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Kosenkov AM, Maiorov SA, Gaidin SG. Astrocytic NMDA Receptors. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:1045-1060. [PMID: 38981700 DOI: 10.1134/s0006297924060063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 07/11/2024]
Abstract
Astrocytic NMDA receptors (NMDARs) are heterotetramers, whose expression and properties are largely determined by their subunit composition. Astrocytic NMDARs are characterized by a low sensitivity to magnesium ions and low calcium conductivity. Their activation plays an important role in the regulation of various intracellular processes, such as gene expression and mitochondrial function. Astrocytic NMDARs are involved in calcium signaling in astrocytes and can act through the ionotropic and metabotropic pathways. Astrocytic NMDARs participate in the interactions of the neuroglia, thus affecting synaptic plasticity. They are also engaged in the astrocyte-vascular interactions and contribute to the regulation of vascular tone. Astrocytic NMDARs are involved in various pathologies, such as ischemia and hyperammonemia, and their blockade prevents negative changes in astrocytes during these diseases.
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Affiliation(s)
- Artem M Kosenkov
- Pushchino Scientific Center for Biological Research, Institute of Cell Biophysics of the Russian Academy of Sciences, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
| | - Sergei A Maiorov
- Pushchino Scientific Center for Biological Research, Institute of Cell Biophysics of the Russian Academy of Sciences, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
| | - Sergei G Gaidin
- Pushchino Scientific Center for Biological Research, Institute of Cell Biophysics of the Russian Academy of Sciences, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
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2
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Spatial contribution of hippocampal BOLD activation in high-resolution fMRI. Sci Rep 2019; 9:3152. [PMID: 30816226 PMCID: PMC6395694 DOI: 10.1038/s41598-019-39614-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 01/29/2019] [Indexed: 12/14/2022] Open
Abstract
While the vascular origin of the BOLD-fMRI signal is established, the exact neurovascular coupling events contributing to this signal are still incompletely understood. Furthermore, the hippocampal spatial properties of the BOLD activation are not elucidated, although electrophysiology approaches have already revealed the precise spatial patterns of neural activity. High magnetic field fMRI offers improved contrast and allows for a better correlation with the underlying neuronal activity because of the increased contribution to the BOLD signal of small blood vessels. Here, we take advantage of these two benefits to investigate the spatial characteristics of the hippocampal activation in a rat model before and after changing the hippocampal plasticity by long-term potentiation (LTP). We found that the hippocampal BOLD signals evoked by electrical stimulation at the perforant pathway increased more at the radiatum layer of the hippocampal CA1 region than at the pyramidal cell layer. The return to the baseline of the hippocampal BOLD activation was prolonged after LTP induction compared with that before most likely due vascular or neurovascular coupling changes. Based on these results, we conclude that high resolution BOLD-fMRI allows the segregation of hippocampal subfields probably based on their underlying vascular or neurovascular coupling features.
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3
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Activity-Dependent Plasticity of Astroglial Potassium and Glutamate Clearance. Neural Plast 2015; 2015:109106. [PMID: 26346563 PMCID: PMC4539499 DOI: 10.1155/2015/109106] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 04/17/2015] [Indexed: 12/21/2022] Open
Abstract
Recent evidence has shown that astrocytes play essential roles in synaptic transmission and plasticity. Nevertheless, how neuronal activity alters astroglial functional properties and whether such properties also display specific forms of plasticity still remain elusive. Here, we review research findings supporting this aspect of astrocytes, focusing on their roles in the clearance of extracellular potassium and glutamate, two neuroactive substances promptly released during excitatory synaptic transmission. Their subsequent removal, which is primarily carried out by glial potassium channels and glutamate transporters, is essential for proper functioning of the brain. Similar to neurons, different forms of short- and long-term plasticity in astroglial uptake have been reported. In addition, we also present novel findings showing robust potentiation of astrocytic inward currents in response to repetitive stimulations at mild frequencies, as low as 0.75 Hz, in acute hippocampal slices. Interestingly, neurotransmission was hardly affected at this frequency range, suggesting that astrocytes may be more sensitive to low frequency stimulation and may exhibit stronger plasticity than neurons to prevent hyperexcitability. Taken together, these important findings strongly indicate that astrocytes display both short- and long-term plasticity in their clearance of excess neuroactive substances from the extracellular space, thereby regulating neuronal activity and brain homeostasis.
