1
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Ghosh SK, Walocha JA. Evolution of staining methods in neuroanatomy: Impetus for emanation of neuron doctrine during the turn of 20th century. Anat Rec (Hoboken) 2024. [PMID: 38523436 DOI: 10.1002/ar.25436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 03/01/2024] [Accepted: 03/11/2024] [Indexed: 03/26/2024]
Abstract
The nervous system is distinctive as compared to other tissue systems in human body owing to intricate structural organization. Histological studies played a key role in unveiling complex details of nervous tissue. However, the process of developing suitable staining method for nerve cells was arduous and spanned across almost half a century. The present study explored details of the journey involving quest for propitious staining method in neuroanatomy culminating in promulgation of neuron doctrine at the onset of 20th century. Initial efforts involving hematoxylin (including its diverse modifications) and subsequent adoption of analogous dye-based stains (like Nissl's method) had limited success in visualization of different parts of a nerve cell and structural details of nervous tissue. This was due to inability of dye-based stains to penetrate the connective tissue sheath of nervous tissue. Eventually, advent of metallic stains in form of silver impregnation method (Golgi stain), reduced silver impregnation method with gold stain (Cajal's stain) and silver carbonate staining method of Río-Hortega unraveled the structure of nervous tissue. The evolution of staining methods catalyzed the refinement of theories pertinent to constitution of nervous tissue. Golgi's staining led to emergence of reticular theory (neurons exist as a network) and Nissl's staining was the basis of the concept of Nervösen Grau (nerve cells and glial cells are embedded in mass of gray matter). Finally, Cajal's staining method successfully elucidated the complex anatomy of nerve terminals and resulted in emanation of neuron doctrine (neurons exists as individual units with adjacent connections).
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Affiliation(s)
- Sanjib Kumar Ghosh
- Department of Anatomy, All India Institute of Medical Sciences, Patna, Bihar, India
| | - Jerzy A Walocha
- Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland
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2
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Gebicke-Haerter PJ. The computational power of the human brain. Front Cell Neurosci 2023; 17:1220030. [PMID: 37608987 PMCID: PMC10441807 DOI: 10.3389/fncel.2023.1220030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 07/05/2023] [Indexed: 08/24/2023] Open
Abstract
At the end of the 20th century, analog systems in computer science have been widely replaced by digital systems due to their higher computing power. Nevertheless, the question keeps being intriguing until now: is the brain analog or digital? Initially, the latter has been favored, considering it as a Turing machine that works like a digital computer. However, more recently, digital and analog processes have been combined to implant human behavior in robots, endowing them with artificial intelligence (AI). Therefore, we think it is timely to compare mathematical models with the biology of computation in the brain. To this end, digital and analog processes clearly identified in cellular and molecular interactions in the Central Nervous System are highlighted. But above that, we try to pinpoint reasons distinguishing in silico computation from salient features of biological computation. First, genuinely analog information processing has been observed in electrical synapses and through gap junctions, the latter both in neurons and astrocytes. Apparently opposed to that, neuronal action potentials (APs) or spikes represent clearly digital events, like the yes/no or 1/0 of a Turing machine. However, spikes are rarely uniform, but can vary in amplitude and widths, which has significant, differential effects on transmitter release at the presynaptic terminal, where notwithstanding the quantal (vesicular) release itself is digital. Conversely, at the dendritic site of the postsynaptic neuron, there are numerous analog events of computation. Moreover, synaptic transmission of information is not only neuronal, but heavily influenced by astrocytes tightly ensheathing the majority of synapses in brain (tripartite synapse). At least at this point, LTP and LTD modifying synaptic plasticity and believed to induce short and long-term memory processes including consolidation (equivalent to RAM and ROM in electronic devices) have to be discussed. The present knowledge of how the brain stores and retrieves memories includes a variety of options (e.g., neuronal network oscillations, engram cells, astrocytic syncytium). Also epigenetic features play crucial roles in memory formation and its consolidation, which necessarily guides to molecular events like gene transcription and translation. In conclusion, brain computation is not only digital or analog, or a combination of both, but encompasses features in parallel, and of higher orders of complexity.
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Affiliation(s)
- Peter J. Gebicke-Haerter
- Institute of Psychopharmacology, Central Institute of Mental Health, Faculty of Medicine, University of Heidelberg, Mannheim, Germany
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3
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Abstract
Satellite glial cells (SGCs) that surround sensory neurons in the peripheral nervous system ganglia originate from neural crest cells. Although several studies have focused on SGCs, the origin and characteristics of SGCs are unknown, and their lineage remains unidentified. Traditionally, it has been considered that SGCs regulate the environment around neurons under pathological conditions, and perform functions of supporting, nourishing, and protecting neurons. However, recent studies demonstrated that SGCs may have the characteristics of stem cells. After nerve injury, SGCs up-regulate the expression of stem cell markers and can differentiate into functional sensory neurons. Moreover, SGCs express several markers of Schwann cell precursors and Schwann cells, such as CDH19, MPZ, PLP1, SOX10, ERBB3, and FABP7. Schwann cell precursors have also been proposed as a potential source of neurons in the peripheral nervous system. The similarity in function and markers suggests that SGCs may represent a subgroup of Schwann cell precursors. Herein, we discuss the roles and functions of SGCs, and the lineage relationship between SGCs and Schwann cell precursors. We also describe a new perspective on the roles and functions of SGCs. In the DRG located on the posterior root of spinal nerves, satellite glial cells wrap around each sensory neuron to form an anatomically and functionally distinct unit with the sensory neurons. Following nerve injury, satellite glial cells up-regulate the expression of progenitor markers, and can differentiate into neurons.
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Ortinski PI, Reissner KJ, Turner J, Anderson TA, Scimemi A. Control of complex behavior by astrocytes and microglia. Neurosci Biobehav Rev 2022; 137:104651. [PMID: 35367512 DOI: 10.1016/j.neubiorev.2022.104651] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/28/2022] [Accepted: 03/21/2022] [Indexed: 02/07/2023]
Abstract
Evidence that glial cells influence behavior has been gaining a steady foothold in scientific literature. Out of the five main subtypes of glial cells in the brain, astrocytes and microglia have received an outsized share of attention with regard to shaping a wide spectrum of behavioral phenomena and there is growing appreciation that the signals intrinsic to these cells as well as their interactions with surrounding neurons reflect behavioral history in a brain region-specific manner. Considerable regional diversity of glial cell phenotypes is beginning to be recognized and may contribute to behavioral outcomes arising from circuit-specific computations within and across discrete brain nuclei. Here, we summarize current knowledge on the impact of astrocyte and microglia activity on behavioral outcomes, with a specific focus on brain areas relevant to higher cognitive control, reward-seeking, and circadian regulation.
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Affiliation(s)
- P I Ortinski
- Department of Neuroscience, University of Kentucky, USA
| | - K J Reissner
- Department of Psychology and Neuroscience, University of North Carolina Chapel Hill, USA
| | - J Turner
- Department of Pharmaceutical Sciences, University of Kentucky, USA
| | - T A Anderson
- Department of Neuroscience, University of Kentucky, USA
| | - A Scimemi
- Department of Biology, State University of New York at Albany, USA
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5
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Landucci E, Mazzantini C, Lana D, Giovannini MG, Pellegrini-Giampietro DE. Neuronal and Astrocytic Morphological Alterations Driven by Prolonged Exposure with Δ9-Tetrahydrocannabinol but Not Cannabidiol. TOXICS 2022; 10:toxics10020048. [PMID: 35202235 PMCID: PMC8879505 DOI: 10.3390/toxics10020048] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/13/2022] [Accepted: 01/18/2022] [Indexed: 12/24/2022]
Abstract
Cannabis derivatives are largely used in the general population for recreational and medical purposes, with the highest prevalence among adolescents, but chronic use and abuse has raised medical concerns. We investigated the prolonged effects of Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) in organotypic hippocampal slices from P7 rats cultured for 2 weeks. Cell death in the CA1 subregion of slices was quantified by propidium iodide (PI) fluorescence, pre-synaptic and post-synaptic marker proteins were analysed by Western blotting and neurodegeneration and astrocytic alterations by NeuN and GFAP by immunofluorescence and confocal laser microscopy. The statistical significance of differences was analysed using ANOVA with a post hoc Dunnett w-test (PI fluorescence intensities and Western blots) or Newman–Keuls (immunohistochemistry data) for multiple comparisons. A probability value (P) of < 0.05 was considered significant. Prolonged (72 h) THC or CBD incubation did not induce cell death but caused modifications in the expression of synaptic proteins and morphological alterations in neurons and astrocytes. In particular, the expression of PSD95 was reduced following incubation for 72 h with THC and was increased following incubation with CBD. THC for 72 h caused disorganisation of CA1 stratum pyramidalis (SP) and complex morphological modifications in a significant number of pyramidal neurons and in astrocytes. Our results suggest that THC or CBD prolonged exposure induce different effects in the hippocampus. In particular, 72 h of THC exposure induced neuronal and glia alterations that must draw our attention to the effects that relatively prolonged use might cause, especially in adolescents.
