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Issa JB, Radvansky BA, Xuan F, Dombeck DA. Lateral entorhinal cortex subpopulations represent experiential epochs surrounding reward. Nat Neurosci 2024; 27:536-546. [PMID: 38272968 PMCID: PMC11097142 DOI: 10.1038/s41593-023-01557-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 12/13/2023] [Indexed: 01/27/2024]
Abstract
During goal-directed navigation, 'what' information, describing the experiences occurring in periods surrounding a reward, can be combined with spatial 'where' information to guide behavior and form episodic memories. This integrative process likely occurs in the hippocampus, which receives spatial information from the medial entorhinal cortex; however, the source of the 'what' information is largely unknown. Here, we show that mouse lateral entorhinal cortex (LEC) represents key experiential epochs during reward-based navigation tasks. We discover separate populations of neurons that signal goal approach and goal departure and a third population signaling reward consumption. When reward location is moved, these populations immediately shift their respective representations of each experiential epoch relative to reward, while optogenetic inhibition of LEC disrupts learning the new reward location. Therefore, the LEC contains a stable code of experiential epochs surrounding and including reward consumption, providing reward-centric information to contextualize the spatial information carried by the medial entorhinal cortex.
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Affiliation(s)
- John B Issa
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - Brad A Radvansky
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - Feng Xuan
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - Daniel A Dombeck
- Department of Neurobiology, Northwestern University, Evanston, IL, USA.
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2
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Zhou F, Tichy AM, Imambocus BN, Sakharwade S, Rodriguez Jimenez FJ, González Martínez M, Jahan I, Habib M, Wilhelmy N, Burre V, Lömker T, Sauter K, Helfrich-Förster C, Pielage J, Grunwald Kadow IC, Janovjak H, Soba P. Optimized design and in vivo application of optogenetically functionalized Drosophila dopamine receptors. Nat Commun 2023; 14:8434. [PMID: 38114457 PMCID: PMC10730509 DOI: 10.1038/s41467-023-43970-0] [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: 05/18/2023] [Accepted: 11/24/2023] [Indexed: 12/21/2023] Open
Abstract
Neuromodulatory signaling via G protein-coupled receptors (GPCRs) plays a pivotal role in regulating neural network function and animal behavior. The recent development of optogenetic tools to induce G protein-mediated signaling provides the promise of acute and cell type-specific manipulation of neuromodulatory signals. However, designing and deploying optogenetically functionalized GPCRs (optoXRs) with accurate specificity and activity to mimic endogenous signaling in vivo remains challenging. Here we optimize the design of optoXRs by considering evolutionary conserved GPCR-G protein interactions and demonstrate the feasibility of this approach using two Drosophila Dopamine receptors (optoDopRs). These optoDopRs exhibit high signaling specificity and light sensitivity in vitro. In vivo, we show receptor and cell type-specific effects of dopaminergic signaling in various behaviors, including the ability of optoDopRs to rescue the loss of the endogenous receptors. This work demonstrates that optoXRs can enable optical control of neuromodulatory receptor-specific signaling in functional and behavioral studies.