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Sibille J, Zapata J, Teillon J, Rouach N. Astroglial calcium signaling displays short-term plasticity and adjusts synaptic efficacy. Front Cell Neurosci 2015; 9:189. [PMID: 26074766 PMCID: PMC4444818 DOI: 10.3389/fncel.2015.00189] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 04/29/2015] [Indexed: 01/14/2023] Open
Abstract
Astrocytes are dynamic signaling brain elements able to sense neuronal inputs and to respond by complex calcium signals, which are thought to represent their excitability. Such signaling has been proposed to modulate, or not, neuronal activities ranging from basal synaptic transmission to epileptiform discharges. However, whether calcium signaling in astrocytes exhibits activity-dependent changes and acutely modulates short-term synaptic plasticity is currently unclear. We here show, using dual recordings of astroglial calcium signals and synaptic transmission, that calcium signaling in astrocytes displays, concomitantly to excitatory synapses, short-term plasticity in response to prolonged repetitive and tetanic stimulations of Schaffer collaterals. We also found that acute inhibition of calcium signaling in astrocytes by intracellular calcium chelation rapidly potentiates excitatory synaptic transmission and short-term plasticity of Shaffer collateral CA1 synapses, i.e., paired-pulse facilitation and responses to tetanic and prolonged repetitive stimulation. These data reveal that calcium signaling of astrocytes is plastic and down-regulates basal transmission and short-term plasticity of hippocampal CA1 glutamatergic synapses.
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Affiliation(s)
- Jérémie Sibille
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050 Paris, France ; Université Paris Diderot, Sorbonne Paris Cité Paris, France
| | - Jonathan Zapata
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050 Paris, France
| | - Jérémie Teillon
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050 Paris, France
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050 Paris, France
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Krzisch M, Temprana SG, Mongiat LA, Armida J, Schmutz V, Virtanen MA, Kocher-Braissant J, Kraftsik R, Vutskits L, Conzelmann KK, Bergami M, Gage FH, Schinder AF, Toni N. Pre-existing astrocytes form functional perisynaptic processes on neurons generated in the adult hippocampus. Brain Struct Funct 2014; 220:2027-42. [PMID: 24748560 PMCID: PMC4481333 DOI: 10.1007/s00429-014-0768-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 03/31/2014] [Indexed: 11/26/2022]
Abstract
The adult dentate gyrus produces new neurons that morphologically and functionally integrate into the hippocampal network. In the adult brain, most excitatory synapses are ensheathed by astrocytic perisynaptic processes that regulate synaptic structure and function. However, these processes are formed during embryonic or early postnatal development and it is unknown whether astrocytes can also ensheathe synapses of neurons born during adulthood and, if so, whether they play a role in their synaptic transmission. Here, we used a combination of serial-section immuno-electron microscopy, confocal microscopy, and electrophysiology to examine the formation of perisynaptic processes on adult-born neurons. We found that the afferent and efferent synapses of newborn neurons are ensheathed by astrocytic processes, irrespective of the age of the neurons or the size of their synapses. The quantification of gliogenesis and the distribution of astrocytic processes on synapses formed by adult-born neurons suggest that the majority of these processes are recruited from pre-existing astrocytes. Furthermore, the inhibition of astrocytic glutamate re-uptake significantly reduced postsynaptic currents and increased paired-pulse facilitation in adult-born neurons, suggesting that perisynaptic processes modulate synaptic transmission on these cells. Finally, some processes were found intercalated between newly formed dendritic spines and potential presynaptic partners, suggesting that they may also play a structural role in the connectivity of new spines. Together, these results indicate that pre-existing astrocytes remodel their processes to ensheathe synapses of adult-born neurons and participate to the functional and structural integration of these cells into the hippocampal network.