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The Microbiota-Gut-Brain Axis and Alzheimer Disease. From Dysbiosis to Neurodegeneration: Focus on the Central Nervous System Glial Cells. J Clin Med 2021; 10:jcm10112358. [PMID: 34072107 PMCID: PMC8199461 DOI: 10.3390/jcm10112358] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/21/2021] [Accepted: 05/24/2021] [Indexed: 02/06/2023] Open
Abstract
The microbiota-gut system can be thought of as a single unit that interacts with the brain via the "two-way" microbiota-gut-brain axis. Through this axis, a constant interplay mediated by the several products originating from the microbiota guarantees the physiological development and shaping of the gut and the brain. In the present review will be described the modalities through which the microbiota and gut control each other, and the main microbiota products conditioning both local and brain homeostasis. Much evidence has accumulated over the past decade in favor of a significant association between dysbiosis, neuroinflammation and neurodegeneration. Presently, the pathogenetic mechanisms triggered by molecules produced by the altered microbiota, also responsible for the onset and evolution of Alzheimer disease, will be described. Our attention will be focused on the role of astrocytes and microglia. Numerous studies have progressively demonstrated how these glial cells are important to ensure an adequate environment for neuronal activity in healthy conditions. Furthermore, it is becoming evident how both cell types can mediate the onset of neuroinflammation and lead to neurodegeneration when subjected to pathological stimuli. Based on this information, the role of the major microbiota products in shifting the activation profiles of astrocytes and microglia from a healthy to a diseased state will be discussed, focusing on Alzheimer disease pathogenesis.
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Lana D, Ugolini F, Nosi D, Wenk GL, Giovannini MG. The Emerging Role of the Interplay Among Astrocytes, Microglia, and Neurons in the Hippocampus in Health and Disease. Front Aging Neurosci 2021; 13:651973. [PMID: 33889084 PMCID: PMC8055856 DOI: 10.3389/fnagi.2021.651973] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 03/11/2021] [Indexed: 12/21/2022] Open
Abstract
For over a century, neurons have been considered the basic functional units of the brain while glia only elements of support. Activation of glia has been long regarded detrimental for survival of neurons but more it appears that this is not the case in all circumstances. In this review, we report and discuss the recent literature on the alterations of astrocytes and microglia during inflammaging, the low-grade, slow, chronic inflammatory response that characterizes normal brain aging, and in acute inflammation. Becoming reactive, astrocytes and microglia undergo transcriptional, functional, and morphological changes that transform them into cells with different properties and functions, such as A1 and A2 astrocytes, and M1 and M2 microglia. This classification of microglia and astrocytes in two different, all-or-none states seems too simplistic, and does not correspond to the diverse variety of phenotypes so far found in the brain. Different interactions occur among the many cell populations of the central nervous system in health and disease conditions. Such interactions give rise to networks of morphological and functional reciprocal reliance and dependency. Alterations affecting one cell population reverberate to the others, favoring or dysregulating their activities. In the last part of this review, we present the modifications of the interplay between neurons and glia in rat models of brain aging and acute inflammation, focusing on the differences between CA1 and CA3 areas of the hippocampus, one of the brain regions most susceptible to different insults. With triple labeling fluorescent immunohistochemistry and confocal microscopy (TIC), it is possible to evaluate and compare quantitatively the morphological and functional alterations of the components of the neuron-astrocyte-microglia triad. In the contiguous and interconnected regions of rat hippocampus, CA1 and CA3 Stratum Radiatum, astrocytes and microglia show a different, finely regulated, and region-specific reactivity, demonstrating that glia responses vary in a significant manner from area to area. It will be of great interest to verify whether these differential reactivities of glia explain the diverse vulnerability of the hippocampal areas to aging or to different damaging insults, and particularly the higher sensitivity of CA1 pyramidal neurons to inflammatory stimuli.
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Affiliation(s)
- Daniele Lana
- Clinical Pharmacology and Oncology, Department of Health Sciences, University of Florence, Florence, Italy
| | - Filippo Ugolini
- Section of Anatomopatology, Department of Health Sciences, University of Florence, Florence, Italy
| | - Daniele Nosi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Gary L Wenk
- Department of Psychology, The Ohio State University, Columbus, OH, United States
| | - Maria Grazia Giovannini
- Clinical Pharmacology and Oncology, Department of Health Sciences, University of Florence, Florence, Italy
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Wang D, Lu J, Xu X, Yuan Y, Zhang Y, Xu J, Chen H, Liu J, Shen Y, Zhang H. Satellite Glial Cells Give Rise to Nociceptive Sensory Neurons. Stem Cell Rev Rep 2021; 17:999-1013. [PMID: 33389681 DOI: 10.1007/s12015-020-10102-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2020] [Indexed: 12/27/2022]
Abstract
Dorsal root ganglia (DRG) sensory neurons can transmit information about noxious stimulus to cerebral cortex via spinal cord, and play an important role in the pain pathway. Alterations of the pain pathway lead to CIPA (congenital insensitivity to pain with anhidrosis) or chronic pain. Accumulating evidence demonstrates that nerve damage leads to the regeneration of neurons in DRG, which may contribute to pain modulation in feedback. Therefore, exploring the regeneration process of DRG neurons would provide a new understanding to the persistent pathological stimulation and contribute to reshape the somatosensory function. It has been reported that a subpopulation of satellite glial cells (SGCs) express Nestin and p75, and could differentiate into glial cells and neurons, suggesting that SGCs may have differentiation plasticity. Our results in the present study show that DRG-derived SGCs (DRG-SGCs) highly express neural crest cell markers Nestin, Sox2, Sox10, and p75, and differentiate into nociceptive sensory neurons in the presence of histone deacetylase inhibitor VPA, Wnt pathway activator CHIR99021, Notch pathway inhibitor RO4929097, and FGF pathway inhibitor SU5402. The nociceptive sensory neurons express multiple functionally-related genes (SCN9A, SCN10A, SP, Trpv1, and TrpA1) and are able to generate action potentials and voltage-gated Na+ currents. Moreover, we found that these cells exhibited rapid calcium transients in response to capsaicin through binding to the Trpv1 vanilloid receptor, confirming that the DRG-SGC-derived cells are nociceptive sensory neurons. Further, we show that Wnt signaling promotes the differentiation of DRG-SGCs into nociceptive sensory neurons by regulating the expression of specific transcription factor Runx1, while Notch and FGF signaling pathways are involved in the expression of SCN9A. These results demonstrate that DRG-SGCs have stem cell characteristics and can efficiently differentiate into functional nociceptive sensory neurons, shedding light on the clinical treatment of sensory neuron-related diseases.
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Affiliation(s)
- Dongyan Wang
- Department of Cell Biology, Medical College of Soochow University, Suzhou, 215123, China
| | - Junhou Lu
- Department of Cell Biology, Medical College of Soochow University, Suzhou, 215123, China
| | - Xiaojing Xu
- Department of Cell Biology, Medical College of Soochow University, Suzhou, 215123, China
| | - Ye Yuan
- Department of Cell Biology, Medical College of Soochow University, Suzhou, 215123, China
| | - Yu Zhang
- Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Suzhou, 215006, China
| | - Jianwei Xu
- National Guizhou Joint Engineering Laboratory for Cell Engineering and Biomedicine Technique, Center for Tissue Engineering and Stem Cell Research, Guizhou Province Key Laboratory of Regenerative Medicine, Guizhou Medical University, Guiyang, 550004, China
| | - Huanhuan Chen
- Department of Cell Biology, Medical College of Soochow University, Suzhou, 215123, China
| | - Jinming Liu
- Department of Cell Biology, Medical College of Soochow University, Suzhou, 215123, China
| | - Yixin Shen
- Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Suzhou, 215006, China.
| | - Huanxiang Zhang
- Department of Cell Biology, Medical College of Soochow University, Suzhou, 215123, China.
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9
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Lana D, Ugolini F, Giovannini MG. Space-Dependent Glia-Neuron Interplay in the Hippocampus of Transgenic Models of β-Amyloid Deposition. Int J Mol Sci 2020; 21:E9441. [PMID: 33322419 PMCID: PMC7763751 DOI: 10.3390/ijms21249441] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/03/2020] [Accepted: 12/09/2020] [Indexed: 12/14/2022] Open
Abstract
This review is focused on the description and discussion of the alterations of astrocytes and microglia interplay in models of Alzheimer's disease (AD). AD is an age-related neurodegenerative pathology with a slowly progressive and irreversible decline of cognitive functions. One of AD's histopathological hallmarks is the deposition of amyloid beta (Aβ) plaques in the brain. Long regarded as a non-specific, mere consequence of AD pathology, activation of microglia and astrocytes is now considered a key factor in both initiation and progression of the disease, and suppression of astrogliosis exacerbates neuropathology. Reactive astrocytes and microglia overexpress many cytokines, chemokines, and signaling molecules that activate or damage neighboring cells and their mutual interplay can result in virtuous/vicious cycles which differ in different brain regions. Heterogeneity of glia, either between or within a particular brain region, is likely to be relevant in healthy conditions and disease processes. Differential crosstalk between astrocytes and microglia in CA1 and CA3 areas of the hippocampus can be responsible for the differential sensitivity of the two areas to insults. Understanding the spatial differences and roles of glia will allow us to assess how these interactions can influence the state and progression of the disease, and will be critical for identifying therapeutic strategies.