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Affiliation(s)
- Fangmin Zhou
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054, Erlangen, Germany
- LIMES Institute, Department of Molecular Brain Physiology and Behavior, University of Bonn, Carl-Troll-Str. 31, 53115, Bonn, Germany
- Neuronal Patterning and Connectivity laboratory, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Alexandra-Madelaine Tichy
- Australian Regenerative Medicine Institute (ARMI), Faculty of Medicine, Nursing and Health Sciences, Monash University, 3800, Clayton, Victoria, Australia
- European Molecular Biology Laboratory Australia (EMBL Australia), Monash University, 3800, Clayton, Victoria, Australia
| | - Bibi Nusreen Imambocus
- LIMES Institute, Department of Molecular Brain Physiology and Behavior, University of Bonn, Carl-Troll-Str. 31, 53115, Bonn, Germany
| | - Shreyas Sakharwade
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054, Erlangen, Germany
- LIMES Institute, Department of Molecular Brain Physiology and Behavior, University of Bonn, Carl-Troll-Str. 31, 53115, Bonn, Germany
| | - Francisco J Rodriguez Jimenez
- Institute of Physiology II, University Clinic Bonn (UKB), University of Bonn, 53115, Bonn, Germany
- ZIEL-Institute of Life and Health, Technical University of Munich, School of Life Sciences, 85354, Freising, Germany
| | - Marco González Martínez
- Institute of Physiology II, University Clinic Bonn (UKB), University of Bonn, 53115, Bonn, Germany
| | - Ishrat Jahan
- Institute of Physiology II, University Clinic Bonn (UKB), University of Bonn, 53115, Bonn, Germany
| | - Margarita Habib
- Neurobiology and Genetics, Biocenter, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Nina Wilhelmy
- Division of Neurobiology and Zoology, RPTU University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Vanessa Burre
- Division of Neurobiology and Zoology, RPTU University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Tatjana Lömker
- Neuronal Patterning and Connectivity laboratory, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Kathrin Sauter
- Neuronal Patterning and Connectivity laboratory, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | | | - Jan Pielage
- Division of Neurobiology and Zoology, RPTU University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Ilona C Grunwald Kadow
- Institute of Physiology II, University Clinic Bonn (UKB), University of Bonn, 53115, Bonn, Germany
- ZIEL-Institute of Life and Health, Technical University of Munich, School of Life Sciences, 85354, Freising, Germany
| | - Harald Janovjak
- Australian Regenerative Medicine Institute (ARMI), Faculty of Medicine, Nursing and Health Sciences, Monash University, 3800, Clayton, Victoria, Australia
- European Molecular Biology Laboratory Australia (EMBL Australia), Monash University, 3800, Clayton, Victoria, Australia
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, 5042, Bedford Park, South Australia, Australia
| | - Peter Soba
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054, Erlangen, Germany.
- LIMES Institute, Department of Molecular Brain Physiology and Behavior, University of Bonn, Carl-Troll-Str. 31, 53115, Bonn, Germany.
- Neuronal Patterning and Connectivity laboratory, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany.
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Datta D, Perone I, Morozov YM, Arellano J, Duque A, Rakic P, van Dyck CH, Arnsten AFT. Localization of PDE4D, HCN1 channels, and mGluR3 in rhesus macaque entorhinal cortex may confer vulnerability in Alzheimer's disease. Cereb Cortex 2023; 33:11501-11516. [PMID: 37874022 PMCID: PMC10724870 DOI: 10.1093/cercor/bhad382] [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: 05/01/2023] [Revised: 08/28/2023] [Accepted: 09/27/2023] [Indexed: 10/25/2023] Open
Abstract
Alzheimer's disease cortical tau pathology initiates in the layer II cell clusters of entorhinal cortex, but it is not known why these specific neurons are so vulnerable. Aging macaques exhibit the same qualitative pattern of tau pathology as humans, including initial pathology in layer II entorhinal cortex clusters, and thus can inform etiological factors driving selective vulnerability. Macaque data have already shown that susceptible neurons in dorsolateral prefrontal cortex express a "signature of flexibility" near glutamate synapses on spines, where cAMP-PKA magnification of calcium signaling opens nearby potassium and hyperpolarization-activated cyclic nucleotide-gated channels to dynamically alter synapse strength. This process is regulated by PDE4A/D, mGluR3, and calbindin, to prevent toxic calcium actions; regulatory actions that are lost with age/inflammation, leading to tau phosphorylation. The current study examined whether a similar "signature of flexibility" expresses in layer II entorhinal cortex, investigating the localization of PDE4D, mGluR3, and HCN1 channels. Results showed a similar pattern to dorsolateral prefrontal cortex, with PDE4D and mGluR3 positioned to regulate internal calcium release near glutamate synapses, and HCN1 channels concentrated on spines. As layer II entorhinal cortex stellate cells do not express calbindin, even when young, they may be particularly vulnerable to magnified calcium actions and ensuing tau pathology.