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Affiliation(s)
- Marine Krzisch
- Department of Fundamental Neurosciences, University of Lausanne, 9 rue du Bugnon, 1005 Lausanne, Switzerland
| | - Silvio G. Temprana
- Laboratory of Neuronal Plasticity, Leloir Institute (IIBBA-CONICET), Buenos Aires, Argentina
| | - Lucas A. Mongiat
- Laboratory of Neuronal Plasticity, Leloir Institute (IIBBA-CONICET), Buenos Aires, Argentina
| | - Jan Armida
- Department of Fundamental Neurosciences, University of Lausanne, 9 rue du Bugnon, 1005 Lausanne, Switzerland
| | - Valentin Schmutz
- Department of Fundamental Neurosciences, University of Lausanne, 9 rue du Bugnon, 1005 Lausanne, Switzerland
| | - Mari A. Virtanen
- Department of Fundamental Neurosciences, University of Geneva, Geneva, Switzerland
| | - Jacqueline Kocher-Braissant
- Department of Fundamental Neurosciences, University of Lausanne, 9 rue du Bugnon, 1005 Lausanne, Switzerland
| | - Rudolf Kraftsik
- Department of Fundamental Neurosciences, University of Lausanne, 9 rue du Bugnon, 1005 Lausanne, Switzerland
| | - Laszlo Vutskits
- Department of Fundamental Neurosciences, University of Geneva, Geneva, Switzerland
- Department of Anesthesiology, Pharmacology and Intensive Care, University Hospital of Geneva, Geneva, Switzerland
| | - Karl-Klaus Conzelmann
- Max von Pettenkofer Institute and Gene Center, Ludwig-Maximilians University Munich, Munich, Germany
| | - Matteo Bergami
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) and University Hospital of Cologne, Cologne, Germany
| | - Fred H. Gage
- Laboratory of Genetics, Salk Institute for Biological Studies, La Jolla, CA USA
| | - Alejandro F. Schinder
- Laboratory of Neuronal Plasticity, Leloir Institute (IIBBA-CONICET), Buenos Aires, Argentina
| | - Nicolas Toni
- Department of Fundamental Neurosciences, University of Lausanne, 9 rue du Bugnon, 1005 Lausanne, Switzerland
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Sampedro-Piquero P, De Bartolo P, Petrosini L, Zancada-Menendez C, Arias JL, Begega A. Astrocytic plasticity as a possible mediator of the cognitive improvements after environmental enrichment in aged rats. Neurobiol Learn Mem 2014; 114:16-25. [PMID: 24727294 DOI: 10.1016/j.nlm.2014.04.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 03/26/2014] [Accepted: 04/01/2014] [Indexed: 11/28/2022]
Abstract
Currently, little is known about the effect of environmental enrichment (EE) on astrocytic plasticity, especially during aging. Given the newly discovered role of the astrocytes in regulating the synaptic transmission and thereby, the cognitive functions, we aimed to study the impact of EE on the performance in a spatial memory task and on the number and morphology of GFAP immunopositive cells in the dorsal hippocampus. After two months of EE (3 h/per day), the animals were tested in the Radial-Arm Water Maze (RAWM) for four days, with six daily trials. Next, we analyzed the changes in the GFAP immunopositive cells in CA1, CA3 and Dentate Gyrus (DG). Behavioral results showed that, even in advanced ages, EE improved the performance in a spatial memory task. Also, we found that aged rats submitted to EE had more GFAP immunopositive cells in the DG and more complex astrocytes, revealed by Sholl analysis, in all hippocampal subfields with respect to the other experimental conditions. Interestingly, the learning of a spatial memory task produced more morphological complexity and higher levels of GFAP immunopositive cells with regard to a standard control group, but not at the same level of the enriched groups. Thus, it is possible that the plastic changes found in the hippocampal astrocytes after EE are involved in a brain reserve to cope with age-related cognitive impairments.