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Affiliation(s)
- Daniele Lana
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Firenze, Italy;
| | - Filippo Ugolini
- Department of Health Sciences, Section of Anatomopathology, University of Florence, Viale Pieraccini 6, 50139 Firenze, Italy;
| | - Maria Grazia Giovannini
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Viale Pieraccini 6, 50139 Firenze, Italy;
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10
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Lana D, Ugolini F, Giovannini MG. An Overview on the Differential Interplay Among Neurons-Astrocytes-Microglia in CA1 and CA3 Hippocampus in Hypoxia/Ischemia. Front Cell Neurosci 2020; 14:585833. [PMID: 33262692 PMCID: PMC7686560 DOI: 10.3389/fncel.2020.585833] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 10/09/2020] [Indexed: 12/13/2022] Open
Abstract
Neurons have been long regarded as the basic functional cells of the brain, whereas astrocytes and microglia have been regarded only as elements of support. However, proper intercommunication among neurons-astrocytes-microglia is of fundamental importance for the functional organization of the brain. Perturbation in the regulation of brain energy metabolism not only in neurons but also in astrocytes and microglia may be one of the pathophysiological mechanisms of neurodegeneration, especially in hypoxia/ischemia. Glial activation has long been considered detrimental for survival of neurons, but recently it appears that glial responses to an insult are not equal but vary in different brain areas. In this review, we first take into consideration the modifications of the vascular unit of the glymphatic system and glial metabolism in hypoxic conditions. Using the method of triple-labeling fluorescent immunohistochemistry coupled with confocal microscopy (TIC), we recently studied the interplay among neurons, astrocytes, and microglia in chronic brain hypoperfusion. We evaluated the quantitative and morpho-functional alterations of the neuron-astrocyte-microglia triads comparing the hippocampal CA1 area, more vulnerable to ischemia, to the CA3 area, less vulnerable. In these contiguous and interconnected areas, in the same experimental hypoxic conditions, astrocytes and microglia show differential, finely regulated, region-specific reactivities. In both areas, astrocytes and microglia form triad clusters with apoptotic, degenerating neurons. In the neuron-astrocyte-microglia triads, the cell body of a damaged neuron is infiltrated and bisected by branches of astrocyte that create a microscar around it while a microglial cell phagocytoses the damaged neuron. These coordinated actions are consistent with the scavenging and protective activities of microglia. In hypoxia, the neuron-astrocyte-microglia triads are more numerous in CA3 than in CA1, further indicating their protective effects. These data, taken from contiguous and interconnected hippocampal areas, demonstrate that glial response to the same hypoxic insult is not equal but varies significantly. Understanding the differences of glial reactivity is of great interest to explain the differential susceptibility of hippocampal areas to hypoxia/ischemia. Further studies may evidence the differential reactivity of glia in different brain areas, explaining the higher or lower sensitivity of these areas to different insults and whether glia may represent a target for future therapeutic interventions.
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Affiliation(s)
- Daniele Lana
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
| | - Filippo Ugolini
- Department of Health Sciences, Section of Anatomopathology, University of Florence, Florence, Italy
| | - Maria G Giovannini
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
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11
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Verkhratsky A, Rodrigues JJ, Pivoriunas A, Zorec R, Semyanov A. Astroglial atrophy in Alzheimer’s disease. Pflugers Arch 2019; 471:1247-1261. [DOI: 10.1007/s00424-019-02310-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/23/2019] [Accepted: 09/03/2019] [Indexed: 12/11/2022]
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12
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Zhu G, Dai B, Chen Z, He L, Guo J, Dan Y, Liang S, Li G. Effects of chronic lead exposure on the sympathoexcitatory response associated with the P2X7 receptor in rat superior cervical ganglia. Auton Neurosci 2019; 219:33-41. [DOI: 10.1016/j.autneu.2019.03.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 02/01/2019] [Accepted: 03/20/2019] [Indexed: 12/23/2022]
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13
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Ugolini F, Lana D, Nardiello P, Nosi D, Pantano D, Casamenti F, Giovannini MG. Different Patterns of Neurodegeneration and Glia Activation in CA1 and CA3 Hippocampal Regions of TgCRND8 Mice. Front Aging Neurosci 2018; 10:372. [PMID: 30483118 PMCID: PMC6243135 DOI: 10.3389/fnagi.2018.00372] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/26/2018] [Indexed: 01/24/2023] Open
Abstract
We investigated the different patterns of neurodegeneration and glia activation in CA1 and CA3 hippocampal areas of TgCRND8 mice. The main feature of this transgenic model is the rapid development of the amyloid pathology, which starts already at 3 months of age. We performed immunohistochemical analyses to compare the different sensibility of the two hippocampal regions to neurodegeneration. We performed qualitative and quantitative evaluations by fluorescence immunohistochemistry with double or triple staining, followed by confocal microscopy and digital image analysis in stratum pyramidale (SP) and stratum radiatum (SR) of CA1 and CA3, separately. We evaluated time-dependent Aβ plaques deposition, expression of inflammatory markers, as well as quantitative and morphological alterations of neurons and glia in transgenic mice at 3 (Tg 3M) and 6 (Tg 6M) months of age, compared to WT mice. In CA1 SR of Tg 6M mice, we found significantly more Medium and Large plaques than in CA3. The pattern of neurodegeneration and astrocytes activation was different in the two areas, indicating higher sensitivity of CA1. In the CA1 SP of Tg 6M mice, we found signs of reactive astrogliosis, such as increase of astrocytes density in SP, increase of GFAP expression in SR, and elongation of astrocytes branches. We found also common patterns of glia activation and neurodegenerative processes in CA1 and CA3 of Tg 6M mice: significant increase of total and reactive microglia density in SP and SR, increased expression of TNFα, of iNOS, and IL1β in astrocytes and increased density of neurons-astrocytes-microglia triads. In CA1 SP, we found decrease of volume and number of pyramidal neurons, paralleled by increase of apoptosis, and, consequently, shrinkage of CA1 SP. These data demonstrate that in TgCRND8 mice, the responses of neurons and glia to neurodegenerative patterns induced by Aβ plaques deposition is not uniform in the two hippocampal areas, and in CA1 pyramidal neurons, the higher sensitivity may be related to the different plaque distribution in this area. All these modifications may be at the basis of memory loss, the peculiar symptom of AD, which was demonstrated in this transgenic mouse model of Aβ deposition, even at early stages.
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Affiliation(s)
- Filippo Ugolini
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
| | - Daniele Lana
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
| | - Pamela Nardiello
- Department of Neuroscience, Psychology, Drug Research and Child Health, NEUROFARBA, Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Daniele Nosi
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Daniela Pantano
- Department of Neuroscience, Psychology, Drug Research and Child Health, NEUROFARBA, Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Fiorella Casamenti
- Department of Neuroscience, Psychology, Drug Research and Child Health, NEUROFARBA, Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Maria Grazia Giovannini
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
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14
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Robertson JM. The Gliocentric Brain. Int J Mol Sci 2018; 19:ijms19103033. [PMID: 30301132 PMCID: PMC6212929 DOI: 10.3390/ijms19103033] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 09/23/2018] [Accepted: 09/28/2018] [Indexed: 01/10/2023] Open
Abstract
The Neuron Doctrine, the cornerstone of research on normal and abnormal brain functions for over a century, has failed to discern the basis of complex cognitive functions. The location and mechanisms of memory storage and recall, consciousness, and learning, remain enigmatic. The purpose of this article is to critically review the Neuron Doctrine in light of empirical data over the past three decades. Similarly, the central role of the synapse and associated neural networks, as well as ancillary hypotheses, such as gamma synchrony and cortical minicolumns, are critically examined. It is concluded that each is fundamentally flawed and that, over the past three decades, the study of non-neuronal cells, particularly astrocytes, has shown that virtually all functions ascribed to neurons are largely the result of direct or indirect actions of glia continuously interacting with neurons and neural networks. Recognition of non-neural cells in higher brain functions is extremely important. The strict adherence of purely neurocentric ideas, deeply ingrained in the great majority of neuroscientists, remains a detriment to understanding normal and abnormal brain functions. By broadening brain information processing beyond neurons, progress in understanding higher level brain functions, as well as neurodegenerative and neurodevelopmental disorders, will progress beyond the impasse that has been evident for decades.
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15
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Ribas KHDS, Ribas VR, Barros SSM, Ribas VR, Filizola MDGN, Ribas RDMG, da Silva PC, Kucera CAC, Martins HADL. The participation of Early Maladaptive Schemas (EMSs) in the perception of pain in patients with migraine: A psychological profile. Dement Neuropsychol 2018; 12:68-74. [PMID: 29682236 PMCID: PMC5901252 DOI: 10.1590/1980-57642018dn12-010010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Young's early maladaptive schemas questionnaire (YSQ-S3) is used to understand psychological aspects. Objective EMSs were evaluated in patients with migraine. Methods Sixty-five subjects were evaluated using the YSQ-S3 under standard conditions in a room with air conditioning at 22 ± 2°C. The subjects were stratified by morbidity (migraine), gender (male/female) and age (18-29 / 30-39 / 40-55). Controls (without migraine), n = 27 and patients (with migraine), n = 38, men (n = 19) and women (n = 46); participants aged 18-29 years, n = 34, aged 30-39 years, n = 14 and aged 40-55 years, n = 17. Data were analyzed using the Chi-square test, with p-values <0.05. Results were expressed as percentages in contingency tables. Results There was a significant association between migraine and female gender (84.21%; p-value <0.05, Table 1), between hypervigilance and inhibition, and unrelenting standards (56.52%; p-value <0.0.014, Table 2) and female gender with migraine. Moreover, there was a significant association between hypervigilance and inhibition, and unrelenting standards (73.68%; p-value <0.0001) and self-punishment (84.21%; p-value <0.0001) in patients with migraine of both genders (Table 3). Conclusion The individuals with migraine had a psychological profile of being overly demanding with themselves and others and self-punishing, where this was more frequent in women.
