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Jeong M, Won J, Lim KS, Jeon CY, Choe Y, Jang JH, Ha CM, Yoon JH, Lee Y, Oh YS. Comparative Anatomy of the Dentate Mossy Cells in Nonhuman Primates: Their Spatial Distributions and Axonal Projections Compared With Mouse Mossy Cells. eNeuro 2024; 11:ENEURO.0151-24.2024. [PMID: 38688719 DOI: 10.1523/eneuro.0151-24.2024] [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: 04/04/2024] [Accepted: 04/18/2024] [Indexed: 05/02/2024] Open
Abstract
Glutamatergic mossy cells (MCs) mediate associational and commissural connectivity, exhibiting significant heterogeneity along the septotemporal axis of the mouse dentate gyrus (DG). However, it remains unclear whether the neuronal features of MCs are conserved across mammals. This study compares the neuroanatomy of MCs in the DG of mice and monkeys. The MC marker, calretinin, distinguishes two subpopulations: septal and temporal. Dual-colored fluorescence labeling is utilized to compare the axonal projection patterns of these subpopulations. In both mice and monkeys, septal and temporal MCs project axons across the longitudinal axis of the ipsilateral DG, indicating conserved associational projections. However, unlike in mice, no MC subpopulations in monkeys make commissural projections to the contralateral DG. In monkeys, temporal MCs send associational fibers exclusively to the inner molecular layer, while septal MCs give rise to wide axonal projections spanning multiple molecular layers, akin to equivalent MC subpopulations in mice. Despite conserved septotemporal heterogeneity, interspecies differences are observed in the topological organization of septal MCs, particularly in the relative axonal density in each molecular layer along the septotemporal axis of the DG. In summary, this comparative analysis sheds light on both conserved and divergent features of MCs in the DG of mice and monkeys. These findings have implications for understanding functional differentiation along the septotemporal axis of the DG and contribute to our knowledge of the anatomical evolution of the DG circuit in mammals.
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Affiliation(s)
- Minseok Jeong
- Department of Brain Sciences, Daegu-Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
| | - Jinyoung Won
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju 28116, Republic of Korea
| | - Kyung Seob Lim
- Futuristic Animal Resource and Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju 28116, Republic of Korea
| | - Chang-Yeop Jeon
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju 28116, Republic of Korea
| | - Youngshik Choe
- Developmental Disorders & Rare Diseases Research Group, Korea Brain Research Institute (KBRI), Daegu 41062, Republic of Korea
| | - Jin-Hyeok Jang
- Department of Brain Sciences, Daegu-Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
| | - Chang Man Ha
- Research Division and Brain Research Core Facilities, Korea Brain Research Institute (KBRI), Daegu 41062, Republic of Korea
| | - Jong Hyuk Yoon
- Neurodegenerative Diseases Research Group, Korea Brain Research Institute (KBRI), Daegu 41062, Republic of Korea
| | - Yongjeon Lee
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju 28116, Republic of Korea
- Department of Functional Genomics, KRIBB School of Bioscience, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
| | - Yong-Seok Oh
- Department of Brain Sciences, Daegu-Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Republic of Korea
- Emotion, Cognition & Behavior Research Group, Korea Brain Research Institute (KBRI), Daegu 41062, Republic of Korea
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Burke CT, Vitko I, Straub J, Nylund EO, Gawda A, Blair K, Sullivan KA, Ergun L, Ottolini M, Patel MK, Perez-Reyes E. EpiPro, a Novel, Synthetic, Activity-Regulated Promoter That Targets Hyperactive Neurons in Epilepsy for Gene Therapy Applications. Int J Mol Sci 2023; 24:14467. [PMID: 37833914 PMCID: PMC10572392 DOI: 10.3390/ijms241914467] [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: 08/17/2023] [Revised: 09/16/2023] [Accepted: 09/21/2023] [Indexed: 10/15/2023] Open
Abstract
Epileptogenesis is characterized by intrinsic changes in neuronal firing, resulting in hyperactive neurons and the subsequent generation of seizure activity. These alterations are accompanied by changes in gene transcription networks, first with the activation of early-immediate genes and later with the long-term activation of genes involved in memory. Our objective was to engineer a promoter containing binding sites for activity-dependent transcription factors upregulated in chronic epilepsy (EpiPro) and validate it in multiple rodent models of epilepsy. First, we assessed the activity dependence of EpiPro: initial electrophysiology studies found that EpiPro-driven GFP expression was associated with increased firing rates when compared with unlabeled neurons, and the assessment of EpiPro-driven GFP expression revealed that GFP expression was increased ~150× after status epilepticus. Following this, we compared EpiPro-driven GFP expression in two rodent models of epilepsy, rat lithium/pilocarpine and mouse electrical kindling. In rodents with chronic epilepsy, GFP expression was increased in most neurons, but particularly in dentate granule cells, providing in vivo evidence to support the "breakdown of the dentate gate" hypothesis of limbic epileptogenesis. Finally, we assessed the time course of EpiPro activation and found that it was rapidly induced after seizures, with inactivation following over weeks, confirming EpiPro's potential utility as a gene therapy driver for epilepsy.
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Affiliation(s)
- Cassidy T. Burke
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Iuliia Vitko
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Justyna Straub
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Elsa O. Nylund
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Agnieszka Gawda
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Kathryn Blair
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Kyle A. Sullivan
- Computational and Predictive Biology, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Lara Ergun
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Matteo Ottolini
- Department of Anesthesiology, University of Virginia, Charlottesville, VA 22908, USA (M.K.P.)
| | - Manoj K. Patel
- Department of Anesthesiology, University of Virginia, Charlottesville, VA 22908, USA (M.K.P.)