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Affiliation(s)
- P Sampedro-Piquero
- Laboratorio de Neurociencias, Departamento de Psicología, Universidad de Oviedo, Instituto de Neurociencias del Principado de Asturias, INEUROPA, Plaza Feijoo s/n, 33003 Oviedo, Spain.
| | - Paola De Bartolo
- Department of Psychology, University "Sapienza", via dei Marsi 78, 00185 Rome, Italy; IRCCS S. Lucia Foundation, via del Fosso di Fiorano 64, 00143 Rome, Italy.
| | - Laura Petrosini
- Department of Psychology, University "Sapienza", via dei Marsi 78, 00185 Rome, Italy; IRCCS S. Lucia Foundation, via del Fosso di Fiorano 64, 00143 Rome, Italy.
| | - C Zancada-Menendez
- Laboratorio de Neurociencias, Departamento de Psicología, Universidad de Oviedo, Instituto de Neurociencias del Principado de Asturias, INEUROPA, Plaza Feijoo s/n, 33003 Oviedo, Spain.
| | - J L Arias
- Laboratorio de Neurociencias, Departamento de Psicología, Universidad de Oviedo, Instituto de Neurociencias del Principado de Asturias, INEUROPA, Plaza Feijoo s/n, 33003 Oviedo, Spain.
| | - A Begega
- Laboratorio de Neurociencias, Departamento de Psicología, Universidad de Oviedo, Instituto de Neurociencias del Principado de Asturias, INEUROPA, Plaza Feijoo s/n, 33003 Oviedo, Spain.
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Sibille J, Pannasch U, Rouach N. Astroglial potassium clearance contributes to short-term plasticity of synaptically evoked currents at the tripartite synapse. J Physiol 2013; 592:87-102. [PMID: 24081156 DOI: 10.1113/jphysiol.2013.261735] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Astroglial processes enclose ∼60% of CA1 hippocampal synapses to form the tripartite synapse. Although astrocytes express ionic channels, neurotransmitter receptors and transporters to detect neuronal activity, the nature, plasticity and impact of the currents induced by neuronal activity on short-term synaptic plasticity remain elusive in hippocampal astrocytes. Using simultaneous electrophysiological recordings of astrocytes and neurons, we found that single stimulation of Schaffer collaterals in hippocampal slices evokes in stratum radiatum astrocytes a complex prolonged inward current synchronized to synaptic and spiking activity in CA1 pyramidal cells. The astroglial current is composed of three components sensitive to neuronal activity, i.e. a long-lasting potassium current mediated by Kir4.1 channels, a transient glutamate transporter current and a slow residual current, partially mediated by GABA transporters and Kir4.1-independent potassium channels. We show that all astroglial membrane currents exhibit activity-dependent short-term plasticity. However, only the astroglial glutamate transporter current displays neuronal-like dynamics and plasticity. As Kir4.1 channel-mediated potassium uptake contributes to 80% of the synaptically evoked astroglial current, we investigated in turn its impact on short-term synaptic plasticity. Using glial conditional Kir4.1 knockout mice, we found that astroglial potassium uptake reduces synaptic responses to repetitive stimulation and post-tetanic potentiation. These results show that astrocytes integrate synaptic activity via multiple ionic channels and transporters and contribute to short-term plasticity in part via potassium clearance mediated by Kir4.1 channels.
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Affiliation(s)
- Jérémie Sibille
- N. Rouach: Neuroglial Interactions in Cerebral Physiopathology, Collège de France, CIRB, CNRS UMR 7241, INSERM U1050, 11, place Marcelin Berthelot, 75005 Paris, France.