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Affiliation(s)
| | - Valdenilson Ribeiro Ribas
- Universidade Federal de Pernambuco, Doutorado em Neuropsiquiatria e Ciências do Comportamento Recife, PE, Brazil
| | | | - Valéria Ribeiro Ribas
- Universidade Federal de Pernambuco, Mestrado em Neuropsiquiatria e Ciências do Comportamento Recife, PE, Brazil
| | | | | | - Paulo César da Silva
- Cérebro e Tecnologia Neurofeedback Recife (CTNR) - Cursos/Pesquisas Jaboatão dos Guararapes, PE, Brazil
| | | | - Hugo André de Lima Martins
- Universidade Federal de Pernambuco, Doutorado em Neuropsiquiatria e Ciências do Comportamento Recife, PE, Brazil
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16
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Zinchenko VP, Gaidin SG, Teplov IY, Kosenkov AM. Inhibition of spontaneous synchronous activity of hippocampal neurons by excitation of GABAergic neurons. BIOCHEMISTRY MOSCOW SUPPLEMENT SERIES A-MEMBRANE AND CELL BIOLOGY 2017. [DOI: 10.1134/s1990747817040110] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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17
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The protective effect of resveratrol in the transmission of neuropathic pain mediated by the P2X 7 receptor in the dorsal root ganglia. Neurochem Int 2016; 103:24-35. [PMID: 28027922 DOI: 10.1016/j.neuint.2016.12.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 11/24/2016] [Accepted: 12/15/2016] [Indexed: 02/02/2023]
Abstract
The P2X7 receptor mediates afferent nerve activation and is related to chronic neuropathic pain. Resveratrol (RES) has also been reported to exhibit anti-inflammatory effects. In this study, we investigated the neuroprotective effect of RES on the transmission of neuropathic pain mediated by the P2X7 receptor. The P2X7 mRNA and protein expression levels in L4-L5 dorsal root ganglia (DRG)s of the chronic constriction injury (CCI) group were significantly higher than those observed in the Ctrl + NS, Sham + RES and Sham groups. RES increased the threshold of thermal and mechanical hypersensitivity in rats with chronic neuropathic pain. The P2X7 mRNA and protein expression levels in the CCI + RES group were decreased compared with those in the CCI group. Our results showed that RES inhibited the upregulated co-expression of P2X7 and glial fibrillary acidic protein (GFAP, a marker of satellite glial cells) in satellite glial cells of DRG in the CCI group. The results demonstrated that the expression of GFAP was increased in the CCI group and that RES inhibited the upregulated expression of GFAP in the rats in the CCI group. In addition, the phosphorylation levels of p38 and extracellular regulated protein kinases (ERK)1/2 in the CCI group were markedly higher than those observed in the Ctrl + NS, Sham + RES and Sham groups, whereas the phosphorylation levels of p38 and ERK1/2 in CCI + RES group were markedly lower than those observed in the CCI group. RES inhibited BzATP-activated currents in DRG non-neurons in the CCI rats. Our data provide evidence that RES may suppress the transmission of neuropathic pain mediated by the P2X7 receptor in the satellite glial cells of dorsal root ganglia.
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18
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Gottipati MK, Verkhratsky A, Parpura V. Probing astroglia with carbon nanotubes: modulation of form and function. Philos Trans R Soc Lond B Biol Sci 2015; 369:20130598. [PMID: 25225092 DOI: 10.1098/rstb.2013.0598] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Carbon nanotubes (CNTs) have shown much promise in neurobiology and biomedicine. Their structural stability and ease of chemical modification make them compatible for biological applications. In this review, we discuss the effects that chemically functionalized CNTs, applied as colloidal solutes or used as strata, have on the morpho-functional properties of astrocytes, the most abundant cells present in the brain, with an insight into the potential use of CNTs in neural prostheses.
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Affiliation(s)
- Manoj K Gottipati
- Department of Neurobiology, University of Alabama, Birmingham, AL 35294, USA Department of Biomedical Engineering, University of Alabama, Birmingham, AL 35294, USA
| | - Alexei Verkhratsky
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain Department of Neurosciences, University of the Basque Country UPV/EHU, 48940 Leioa, Spain
| | - Vladimir Parpura
- Department of Neurobiology, University of Alabama, Birmingham, AL 35294, USA Department of Biomedical Engineering, University of Alabama, Birmingham, AL 35294, USA Department of Biotechnology, University of Rijeka, 51000 Rijeka, Croatia
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19
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Kim HJ, Ahn HJ, Lee S, Kim JH, Park J, Jeon SH, Kim SH. Intrinsic dorsoventral patterning and extrinsic EGFR signaling genes control glial cell development in the Drosophila nervous system. Neuroscience 2015; 307:242-52. [PMID: 26318336 DOI: 10.1016/j.neuroscience.2015.08.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 08/08/2015] [Accepted: 08/20/2015] [Indexed: 11/26/2022]
Abstract
Dorsoventral patterning and epidermal growth factor receptor (EGFR) signaling genes are essential for determining neural identity and differentiation of the Drosophila nervous system. Their role in glial cell development in the Drosophila nervous system is not clearly established. Our study demonstrated that the dorsoventral patterning genes, vnd, ind, and msh, are intrinsically essential for the proper expression of a master glial cell regulator, gcm, and a differentiation gene, repo, in the lateral glia. In addition, we showed that esg is particularly required for their expression in the peripheral glia. These results indicate that the dorsoventral patterning and EGFR signaling genes are essential for identity determination and differentiation of the lateral glia by regulating proper expression of gcm and repo in the lateral glia from the early glial development. In contrast, overexpression of vnd, msh, spi, and Egfr genes repressed the expression of Repo in the ventral neuroectoderm, indicating that maintenance of correct columnar identity along the dorsoventral axis by proper expression of these genes is essential for restrictive formation of glial precursor cells in the lateral neuroectoderm. Therefore, the dorsoventral patterning and EGFR signaling genes play essential roles in correct identity determination and differentiation of lateral glia in the Drosophila nervous system.
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Affiliation(s)
- H J Kim
- Department of Chemistry, Konkuk University, Seoul 143-701, Republic of Korea
| | - H J Ahn
- Department of Chemistry, Konkuk University, Seoul 143-701, Republic of Korea
| | - S Lee
- Department of Chemistry, Konkuk University, Seoul 143-701, Republic of Korea
| | - J H Kim
- Department of Chemistry, Konkuk University, Seoul 143-701, Republic of Korea
| | - J Park
- Department of Chemistry, Konkuk University, Seoul 143-701, Republic of Korea
| | - S-H Jeon
- Department of Biology Education, Seoul National University, Seoul 151-742, Republic of Korea
| | - S H Kim
- Department of Chemistry, Konkuk University, Seoul 143-701, Republic of Korea.
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20
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Illes P, Verkhratsky A. Purinergic neurone-glia signalling in cognitive-related pathologies. Neuropharmacology 2015; 104:62-75. [PMID: 26256423 DOI: 10.1016/j.neuropharm.2015.08.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 07/19/2015] [Accepted: 08/03/2015] [Indexed: 12/31/2022]
Abstract
Neuroglia, represented by astrocytes, oligodendrocytes, NG glia and microglia are homeostatic, myelinating and defensive cells of the brain. Neuroglial cells express various combinations of purinoceptors, which contribute to multiple intercellular signalling pathways in the healthy and diseased nervous system. Neurological diseases are invariably associated with profound neuroglial remodelling, which is manifest by reactive gliosis, pathological remodelling and functional atrophy of various types of glial cells. Gliopathology is disease and region specific and produces multiple glial phenotypes that may be neuroprotective or neurotoxic. In this review we summarise recent knowledge on the role of glial purinergic signalling in cognitive-related neurological diseases. This article is part of the Special Issue entitled 'Purines in Neurodegeneration and Neuroregeneration'.
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Affiliation(s)
- Peter Illes
- Rudolf Boehm Institute for Pharmacology and Toxicology, University of Leipzig, 04107 Leipzig, Germany.
| | - Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester, M13 9PT, UK; Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain; Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain; University of Nizhny Novgorod, Nizhny Novgorod 603022, Russia.
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21
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Kuriu T, Kakimoto Y, Araki O. Computational simulation: astrocyte-induced depolarization of neighboring neurons mediates synchronous UP states in a neural network. J Biol Phys 2015; 41:377-90. [PMID: 25940565 DOI: 10.1007/s10867-015-9385-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Accepted: 03/19/2015] [Indexed: 11/30/2022] Open
Abstract
Although recent reports have suggested that synchronous neuronal UP states are mediated by astrocytic activity, the mechanism responsible for this remains unknown. Astrocytic glutamate release synchronously depolarizes adjacent neurons, while synaptic transmissions are blocked. The purpose of this study was to confirm that astrocytic depolarization, propagated through synaptic connections, can lead to synchronous neuronal UP states. We applied astrocytic currents to local neurons in a neural network consisting of model cortical neurons. Our results show that astrocytic depolarization may generate synchronous UP states for hundreds of milliseconds in neurons even if they do not directly receive glutamate release from the activated astrocyte.
