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Su J, Huang F, Tian Y, Tian R, Qianqian G, Bello ST, Zeng D, Jendrichovsky P, Lau CG, Xiong W, Yu D, Tortorella M, Chen X, He J. Entorhinohippocampal cholecystokinin modulates spatial learning by facilitating neuroplasticity of hippocampal CA3-CA1 synapses. Cell Rep 2023; 42:113467. [PMID: 37979171 DOI: 10.1016/j.celrep.2023.113467] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 10/01/2023] [Accepted: 11/03/2023] [Indexed: 11/20/2023] Open
Abstract
The hippocampus is broadly impacted by neuromodulations. However, how neuropeptides shape the function of the hippocampus and the related spatial learning and memory remains unclear. Here, we discover the crucial role of cholecystokinin (CCK) in heterosynaptic neuromodulation from the medial entorhinal cortex (MEC) to the hippocampus. Systematic knockout of the CCK gene impairs CA3-CA1 LTP and space-related performance. The MEC provides most of the CCK-positive neurons projecting to the hippocampal region, which potentiates CA3-CA1 long-term plasticity heterosynaptically in a frequency- and NMDA receptor (NMDAR)-dependent manner. Selective inhibition of MEC CCKergic neurons or downregulation of their CCK mRNA levels also impairs CA3-CA1 LTP formation and animals' performance in the water maze. This excitatory extrahippocampal projection releases CCK upon high-frequency excitation and is active during animal exploration. Our results reveal the critical role of entorhinal CCKergic projections in bridging intra- and extrahippocampal circuitry at electrophysiological and behavioral levels.
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Affiliation(s)
- Junfeng Su
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, P.R. China
| | - Fengwen Huang
- Department of Neuroscience, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, P.R. China; Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong SAR, P.R. China.
| | - Yu Tian
- Department of Neuroscience, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, P.R. China
| | - Ran Tian
- Department of Neuroscience, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, P.R. China
| | - Gao Qianqian
- Department of Neuroscience, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, P.R. China
| | - Stephen Temitayo Bello
- Department of Neuroscience, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, P.R. China; Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong SAR, P.R. China
| | - Dingxaun Zeng
- Department of Neuroscience, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, P.R. China
| | - Peter Jendrichovsky
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, P.R. China
| | - C Geoffrey Lau
- Department of Neuroscience, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, P.R. China
| | - Wenjun Xiong
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, P.R. China; City University of Hong Kong Shenzhen Research Institute, Shenzhen, P.R. China
| | - Daiguan Yu
- Key Laboratory of Regenerative Biology, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, P.R. China
| | - Micky Tortorella
- Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong SAR, P.R. China; Key Laboratory of Regenerative Biology, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, P.R. China
| | - Xi Chen
- Department of Neuroscience, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, P.R. China; City University of Hong Kong Shenzhen Research Institute, Shenzhen, P.R. China.
| | - Jufang He
- Department of Neuroscience, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, P.R. China; Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, P.R. China; City University of Hong Kong Shenzhen Research Institute, Shenzhen, P.R. China.
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Subramaniyan M, Manivannan S, Chelur V, Tsetsenis T, Jiang E, Dani JA. Fear conditioning potentiates the hippocampal CA1 commissural pathway in vivo and increases awake phase sleep. Hippocampus 2021; 31:1154-1175. [PMID: 34418215 PMCID: PMC9290090 DOI: 10.1002/hipo.23381] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 06/10/2021] [Accepted: 07/24/2021] [Indexed: 11/24/2022]
Abstract
The hippocampus is essential for spatial learning and memory. To assess learning we used contextual fear conditioning (cFC), where animals learn to associate a place with aversive events like foot‐shocks. Candidate memory mechanisms for cFC are long‐term potentiation (LTP) and long‐term depression (LTD), but there is little direct evidence of them operating in the hippocampus in vivo following cFC. Also, little is known about the behavioral state changes induced by cFC. To address these issues, we recorded local field potentials in freely behaving mice by stimulating in the left dorsal CA1 region and recording in the right dorsal CA1 region. Synaptic strength in the commissural pathway was monitored by measuring field excitatory postsynaptic potentials (fEPSPs) before and after cFC. After cFC, the commissural pathway's synaptic strength was potentiated. Although recordings occurred during the wake phase of the light/dark cycle, the mice slept more in the post‐conditioning period than in the pre‐conditioning period. Relative to awake periods, in non‐rapid eye movement (NREM) sleep the fEPSPs were larger in both pre‐ and post‐conditioning periods. We also found a significant negative correlation between the animal's speed and fEPSP size. Therefore, to avoid confounds in the fEFSP potentiation estimates, we controlled for speed‐related and sleep‐related fEPSP changes and still found that cFC induced long‐term potentiation, but no significant long‐term depression. Synaptic strength changes were not found in the control group that simply explored the fear‐conditioning chamber, indicating that exploration of the novel place did not produce the measurable effects caused by cFC. These results show that following cFC, the CA1 commissural pathway is potentiated, likely contributing to the functional integration of the left and right hippocampi in fear memory consolidation. In addition, the cFC paradigm produces significant changes in an animal's behavioral state, which are observable as proximal changes in sleep patterns.