- UVA Brain Institute, University of Virginia, Charlottesville, VA 22908, USA
| | - Edward Perez-Reyes
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
- UVA Brain Institute, University of Virginia, Charlottesville, VA 22908, USA
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3
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Maliković J, Amrein I, Vinciguerra L, Lalošević D, Wolfer DP, Slomianka L. Cell numbers in the reflected blade of CA3 and their relation to other hippocampal principal cell populations across seven species. Front Neuroanat 2023; 16:1070035. [PMID: 36686574 PMCID: PMC9846821 DOI: 10.3389/fnana.2022.1070035] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 11/30/2022] [Indexed: 01/06/2023] Open
Abstract
The hippocampus of many mammals contains a histoarchitectural region that is not present in laboratory mice and rats-the reflected blade of the CA3 pyramidal cell layer. Pyramidal cells of the reflected blade do not extend dendrites into the hippocampal molecular layer, and recent evidence indicates that they, like the proximal CA3 pyramids in laboratory rats and mice, partially integrate functionally with the dentate circuitry in pattern separation. Quantitative assessments of phylogenetic or disease-related changes in the hippocampal structure and function treat the reflected blade heterogeneously. Depending on the ease with which it can be differentiated, it is either assigned to the dentate hilus or to the remainder of CA3. Here, we investigate the impact that the differential assignment of reflected blade neurons may have on the outcomes of quantitative comparisons. We find it to be massive. If reflected blade neurons are treated as a separate entity or pooled with dentate hilar cells, the quantitative makeup of hippocampal cell populations can differentiate between species in a taxonomically sensible way. Assigning reflected blade neurons to CA3 greatly diminishes the differentiating power of all hippocampal principal cell populations, which may point towards a quantitative hippocampal archetype. A heterogeneous assignment results in a differentiation pattern with little taxonomic semblance. The outcomes point towards the reflected blade as either a major potential player in hippocampal functional and structural differentiation or a region that may have cloaked that hippocampi are more similarly organized across species than generally believed.
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Affiliation(s)
- Jovana Maliković
- Division of Functional Neuroanatomy, Institute of Anatomy, University of Zürich, Zürich, Switzerland
| | - Irmgard Amrein
- Division of Functional Neuroanatomy, Institute of Anatomy, University of Zürich, Zürich, Switzerland,Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | | | | | - David P. Wolfer
- Division of Functional Neuroanatomy, Institute of Anatomy, University of Zürich, Zürich, Switzerland,Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Lutz Slomianka
- Division of Functional Neuroanatomy, Institute of Anatomy, University of Zürich, Zürich, Switzerland,Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland,*Correspondence: Lutz Slomianka
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4
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Kecskés A, Czéh B, Kecskés M. Mossy cells of the dentate gyrus: Drivers or inhibitors of epileptic seizures? BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119279. [PMID: 35526721 DOI: 10.1016/j.bbamcr.2022.119279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 04/22/2022] [Accepted: 04/25/2022] [Indexed: 05/12/2023]
Abstract
Mossy cells (MCs) are glutamatergic cells of the dentate gyrus with an important role in temporal lobe epilepsy. Under physiological conditions MCs can control both network excitations via direct synapses to granule cells and inhibition via connections to GABAergic interneurons innervating granule cells. In temporal lobe epilepsy mossy cell loss is one of the major hallmarks, but whether the surviving MCs drive or inhibit seizure initiation and generalization is still a debate. The aim of the present review is to summarize the latest findings on the role of mossy cells in healthy and overexcited hippocampus.
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Affiliation(s)
- Angéla Kecskés
- Department of Pharmacology and Pharmacotherapy, Medical School & Szentagothai Research Centre, Molecular Pharmacology Research Group, Centre for Neuroscience, University of Pécs, H-7624 Pécs, Hungary
| | - Boldizsár Czéh
- Department of Laboratory Medicine, Medical School & Szentagothai Research Centre, Histology and Light Microscopy Core Facility, Centre for Neuroscience, University of Pécs, H-7624 Pécs, Hungary
| | - Miklós Kecskés
- Institute of Physiology, Medical School & Szentagothai Research Centre, Molecular Neuroendocrinology Research Group, Centre for Neuroscience, University of Pécs, H-7624 Pécs, Hungary.
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Revealing the Precise Role of Calretinin Neurons in Epilepsy: We Are on the Way. Neurosci Bull 2021; 38:209-222. [PMID: 34324145 PMCID: PMC8821741 DOI: 10.1007/s12264-021-00753-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/24/2021] [Indexed: 02/03/2023] Open
Abstract
Epilepsy is a common neurological disorder characterized by hyperexcitability in the brain. Its pathogenesis is classically associated with an imbalance of excitatory and inhibitory neurons. Calretinin (CR) is one of the three major types of calcium-binding proteins present in inhibitory GABAergic neurons. The functions of CR and its role in neural excitability are still unknown. Recent data suggest that CR neurons have diverse neurotransmitters, morphologies, distributions, and functions in different brain regions across various species. Notably, CR neurons in the hippocampus, amygdala, neocortex, and thalamus are extremely susceptible to excitotoxicity in the epileptic brain, but the causal relationship is unknown. In this review, we focus on the heterogeneous functions of CR neurons in different brain regions and their relationship with neural excitability and epilepsy. Importantly, we provide perspectives on future investigations of the role of CR neurons in epilepsy.