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Affiliation(s)
- Takayuki Kuriu
- Department of Applied Physics, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-8585, Japan
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22
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Canavero S, Bonicalzi V. Pain Myths and the Genesis of Central Pain. PAIN MEDICINE 2015; 16:240-8. [DOI: 10.1111/pme.12509] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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23
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Mitterauer BJ. Balancing and imbalancing effects of astrocytic receptors in tripartite synapses. Common pathophysiological model of mental disorders and epilepsy. Med Hypotheses 2015; 84:315-20. [PMID: 25655220 DOI: 10.1016/j.mehy.2015.01.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 01/15/2015] [Indexed: 02/01/2023]
Abstract
Based on a logic of balance mechanisms influencing information processing in tripartite synapses are proposed. It is hypothesized that the number of expressed astrocytic receptors determines balanced and imbalanced synaptic states. Synaptic information processing in mental disorders is underbalanced in depression, overbalanced in mania, and completely unbalanced in schizophrenia. The synaptic pathophysiology of the epileptic syndrome may also be based on comparable imbalances. In addition, this model of synaptic balancing enables a deduction in explaining the therapeutic effect of ECT in therapy resistant depression. Together, the model proposed may represent a contribution to the search for common synaptic mechanisms in normal brains and its various disorders.
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24
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Metna-Laurent M, Marsicano G. Rising stars: modulation of brain functions by astroglial type-1 cannabinoid receptors. Glia 2014; 63:353-64. [PMID: 25452006 DOI: 10.1002/glia.22773] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 11/13/2014] [Indexed: 01/03/2023]
Abstract
The type-1-cannabinoid (CB1 ) receptor is amongst the most widely expressed G protein-coupled receptors in the brain. In few decades, CB1 receptors have been shown to regulate a large array of functions from brain cell development and survival to complex cognitive processes. Understanding the cellular mechanisms underlying these functions of CB1 is complex due to the heterogeneity of the brain cell types on which the receptor is expressed. Although the large majority of CB1 receptors act on neurons, early studies pointed to a direct control of CB1 receptors over astroglial functions including brain energy supply and neuroprotection. In line with the growing concept of the tripartite synapse highlighting astrocytes as direct players in synaptic plasticity, astroglial CB1 receptor signaling recently emerged as the mediator of several forms of synaptic plasticity associated to important cognitive functions. Here, we shortly review the current knowledge on CB1 receptor-mediated astroglial functions. This functional spectrum is large and most of the mechanisms by which CB1 receptors control astrocytes, as well as their consequences in vivo, are still unknown, requiring innovative approaches to improve this new cannabinoid research field.
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25
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V.M FDL, W H. Relevance of excitable media theory and retinal spreading depression experiments in preclinical pharmacological research. Curr Neuropharmacol 2014; 12:413-33. [PMID: 25426010 PMCID: PMC4243032 DOI: 10.2174/1570159x12666140630190800] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 06/29/2014] [Accepted: 06/29/2014] [Indexed: 11/22/2022] Open
Abstract
In preclinical neuropharmacological research, molecular, cell-based, and systems using animals are well established. On the tissue level the situation is less comfortable, although during the last decades some effort went into establishing such systems, i.e. using slices of the vertebrate brain together with optical and electrophysiological techniques. However, these methods are neither fast, nor can they be automated or upscaled. By contrast, the chicken retina can be used as a suitable model. It is easy accessible and can be kept alive in vitro for hours up to days. Due to its structure, in addition the retina displays remarkable intrinsic optical signals, which can be easily used in experiments. Also to electrophysiological methods the retina is well accessible. In excitable tissue, to which the brain and the retina belong, propagating excitation waves can be expected, and the spreading depression is such a phenomenon. It has been first observed in the forties of the last century. Later, Martins-Ferreira established it in the chicken retina (retinal spreading depression or RSD). The electrophysiological characteristics of it are identical with those of the cortical SD. The metabolic differences are known and can be taken into account. The experimental advantage of the RSD compared to the cortical SD is the pronounced intrinsic optical signal (IOS) associated with the travelling wave. This is due to the maximum transparency of retinal tissue in the functional state; thus any physiological event will change it markedly and therefore can be easily seen even by naked eye. The theory can explain wave spread in one (action potentials), two (RSDs) and three dimensions (one heart beat). In this review we present the experimental and the excitable media context for the data interpretation using as example the cholinergic pharmacology in relation to functional syndromes. We also discuss the intrinsic optical signal and how to use it in pre-clinical research.
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Affiliation(s)
- Fernandes de Lima V.M
- Medical Faculty, Federal University São João Del Rei, CCO, Divinopolis, MG, Brazil LIM- 26 Medical Faculty, USP, Medical Faculty, Sao Paulo, Brazil
| | - Hanke W
- University of Hohenheim, Inst. Physiol., Stuttgart, Germany
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26
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Abstract
The multifunctional properties of astrocytes signify their importance in brain physiology and neurological function. In addition to defining the brain architecture, astrocytes are primary elements of brain ion, pH and neurotransmitter homoeostasis. GS (glutamine synthetase), which catalyses the ATP-dependent condensation of ammonia and glutamate to form glutamine, is an enzyme particularly found in astrocytes. GS plays a pivotal role in glutamate and glutamine homoeostasis, orchestrating astrocyte glutamate uptake/release and the glutamate-glutamine cycle. Furthermore, astrocytes bear the brunt of clearing ammonia in the brain, preventing neurotoxicity. The present review depicts the central function of astrocytes, concentrating on the importance of GS in glutamate/glutamine metabolism and ammonia detoxification in health and disease.
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27
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Information handling by the brain: proposal of a new "paradigm" involving the roamer type of volume transmission and the tunneling nanotube type of wiring transmission. J Neural Transm (Vienna) 2014; 121:1431-49. [PMID: 24866694 DOI: 10.1007/s00702-014-1240-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 05/06/2014] [Indexed: 12/13/2022]
Abstract
The current view on the organization of the central nervous system (CNS) is basically anchored to the paradigm describing the brain as formed by networks of neurons interconnected by synapses. Synaptic contacts are a fundamental characteristic for describing CNS operations, but increasing evidence accumulated in the last 30 years pointed to a refinement of this view. A possible overcoming of the classical "neuroscience paradigm" will be here outlined, based on the following hypotheses: (1) the basic morpho-functional unit in the brain is a compartment of tissue (functional module) where different resident cells (not only neurons) work as an integrated unit; (2) in these complex networks, a spectrum of intercellular communication processes is exploited, that can be classified according to a dichotomous criterion: wiring transmission (occurring through physically delimited channels) and volume transmission (exploiting diffusion in the extracellular space); (3) the connections between cells can themselves be described as a network, leading to an information processing occurring at different levels from cell network down to molecular level; (4) recent evidence of the existence of specialized structures (microvesicles and tunneling nanotubes) for intercellular exchange of materials, could allow a further type of polymorphism of the CNS networks based on at least transient changes in cell phenotype. When compared to the classical paradigm, the proposed scheme of cellular organization could allow a strong increase of the degrees of freedom available to the whole system and then of its plasticity. Furthermore, long range coordination and correlation can be more easily accommodated within this framework.
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28
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Tewari S, Parpura V. Data and model tango to aid the understanding of astrocyte-neuron signaling. Front Comput Neurosci 2014; 8:3. [PMID: 24478686 PMCID: PMC3900764 DOI: 10.3389/fncom.2014.00003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 01/07/2014] [Indexed: 11/13/2022] Open
Affiliation(s)
- Shivendra Tewari
- Department of Molecular and Integrative Physiology, University of Michigan Ann Arbor, MI, USA
| | - Vladimir Parpura
- Department of Neurobiology, University of Alabama at Birmingham Birmingham, AL, USA ; Department of Biotechnology, University or Rijeka Rijeka, Croatia
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29
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Verkhratsky A, Burnstock G. Purinergic and glutamatergic receptors on astroglia. ADVANCES IN NEUROBIOLOGY 2014; 11:55-79. [PMID: 25236724 DOI: 10.1007/978-3-319-08894-5_4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Astroglial cells express many neurotransmitter receptors; the receptors to glutamate and ATP being the most abundant. Here, we provide a concise overview on the expression and main properties of astroglial glutamate receptors (ionotropic receptors represented by AMPA and NMDA subtypes) and metabotropic (mainly mGluR5 and mGluR3 subtypes) and purinoceptors (adenosine receptors of A1, A2A, A2B, and A3 types, ionotropic P2X1/5 and P2X7 subtypes, and metabotropic P2Y purinoceptors). We also discuss the role of these receptors in glial physiology and pathophysiology.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Life Sciences, School of Biological Sciences, The University of Manchester, 1.124 Stopford Building, Oxford Road, Manchester, M13 9PT, UK,
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30
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Robertson JM. Astrocytes and the evolution of the human brain. Med Hypotheses 2013; 82:236-9. [PMID: 24388487 DOI: 10.1016/j.mehy.2013.12.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 12/10/2013] [Indexed: 12/01/2022]
Abstract
Cells within the astroglial lineage are proposed as the origin of human brain evolution. It is now widely accepted that they direct mammalian fetal neurogenesis, gliogenesis, laminar cytoarchitectonics, synaptic connectivity and neuronal network formation. Furthermore, genetic, anatomical and functional studies have recently identified multiple astrocyte exaptations that strongly suggest a direct relation to the increased size and complexity of the human brain.
