arousal, novelty detection and in plasticity processes underlying learning and memory in mammalian systems. Although the effects of phasic NE release events on plasticity and memory are prevalently documented, it is less understood what effects chronic NE reuptake inhibition and sustained increases in noradrenergic tone, might have on plasticity and cognitive processes in rodent models of learning and memory. This study investigates the effects of chronic NE reuptake inhibition on hippocampal plasticity and memory in rats. Rats were administered NE reuptake inhibitors (NRIs) desipramine (DMI; 0, 3, or 7.5mg/kg/day) or nortriptyline (NTP; 0, 10 or 20mg/kg/day) in drinking water. Long-term potentiation (LTP; 200 Hz) of the perforant path-dentate gyrus evoked potential was examined in urethane anesthetized rats after 30-32 days of DMI treatment. Short- (4-h) and long-term (24-h) spatial memory was tested in separate rats administered 0 or 7.5mg/kg/day DMI (25-30 days) using a two-trial spatial memory test. Additionally, the effects of chronically administered DMI and NTP were tested in rats using a two-trial, Object Recognition Test (ORT) at 2- and 24-h after 45 and 60 days of drug administration. Rats administered 3 or 7.5mg/kg/day DMI had attenuated LTP of the EPSP slope but not the population spike at the perforant path-dentate gyrus synapse. Short- and long-term memory for objects is differentially disrupted in rats after prolonged administration of DMI and NTP. Rats that were administered 7.5mg/kg/day DMI showed decreased memory for a two-trial spatial task when tested at 4-h. In the novel ORT, rats receiving 0 or 7.5mg/kg/day DMI showed a preference for the arm containing a Novel object when tested at both 2- and 24-h demonstrating both short- and long-term memory retention of the Familiar object. Rats that received either dose of NTP or 3mg/kg/day DMI showed impaired memory at 2-h, however this impairment was largely reversed at 24-h. Animals in the high-dose NTP (20mg/kg/day) group were impaired at both short- and long-term intervals. Activity levels, used as an index of location memory during the ORT, demonstrated that rats receiving DMI were again impaired at retaining memory for location. DMI dose-dependently disrupts LTP in the dentate gyrus of anesthetized rats and also disrupts memory for tests of spatial memory when administered for long periods.
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Maity S, Jarome TJ, Blair J, Lubin FD, Nguyen PV. Noradrenaline goes nuclear: epigenetic modifications during long-lasting synaptic potentiation triggered by activation of β-adrenergic receptors. J Physiol 2015; 594:863-81. [PMID: 26574176 DOI: 10.1113/jp271432] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 10/23/2015] [Indexed: 12/27/2022] Open
Abstract
KEY POINTS Transcription is recruited by noradrenaline in the hippocampus. Epigenetic mechanisms are recruited by hippocampal noradrenergic receptor activation. Epigenetic regulation by noradrenaline offers a novel mechanism for long-term potentiation ABSTRACT Noradrenaline (NA) is a neuromodulator that can effect long-lasting changes in synaptic strength such as long-term potentiation (LTP), a putative cellular mechanism for memory formation in the mammalian brain. Persistent LTP requires alterations in gene expression that may involve epigenetic mechanisms such as DNA methylation, histone acetylation and histone phosphorylation. It is known that β-adrenergic receptors and NA can boost LTP maintenance by regulating translation. However, it is unclear whether NA can additionally engage epigenetic mechanisms to regulate transcription and boost LTP endurance. To address this issue, we probed NA-treated mouse hippocampal slices with pharmacological inhibitors targeting epigenetic regulatory pathways and discovered that NA activates β-adrenergic receptors to boost LTP maintenance in area CA1 through DNA methylation and post-translational histone modifications. Specifically, NA paired with 100 Hz stimulation enhanced histone H3 acetylation and phosphorylation, both of which were required for NA-induced boosting of LTP maintenance. Together, our findings identify NA as a neuromodulatory transmitter capable of triggering epigenetic, transcriptional control of genes required for establishing persistent LTP in the mouse hippocampus. These modifications may contribute to the stabilization of memory.