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Meyer G, González-Arnay E, Moll U, Nemajerova A, Tissir F, González-Gómez M. Cajal-Retzius neurons are required for the development of the human hippocampal fissure. J Anat 2019; 235:569-589. [PMID: 30861578 DOI: 10.1111/joa.12947] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2019] [Indexed: 01/14/2023] Open
Abstract
Cajal-Retzius neurons (CRN) are the main source of Reelin in the marginal zone of the developing neocortex and hippocampus (HC). They also express the transcription factor p73 and are complemented by later-appearing GABAergic Reelin+ interneurons. The human dorsal HC forms at gestational week 10 (GW10), when it develops a rudimentary Ammonic plate and incipient dentate migration, although the dorsal hippocampal fissure (HF) remains shallow and contains few CRN. The dorsal HC transforms into the indusium griseum (IG), concurrently with the rostro-caudal appearance of the corpus callosum, by GW14-17. Dorsal and ventral HC merge at the site of the former caudal hem, which is located at the level of the future atrium of the lateral ventricle and closely connected with the choroid plexus. The ventral HC forms at GW11 in the temporal lobe. The ventral HF is wide open at GW14-16 and densely populated by large numbers of CRNs. These are in intimate contact with the meninges and meningeal blood vessels, suggesting signalling through diverse pathways. At GW17, the fissure deepens and begins to fuse, although it is still marked by p73/Reelin+ CRNs. The p73KO mouse illustrates the importance of p73 in CRN for HF formation. In the mutant, Tbr1/Reelin+ CRNs are born in the hem but do not leave it and subsequently disappear, so that the mutant cortex and HC lack CRN from the onset of corticogenesis. The HF is absent, which leads to profound architectonic alterations of the HC. To determine which p73 isoform is important for HF formation, isoform-specific TAp73- and DeltaNp73-deficient embryonic and early postnatal mice were examined. In both mutants, the number of CRNs was reduced, but each of their phenotypes was much milder than in the global p73KO mutant missing both isoforms. In the TAp73KO mice, the HF of the dorsal HC failed to form, but was present in the ventral HC. In the DeltaNp73KO mice, the HC had a mild patterning defect along with a shorter HF. Complex interactions between both isoforms in CRNs may contribute to their crucial activity in the developing brain.
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Affiliation(s)
- Gundela Meyer
- Department of Basic Medical Sciences, University La Laguna, La Laguna, Spain
| | | | - Ute Moll
- Department of Pathology, Stony Brook University, Stony Brook, NY, USA
| | - Alice Nemajerova
- Department of Pathology, Stony Brook University, Stony Brook, NY, USA
| | - Fadel Tissir
- Developmental Neurobiology Group, Institute of NeuroScience, UCL Louvain, Brussels, Belgium
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7
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LaGamma CT, Tang WW, Morgan AA, McGowan JC, Brachman RA, Denny CA. Antidepressant but Not Prophylactic Ketamine Administration Alters Calretinin and Calbindin Expression in the Ventral Hippocampus. Front Mol Neurosci 2018; 11:404. [PMID: 30459554 PMCID: PMC6232342 DOI: 10.3389/fnmol.2018.00404] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/15/2018] [Indexed: 01/20/2023] Open
Abstract
Ketamine has been found to have rapid, long-lasting antidepressant effects in treatment-resistant (TR) patients with major depressive disorder (MDD). Recently, we have also shown that ketamine acts as a prophylactic to protect against the development of stress-induced depressive-like behavior in mice, indicating that a preventative treatment against mental illness using ketamine is possible. While there is significant investigation into ketamine’s antidepressant mechanism of action, little is known about ketamine’s underlying prophylactic mechanism. More specifically, whether ketamine’s prophylactic action is molecularly similar to or divergent from its antidepressant action is entirely unknown. Here, we sought to characterize immunohistochemical signatures of cell populations governing ketamine’s antidepressant and prophylactic effects. 129S6/SvEv mice were treated with saline (Sal) or ketamine (K) either before a social defeat (SD) stressor as a prophylactic, or after SD as an antidepressant, then subsequently assessed for depressive-like behavior. Post-fixed brains were processed for doublecortin (DCX), calretinin (CR) and calbindin (CB) expression. The number of DCX+ neurons in the dentate gyrus (DG) of the hippocampus (HPC) was not affected by prophylactic or antidepressant ketamine treatment, while the number of CR+ neurons in the ventral hilus increased with antidepressant ketamine under SD conditions. Moreover, antidepressant, but not prophylactic ketamine administration significantly altered CR and CB expression in the ventral HPC (vHPC). These data show that while antidepressant ketamine treatment mediates some of its effects via adult hippocampal markers, prophylactic ketamine administration does not, at least in 129S6/SvEv mice. These data suggest that long-lasting behavioral effects of prophylactic ketamine are independent of hippocampal DCX, CR and CB expression in stress-susceptible mice.