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31
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Robertson JM. Astrocyte domains and the three-dimensional and seamless expression of consciousness and explicit memories. Med Hypotheses 2013; 81:1017-24. [DOI: 10.1016/j.mehy.2013.09.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 08/30/2013] [Accepted: 09/13/2013] [Indexed: 01/19/2023]
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32
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Liu J, Li G, Peng H, Tu G, Kong F, Liu S, Gao Y, Xu H, Qiu S, Fan B, Zhu Q, Yu S, Zheng C, Wu B, Peng L, Song M, Wu Q, Li G, Liang S. Sensory-sympathetic coupling in superior cervical ganglia after myocardial ischemic injury facilitates sympathoexcitatory action via P2X7 receptor. Purinergic Signal 2013; 9:463-79. [PMID: 23754120 PMCID: PMC3757147 DOI: 10.1007/s11302-013-9367-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 05/13/2013] [Indexed: 12/17/2022] Open
Abstract
P2X receptors participate in cardiovascular regulation and disease. After myocardial ischemic injury, sensory-sympathetic coupling between rat cervical DRG nerves and superior cervical ganglia (SCG) facilitated sympathoexcitatory action via P2X7 receptor. The results showed that after myocardial ischemic injury, the systolic blood pressure, heart rate, serum cardiac enzymes, IL-6, and TNF-α were increased, while the levels of P2X7 mRNA and protein in SCG were also upregulated. However, these alterations diminished after treatment of myocardial ischemic (MI) rats with the P2X7 antagonist oxATP. After siRNA P2X7 in MI rats, the systolic blood pressure, heart rate, serum cardiac enzymes, the expression levels of the satellite glial cell (SGC) or P2X7 were significantly lower than those in MI group. The phosphorylation of ERK 1/2 in SCG participated in the molecular mechanism of the sympathoexcitatory action induced by the myocardial ischemic injury. Retrograde tracing test revealed the sprouting of CGRP or SP sensory nerves (the markers of sensory afferent fibers) from DRG to SCG neurons. The upregulated P2X7 receptor promoted the activation of SGCs in SCG, resulting in the formation of sensory-sympathetic coupling which facilitated the sympathoexcitatory action. P2X7 antagonist oxATP could inhibit the activation of SGCs and interrupt the formation of sensory-sympathetic coupling in SCG after the myocardial ischemic injury. Our findings may benefit the treatment of coronary heart disease and other cardiovascular diseases.
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Affiliation(s)
- Jun Liu
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
| | - Guilin Li
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
| | - Haiying Peng
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
| | - Guihua Tu
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
| | - Fanjun Kong
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
| | - Shuangmei Liu
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
| | - Yun Gao
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
| | - Hong Xu
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
| | - Shuyi Qiu
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
| | - Bo Fan
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
| | - Qicheng Zhu
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
| | - Shicheng Yu
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
| | - Chaoran Zheng
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
| | - Bing Wu
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
| | - Lichao Peng
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
| | - Miaomiao Song
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
| | - Qin Wu
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
| | - Guodong Li
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
| | - Shangdong Liang
- />Department of Physiology, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
- />Key Laboratory of Basic Medicine, Medical College of Nanchang University, Nanchang, Jiangxi 330006 People’s Republic of China
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Parpura V, Verkhratsky A. Astrocytes revisited: concise historic outlook on glutamate homeostasis and signaling. Croat Med J 2013; 53:518-28. [PMID: 23275317 PMCID: PMC3541578 DOI: 10.3325/cmj.2012.53.518] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Astroglia is a main type of brain neuroglia, which includes many cell sub-types that differ in their morphology and physiological properties and yet are united by the main function, which is the maintenance of brain homeostasis. Astrocytes employ a variety of mechanisms for communicating with neuronal networks. The communication mediated by neurotransmitter glutamate has received a particular attention. Glutamate is de novo synthesized exclusively in astrocytes; astroglia-derived glutamine is the source of glutamate for neurons. Glutamate is released from both neurons and astroglia through exocytosis, although various other mechanisms may also play a role. Glutamate-activated specific receptors trigger excitatory responses in neurons and astroglia. Here we overview main properties of glutamatergic transmission in neuronal-glial networks and identify some future challenges facing the field.
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Affiliation(s)
- Vladimir Parpura
- Department of Neurobiology, University of Alabama, Birmingham, AL 35294-0021, USA.
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Agnati LF, Guidolin D, Battistin L, Pagnoni G, Fuxe K. The neurobiology of imagination: possible role of interaction-dominant dynamics and default mode network. Front Psychol 2013; 4:296. [PMID: 23745117 PMCID: PMC3662866 DOI: 10.3389/fpsyg.2013.00296] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 05/07/2013] [Indexed: 11/29/2022] Open
Abstract
This work aims at presenting some hypotheses about the potential neurobiological substrate of imagery and imagination. For the present purposes, we will define imagery as the production of mental images associated with previous percepts, and imagination as the faculty of forming mental images of a novel character relating to something that has never been actually experienced by the subject but at a great extent emerges from his inner world. The two processes appear intimately related and imagery can arguably be considered as one of the main components of imagination. In this proposal, we argue that exaptation and redeployment, two basic concepts capturing important aspects of the evolution of biological structures and functions (Anderson, 2007), could also be useful in explaining imagery and imagination. As far as imagery is concerned it is proposed that neural structures originally implicated in performing certain functions, e.g., motor actions, can be reused for the imagery of the virtual execution of that function. As far as imagination is concerned we speculate that it can be the result of a “tinkering” that combines and modifies stored perceptual information and concepts leading to the creation of novel “mental objects” that are shaped by the subject peculiar inner world. Hence it is related to his self-awareness. The neurobiological substrate of the tinkering process could be found in a hierarchical model of the brain characterized by a multiplicity of functional modules (FMs) that can be assembled according to different spatial and temporal scales. Thus, it is surmised that a possible mechanism for the emergence of imagination could be represented by modulatory mechanisms controlling the perviousness of “modifiers” along the communication channels within and between FMs leading to their dynamically reassembling into novel configurations.
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Tu G, Li G, Peng H, Hu J, Liu J, Kong F, Liu S, Gao Y, Xu C, Xu X, Qiu S, Fan B, Zhu Q, Yu S, Zheng C, Wu B, Peng L, Song M, Wu Q, Liang S. P2X(7) inhibition in stellate ganglia prevents the increased sympathoexcitatory reflex via sensory-sympathetic coupling induced by myocardial ischemic injury. Brain Res Bull 2013; 96:71-85. [PMID: 23688519 DOI: 10.1016/j.brainresbull.2013.05.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 05/08/2013] [Accepted: 05/09/2013] [Indexed: 12/11/2022]
Abstract
Purinergic signaling has been found to participate in the regulation of cardiovascular function. In this study, using a rat myocardial ischemic injury model, the sympathoexcitatory reflex mediated by P2X7 receptor via sensory-sympathetic coupling between cervical dorsal root ganglia (DRG) nerves and stellate ganglia (SG) nerves was explored. Our results showed that the systolic blood pressure, heart rate, serum cardiac enzymes concentrations, interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) concentrations were increased, and the expression levels of P2X7 mRNA and protein in DRG and SG were up-regulated after myocardial ischemic injury. Administration of brilliant blue G (BBG), a selective P2X7 antagonist, decreased the elevation of systolic blood pressure, heart rate, serum cardiac enzyme, IL-6 and TNF-α, and inhibited the up-regulated expression of P2X7 mRNA and protein in DRG and SG after myocardial ischemic injury. Retrograde tracing test showed that there were calcitonin gene-related peptide sensory nerves and substance P sensory nerves sprouting from DRG to SG, which played an important role in the development of myocardial ischemic injury. The up-regulated P2X7 receptor expression levels on the surface membrane of satellite glial cells contributed to the activation of sensory-sympathetic coupling, which in turn facilitated the sympathoexcitatory reflex. BBG can inhibit the activation of satellite glial cells and interrupt the generation of sensory-sympathetic coupling in the cervical sympathetic ganglia after the myocardial ischemic injury. Taken together, these findings may provide a new therapeutic approach for treating coronary heart disease, hypertension and other cardiovascular diseases.