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Affiliation(s)
- Sabyasachi Maity
- Department of Physiology, University of Alberta School of Medicine, Edmonton, AB, T6G 2H7, Canada
| | - Timothy J Jarome
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Jessica Blair
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Farah D Lubin
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.,Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Peter V Nguyen
- Department of Physiology, University of Alberta School of Medicine, Edmonton, AB, T6G 2H7, Canada.,Department of Psychiatry, University of Alberta School of Medicine, Edmonton, AB, T6G 2H7, Canada.,Neuroscience and Mental Health Institute, University of Alberta School of Medicine, Edmonton, AB, T6G 2H7, Canada
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Simone J, Bogue EA, Bhatti DL, Day LE, Farr NA, Grossman AM, Holmes PV. Ethinyl estradiol and levonorgestrel alter cognition and anxiety in rats concurrent with a decrease in tyrosine hydroxylase expression in the locus coeruleus and brain-derived neurotrophic factor expression in the hippocampus. Psychoneuroendocrinology 2015; 62:265-78. [PMID: 26352480 DOI: 10.1016/j.psyneuen.2015.08.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 08/18/2015] [Accepted: 08/18/2015] [Indexed: 12/31/2022]
Abstract
In the United States, more than ten million women use contraceptive hormones. Ethinyl estradiol and levonorgestrel have been mainstay contraceptive hormones for the last four decades. Surprisingly, there is scant information regarding their action on the central nervous system and behavior. Intact female rats received three weeks of subcutaneous ethinyl estradiol (10 or 30μg/rat/day), levonorgestrel (20 or 60μg/rat/day), a combination of both (10/20μg/rat/day and 30/60μg/rat/day), or vehicle. Subsequently, the rats were tested in three versions of the novel object recognition test to assess learning and memory, and a battery of tests for anxiety-like behavior. Serum estradiol and ovarian weights were measured. All treatment groups exhibited low endogenous 17β-estradiol levels at the time of testing. Dose-dependent effects of drug treatment manifested in both cognitive and anxiety tests. All low dose drugs decreased anxiety-like behavior and impaired performance on novel object recognition. In contrast, the high dose ethinyl estradiol increased anxiety-like behavior and improved performance in cognitive testing. In the cell molecular analyses, low doses of all drugs induced a decrease in tyrosine hydroxylase mRNA and protein in the locus coeruleus. At the same time, low doses of ethinyl estradiol and ethinyl estradiol/levonorgestrel increased galanin protein in this structure. Consistent with the findings above, the low dose treatments of ethinyl estradiol and combination ethinyl estradiol/levonorgestrel reduced brain-derived neurotrophic factor mRNA in the hippocampus. These effects of ethinyl estradiol 10μg alone and in combination with levonorgestrel 20μg suggest a diminution of norepinephrine input into the hippocampus resulting in a decline in learning and memory.
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Affiliation(s)
- Jean Simone
- Neuroscience, Biomedical and Health Sciences Institute, University of Georgia, 150 Paul D. Coverdell Center, Athens, GA 30602, USA.
| | - Elizabeth A Bogue
- Neuroscience, Biomedical and Health Sciences Institute, University of Georgia, 150 Paul D. Coverdell Center, Athens, GA 30602, USA.
| | - Dionnet L Bhatti
- Neuroscience, Biomedical and Health Sciences Institute, University of Georgia, 150 Paul D. Coverdell Center, Athens, GA 30602, USA.
| | - Laura E Day
- Neuroscience, Biomedical and Health Sciences Institute, University of Georgia, 150 Paul D. Coverdell Center, Athens, GA 30602, USA.
| | - Nathan A Farr
- Neuroscience, Biomedical and Health Sciences Institute, University of Georgia, 150 Paul D. Coverdell Center, Athens, GA 30602, USA.
| | - Anna M Grossman
- Neuroscience, Biomedical and Health Sciences Institute, University of Georgia, 150 Paul D. Coverdell Center, Athens, GA 30602, USA.
| | - Philip V Holmes
- Neuroscience, Biomedical and Health Sciences Institute, University of Georgia, 150 Paul D. Coverdell Center, Athens, GA 30602, USA; Psychology, University of Georgia, 125 Baldwin Street, Athens, GA 30602, USA.