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Affiliation(s)
- Christina T LaGamma
- Division of Integrative Neuroscience, Research Foundation for Mental Hygiene, Inc. (RFMH)/New York State Psychiatric Institute (NYSPI), New York, NY, United States
| | - William W Tang
- Department of Psychiatry, Columbia University, New York, NY, United States
| | - Ashlea A Morgan
- Doctoral Program in Neurobiology and Behavior, Columbia University, New York, NY, United States
| | | | - Rebecca A Brachman
- Department of Psychiatry, Columbia University, New York, NY, United States
| | - Christine A Denny
- Division of Integrative Neuroscience, Research Foundation for Mental Hygiene, Inc. (RFMH)/New York State Psychiatric Institute (NYSPI), New York, NY, United States.,Department of Psychiatry, Columbia University, New York, NY, United States
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8
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Herrera-Molina R, Mlinac-Jerkovic K, Ilic K, Stöber F, Vemula SK, Sandoval M, Milosevic NJ, Simic G, Smalla KH, Goldschmidt J, Bognar SK, Montag D. Neuroplastin deletion in glutamatergic neurons impairs selective brain functions and calcium regulation: implication for cognitive deterioration. Sci Rep 2017; 7:7273. [PMID: 28779130 PMCID: PMC5544750 DOI: 10.1038/s41598-017-07839-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 05/26/2017] [Indexed: 02/05/2023] Open
Abstract
The cell adhesion molecule neuroplastin (Np) is a novel candidate to influence human intelligence. Np-deficient mice display complex cognitive deficits and reduced levels of Plasma Membrane Ca2+ ATPases (PMCAs), an essential regulator of the intracellular Ca2+ concentration ([iCa2+]) and neuronal activity. We show abundant expression and conserved cellular and molecular features of Np in glutamatergic neurons in human hippocampal-cortical pathways as characterized for the rodent brain. In Nptnlox/loxEmx1Cre mice, glutamatergic neuron-selective Np ablation resulted in behavioral deficits indicating hippocampal, striatal, and sensorimotor dysfunction paralleled by highly altered activities in hippocampal CA1 area, sensorimotor cortex layers I-III/IV, and the striatal sensorimotor domain detected by single-photon emission computed tomography. Altered hippocampal and cortical activities correlated with reduction of distinct PMCA paralogs in Nptnlox/loxEmx1Cre mice and increased [iCa2+] in cultured mutant neurons. Human and rodent Np enhanced the post-transcriptional expression of and co-localized with PMCA paralogs in the plasma membrane of transfected cells. Our results indicate Np as essential for PMCA expression in glutamatergic neurons allowing proper [iCa2+] regulation and normal circuit activity. Neuron-type-specific Np ablation empowers the investigation of circuit-coded learning and memory and identification of causal mechanisms leading to cognitive deterioration.
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Affiliation(s)
- Rodrigo Herrera-Molina
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Kristina Mlinac-Jerkovic
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Katarina Ilic
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Franziska Stöber
- Department of Systems Physiology; Special Laboratories, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Sampath Kumar Vemula
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Mauricio Sandoval
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Natasa Jovanov Milosevic
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Goran Simic
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Karl-Heinz Smalla
- Department of Molecular Biology Techniques, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Jürgen Goldschmidt
- Department of Systems Physiology; Special Laboratories, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Svjetlana Kalanj Bognar
- Croatian Institute for Brain Research, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Dirk Montag
- Neurogenetics, Leibniz Institute for Neurobiology, Magdeburg, Germany.
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9
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Sullivan B, Robison G, Pushkar Y, Young JK, Manaye KF. Copper accumulation in rodent brain astrocytes: A species difference. J Trace Elem Med Biol 2017; 39:6-13. [PMID: 27908425 PMCID: PMC5141684 DOI: 10.1016/j.jtemb.2016.06.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 05/23/2016] [Accepted: 06/30/2016] [Indexed: 12/15/2022]
Abstract
Changes in Cu homeostasis have been implicated in multiple neurodegenerative diseases. Factors controlling and regulating the distribution of Cu in the brain remain largely unknown. We have previously reported that a sub-set of astrocytes in the subventricular zone (SVZ) contain Cu-rich aggregates. Here we expand previous studies with detailed X-ray fluorescent imaging (XRF) analysis of the additional brain areas of hippocampus (HP) and rostral migratory stream (RMS). We also use conventional DAB (3,3'-diaminobenzidine) staining which accesses both peroxidase and pseudo-peroxidase activities. Both the HP and RMS support neurogenesis while the latter also serves as a migratory pathway for neuronal precursors. Some variations in neurogenic activities have been noticed between species (such as mice and rats). We report here that in rats, the HP, rostral migratory stream (RMS) and third ventricle contain glia which stain positively for DAB and contain copper-rich aggregates as measured by XRF. In contrast, mice hippocampi and RMS display neither DAB+ aggregates nor Cu-rich accumulations via XRF. DAB+ aggregates were not induced in the HP of mice transgenic for human amyloid precursor protein (APP) and presenilin, suggesting that accumulations positively stained for DAB are not directly caused by APP. These observed critical differences suggest different properties of the astrocytes in two species. Results suggest that the rat model may have important advantages over the mouse model for the study of hippocampal aging and neurodegeneration.
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Affiliation(s)
- Brendan Sullivan
- Department of Physics and Astronomy, Purdue University, 525 Northwestern Ave., West Lafayette, IN 47907, United States
| | - Gregory Robison
- Department of Physics and Astronomy, Purdue University, 525 Northwestern Ave., West Lafayette, IN 47907, United States; Department of Physics, Hanover College, Hanover, IN, United States
| | - Yulia Pushkar
- Department of Physics and Astronomy, Purdue University, 525 Northwestern Ave., West Lafayette, IN 47907, United States.