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Affiliation(s)
- Guihua Tu
- Department of Physiology, Information Engineering College of Nanchang University, Nanchang, Jiangxi 330006, PR China
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Verkhratsky A, Parpura V. Store-operated calcium entry in neuroglia. Neurosci Bull 2013; 30:125-33. [PMID: 23677809 DOI: 10.1007/s12264-013-1343-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Accepted: 02/14/2013] [Indexed: 11/30/2022] Open
Abstract
Neuroglial cells are homeostatic neural cells. Generally, they are electrically non-excitable and their activation is associated with the generation of complex intracellular Ca(2+) signals that define the "Ca(2+) excitability" of glia. In mammalian glial cells the major source of Ca(2+) for this excitability is the lumen of the endoplasmic reticulum (ER), which is ultimately (re)filled from the extracellular space. This occurs via store-operated Ca(2+) entry (SOCE) which is supported by a specific signaling system connecting the ER with plasmalemmal Ca(2+) entry. Here, emptying of the ER Ca(2+) store is necessary and sufficient for the activation of SOCE, and without Ca(2+) influx via SOCE the ER store cannot be refilled. The molecular arrangements underlying SOCE are relatively complex and include plasmalemmal channels, ER Ca(2+) sensors, such as stromal interaction molecule, and possibly ER Ca(2+) pumps (of the SERCA type). There are at least two sets of plasmalemmal channels mediating SOCE, the Ca(2+)-release activated channels, Orai, and transient receptor potential (TRP) channels. The molecular identity of neuroglial SOCE has not been yet identified unequivocally. However, it seems that Orai is predominantly expressed in microglia, whereas astrocytes and oligodendrocytes rely more on TRP channels to produce SOCE. In physiological conditions the SOCE pathway is instrumental for the sustained phase of the Ca(2+) signal observed following stimulation of metabotropic receptors on glial cells.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester, M13 9PT, UK,
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Najjar S, Pearlman DM, Alper K, Najjar A, Devinsky O. Neuroinflammation and psychiatric illness. J Neuroinflammation 2013; 10:43. [PMID: 23547920 PMCID: PMC3626880 DOI: 10.1186/1742-2094-10-43] [Citation(s) in RCA: 456] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 01/28/2013] [Indexed: 12/19/2022] Open
Abstract
Multiple lines of evidence support the pathogenic role of neuroinflammation in psychiatric illness. While systemic autoimmune diseases are well-documented causes of neuropsychiatric disorders, synaptic autoimmune encephalitides with psychotic symptoms often go under-recognized. Parallel to the link between psychiatric symptoms and autoimmunity in autoimmune diseases, neuroimmunological abnormalities occur in classical psychiatric disorders (for example, major depressive, bipolar, schizophrenia, and obsessive-compulsive disorders). Investigations into the pathophysiology of these conditions traditionally stressed dysregulation of the glutamatergic and monoaminergic systems, but the mechanisms causing these neurotransmitter abnormalities remained elusive. We review the link between autoimmunity and neuropsychiatric disorders, and the human and experimental evidence supporting the pathogenic role of neuroinflammation in selected classical psychiatric disorders. Understanding how psychosocial, genetic, immunological and neurotransmitter systems interact can reveal pathogenic clues and help target new preventive and symptomatic therapies.
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Affiliation(s)
- Souhel Najjar
- Department of Neurology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA.
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Abstract
Astroglia encompass a subset of versatile glial cells that fulfill a major homeostatic role in the mammalian brain. Since any brain disease results from failure in brain homeostasis, astroglial cells are involved in many, if not all, aspects of neurological and/or psychiatric disorders. In this article, the roles of astrocytes as homeostatic cells in healthy and diseased brains are surveyed. These cells can mount the defence response to the insult of the brain, astrogliosis, when and where they display hypertrophy. Interestingly, astrocytes can alternatively display atrophy in some pathological conditions. Various pathologies, including Alexander and Alzheimer's diseases, amyotrophic lateral sclerosis, stroke and epilepsy, to mention a few, are discussed. Astrocytes could represent a novel target for medical intervention in the treatment of brain disorders.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester, UK
- Ikerbasque, Basque Foundation for Science, 48011, Bilbao, Spain
- Department of Neurosciences, University of the Basque Country UPV/EHU 48940, Leioa, Spain
- Institute of Experimental Medicine, ASCR, Videnska 1083, 142 20, Prague, Czech Republic
| | - José J Rodríguez
- Ikerbasque, Basque Foundation for Science, 48011, Bilbao, Spain
- Department of Neurosciences, University of the Basque Country UPV/EHU 48940, Leioa, Spain
- Institute of Experimental Medicine, ASCR, Videnska 1083, 142 20, Prague, Czech Republic
| | - Vladimir Parpura
- Ikerbasque, Basque Foundation for Science, 48011, Bilbao, Spain
- Department of Neurosciences, University of the Basque Country UPV/EHU 48940, Leioa, Spain
- Department of Neurobiology, Center for Glial Biology in Medicine, Civitan International Research Center, Atomic Force Microscopy & Nanotechnology Laboratories, & Evelyn F McKnight Brain Institute, University of Alabama, Birmingham, AL, USA
- Department of Biotechnology, University of Rijeka, 51000 Rijeka, Croatia
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Parpura V, Verkhratsky A. Astroglial amino acid-based transmitter receptors. Amino Acids 2013; 44:1151-8. [DOI: 10.1007/s00726-013-1458-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 01/02/2013] [Indexed: 10/27/2022]
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Mack AF, Tiedemann K. Cultures of astroglial cells derived from brain of adult cichlid fish. J Neurosci Methods 2013; 212:269-75. [DOI: 10.1016/j.jneumeth.2012.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 10/22/2012] [Accepted: 11/08/2012] [Indexed: 10/27/2022]
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Abstract
Astrocytes exhibit their excitability based on variations in cytosolic Ca(2+) levels, which leads to variety of signalling events. Only recently, however, intracellular fluctuations of more abundant cation Na(+) are brought in the limelight of glial signalling. Indeed, astrocytes possess several plasmalemmal molecular entities that allow rapid transport of Na(+) across the plasma membrane: (1) ionotropic receptors, (2) canonical transient receptor potential cation channels, (3) neurotransmitter transporters and (4) sodium-calcium exchanger. Concerted action of these molecules in controlling cytosolic Na(+) may complement Ca(2+) signalling to provide basis for complex bidirectional astrocyte-neurone communication at the tripartite synapse.
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Parpura V, Verkhratsky A. The astrocyte excitability brief: From receptors to gliotransmission. Neurochem Int 2012; 61:610-21. [DOI: 10.1016/j.neuint.2011.12.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2011] [Revised: 11/14/2011] [Accepted: 12/01/2011] [Indexed: 01/23/2023]
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Kulijewicz-Nawrot M, Verkhratsky A, Chvátal A, Syková E, Rodríguez JJ. Astrocytic cytoskeletal atrophy in the medial prefrontal cortex of a triple transgenic mouse model of Alzheimer's disease. J Anat 2012; 221:252-62. [PMID: 22738374 DOI: 10.1111/j.1469-7580.2012.01536.x] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by the loss of cognitive functions, reflecting pathological damage to the medial prefrontal cortex (mPFC) as well as to the hippocampus and the entorhinal cortex. Astrocytes maintain the internal homeostasis of the CNS and are fundamentally involved in neuropathological processes, including AD. Here, we analysed the astrocytic cytoskeletal changes within the mPFC of a triple transgenic mouse model of AD (3 × Tg-AD) by measuring the surface area and volume of glial fibrillary acidic protein (GFAP)-positive profiles in relation to the build-up and presence of amyloid-β (Aβ), and compared the results with those found in non-transgenic control animals at different ages. 3 × Tg-AD animals showed clear astroglial cytoskeletal atrophy, which appeared at an early age (3 months; 33% and 47% decrease in GFAP-positive surface area and volume, respectively) and remained throughout the disease progression at 9, 12 and 18 months old (29% and 36%; 37% and 35%; 43% and 37%, respectively). This atrophy was independent of Aβ accumulation, as only a few GFAP-positive cells were localized around Aβ aggregates, which suggests no direct relationship with Aβ toxicity. Thus, our results indicate that the progressive reduction in astrocytic branching and domain in the mPFC can account for the integrative dysfunction leading to the cognitive deficits and memory disturbances observed in AD.
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Parpura V, Verkhratsky A. Neuroglia at the crossroads of homoeostasis, metabolism and signalling: evolution of the concept. ASN Neuro 2012; 4:201-5. [PMID: 22455879 PMCID: PMC3342593 DOI: 10.1042/an20120019] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 03/28/2012] [Accepted: 03/29/2012] [Indexed: 11/22/2022] Open
Abstract
Ever since Rudolf Virchow in 1858 publicly announced his apprehension of neuroglia being a true connective substance, this concept has been evolving to encompass a heterogeneous population of cells with various forms and functions. We briefly compare the 19th-20th century perspectives on neuroglia with the up-to-date view of these cells as an integral, and possibly integrating, component of brain metabolism and signalling in heath and disease. We conclude that the unifying property of otherwise diverse functions of various neuroglial cell sub-types is to maintain brain homoeostasis at different levels, from whole organ to molecular.