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Maity S, Rah S, Sonenberg N, Gkogkas CG, Nguyen PV. Norepinephrine triggers metaplasticity of LTP by increasing translation of specific mRNAs. ACTA ACUST UNITED AC 2015; 22:499-508. [PMID: 26373828 PMCID: PMC4579357 DOI: 10.1101/lm.039222.115] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 06/30/2015] [Indexed: 12/24/2022]
Abstract
Norepinephrine (NE) is a key modulator of synaptic plasticity in the hippocampus, a brain structure crucially involved in memory formation. NE boosts synaptic plasticity mostly through initiation of signaling cascades downstream from beta (β)-adrenergic receptors (β-ARs). Previous studies demonstrated that a β-adrenergic receptor agonist, isoproterenol, can modify the threshold for long-term potentiation (LTP), a putative cellular mechanism for learning and memory, in a process known as “metaplasticity.” Metaplasticity is the ability of synaptic plasticity to be modified by prior experience. We asked whether NE itself could engage metaplastic mechanisms in area CA1 of mouse hippocampal slices. Using extracellular field potential recording and stimulation, we show that application of NE (10 µM), which did not alter basal synaptic strength, enhances the future maintenance of LTP elicited by subthreshold, high-frequency stimulation (HFS: 1 × 100 Hz, 1 sec). HFS applied 30 min after NE washout induced long-lasting (>4 h) LTP, which was significantly extended in duration relative to HFS alone. This NE-induced metaplasticity required β1-AR activation, as coapplication of the β1-receptor antagonist CGP-20712A (1 µM) attenuated maintenance of LTP. We also found that NE-mediated metaplasticity was translation- and transcription-dependent. Polysomal profiles of CA1 revealed increased translation rates for specific mRNAs during NE-induced metaplasticity. Thus, activation of β-ARs by NE primes synapses for future long-lasting plasticity on time scales extending beyond fast synaptic transmission; this may facilitate neural information processing and the subsequent formation of lasting memories.
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Affiliation(s)
- Sabyasachi Maity
- Department of Physiology, University of Alberta School of Medicine, Edmonton, Alberta T6G 2H7, Canada
| | - Sean Rah
- Department of Physiology, University of Alberta School of Medicine, Edmonton, Alberta T6G 2H7, Canada
| | - Nahum Sonenberg
- Department of Biochemistry, Goodman Cancer Centre, McGill University, Montreal, Quebec H3A 1A3, Canada
| | - Christos G Gkogkas
- Patrick Wild Centre and Centre for Integrative Biology, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
| | - Peter V Nguyen
- Department of Physiology, University of Alberta School of Medicine, Edmonton, Alberta T6G 2H7, Canada Department of Psychiatry, University of Alberta School of Medicine, Edmonton, Alberta T6G 2H7, Canada Neuroscience and Mental Health Institute, University of Alberta School of Medicine, Edmonton, Alberta T6G 2H7, Canada
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Stepan J, Dine J, Eder M. Functional optical probing of the hippocampal trisynaptic circuit in vitro: network dynamics, filter properties, and polysynaptic induction of CA1 LTP. Front Neurosci 2015; 9:160. [PMID: 25999809 PMCID: PMC4422028 DOI: 10.3389/fnins.2015.00160] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 04/19/2015] [Indexed: 12/21/2022] Open
Abstract
Decades of brain research have identified various parallel loops linking the hippocampus with neocortical areas, enabling the acquisition of spatial and episodic memories. Especially the hippocampal trisynaptic circuit [entorhinal cortex layer II → dentate gyrus (DG) → cornu ammonis (CA)-3 → CA1] was studied in great detail because of its seemingly simple connectivity and characteristic structures that are experimentally well accessible. While numerous researchers focused on functional aspects, obtained from a limited number of cells in distinct hippocampal subregions, little is known about the neuronal network dynamics which drive information across multiple synapses for subsequent long-term storage. Fast voltage-sensitive dye imaging in vitro allows real-time recording of activity patterns in large/meso-scale neuronal networks with high spatial resolution. In this way, we recently found that entorhinal theta-frequency input to the DG most effectively passes filter mechanisms of the trisynaptic circuit network, generating activity waves which propagate across the entire DG-CA axis. These "trisynaptic circuit waves" involve high-frequency firing of CA3 pyramidal neurons, leading to a rapid induction of classical NMDA receptor-dependent long-term potentiation (LTP) at CA3-CA1 synapses (CA1 LTP). CA1 LTP has been substantially evidenced to be essential for some forms of explicit learning in mammals. Here, we review data with particular reference to whole network-level approaches, illustrating how activity propagation can take place within the trisynaptic circuit to drive formation of CA1 LTP.