| | - John K Young
- Department of Anatomy, Howard University College of Medicine 520 W St., NW, Washington DC 20059, United States
| | - Kebreten F Manaye
- Department of Physiology, Howard University College of Medicine 520 W St., NW, Washington DC 20059, United States
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10
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van Dijk RM, Huang SH, Slomianka L, Amrein I. Taxonomic Separation of Hippocampal Networks: Principal Cell Populations and Adult Neurogenesis. Front Neuroanat 2016; 10:22. [PMID: 27013984 PMCID: PMC4783399 DOI: 10.3389/fnana.2016.00022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 02/23/2016] [Indexed: 11/13/2022] Open
Abstract
While many differences in hippocampal anatomy have been described between species, it is typically not clear if they are specific to a particular species and related to functional requirements or if they are shared by species of larger taxonomic units. Without such information, it is difficult to infer how anatomical differences may impact on hippocampal function, because multiple taxonomic levels need to be considered to associate behavioral and anatomical changes. To provide information on anatomical changes within and across taxonomic ranks, we present a quantitative assessment of hippocampal principal cell populations in 20 species or strain groups, with emphasis on rodents, the taxonomic group that provides most animals used in laboratory research. Of special interest is the importance of adult hippocampal neurogenesis (AHN) in species-specific adaptations relative to other cell populations. Correspondence analysis of cell numbers shows that across taxonomic units, phylogenetically related species cluster together, sharing similar proportions of principal cell populations. CA3 and hilus are strong separators that place rodent species into a tight cluster based on their relatively large CA3 and small hilus while non-rodent species (including humans and non-human primates) are placed on the opposite side of the spectrum. Hilus and CA3 are also separators within rodents, with a very large CA3 and rather small hilar cell populations separating mole-rats from other rodents that, in turn, are separated from each other by smaller changes in the proportions of CA1 and granule cells. When adult neurogenesis is included, the relatively small populations of young neurons, proliferating cells and hilar neurons become main drivers of taxonomic separation within rodents. The observations provide challenges to the computational modeling of hippocampal function, suggest differences in the organization of hippocampal information streams in rodent and non-rodent species, and support emerging concepts of functional and structural interactions between CA3 and the dentate gyrus.
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Affiliation(s)
- R Maarten van Dijk
- Functional Neuroanatomy, Institute of Anatomy, University of ZürichZurich, Switzerland; Neuroscience Center Zurich, University of Zurich and ETH ZurichZürich, Switzerland; Department of Health Sciences and Technology, Institute of Human Movement Sciences and Sport, ETH ZurichZürich, Switzerland
| | - Shih-Hui Huang
- Functional Neuroanatomy, Institute of Anatomy, University of ZürichZurich, Switzerland; Neuroscience Center Zurich, University of Zurich and ETH ZurichZürich, Switzerland; Department of Health Sciences and Technology, Institute of Human Movement Sciences and Sport, ETH ZurichZürich, Switzerland
| | - Lutz Slomianka
- Functional Neuroanatomy, Institute of Anatomy, University of Zürich Zurich, Switzerland
| | - Irmgard Amrein
- Functional Neuroanatomy, Institute of Anatomy, University of ZürichZurich, Switzerland; Neuroscience Center Zurich, University of Zurich and ETH ZurichZürich, Switzerland
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11
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Amrein I, Nosswitz M, Slomianka L, van Dijk RM, Engler S, Klaus F, Raineteau O, Azim K. Septo-temporal distribution and lineage progression of hippocampal neurogenesis in a primate (Callithrix jacchus) in comparison to mice. Front Neuroanat 2015; 9:85. [PMID: 26175670 PMCID: PMC4484228 DOI: 10.3389/fnana.2015.00085] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 06/11/2015] [Indexed: 12/17/2022] Open
Abstract
Adult born neurons in the hippocampus show species-specific differences in their numbers, the pace of their maturation and their spatial distribution. Here, we present quantitative data on adult hippocampal neurogenesis in a New World primate, the common marmoset (Callithrix jacchus) that demonstrate parts of the lineage progression and age-related changes. Proliferation was largely (∼70%) restricted to stem cells or early progenitor cells, whilst the remainder of the cycling pool could be assigned almost exclusively to Tbr2+ intermediate precursor cells in both neonate and adult animals (20–122 months). Proliferating DCX+ neuroblasts were virtually absent in adults, although rare MCM2+/DCX+ co-expression revealed a small, persisting proliferative potential. Co-expression of DCX with calretinin was very limited in marmosets, suggesting that these markers label distinct maturational stages. In adult marmosets, numbers of MCM2+, Ki67+, and significantly Tbr2+, DCX+, and CR+ cells declined with age. The distributions of granule cells, proliferating cells and DCX+ young neurons along the hippocampal longitudinal axis were equal in marmosets and mice. In both species, a gradient along the hippocampal septo-temporal axis was apparent for DCX+ and resident granule cells. Both cell numbers are higher septally than temporally, whilst proliferating cells were evenly distributed along this axis. Relative to resident granule cells, however, the ratio of proliferating cells and DCX+ neurons remained constant in the septal, middle, and temporal hippocampus. In marmosets, the extended phase of the maturation of young neurons that characterizes primate hippocampal neurogenesis was due to the extension in a large CR+/DCX- cell population. This clear dissociation between DCX+ and CR+ young neurons has not been reported for other species and may therefore represent a key primate-specific feature of adult hippocampal neurogenesis.