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Affiliation(s)
- Vladimir Parpura
- *Department of Neurobiology, Center for Glial Biology in Medicine, Atomic Force Microscopy and Nanotechnology Laboratories, Civitan International Research Center, Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham, AL 35294, U.S.A
- †IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
- ‡Department of Neurosciences, University of the Basque Country UPVEHU, 48940, Leioa, Spain
- §School of Medicine, University of Split, 21000 Split, Croatia
| | - Alexei Verkhratsky
- †IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain
- ‡Department of Neurosciences, University of the Basque Country UPVEHU, 48940, Leioa, Spain
- ‖Faculty of Life Sciences, The University of Manchester, Manchester, M13 9PT, U.K
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Franke H, Verkhratsky A, Burnstock G, Illes P. Pathophysiology of astroglial purinergic signalling. Purinergic Signal 2012; 8:629-57. [PMID: 22544529 DOI: 10.1007/s11302-012-9300-0] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 02/01/2012] [Indexed: 12/13/2022] Open
Abstract
Astrocytes are fundamental for central nervous system (CNS) physiology and are the fulcrum of neurological diseases. Astroglial cells control development of the nervous system, regulate synaptogenesis, maturation, maintenance and plasticity of synapses and are central for nervous system homeostasis. Astroglial reactions determine progression and outcome of many neuropathologies and are critical for regeneration and remodelling of neural circuits following trauma, stroke, ischaemia or neurodegenerative disorders. They secrete multiple neurotransmitters and neurohormones to communicate with neurones, microglia and the vascular walls of capillaries. Signalling through release of ATP is the most widespread mean of communication between astrocytes and other types of neural cells. ATP serves as a fast excitatory neurotransmitter and has pronounced long-term (trophic) roles in cell proliferation, growth, and development. During pathology, ATP is released from damaged cells and acts both as a cytotoxic factor and a proinflammatory mediator, being a universal "danger" signal. In this review, we summarise contemporary knowledge on the role of purinergic receptors (P2Rs) in a variety of diseases in relation to changes of astrocytic functions and nucleotide signalling. We have focussed on the role of the ionotropic P2X and metabotropic P2YRs working alone or in concert to modify the release of neurotransmitters, to activate signalling cascades and to change the expression levels of ion channels and protein kinases. All these effects are of great importance for the initiation, progression and maintenance of astrogliosis-the conserved and ubiquitous glial defensive reaction to CNS pathologies. We highlighted specific aspects of reactive astrogliosis, especially with respect to the involvement of the P2X(7) and P2Y(1)R subtypes. Reactive astrogliosis exerts both beneficial and detrimental effects in a context-specific manner determined by distinct molecular signalling cascades. Understanding the role of purinergic signalling in astrocytes is critical to identifying new therapeutic principles to treat acute and chronic neurological diseases.
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Affiliation(s)
- Heike Franke
- Rudolf Boehm Institute of Pharmacology and Toxicology, University of Leipzig, Härtelstrasse 16-18, 04107, Leipzig, Germany.
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Verkhratsky A, Rodríguez JJ, Parpura V. Calcium signalling in astroglia. Mol Cell Endocrinol 2012; 353:45-56. [PMID: 21945602 DOI: 10.1016/j.mce.2011.08.039] [Citation(s) in RCA: 171] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 08/28/2011] [Accepted: 08/31/2011] [Indexed: 12/15/2022]
Abstract
Astroglia possess excitability based on movements of Ca(2+) ions between intracellular compartments and plasmalemmal Ca(2+) fluxes. This "Ca(2+) excitability" is controlled by several families of proteins located in the plasma membrane, within the cytosol and in the intracellular organelles, most notably in the endoplasmic reticulum (ER) and mitochondria. Accumulation of cytosolic Ca(2+) can be caused by the entry of Ca(2+) from the extracellular space through ionotropic receptors and store-operated channels expressed in astrocytes. Plasmalemmal Ca(2+) ATP-ase and sodium-calcium exchanger extrude cytosolic Ca(2+) to the extracellular space; the exchanger can also operate in reverse, depending of the intercellular Na(+) concentration, to deliver Ca(2+) to the cytosol. The ER internal store possesses inositol 1,4,5-trisphosphate receptors which can be activated upon stimulation of astrocytes through a multiple plasma membrane metabotropic G-protein coupled receptors. This leads to release of Ca(2+) from the ER and its elevation in the cytosol, the level of which can be modulated by mitochondria. The mitochondrial uniporter takes up Ca(2+) into the matrix, while free Ca(2+) exits the matrix through the mitochondrial Na(+)/Ca(2+) exchanger as well as via transient openings of the mitochondrial permeability transition pore. One of the prominent consequences of astroglial Ca(2+) excitability is gliotransmission, a release of transmitters from astroglia which can lead to signalling to adjacent neurones.
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Exocytosis in astrocytes: transmitter release and membrane signal regulation. Neurochem Res 2012; 37:2351-63. [PMID: 22528833 DOI: 10.1007/s11064-012-0773-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 03/28/2012] [Accepted: 03/29/2012] [Indexed: 12/14/2022]
Abstract
Astrocytes, a type of glial cells in the brain, are eukaryotic cells, and a hallmark of these are subcellular organelles, such as secretory vesicles. In neurons vesicles play a key role in signaling. Upon a stimulus-an increase in cytosolic concentration of free Ca(2+) ([Ca(2+)](i))-the membrane of vesicle fuses with the presynaptic plasma membrane, allowing the exit of neurotransmitters into the extracellular space and their diffusion to the postsynaptic receptors. For decades it was thought that such vesicle-based mechanisms of gliotransmitter release were not present in astrocytes. However, in the last 30 years experimental evidence showed that astrocytes are endowed with mechanisms for vesicle- and non-vesicle-based gliotransmitter release mechanisms. The aim of this review is to focus on exocytosis, which may play a role in gliotransmission and also in other forms of cell-to-cell communication, such as the delivery of transporters, ion channels and antigen presenting molecules to the cell surface.
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Verkhratsky A, Rodríguez JJ, Parpura V. Neurotransmitters and integration in neuronal-astroglial networks. Neurochem Res 2012; 37:2326-38. [PMID: 22476701 DOI: 10.1007/s11064-012-0765-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 03/18/2012] [Accepted: 03/22/2012] [Indexed: 10/28/2022]
Abstract
Two major neural cell types, glia, astrocytes in particular, and neurones can release chemical transmitters that act as soluble signalling compounds for intercellular communication. Exocytosis, a process which depends on an increase in cytosolic Ca(2+) levels, represents a common denominator for release of neurotransmitters, stored in secretory vesicles, from these neural cells. While neurones rely predominately on the immediate entry of Ca(2+) from the extracellular space to the cytosol in this process, astrocytes support their cytosolic Ca(2+) increases by appropriating this ion from the intracellular endoplasmic reticulum store and extracellular space. Additionally, astrocytes can release neurotransmitters using a variety of non-vesicular pathways which are mediated by an assortment of plasmalemmal channels and transporters. Once a neuronal and/or astrocytic neurotransmitter is released into the extracellular space, it can activate plasma membrane neurotransmitter receptors on neural cells, causing autocrine and/or paracrine signalling. Moreover, chemical transmission is essential not only for homocellular, but also for heterocellular bi-directional communication in the brain. Further detailed understanding of chemical transmission will aid our comprehension of the brain (dys)function in heath and disease.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester, M13 9PT, UK.
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Wang F, Smith NA, Xu Q, Fujita T, Baba A, Matsuda T, Takano T, Bekar L, Nedergaard M. Astrocytes modulate neural network activity by Ca²+-dependent uptake of extracellular K+. Sci Signal 2012; 5:ra26. [PMID: 22472648 DOI: 10.1126/scisignal.2002334] [Citation(s) in RCA: 204] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Astrocytes are electrically nonexcitable cells that display increases in cytosolic calcium ion (Ca²+) in response to various neurotransmitters and neuromodulators. However, the physiological role of astrocytic Ca²+ signaling remains controversial. We show here that astrocytic Ca²+ signaling ex vivo and in vivo stimulated the Na+,K+-ATPase (Na+- and K+-dependent adenosine triphosphatase), leading to a transient decrease in the extracellular potassium ion (K+) concentration. This in turn led to neuronal hyperpolarization and suppressed baseline excitatory synaptic activity, detected as a reduced frequency of excitatory postsynaptic currents. Synaptic failures decreased in parallel, leading to an increase in synaptic fidelity. The net result was that astrocytes, through active uptake of K+, improved the signal-to-noise ratio of synaptic transmission. Active control of the extracellular K+ concentration thus provides astrocytes with a simple yet powerful mechanism to rapidly modulate network activity.
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Affiliation(s)
- Fushun Wang
- Division of Glia Disease and Therapeutics, Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical School, Rochester, NY 14640, USA
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Parpura V, Heneka MT, Montana V, Oliet SHR, Schousboe A, Haydon PG, Stout RF, Spray DC, Reichenbach A, Pannicke T, Pekny M, Pekna M, Zorec R, Verkhratsky A. Glial cells in (patho)physiology. J Neurochem 2012; 121:4-27. [PMID: 22251135 DOI: 10.1111/j.1471-4159.2012.07664.x] [Citation(s) in RCA: 402] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Neuroglial cells define brain homeostasis and mount defense against pathological insults. Astroglia regulate neurogenesis and development of brain circuits. In the adult brain, astrocytes enter into intimate dynamic relationship with neurons, especially at synaptic sites where they functionally form the tripartite synapse. At these sites, astrocytes regulate ion and neurotransmitter homeostasis, metabolically support neurons and monitor synaptic activity; one of the readouts of the latter manifests in astrocytic intracellular Ca(2+) signals. This form of astrocytic excitability can lead to release of chemical transmitters via Ca(2+) -dependent exocytosis. Once in the extracellular space, gliotransmitters can modulate synaptic plasticity and cause changes in behavior. Besides these physiological tasks, astrocytes are fundamental for progression and outcome of neurological diseases. In Alzheimer's disease, for example, astrocytes may contribute to the etiology of this disorder. Highly lethal glial-derived tumors use signaling trickery to coerce normal brain cells to assist tumor invasiveness. This review not only sheds new light on the brain operation in health and disease, but also points to many unknowns.
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Affiliation(s)
- Vladimir Parpura
- Department of Neurobiology, Center for Glial Biology in Medicine, Civitan International Research Center, Atomic Force Microscopy & Nanotechnology Laboratories, and Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham, Alabama, USA.
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