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Affiliation(s)
- Dibyadeep Datta
- Departments of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Isabella Perone
- Departments of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Yury M Morozov
- Departments of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Jon Arellano
- Departments of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Alvaro Duque
- Departments of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Pasko Rakic
- Departments of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | | | - Amy F T Arnsten
- Departments of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
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Issa JB, Radvansky BA, Xuan F, Dombeck DA. Lateral entorhinal cortex subpopulations represent experiential epochs surrounding reward. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.09.561557. [PMID: 37873482 PMCID: PMC10592707 DOI: 10.1101/2023.10.09.561557] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
During goal-directed navigation, "what" information, which describes the experiences occurring in periods surrounding a reward, can be combined with spatial "where" information to guide behavior and form episodic memories1,2. This integrative process is thought to occur in the hippocampus3, which receives spatial information from the medial entorhinal cortex (MEC)4; however, the source of the "what" information and how it is represented is largely unknown. Here, by establishing a novel imaging method, we show that the lateral entorhinal cortex (LEC) of mice represents key experiential epochs during a reward-based navigation task. We discover a population of neurons that signals goal approach and a separate population of neurons that signals goal departure. A third population of neurons signals reward consumption. When reward location is moved, these populations immediately shift their respective representations of each experiential epoch relative to reward, while optogenetic inhibition of LEC disrupts learning of the new reward location. Together, these results indicate the LEC provides a stable code of experiential epochs surrounding and including reward consumption, providing reward-centric information to contextualize the spatial information carried by the MEC. Such parallel representations are well-suited for generating episodic memories of rewarding experiences and guiding flexible and efficient goal-directed navigation5-7.
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Affiliation(s)
- John B. Issa
- Department of Neurobiology, Northwestern University, Evanston, IL 60608, USA
| | - Brad A. Radvansky
- Department of Neurobiology, Northwestern University, Evanston, IL 60608, USA
| | - Feng Xuan
- Department of Neurobiology, Northwestern University, Evanston, IL 60608, USA
| | - Daniel A. Dombeck
- Department of Neurobiology, Northwestern University, Evanston, IL 60608, USA
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Olajide OJ, La Rue C, Bergdahl A, Chapman CA. Inhibiting amyloid beta (1–42) peptide-induced mitochondrial dysfunction prevents the degradation of synaptic proteins in the entorhinal cortex. Front Aging Neurosci 2022; 14:960314. [PMID: 36275011 PMCID: PMC9582742 DOI: 10.3389/fnagi.2022.960314] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 09/20/2022] [Indexed: 11/22/2022] Open
Abstract
Increasing evidence suggests that mitochondrial dysfunction and aberrant release of mitochondrial reactive oxygen species (ROS) play crucial roles in early synaptic perturbations and neuropathology that drive memory deficits in Alzheimer’s disease (AD). We recently showed that solubilized human amyloid beta peptide 1–42 (hAβ1–42) causes rapid alterations at glutamatergic synapses in the entorhinal cortex (EC) through the activation of both GluN2A- and GluN2B-containing NMDA receptors. However, whether disruption of mitochondrial dynamics and increased ROS contributes to mechanisms mediating hAβ1–42-induced synaptic perturbations in the EC is unknown. Here we assessed the impact of hAβ1–42 on mitochondrial respiratory functions, and the expression of key mitochondrial and synaptic proteins in the EC. Measurements of mitochondrial respiratory function in wild-type EC slices exposed to 1 μM hAβ1–42 revealed marked reductions in tissue oxygen consumption and energy production efficiency relative to control. hAβ1–42 also markedly reduced the immunoexpression of both mitochondrial superoxide dismutase (SOD2) and mitochondrial-cytochrome c protein but had no significant impact on cytosolic-cytochrome c expression, voltage-dependent anion channel protein (a marker for mitochondrial density/integrity), and the immunoexpression of protein markers for all five mitochondrial complexes. The rapid impairments in mitochondrial functions induced by hAβ1–42 were accompanied by reductions in the presynaptic marker synaptophysin, postsynaptic density protein (PSD95), and the vesicular acetylcholine transporter, with no significant changes in the degradative enzyme acetylcholinesterase. We then assessed whether reducing hAβ1–42-induced increases in ROS could prevent dysregulation of entorhinal synaptic proteins, and found that synaptic impairments induced by hAβ1–42 were prevented by the mitochondria-targeted antioxidant drug mitoquinone mesylate, and by the SOD and catalase mimetic EUK134. These findings indicate that hAβ1–2 can rapidly disrupt mitochondrial functions and increase ROS in the entorhinal, and that this may contribute to synaptic dysfunctions that may promote early AD-related neuropathology.