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Lisachev PD, Pustylnyak VO, Shtark MB, Epstein OI. Induction of S100B gene expression in long-term potentiation in the hippocampal CA1 field depends on activity of NMDA receptors. Bull Exp Biol Med 2013; 154:485-8. [PMID: 23486587 DOI: 10.1007/s10517-013-1983-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The effects of NMDA receptor blocker MK-801 on the increase in S100B protein mRNA content induced by long-term posttetanic potentiation in the hippocampal sections were studied. The level of S100B mRNA after 30-min tetanization in the presence of 10 μM MK-801 constituted 132% of the basal level, which was significantly (226%) lower than the control level. Hence, gene expression, induced by long-term posttetanic potentiation, in the glial cells (similarly as in the neurons) depended significantly on NMDA receptors.
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Affiliation(s)
- P D Lisachev
- Designing and Technological Institute of Computer Engineering, Siberian Division of the Russian Academy of Sciences, Novosibirsk, Russia
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Kuzum D, Jeyasingh RGD, Lee B, Wong HSP. Nanoelectronic programmable synapses based on phase change materials for brain-inspired computing. NANO LETTERS 2012; 12:2179-86. [PMID: 21668029 DOI: 10.1021/nl201040y] [Citation(s) in RCA: 354] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Brain-inspired computing is an emerging field, which aims to extend the capabilities of information technology beyond digital logic. A compact nanoscale device, emulating biological synapses, is needed as the building block for brain-like computational systems. Here, we report a new nanoscale electronic synapse based on technologically mature phase change materials employed in optical data storage and nonvolatile memory applications. We utilize continuous resistance transitions in phase change materials to mimic the analog nature of biological synapses, enabling the implementation of a synaptic learning rule. We demonstrate different forms of spike-timing-dependent plasticity using the same nanoscale synapse with picojoule level energy consumption.
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Affiliation(s)
- Duygu Kuzum
- Center for Integrated Systems, Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA.
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STDP pattern onset learning depends on background activity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 718:19-31. [PMID: 21744207 DOI: 10.1007/978-1-4614-0164-3_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Spike-timing dependent plasticity is a learning mechanism used extensively within neural modelling. The learning rule has previously been shown to allow a neuron to learn a repeated spatio-temporal pattern among its afferents and respond at its onset. In this study we reconfirm these previous results and additionally adduce that such learning is dependent on background activity. Furthermore, we found that the onset learning is unstable when in a noisy framework. Specifically, if the level of background activity changes during learning the response latency of a neuron may increase and with the adding of additional noise the distribution of response latencies degrades. Consequently, we present preliminary insights into the neuron's encoding: viz. that a neuron may encode the coincidence of spikes from a subsection of a stimulus' afferents, but the temporal precision of the onset response depends on some background activity, which must be similar to that present during learning.
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11
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Central and peripheral cytokines mediate immune-brain connectivity. Neurochem Res 2010; 36:1-6. [PMID: 20820913 DOI: 10.1007/s11064-010-0252-x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2010] [Indexed: 01/18/2023]
Abstract
The immune system is a homeostatic system that contributes to maintain the constancy of the molecular and cellular components of the organism. Immune cells can detect the intrusion of foreign antigens or alteration of self-components and send information to the central nervous system (CNS) about this kind of perturbations, acting as a receptor sensorial organ. The brain can respond to such signals by emitting neuro/endocrine signals capable of affecting immune reactivity. Thus, the immune system, as other physiologic systems, is under brain control. Under disease conditions, when priorities for survival change, the immune system can, within defined limits, reset brain-integrated neuro-endocrine mechanisms in order to favour immune processes at the expenses of other physiologic systems. In addition, some cytokines initially conceived as immune products, such as IL-1 and IL-6, are also produced in the "healthy" brain by glial cells and even by some neurons. These and other cytokines have the capacity to affect synaptic plasticity acting as mediators of interactions between astrocytes and pre- and post-synaptic neurons that constitute what is actually defined as a tripartite synapse. Since the production of cytokines in the brain is affected by peripheral immune and central neural signals, it is conceivable that tripartite synapses can, in turn, serve as a relay system in immune-CNS communication.
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