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Affiliation(s)
- Irmgard Amrein
- Functional Neuroanatomy, Institute of Anatomy, University of Zürich Zürich, Switzerland ; Neuroscience Center Zurich, University of Zürich and ETH Zürich Zürich, Switzerland
| | - Michael Nosswitz
- Functional Neuroanatomy, Institute of Anatomy, University of Zürich Zürich, Switzerland
| | - Lutz Slomianka
- Functional Neuroanatomy, Institute of Anatomy, University of Zürich Zürich, Switzerland
| | - R Maarten van Dijk
- Functional Neuroanatomy, Institute of Anatomy, University of Zürich Zürich, Switzerland ; Institute of Human Movement Sciences and Sport, Department of Health Sciences and Technology, ETH Zürich Zürich, Switzerland
| | - Stefanie Engler
- Functional Neuroanatomy, Institute of Anatomy, University of Zürich Zürich, Switzerland
| | - Fabienne Klaus
- Functional Neuroanatomy, Institute of Anatomy, University of Zürich Zürich, Switzerland
| | - Olivier Raineteau
- Inserm U846, Stem Cell and Brain Research Institute, Bron France ; Université de Lyon, Bron France
| | - Kasum Azim
- Neuroscience Center Zurich, University of Zürich and ETH Zürich Zürich, Switzerland
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Tóth K, Maglóczky Z. The vulnerability of calretinin-containing hippocampal interneurons to temporal lobe epilepsy. Front Neuroanat 2014; 8:100. [PMID: 25324731 PMCID: PMC4179514 DOI: 10.3389/fnana.2014.00100] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 09/04/2014] [Indexed: 01/21/2023] Open
Abstract
This review focuses on the vulnerability of a special interneuron type—the calretinin (CR)-containing interneurons—in temporal lobe epilepsy (TLE). CR is a calcium-binding protein expressed mainly by GABAergic interneurons in the hippocampus. Despite their morphological heterogeneity, CR-containing interneurons form a distinct subpopulation of inhibitory cells, innervating other interneurons in rodents and to some extent principal cells in the human. Their dendrites are strongly connected by zona adherentiae and presumably by gap junctions both in rats and humans. CR-containing interneurons are suggested to play a key role in the hippocampal inhibitory network, since they can effectively synchronize dendritic inhibitory interneurons. The sensitivity of CR-expressing interneurons to epilepsy was discussed in several reports, both in animal models and in humans. In the sclerotic hippocampus the density of CR-immunopositive cells is decreased significantly. In the non-sclerotic hippocampus, the CR-containing interneurons are preserved, but their dendritic tree is varicose, segmented, and zona-adherentia-type contacts can be less frequently observed among dendrites. Therefore, the dendritic inhibition of pyramidal cells may be less effective in TLE. This can be partially explained by the impairment of the CR-containing interneuron ensemble in the epileptic hippocampus, which may result in an asynchronous and thus less effective dendritic inhibition of the principal cells. This phenomenon, together with the sprouting of excitatory pathway axons and enhanced innervation of principal cells, may be involved in seizure generation. Preventing the loss of CR-positive cells and preserving the integrity of CR-positive dendrite gap junctions may have antiepileptic effects, maintaining proper inhibitory function and helping to protect principal cells in epilepsy.
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Affiliation(s)
- Kinga Tóth
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences Budapest, Hungary ; Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary
| | - Zsófia Maglóczky
- Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary
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Baizer JS, Wong KM, Paolone NA, Weinstock N, Salvi RJ, Manohar S, Witelson SF, Baker JF, Sherwood CC, Hof PR. Laminar and neurochemical organization of the dorsal cochlear nucleus of the human, monkey, cat, and rodents. Anat Rec (Hoboken) 2014; 297:1865-84. [PMID: 25132345 DOI: 10.1002/ar.23000] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Accepted: 06/09/2014] [Indexed: 01/02/2023]
Abstract
The dorsal cochlear nucleus (DCN) is a brainstem structure that receives input from the auditory nerve. Many studies in a diversity of species have shown that the DCN has a laminar organization and identifiable neuron types with predictable synaptic relations to each other. In contrast, studies on the human DCN have found a less distinct laminar organization and fewer cell types, although there has been disagreement among studies in how to characterize laminar organization and which of the cell types identified in other animals are also present in humans. We have reexamined DCN organization in the human using immunohistochemistry to analyze the expression of several proteins that have been useful in delineating the neurochemical organization of other brainstem structures in humans: nonphosphorylated neurofilament protein (NPNFP), nitric oxide synthase (nNOS), and three calcium-binding proteins. The results for humans suggest a laminar organization with only two layers, and the presence of large projection neurons that are enriched in NPNFP. We did not observe evidence in humans of the inhibitory interneurons that have been described in the cat and rodent DCN. To compare humans and other animals directly we used immunohistochemistry to examine the DCN in the macaque monkey, the cat, and three rodents. We found similarities between macaque monkey and human in the expression of NPNFP and nNOS, and unexpected differences among species in the patterns of expression of the calcium-binding proteins.
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Affiliation(s)
- Joan S Baizer
- Department of Physiology and Biophysics, University at Buffalo, Buffalo, New York
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14
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Slomianka L, Drenth T, Cavegn N, Menges D, Lazic SE, Phalanndwa M, Chimimba CT, Amrein I. The hippocampus of the eastern rock sengi: cytoarchitecture, markers of neuronal function, principal cell numbers, and adult neurogenesis. Front Neuroanat 2013; 7:34. [PMID: 24194702 PMCID: PMC3810719 DOI: 10.3389/fnana.2013.00034] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 09/26/2013] [Indexed: 12/04/2022] Open
Abstract
The brains of sengis (elephant shrews, order Macroscelidae) have long been known to contain a hippocampus that in terms of allometric progression indices is larger than that of most primates and equal in size to that of humans. In this report, we provide descriptions of hippocampal cytoarchitecture in the eastern rock sengi (Elephantulus myurus), of the distributions of hippocampal calretinin, calbindin, parvalbumin, and somatostatin, of principal neuron numbers, and of cell numbers related to proliferation and neuronal differentiation in adult hippocampal neurogenesis. Sengi hippocampal cytoarchitecture is an amalgamation of characters that are found in CA1 of, e.g., guinea pig and rabbits and in CA3 and dentate gyrus of primates. Correspondence analysis of total cell numbers and quantitative relations between principal cell populations relate this sengi to macaque monkeys and domestic pigs, and distinguish the sengi from distinct patterns of relations found in humans, dogs, and murine rodents. Calretinin and calbindin are present in some cell populations that also express these proteins in other species, e.g., interneurons at the stratum oriens/alveus border or temporal hilar mossy cells, but neurons expressing these markers are often scarce or absent in other layers. The distributions of parvalbumin and somatostatin resemble those in other species. Normalized numbers of PCNA+ proliferating cells and doublecortin-positive (DCX+) differentiating cells of neuronal lineage fall within the overall ranges of murid rodents, but differed from three murid species captured in the same habitat in that fewer DCX+ cells relative to PCNA+ were observed. The large and well-differentiated sengi hippocampus is not accompanied by correspondingly sized cortical and subcortical limbic areas that are the main hippocampal sources of afferents and targets of efferents. This points to intrinsic hippocampal information processing as the selective advantage of the large sengi hippocampus.