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Affiliation(s)
- Jens Stepan
- Department Stress Neurobiology and Neurogenetics, Max Planck Institute of PsychiatryMunich, Germany
| | | | - Matthias Eder
- Department Stress Neurobiology and Neurogenetics, Max Planck Institute of PsychiatryMunich, Germany
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40
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Hansen N, Manahan-Vaughan D. Hippocampal long-term potentiation that is elicited by perforant path stimulation or that occurs in conjunction with spatial learning is tightly controlled by beta-adrenoreceptors and the locus coeruleus. Hippocampus 2015; 25:1285-98. [PMID: 25727388 PMCID: PMC6680149 DOI: 10.1002/hipo.22436] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/20/2015] [Indexed: 11/19/2022]
Abstract
The noradrenergic system, driven by locus coeruleus (LC) activation, plays a key role in the regulating and directing of changes in hippocampal synaptic efficacy. The LC releases noradrenaline in response to novel experience and LC activation leads to an enhancement of hippocampus‐based learning, and facilitates synaptic plasticity in the form of long‐term depression (LTD) and long‐term potentiation (LTP) that occur in association with spatial learning. The predominant receptor for mediating these effects is the β‐adrenoreceptor. Interestingly, the dependency of synaptic plasticity on this receptor is different in the hippocampal subfields whereby in the CA1 in vivo, LTP, but not LTD requires β‐adrenoreceptor activation, whereas in the mossy fiber synapse LTP and LTD do not depend on this receptor. By contrast, synaptic plasticity that is facilitated by spatial learning is highly dependent on β‐adrenoreceptor activation in both hippocampal subfields. Here, we explored whether LTP induced by perforant‐path (pp) stimulation in vivo or that is facilitated by spatial learning depends on β‐adrenoreceptors. We found that under both LTP conditions, antagonising the receptors disabled the persistence of LTP. β‐adrenoreceptor‐antagonism also prevented spatial learning. Strikingly, activation of the LC before high‐frequency stimulation (HFS) of the pp prevented short‐term potentiation but not LTP, and LC stimulation after pp‐HFS‐induced depotentiation of LTP. This depotentiation was prevented by β‐adrenoreceptor‐antagonism. These data suggest that β‐adrenoreceptor‐activation, resulting from noradrenaline release from the LC during enhanced arousal and learning, comprises a mechanism whereby the duration and degree of LTP is regulated and fine tuned. This may serve to optimize the creation of a spatial memory engram by means of LTP and LTD. This process can be expected to support the special role of the dentate gyrus as a crucial subregional locus for detecting and processing novelty within the hippocampus. © 2015 The Authors Hippocampus Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Niels Hansen
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
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41
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Bhagya V, Srikumar B, Raju T, Shankaranarayana Rao B. The selective noradrenergic reuptake inhibitor reboxetine restores spatial learning deficits, biochemical changes, and hippocampal synaptic plasticity in an animal model of depression. J Neurosci Res 2014; 93:104-20. [DOI: 10.1002/jnr.23473] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 07/07/2014] [Accepted: 07/24/2014] [Indexed: 12/21/2022]
Affiliation(s)
- V. Bhagya
- Department of Neurophysiology; National Institute of Mental Health and Neuro Sciences; Bangalore India
| | - B.N. Srikumar
- Department of Neurophysiology; National Institute of Mental Health and Neuro Sciences; Bangalore India
| | - T.R. Raju
- Department of Neurophysiology; National Institute of Mental Health and Neuro Sciences; Bangalore India
| | - B.S. Shankaranarayana Rao
- Department of Neurophysiology; National Institute of Mental Health and Neuro Sciences; Bangalore India