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Affiliation(s)
- Manivannan Subramaniyan
- Department of Neuroscience, Mahoney Institute for Neurosciences, Perelman School for Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sumithrra Manivannan
- Department of Neuroscience, Mahoney Institute for Neurosciences, Perelman School for Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Vikas Chelur
- Department of Neuroscience, Mahoney Institute for Neurosciences, Perelman School for Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Theodoros Tsetsenis
- Department of Neuroscience, Mahoney Institute for Neurosciences, Perelman School for Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Evan Jiang
- Department of Neuroscience, Mahoney Institute for Neurosciences, Perelman School for Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - John A Dani
- Department of Neuroscience, Mahoney Institute for Neurosciences, Perelman School for Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Scheiblich H, Steinert JR. Nitrergic modulation of neuronal excitability in the mouse hippocampus is mediated via regulation of Kv2 and voltage-gated sodium channels. Hippocampus 2021; 31:1020-1038. [PMID: 34047430 DOI: 10.1002/hipo.23366] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/10/2021] [Accepted: 05/19/2021] [Indexed: 12/21/2022]
Abstract
Regulation of neuronal activity is a necessity for communication and information transmission. Many regulatory processes which have been studied provide a complex picture of how neurons can respond to permanently changing functional requirements. One such activity-dependent mechanism involves signaling mediated by nitric oxide (NO). Within the brain, NO is generated in response to neuronal NO synthase (nNOS) activation but NO-dependent pathways regulating neuronal excitability in the hippocampus remain to be fully elucidated. This study was set out to systematically assess the effects of NO on ion channel activities and intrinsic excitabilities of pyramidal neurons within the CA1 region of the mouse hippocampus. We characterized whole-cell potassium and sodium currents, both involved in action potential (AP) shaping and propagation and determined NO-mediated changes in excitabilities and AP waveforms. Our data describe a novel signaling by which NO, in a cGMP-independent manner, suppresses voltage-gated Kv2 potassium and voltage-gated sodium channel activities, thereby widening AP waveforms and reducing depolarization-induced AP firing rates. Our data show that glutathione, which possesses denitrosylating activity, is sufficient to prevent the observed nitrergic effects on potassium and sodium channels, whereas inhibition of cGMP signaling is also sufficient to abolish NO modulation of sodium currents. We propose that NO suppresses both ion channel activities via redox signaling and that an additional cGMP-mediated component is required to exert effects on sodium currents. Both mechanisms result in a dampened excitability and firing ability providing new data on nitrergic activities in the context of activity-dependent regulation of neuronal function following nNOS activation.