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Affiliation(s)
- Olayemi Joseph Olajide
- Department of Psychology, Center for Studies in Behavioral Neurobiology, Concordia University, Montreal, QC, Canada
- Division of Neurobiology, Department of Anatomy, College of Health Sciences, University of Ilorin, Ilorin, Nigeria
| | - Claudia La Rue
- Department of Psychology, Center for Studies in Behavioral Neurobiology, Concordia University, Montreal, QC, Canada
| | - Andreas Bergdahl
- Department of Health, Kinesiology and Applied Physiology, Concordia University, Montreal, QC, Canada
| | - Clifton Andrew Chapman
- Department of Psychology, Center for Studies in Behavioral Neurobiology, Concordia University, Montreal, QC, Canada
- *Correspondence: Clifton Andrew Chapman,
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Gao SH, Tao Y, Zhu Y, Huang H, Shen LL, Gao CY. Activation of Dopamine D2 Receptors Alleviates Neuronal Hyperexcitability in the Lateral Entorhinal Cortex via Inhibition of HCN Current in a Rat Model of Chronic Inflammatory Pain. Neurosci Bull 2022; 38:1041-1056. [PMID: 35705785 PMCID: PMC9468209 DOI: 10.1007/s12264-022-00892-z] [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: 10/31/2021] [Accepted: 04/10/2022] [Indexed: 10/18/2022] Open
Abstract
Functional changes in synaptic transmission from the lateral entorhinal cortex to the dentate gyrus (LEC-DG) are considered responsible for the chronification of pain. However, the underlying alterations in fan cells, which are the predominant neurons in the LEC that project to the DG, remain elusive. Here, we investigated possible mechanisms using a rat model of complete Freund's adjuvant (CFA)-induced inflammatory pain. We found a substantial increase in hyperpolarization-activated/cyclic nucleotide-gated currents (Ih), which led to the hyperexcitability of LEC fan cells of CFA slices. This phenomenon was attenuated in CFA slices by activating dopamine D2, but not D1, receptors. Chemogenetic activation of the ventral tegmental area -LEC projection had a D2 receptor-dependent analgesic effect. Intra-LEC microinjection of a D2 receptor agonist also suppressed CFA-induced behavioral hypersensitivity, and this effect was attenuated by pre-activation of the Ih. Our findings suggest that down-regulating the excitability of LEC fan cells through activation of the dopamine D2 receptor may be a strategy for treating chronic inflammatory pain.
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Affiliation(s)
- Shi-Hao Gao
- Department of Rehabilitation, Daping Hospital, Army Medical University, Chongqing, 400042, China
- Army 953 Hospital, Army Medical University, Shigatse, 857000, China
| | - Yong Tao
- Department of Rehabilitation, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Yang Zhu
- Department of Rehabilitation, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Hao Huang
- Department of Rehabilitation, Daping Hospital, Army Medical University, Chongqing, 400042, China
| | - Lin-Lin Shen
- Department of Respiratory and Critical Care Medicine, Xinqiao Hospital, Army Medical University, Chongqing, 400037, China.
| | - Chang-Yue Gao
- Department of Rehabilitation, Daping Hospital, Army Medical University, Chongqing, 400042, China.