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Branca C, Wisely EV, Hartman LK, Caccamo A, Oddo S. Administration of a selective β2 adrenergic receptor antagonist exacerbates neuropathology and cognitive deficits in a mouse model of Alzheimer's disease. Neurobiol Aging 2014; 35:2726-2735. [PMID: 25034342 DOI: 10.1016/j.neurobiolaging.2014.06.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 05/29/2014] [Accepted: 06/10/2014] [Indexed: 01/23/2023]
Abstract
Currently, there are no available approaches to cure or slow down the progression of Alzheimer's disease (AD), which is characterized by the accumulation of extracellular amyloid-β (Aβ) deposits and intraneuronal tangles that comprised hyperphosphorylated tau. The β2 adrenergic receptors (β2ARs) are expressed throughout the cortex and hippocampus and play a key role in cognitive functions. Alterations in the function of these receptors have been linked to AD; however, these data remain controversial as apparent contradicting reports have been published. Given the current demographics of growing elderly population and the high likelihood of concurrent β-blocker use for other chronic conditions, more studies into the role of this receptor in AD animal models are needed. Here, we show that administration of ICI 118,551 (ICI), a selective β2AR antagonist, exacerbates cognitive deficits in a mouse model of AD, the 3xTg-AD mice. Neuropathologically, ICI increased Aβ levels and Aβ plaque burden. Concomitantly, ICI-treated 3xTg-AD mice showed an increase in tau phosphorylation and accumulation. Mechanistically, these changes were linked to an increase in amyloidogenic amyloid precursor protein processing. These results suggest that under the conditions used here, selective pharmacologic inhibition of β2ARs has detrimental effects on AD-like pathology in mice. Overall, these studies strengthen the notion that the link between β2ARs and AD is likely highly complex and suggest caution in generalizing the beneficial effects of β blockers on AD.
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Affiliation(s)
- Caterina Branca
- Banner Sun Health Research Institute, Sun City, AZ, USA; Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Elena V Wisely
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | | | - Antonella Caccamo
- Banner Sun Health Research Institute, Sun City, AZ, USA; Department of Biological, Geological and Environmental Sciences, University of Catania, Catania, Italy
| | - Salvatore Oddo
- Banner Sun Health Research Institute, Sun City, AZ, USA; Department of Basic Medical Sciences, University of Arizona College of Medicine at Phoenix, Phoenix, AZ, USA.
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Hansen N, Manahan-Vaughan D. Locus Coeruleus Stimulation Facilitates Long-Term Depression in the Dentate Gyrus That Requires Activation of β-Adrenergic Receptors. Cereb Cortex 2014; 25:1889-96. [PMID: 24464942 PMCID: PMC4459289 DOI: 10.1093/cercor/bht429] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Synaptic plasticity comprises a cellular mechanism through which the hippocampus most likely enables memory formation. Neuromodulation, related to arousal, is a key aspect in information storage. The activation of locus coeruleus (LC) neurons by novel experience leads to noradrenaline release in the hippocampus at the level of the dentate gyrus (DG). We explored whether synaptic plasticity in the DG is influenced by activation of the LC via electrical stimulation. Coupling of test-pulses that evoked stable basal synaptic transmission in the DG with stimulation of the LC induced β-adrenoreceptor-dependent long-term depression (LTD) at perforant path–DG synapses in adult rats. Furthermore, persistent LTD (>24 h) induced by perforant path stimulation also required activation of β-adrenergic receptors: Whereas a β-adrenergic receptor antagonist (propranolol) prevented, an agonist (isoproterenol) strengthened the persistence of LTD for over 24 h. These findings support the hypothesis that persistent LTD in the DG is modulated by β-adrenergic receptors. Furthermore, LC activation potently facilitates DG LTD. This suggests in turn that synaptic plasticity in the DG is tightly regulated by activity in the noradrenergic system. This may reflect the role of the LC in selecting salient information for subsequent synaptic processing in the hippocampus.