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Affiliation(s)
- Hannah Scheiblich
- Department of Neurodegenerative Disease and Geriatric Psychiatry/Neurology, University of Bonn Medical Center, Bonn, Germany
| | - Joern R Steinert
- Faculty of Medicine and Health Sciences, University of Nottingham, School of Life Sciences, Queen's Medical Centre, Nottingham, UK
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Nicholson E, Kullmann DM. Nicotinic receptor activation induces NMDA receptor independent long-term potentiation of glutamatergic signalling in hippocampal oriens interneurons. J Physiol 2021; 599:667-676. [PMID: 33251594 PMCID: PMC7839446 DOI: 10.1113/jp280397] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 11/23/2020] [Indexed: 12/19/2022] Open
Abstract
KEY POINTS Long-term potentiation of glutamatergic transmission to hippocampal interneurons in stratum oriens does not require NMDA receptors and the induction mechanisms are incompletely understood. Extracellular stimulation, conventionally used to monitor synaptic strength and induce long-term potentiation (LTP), does not exclusively recruit glutamatergic axons. We used optogenetic stimulation of either glutamatergic or cholinergic afferents to probe the relative roles of different signalling mechanisms in LTP induction. Selective stimulation of cholinergic axons was sufficient to induce LTP, which was prevented by chelating postsynaptic Ca2+ or blocking nicotinic receptors. The present study adds nicotinic receptors to the list of sources of Ca2+ that induce NMDA receptor independent LTP in hippocampal oriens interneurons. ABSTRACT Many interneurons located in stratum oriens of the rodent hippocampus exhibit a form of long-term potentiation (LTP) of glutamatergic transmission that does not depend on NMDA receptors for its induction but, instead, requires Ca2+ -permeable AMPA receptors and group I metabotropic glutamate receptors. A role for cholinergic signalling has also been reported. However, electrical stimulation of presynaptic axons, conventionally used to evoke synaptic responses, does not allow the relative roles of glutamatergic and cholinergic synapses in the induction of LTP to be distinguished. Here, we show that repetitive optogenetic stimulation confined to cholinergic axons is sufficient to trigger a lasting potentiation of glutamatergic signalling. This phenomenon shows partial occlusion with LTP induced by electrical stimulation, and is sensitive to postsynaptic Ca2+ chelation and blockers of nicotinic receptors. ACh release from cholinergic axons is thus sufficient to trigger heterosynaptic potentiation of glutamatergic signalling to oriens interneurons in the hippocampus.
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Unmasking the relevance of hemispheric asymmetries—Break on through (to the other side). Prog Neurobiol 2020; 192:101823. [DOI: 10.1016/j.pneurobio.2020.101823] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 04/17/2020] [Accepted: 05/13/2020] [Indexed: 12/21/2022]
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Moreno A. Molecular mechanisms of forgetting. Eur J Neurosci 2020; 54:6912-6932. [DOI: 10.1111/ejn.14839] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 04/23/2020] [Accepted: 05/18/2020] [Indexed: 11/30/2022]
Affiliation(s)
- Andrea Moreno
- Danish Institute of Translational Neuroscience (DANDRITE) Aarhus University Aarhus C Denmark
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McHail DG, Dumas TC. Hippocampal gamma rhythms during Y‐maze navigation in the juvenile rat. Hippocampus 2020; 30:505-525. [DOI: 10.1002/hipo.23168] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 09/01/2019] [Accepted: 09/17/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Daniel G. McHail
- Interdisciplinary Program in NeuroscienceGeorge Mason University Fairfax Virginia
| | - Theodore C. Dumas
- Interdisciplinary Program in NeuroscienceGeorge Mason University Fairfax Virginia
- Psychology DepartmentGeorge Mason University Fairfax Virginia
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Esteves M, Ganz E, Sousa N, Leite-Almeida H. Asymmetrical Brain Plasticity: Physiology and Pathology. Neuroscience 2020; 454:3-14. [PMID: 32027996 DOI: 10.1016/j.neuroscience.2020.01.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 01/11/2020] [Accepted: 01/14/2020] [Indexed: 10/25/2022]
Abstract
The brain is inherently asymmetrical. How that attribute, manifest both structurally (volumetric, cytological, molecular) as well as functionally, relates to cognitive function, is not fully understood. Since the early descriptions of Paul Broca and Marc Dax it has been known that the processing of language in the brain is fundamentally asymmetrical. Contemporary imaging studies have corroborated early observations, and have also revealed significant functional links to multiple other systems, such as those sub serving memory or emotion. Recent studies have demonstrated that laterality is both plastic and adaptive. Learning and training have shown to affect regional changes in asymmetry, such as that observed in the volume of the planum temporale associated with musical practice. Increasing task complexity has been demonstrated to induce recruitment of contralateral regions, suggesting that laterality is a manifestation of functional reserve. Indeed, in terms of cognitive function, successful aging is often associated with a reduction of asymmetrical activity. The goal of this review is to survey and critically appraise the current literature addressing brain laterality, both morphological and functional, with particular emphasis on the asymmetrical plasticity associated with environmental factors and training. The plastic recruitment of contralateral areas associated with aging and unilateral lesions will be discussed in the context of the loss of asymmetry as a compensatory mechanism, and specific instances of maladaptive plasticity will be explored.