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Affiliation(s)
- Lutz Slomianka
- Institute of Anatomy, University of ZürichZürich, Switzerland
| | - Tanja Drenth
- Institute of Anatomy, University of ZürichZürich, Switzerland
| | - Nicole Cavegn
- Institute of Anatomy, University of ZürichZürich, Switzerland
| | - Dominik Menges
- Institute of Anatomy, University of ZürichZürich, Switzerland
| | - Stanley E. Lazic
- In Silico Lead Discovery, Novartis Institutes for Biomedical ResearchBasel, Switzerland
| | - Mashudu Phalanndwa
- Mammal Research Institute, Department of Zoology and Entomology, University of PretoriaHatfield, South Africa
- Western Cape Nature Conservation Board (CapeNature)Cape Town, South Africa
| | - Christian T. Chimimba
- Mammal Research Institute, Department of Zoology and Entomology, University of PretoriaHatfield, South Africa
- Department of Science and Technology-National Research Foundation Centre of Excellence for Invasion Biology, Department of Zoology and Entomology University of PretoriaHatfield, South Africa
| | - Irmgard Amrein
- Institute of Anatomy, University of ZürichZürich, Switzerland
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Patzke N, Olaleye O, Haagensen M, Hof PR, Ihunwo AO, Manger PR. Organization and chemical neuroanatomy of the African elephant (Loxodonta africana) hippocampus. Brain Struct Funct 2013; 219:1587-601. [DOI: 10.1007/s00429-013-0587-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 05/22/2013] [Indexed: 10/26/2022]
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Scharfman HE, Myers CE. Hilar mossy cells of the dentate gyrus: a historical perspective. Front Neural Circuits 2013; 6:106. [PMID: 23420672 PMCID: PMC3572871 DOI: 10.3389/fncir.2012.00106] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 12/02/2012] [Indexed: 11/24/2022] Open
Abstract
The circuitry of the dentate gyrus (DG) of the hippocampus is unique compared to other hippocampal subfields because there are two glutamatergic principal cells instead of one: granule cells, which are the vast majority of the cells in the DG, and the so-called “mossy cells.” The distinctive appearance of mossy cells, the extensive divergence of their axons, and their vulnerability to excitotoxicity relative to granule cells has led to a great deal of interest in mossy cells. Nevertheless, there is no consensus about the normal functions of mossy cells and the implications of their vulnerability. There even seems to be some ambiguity about exactly what mossy cells are. Here we review initial studies of mossy cells, characteristics that define them, and suggest a practical definition to allow investigators to distinguish mossy cells from other hilar neurons even if all morphological and physiological information is unavailable due to technical limitations of their experiments. In addition, hypotheses are discussed about the role of mossy cells in the DG network, reasons for their vulnerability and their implications for disease.
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Affiliation(s)
- Helen E Scharfman
- New York University Langone Medical Center New York, NY, USA ; Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research Orangeburg, NY, USA
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Kim M, Soontornniyomkij V, Ji B, Zhou X. System-wide immunohistochemical analysis of protein co-localization. PLoS One 2012; 7:e32043. [PMID: 22363794 PMCID: PMC3283725 DOI: 10.1371/journal.pone.0032043] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 01/18/2012] [Indexed: 12/02/2022] Open
Abstract
Background The analysis of co-localized protein expression in a tissue section is often conducted with immunofluorescence histochemical staining which is typically visualized in localized regions. On the other hand, chromogenic immunohistochemical staining, in general, is not suitable for the detection of protein co-localization. Here, we developed a new protocol, based on chromogenic immunohistochemical stain, for system-wide detection of protein co-localization and differential expression. Methodology/Principal Findings In combination with a removable chromogenic stain, an efficient antibody stripping method was developed to enable sequential immunostaining with different primary antibodies regardless of antibody's host species. Sections were scanned after each staining, and the images were superimposed together for the detection of protein co-localization and differential expression. As a proof of principle, differential expression and co-localization of glutamic acid decarboxylase67 (GAD67) and parvalbumin proteins was examined in mouse cortex. Conclusions/Significance All parvalbumin-containing neurons express GAD67 protein, and GAD67-positive neurons that do not express parvalbumin were readily visualized from thousands of other neurons across mouse cortex. The method provided a global view of protein co-localization as well as differential expression across an entire tissue section. Repeated use of the same section could combine assessments of co-localization and differential expression of multiple proteins.