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Affiliation(s)
- Niels Hansen
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, 44780 Bochum, Germany
| | - Denise Manahan-Vaughan
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, 44780 Bochum, Germany
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Lethbridge RL, Walling SG, Harley CW. Modulation of the perforant path-evoked potential in dentate gyrus as a function of intrahippocampal β-adrenoceptor agonist concentration in urethane-anesthetized rat. Brain Behav 2014; 4:95-103. [PMID: 24653959 PMCID: PMC3937711 DOI: 10.1002/brb3.199] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 10/04/2013] [Accepted: 11/24/2013] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND β-adrenoceptor activation in the hippocampus is sufficient to induce heterosynaptic long-term potentiation of perforant path input to the dentate gyrus. However, in vitro and in vivo studies suggest the plasticity effects of β-adrenoceptor activation may vary depending on the level of receptor activation. METHODS The present experiments use an in vivo model concurrently infusing differing concentrations of the β-adrenoceptor agonist, isoproterenol (ISO; 0, 0.1, 1, 10, and 100 μmol/L in aCSF; 1 μL over 12.5 min) in the dentate gyrus, while monitoring changes in the perforant path-evoked potential at the same site. RESULTS Long-term depression (LTD) of fEPSP slope was elicited by 0.1 μmol/L ISO. Higher doses did not alter fEPSP slope. Maximal long-term potentiation of the perforant path-evoked population spike (183% >3 h) occurred at 10 μmol/L ISO. Transient depression of spike amplitude occurred at 0.1 μmol/L ISO. CONCLUSIONS These data demonstrate concentration-dependent effects of β-adrenoceptor activation on the perforant path-evoked potential. Long-term depression and long-term potentiation of perforant path-evoked responses are variably elicited as a function of the degree of receptor activation.
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Affiliation(s)
- Rebecca L Lethbridge
- Behavioral Neuroscience, Psychology Department, Memorial University of Newfoundland St. John's, NL, A1B 3X9, Canada
| | - Susan G Walling
- Behavioral Neuroscience, Psychology Department, Memorial University of Newfoundland St. John's, NL, A1B 3X9, Canada
| | - Carolyn W Harley
- Behavioral Neuroscience, Psychology Department, Memorial University of Newfoundland St. John's, NL, A1B 3X9, Canada
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Zhang M, Patriarchi T, Stein IS, Qian H, Matt L, Nguyen M, Xiang YK, Hell JW. Adenylyl cyclase anchoring by a kinase anchor protein AKAP5 (AKAP79/150) is important for postsynaptic β-adrenergic signaling. J Biol Chem 2013; 288:17918-31. [PMID: 23649627 DOI: 10.1074/jbc.m112.449462] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Recent evidence indicates that the A kinase anchor protein AKAP5 (AKAP79/150) interacts not only with PKA but also with various adenylyl cyclase (AC) isoforms. However, the physiological relevance of AC-AKAP5 binding is largely unexplored. We now show that postsynaptic targeting of AC by AKAP5 is important for phosphorylation of the AMPA-type glutamate receptor subunit GluA1 on Ser-845 by PKA and for synaptic plasticity. Phosphorylation of GluA1 on Ser-845 is strongly reduced (by 70%) under basal conditions in AKAP5 KO mice but not at all in D36 mice, in which the PKA binding site of AKAP5 (i.e. the C-terminal 36 residues) has been deleted without affecting AC association with GluA1. The increase in Ser-845 phosphorylation upon β-adrenergic stimulation is much more severely impaired in AKAP5 KO than in D36 mice. In parallel, long term potentiation induced by a 5-Hz/180-s tetanus, which mimics the endogenous θ-rhythm and depends on β-adrenergic stimulation, is only modestly affected in acute forebrain slices from D36 mice but completely abrogated in AKAP5 KO mice. Accordingly, anchoring of not only PKA but also AC by AKAP5 is important for regulation of postsynaptic functions and specifically AMPA receptor activity.
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Affiliation(s)
- Mingxu Zhang
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
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Abstract
Over more than a century of research has established the fact that sleep benefits the retention of memory. In this review we aim to comprehensively cover the field of "sleep and memory" research by providing a historical perspective on concepts and a discussion of more recent key findings. Whereas initial theories posed a passive role for sleep enhancing memories by protecting them from interfering stimuli, current theories highlight an active role for sleep in which memories undergo a process of system consolidation during sleep. Whereas older research concentrated on the role of rapid-eye-movement (REM) sleep, recent work has revealed the importance of slow-wave sleep (SWS) for memory consolidation and also enlightened some of the underlying electrophysiological, neurochemical, and genetic mechanisms, as well as developmental aspects in these processes. Specifically, newer findings characterize sleep as a brain state optimizing memory consolidation, in opposition to the waking brain being optimized for encoding of memories. Consolidation originates from reactivation of recently encoded neuronal memory representations, which occur during SWS and transform respective representations for integration into long-term memory. Ensuing REM sleep may stabilize transformed memories. While elaborated with respect to hippocampus-dependent memories, the concept of an active redistribution of memory representations from networks serving as temporary store into long-term stores might hold also for non-hippocampus-dependent memory, and even for nonneuronal, i.e., immunological memories, giving rise to the idea that the offline consolidation of memory during sleep represents a principle of long-term memory formation established in quite different physiological systems.