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Effects of Inositol-Enhanced Bonded Arginine Silicate Ingestion on Cognitive and Executive Function in Gamers. Nutrients 2021; 13:nu13113758. [PMID: 34836014 PMCID: PMC8618773 DOI: 10.3390/nu13113758] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/18/2021] [Accepted: 10/22/2021] [Indexed: 12/15/2022] Open
Abstract
Inositol stabilized arginine silicate (ASI) ingestion has been reported to increase nitric oxide levels while inositol (I) has been reported to enhance neurotransmission. The current study examined whether acute ASI + I (Inositol-enhanced bonded arginine silicate) ingestion affects cognitive function in e-sport gamers. In a double blind, randomized, placebo controlled, and crossover trial, 26 healthy male (n = 18) and female (n = 8) experienced gamers (23 ± 5 years, 171 ± 11 cm, 71.1 ± 14 kg, 20.7 ± 3.5 kg/m2) were randomly assigned to consume 1600 mg of ASI + I (nooLVL®, Nutrition 21) or 1600 mg of a maltodextrin placebo (PLA). Prior to testing, participants recorded their diet, refrained from consuming atypical amounts of stimulants and foods high in arginine and nitrates, and fasted for 8 h. During testing sessions, participants completed stimulant sensitivity questionnaires and performed cognitive function tests (i.e., Berg-Wisconsin Card Sorting task test, Go/No-Go test, Sternberg Task Test, Psychomotor Vigilance Task Test, Cambridge Brain Sciences Reasoning and Concentration test) and a light reaction test. Participants then ingested treatments in a randomized manner. Fifteen minutes following ingestion, participants repeated tests (Pre-Game). Participants then played their favorite video game for 1-h and repeated the battery of tests (Post-Game). Participants observed a 7–14-day washout period and then replicated the study with the alternative treatment. Data were analyzed by General Linear Model (GLM) univariate analyses with repeated measures using weight as a covariate, paired t-tests (not adjusted to weight), and mean changes from baseline with 95% Confidence Intervals (CI). Pairwise comparison revealed that there was a significant improvement in Sternberg Mean Present Reaction Time (ASI + I vs. PLA; p < 0.05). In Post-Game assessments, 4-letter Absent Reaction Time (p < 0.05), 6-letter Present Reaction Time (p < 0.01), 6-letter Absent Reaction Time (p < 0.01), Mean Present Reaction Time (p < 0.02), and Mean Absent Reaction Time (p < 0.03) were improved with ASI + I vs. PLA. There was a non-significant trend in Pre-Game Sternberg 4-letter Present Reaction time in ASI + I vs. PLA (p < 0.07). ASI + I ingestion better maintained changes in Go/No-Go Mean Accuracy and Reaction Time, Psychomotor Vigilance Task Reaction Time, and Cambridge Post-Game Visio-spatial Processing and Planning. Results provide evidence that ASI + I ingestion prior to playing video games may enhance some measures of short-term and working memory, reaction time, reasoning, and concentration in experienced gamers.
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Olajide OJ, Chapman CA. Amyloid-β (1-42) peptide induces rapid NMDA receptor-dependent alterations at glutamatergic synapses in the entorhinal cortex. Neurobiol Aging 2021; 105:296-309. [PMID: 34144329 DOI: 10.1016/j.neurobiolaging.2021.05.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 04/26/2021] [Accepted: 05/11/2021] [Indexed: 12/29/2022]
Abstract
The hippocampus and entorhinal cortex (EC) accumulate amyloid beta peptides (Aβ) that promote neuropathology in Alzheimer's disease, but the early effects of Aβ on excitatory synaptic transmission in the EC have not been well characterized. To assess the acute effects of Aβ1-42 on glutamatergic synapses, acute brain slices from wildtype rats were exposed to Aβ1-42 or control solution for 3 hours, and tissue was analyzed using protein immunoblotting and quantitative PCR. Presynaptically, Aβ1-42 induced marked reductions in synaptophysin, synapsin-2a mRNA, and mGluR3 mRNA, and increased both VGluT2 protein and Ca2+-activated channel KCa2.2 mRNA levels. Postsynaptically, Aβ1-42 reduced PSD95 and GluN2B protein, and also downregulated GluN2B and GluN2A mRNA, without affecting scaffolding elements SAP97 and PICK1. mGluR5 mRNA was strongly increased, while mGluR1 mRNA was unaffected. Blocking either GluN2A- or GluN2B-containing NMDA receptors did not significantly prevent synaptic changes induced by Aβ1-42, but combined blockade did prevent synaptic alterations. These findings demonstrate that Aβ1-42 rapidly disrupts glutamatergic transmission in the EC through mechanisms involving concurrent activation of GluN2A- and GluN2B-containing NMDA receptors.
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Affiliation(s)
- Olayemi Joseph Olajide
- Division of Neurobiology, Department of Anatomy, University of Ilorin, Ilorin, Nigeria; Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, Québec, Canada
| | - Clifton Andrew Chapman
- Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, Québec, Canada.