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Affiliation(s)
- M Esteves
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal; Clinical Academic Center - Braga, Braga, Portugal
| | - E Ganz
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal; Clinical Academic Center - Braga, Braga, Portugal
| | - N Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal; Clinical Academic Center - Braga, Braga, Portugal
| | - H Leite-Almeida
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal; Clinical Academic Center - Braga, Braga, Portugal.
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Ultrastructure of light-activated axons following optogenetic stimulation to produce late-phase long-term potentiation. PLoS One 2020; 15:e0226797. [PMID: 31940316 PMCID: PMC6961864 DOI: 10.1371/journal.pone.0226797] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 12/04/2019] [Indexed: 12/03/2022] Open
Abstract
Analysis of neuronal compartments has revealed many state-dependent changes in geometry but establishing synapse-specific mechanisms at the nanoscale has proven elusive. We co-expressed channelrhodopsin2-GFP and mAPEX2 in a subset of hippocampal CA3 neurons and used trains of light to induce late-phase long-term potentiation (L-LTP) in area CA1. L-LTP was shown to be specific to the labeled axons by severing CA3 inputs, which prevented back-propagating recruitment of unlabeled axons. Membrane-associated mAPEX2 tolerated microwave-enhanced chemical fixation and drove tyramide signal amplification to deposit Alexa Fluor dyes in the light-activated axons. Subsequent post-embedding immunogold labeling resulted in outstanding ultrastructure and clear distinctions between labeled (activated), and unlabeled axons without obscuring subcellular organelles. The gold-labeled axons in potentiated slices were reconstructed through serial section electron microscopy; presynaptic vesicles and other constituents could be quantified unambiguously. The genetic specification, reliable physiology, and compatibility with established methods for ultrastructural preservation make this an ideal approach to link synapse ultrastructure and function in intact circuits.
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Jordan JT. The rodent hippocampus as a bilateral structure: A review of hemispheric lateralization. Hippocampus 2019; 30:278-292. [DOI: 10.1002/hipo.23188] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 10/24/2019] [Accepted: 12/09/2019] [Indexed: 12/26/2022]
Affiliation(s)
- Jake T. Jordan
- Department of BiologyThe Graduate Center, City University of New York New York New York
- Department of PsychologyQueens College, City University of New York Flushing New York
- Department of NeuroscienceAlbert Einstein College of Medicine Bronx NY 10461
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Darwish B, Chamaa F, Al-Chaer ED, Saadé NE, Abou-Kheir W. Intranigral Injection of Endotoxin Suppresses Proliferation of Hippocampal Progenitor Cells. Front Neurosci 2019; 13:687. [PMID: 31333405 PMCID: PMC6616074 DOI: 10.3389/fnins.2019.00687] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 06/17/2019] [Indexed: 11/13/2022] Open
Abstract
Brain inflammation can result in functional disorders observed in several neurodegenerative diseases and that can be also associated with reduced neurogenesis. In this study, we investigate the effect of mild inflammation, induced by unilateral injection of Endotoxin (ET) in the substantia nigra (SN)/Ventral Tegmental Area, on the proliferation and survival of stem/progenitor cells in the dentate gyrus (DG) of the hippocampus. Adult female rats received unilateral injection of ET (2 μg/2 μl saline) or sterile saline (2 μl) in the right SN followed by 5′-Bromo-2′-deoxyuridine (BrdU) injections (66 mg/kg/injection). Intranigral ET injection induced bilateral decrease in the number of newly born BrdU positive cells in the DG. This effect was paralleled by a significant decrease in the exploratory behavior of rats, as assessed by the Y-maze novel arm exploration task. ET also induced a transient decrease in the number of tyrosine hydroxylase-positive cells in the injected SN, impaired motor behavior, and caused microglial activation in the SN. This study provides an experimental simulation of the remote effects of moderate and reversible neuroinflammation resulting in impaired communication between midbrain dopaminergic neurons and the hippocampus.
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Affiliation(s)
- Batoul Darwish
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Farah Chamaa
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Elie D Al-Chaer
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Nayef E Saadé
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Wassim Abou-Kheir
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
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