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Affiliation(s)
- Björn Rasch
- Division of Biopsychology, Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland.
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Vagus nerve stimulation induced long-lasting enhancement of synaptic transmission and decreased granule cell discharge in the hippocampal dentate gyrus of urethane-anesthetized rats. Brain Res 2013. [DOI: 10.1016/j.brainres.2012.11.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Swanger SA, Bassell GJ. Dendritic protein synthesis in the normal and diseased brain. Neuroscience 2012; 232:106-27. [PMID: 23262237 DOI: 10.1016/j.neuroscience.2012.12.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 11/21/2012] [Accepted: 12/01/2012] [Indexed: 01/25/2023]
Abstract
Synaptic activity is a spatially limited process that requires a precise, yet dynamic, complement of proteins within the synaptic micro-domain. The maintenance and regulation of these synaptic proteins is regulated, in part, by local mRNA translation in dendrites. Protein synthesis within the postsynaptic compartment allows neurons tight spatial and temporal control of synaptic protein expression, which is critical for proper functioning of synapses and neural circuits. In this review, we discuss the identity of proteins synthesized within dendrites, the receptor-mediated mechanisms regulating their synthesis, and the possible roles for these locally synthesized proteins. We also explore how our current understanding of dendritic protein synthesis in the hippocampus can be applied to new brain regions and to understanding the pathological mechanisms underlying varied neurological diseases.
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Affiliation(s)
- S A Swanger
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - G J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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Connor SA, Maity S, Roy B, Ali DW, Nguyen PV. Conversion of short-term potentiation to long-term potentiation in mouse CA1 by coactivation of -adrenergic and muscarinic receptors. Learn Mem 2012; 19:535-42. [DOI: 10.1101/lm.026898.112] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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50
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Velho TAF, Lu K, Ribeiro S, Pinaud R, Vicario D, Mello CV. Noradrenergic control of gene expression and long-term neuronal adaptation evoked by learned vocalizations in songbirds. PLoS One 2012; 7:e36276. [PMID: 22574146 PMCID: PMC3344865 DOI: 10.1371/journal.pone.0036276] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 04/02/2012] [Indexed: 11/17/2022] Open
Abstract
Norepinephrine (NE) is thought to play important roles in the consolidation and retrieval of long-term memories, but its role in the processing and memorization of complex acoustic signals used for vocal communication has yet to be determined. We have used a combination of gene expression analysis, electrophysiological recordings and pharmacological manipulations in zebra finches to examine the role of noradrenergic transmission in the brain's response to birdsong, a learned vocal behavior that shares important features with human speech. We show that noradrenergic transmission is required for both the expression of activity-dependent genes and the long-term maintenance of stimulus-specific electrophysiological adaptation that are induced in central auditory neurons by stimulation with birdsong. Specifically, we show that the caudomedial nidopallium (NCM), an area directly involved in the auditory processing and memorization of birdsong, receives strong noradrenergic innervation. Song-responsive neurons in this area express α-adrenergic receptors and are in close proximity to noradrenergic terminals. We further show that local α-adrenergic antagonism interferes with song-induced gene expression, without affecting spontaneous or evoked electrophysiological activity, thus dissociating the molecular and electrophysiological responses to song. Moreover, α-adrenergic antagonism disrupts the maintenance but not the acquisition of the adapted physiological state. We suggest that the noradrenergic system regulates long-term changes in song-responsive neurons by modulating the gene expression response that is associated with the electrophysiological activation triggered by song. We also suggest that this mechanism may be an important contributor to long-term auditory memories of learned vocalizations.
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Affiliation(s)
- Tarciso A F Velho
- Department of Behavioral Neuroscience and Neurological Sciences Institute, Oregon Health and Science University, Portland, Oregon, United States of America
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