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Lothmann K, Amunts K, Herold C. The Neurotransmitter Receptor Architecture of the Mouse Olfactory System. Front Neuroanat 2021; 15:632549. [PMID: 33967704 PMCID: PMC8102831 DOI: 10.3389/fnana.2021.632549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 03/03/2021] [Indexed: 11/13/2022] Open
Abstract
The uptake, transmission and processing of sensory olfactory information is modulated by inhibitory and excitatory receptors in the olfactory system. Previous studies have focused on the function of individual receptors in distinct brain areas, but the receptor architecture of the whole system remains unclear. Here, we analyzed the receptor profiles of the whole olfactory system of adult male mice. We examined the distribution patterns of glutamatergic (AMPA, kainate, mGlu2/3, and NMDA), GABAergic (GABAA, GABAA(BZ), and GABAB), dopaminergic (D1/5) and noradrenergic (α1 and α2) neurotransmitter receptors by quantitative in vitro receptor autoradiography combined with an analysis of the cyto- and myelo-architecture. We observed that each subarea of the olfactory system is characterized by individual densities of distinct neurotransmitter receptor types, leading to a region- and layer-specific receptor profile. Thereby, the investigated receptors in the respective areas and strata showed a heterogeneous expression. Generally, we detected high densities of mGlu2/3Rs, GABAA(BZ)Rs and GABABRs. Noradrenergic receptors revealed a highly heterogenic distribution, while the dopaminergic receptor D1/5 displayed low concentrations, except in the olfactory tubercle and the dorsal endopiriform nucleus. The similarities and dissimilarities of the area-specific multireceptor profiles were analyzed by a hierarchical cluster analysis. A three-cluster solution was found that divided the areas into the (1) olfactory relay stations (main and accessory olfactory bulb), (2) the olfactory cortex (anterior olfactory cortex, dorsal peduncular cortex, taenia tecta, piriform cortex, endopiriform nucleus, entorhinal cortex, orbitofrontal cortex) and the (3) olfactory tubercle, constituting its own cluster. The multimodal receptor-architectonic analysis of each component of the olfactory system provides new insights into its neurochemical organization and future possibilities for pharmaceutic targeting.
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Affiliation(s)
- Kimberley Lothmann
- C. & O. Vogt-Institute of Brain Research, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University of Düsseldorf, Düsseldorf, Germany
| | - Katrin Amunts
- C. & O. Vogt-Institute of Brain Research, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University of Düsseldorf, Düsseldorf, Germany.,Institute of Neuroscience and Medicine INM-1, Research Centre Jülich, Jülich, Germany
| | - Christina Herold
- C. & O. Vogt-Institute of Brain Research, Medical Faculty, University Hospital Düsseldorf, Heinrich Heine University of Düsseldorf, Düsseldorf, Germany
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10
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Arnsten AFT, Datta D, Tredici KD, Braak H. Hypothesis: Tau pathology is an initiating factor in sporadic Alzheimer's disease. Alzheimers Dement 2020; 17:115-124. [PMID: 33075193 PMCID: PMC7983919 DOI: 10.1002/alz.12192] [Citation(s) in RCA: 148] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 08/16/2020] [Accepted: 08/19/2020] [Indexed: 12/12/2022]
Abstract
The etiology of the common, sporadic form of Alzheimer's disease (sAD) is unknown. We hypothesize that tau pathology within select projection neurons with susceptible microenvironments can initiate sAD. This postulate rests on extensive data demonstrating that in human brains tau pathology appears about a decade before the formation of Aβ plaques (Aβps), especially targeting glutamate projection neurons in the association cortex. Data from aging rhesus monkeys show abnormal tau phosphorylation within vulnerable neurons, associated with calcium dysregulation. Abnormally phosphorylated tau (pTau) on microtubules traps APP‐containing endosomes, which can increase Aβ production. As Aβ oligomers increase abnormal phosphorylation of tau, this would drive vicious cycles leading to sAD pathology over a long lifespan, with genetic and environmental factors that may accelerate pathological events. This hypothesis could be testable in the aged monkey association cortex that naturally expresses characteristics capable of promoting and sustaining abnormal tau phosphorylation and Aβ production.
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Affiliation(s)
- Amy F T Arnsten
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Dibyadeep Datta
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Kelly Del Tredici
- Clinical Neuroanatomy Section, Department of Neurology, Center for Biomedical Research, University of Ulm, Ulm, Germany
| | - Heiko Braak
- Clinical Neuroanatomy Section, Department of Neurology, Center for Biomedical Research, University of Ulm, Ulm, Germany
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