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Affiliation(s)
- MinJung Kim
- Department of Psychiatry, University of California San Diego, La Jolla, California, United States of America
| | - Virawudh Soontornniyomkij
- Department of Psychiatry, University of California San Diego, La Jolla, California, United States of America
| | - Baohu Ji
- Department of Psychiatry, University of California San Diego, La Jolla, California, United States of America
| | - Xianjin Zhou
- Department of Psychiatry, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
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Volz F, Bock HH, Gierthmuehlen M, Zentner J, Haas CA, Freiman TM. Stereologic estimation of hippocampal GluR2/3- and calretinin-immunoreactive hilar neurons (presumptive mossy cells) in two mouse models of temporal lobe epilepsy. Epilepsia 2011; 52:1579-89. [PMID: 21635231 DOI: 10.1111/j.1528-1167.2011.03086.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE Hippocampal mossy cells receive dense innervation from dentate granule cells and, in turn, mossy cells innervate both granule cells and interneurons. Mossy cell loss is thought to trigger granule cell mossy fiber sprouting, which may affect granule cell excitability. The aim of this study was to quantify mossy cell loss in two animal models of temporal lobe epilepsy, and determine whether there exists a relationship between mossy cell loss, mossy fiber sprouting, and granule cell dispersion. METHODS Representative hippocampal sections from p35 knockout mice and mice with unilateral intrahippocampal kainate injection were immunolabeled for GluR2/3, two subunits of the amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor and calretinin to identify mossy cells. Mossy fibers were immunostained against synaptoporin. KEY FINDINGS p35 Knockout mice showed no hilar cell death, but moderate mossy fiber sprouting and granule cell dispersion. In the kainate-injected hippocampus, there was an 80% and 85% reduction of GluR2/3- and GluR2/3/calretinin-positive hilar neurons, respectively, and dense mossy fiber sprouting and significant granule cell dispersion. In the contralateral hippocampus there was a 52% loss of GluR2/3-, but only a 20% loss of GluR2/3-calretinin-immunoreactive presumptive mossy cells, and granule cell dispersion; no mossy fiber sprouting was observed. SIGNIFICANCE These results indicate a probable lack of causality between mossy cell death and mossy fiber sprouting.
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Affiliation(s)
- Florian Volz
- Department of Neurosurgery, University Medical Center, Albert-Ludwigs-University, Freiburg, Germany
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19
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Burchiel KJ. Mesial temporal lobe epilepsy. J Neurosurg 2009; 111:1235. [PMID: 19392600 DOI: 10.3171/2008.11.jns081441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Lavenex P, Lavenex PB, Bennett JL, Amaral DG. Postmortem changes in the neuroanatomical characteristics of the primate brain: hippocampal formation. J Comp Neurol 2009; 512:27-51. [PMID: 18972553 DOI: 10.1002/cne.21906] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Comparative studies of the structural organization of the brain are fundamental to our understanding of human brain function. However, whereas brains of experimental animals are fixed by perfusion of a fixative through the vasculature, human or ape brains are fixed by immersion after varying postmortem intervals. Although differential treatments might affect the fundamental characteristics of the tissue, this question has not been evaluated empirically in primate brains. Monkey brains were either perfused or acquired after varying postmortem intervals before immersion-fixation in 4% paraformaldehyde. We found that the fixation method affected the neuroanatomical characteristics of the monkey hippocampal formation. Soma size was smaller in Nissl-stained, immersion-fixed tissue, although overall brain volume was larger as compared to perfusion-fixed tissue. Nonphosphorylated high-molecular-weight neurofilament immunoreactivity was lower in CA3 pyramidal neurons, dentate mossy cells, and the entorhinal cortex, whereas it was higher in the mossy fiber pathway in immersion-fixed tissue. Serotonin-immunoreactive fibers were well stained in perfused tissue but were undetectable in immersion-fixed tissue. Although regional immunoreactivity patterns for calcium-binding proteins were not affected, intracellular staining degraded with increasing postmortem intervals. Somatostatin-immunoreactive clusters of large axonal varicosities, previously reported only in humans, were observed in immersion-fixed monkey tissue. In addition, calretinin-immunoreactive multipolar neurons, previously observed only in rodents, were found in the rostral dentate gyrus in both perfused and immersion-fixed brains. In conclusion, comparative studies of the brain must evaluate the effects of fixation on the staining pattern of each marker in every structure of interest before drawing conclusions about species differences.
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Affiliation(s)
- Pierre Lavenex
- Department of Medicine, Unit of Physiology, University of Fribourg, 1700 Fribourg, Switzerland.
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Kondo H, Lavenex P, Amaral DG. Intrinsic connections of the macaque monkey hippocampal formation: I. Dentate gyrus. J Comp Neurol 2008; 511:497-520. [PMID: 18844234 DOI: 10.1002/cne.21825] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We have carried out a detailed analysis of the intrinsic connectivity of the Macaca fascicularis monkey hippocampal formation. Here we report findings on the topographical organization of the major connections of the dentate gyrus. Localized anterograde tracer injections were made at various rostrocaudal levels of the dentate gyrus, and we investigated the three-dimensional organization of the mossy fibers, the associational projection, and the local projections. The mossy fibers travel throughout the transverse extent of CA3 at the level of the cells of origin. Once the mossy fibers reach the distal portion of CA3, they change course and travel for 3-5 mm rostrally. The associational projection, originating from cells in the polymorphic layer, terminates in the inner one-third of the molecular layer. The associational projection, though modest at the level of origin, travels both rostrally and caudally from the injection site for as much as 80% of the rostrocaudal extent of the dentate gyrus. The caudally directed projection is typically more extensive and denser than the rostrally directed projection. Cells in the polymorphic layer originate local projections that terminate in the outer two-thirds of the molecular layer. These projections are densest at the level of the cells of origin but also extend several millimeters rostrocaudally. Overall, the topographic organization of the intrinsic connections of the monkey dentate gyrus is largely similar to that of the rat. Such extensive longitudinal connections have the potential for integrating information across much of the rostrocaudal extent of the dentate gyrus.
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Affiliation(s)
- Hideki Kondo
- Department of Psychiatry and Behavioral Sciences, The MIND Institute, The Center for Neuroscience, University of California, Davis, Davis, California 95817, USA
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