1
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Renden RB, Institoris A, Sharma K, Tran CHT. Modulatory effects of noradrenergic and serotonergic signaling pathway on neurovascular coupling. Commun Biol 2024; 7:287. [PMID: 38459113 PMCID: PMC10923894 DOI: 10.1038/s42003-024-05996-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Accepted: 02/28/2024] [Indexed: 03/10/2024] Open
Abstract
Dynamic changes in astrocyte Ca2+ are recognized as contributors to functional hyperemia, a critical response to increased neuronal activity mediated by a process known as neurovascular coupling (NVC). Although the critical role of glutamatergic signaling in this process has been extensively investigated, the impact of behavioral state, and the release of behavior-associated neurotransmitters, such as norepinephrine and serotonin, on astrocyte Ca2+ dynamics and functional hyperemia have received less attention. We used two-photon imaging of the barrel cortex in awake mice to examine the role of noradrenergic and serotonergic projections in NVC. We found that both neurotransmitters facilitated sensory stimulation-induced increases in astrocyte Ca2+. Interestingly, while ablation of serotonergic neurons reduced sensory stimulation-induced functional hyperemia, ablation of noradrenergic neurons caused both attenuation and potentiation of functional hyperemia. Our study demonstrates that norepinephrine and serotonin are involved in modulating sensory stimulation-induced astrocyte Ca2+ elevations and identifies their differential effects in regulating functional hyperemia.
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Affiliation(s)
- Robert B Renden
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada Reno, Reno, NV, USA
| | - Adam Institoris
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Kushal Sharma
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada Reno, Reno, NV, USA
| | - Cam Ha T Tran
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada Reno, Reno, NV, USA.
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2
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Slaoui L, Gilbert A, Rancillac A, Delaunay-Piednoir B, Chagnot A, Gerard Q, Letort G, Mailly P, Robil N, Gelot A, Lefebvre M, Favier M, Dias K, Jourdren L, Federici L, Auvity S, Cisternino S, Vivien D, Cohen-Salmon M, Boulay AC. In mice and humans, brain microvascular contractility matures postnatally. Brain Struct Funct 2023; 228:475-492. [PMID: 36380034 DOI: 10.1007/s00429-022-02592-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 10/25/2022] [Indexed: 11/17/2022]
Abstract
Although great efforts to characterize the embryonic phase of brain microvascular system development have been made, its postnatal maturation has barely been described. Here, we compared the molecular and functional properties of brain vascular cells on postnatal day (P)5 vs. P15, via a transcriptomic analysis of purified mouse cortical microvessels (MVs) and the identification of vascular-cell-type-specific or -preferentially expressed transcripts. We found that endothelial cells (EC), vascular smooth muscle cells (VSMC) and fibroblasts (FB) follow specific molecular maturation programs over this time period. Focusing on VSMCs, we showed that the arteriolar VSMC network expands and becomes contractile resulting in a greater cerebral blood flow (CBF), with heterogenous developmental trajectories within cortical regions. Samples of the human brain cortex showed the same postnatal maturation process. Thus, the postnatal phase is a critical period during which arteriolar VSMC contractility required for vessel tone and brain perfusion is acquired and mature.
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Affiliation(s)
- Leila Slaoui
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Alice Gilbert
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Armelle Rancillac
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Barbara Delaunay-Piednoir
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Audrey Chagnot
- UNICAEN, INSERM UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), GIP Cyceron, Institute Blood and Brain @ Caen-Normandie (BB@C), Normandie University, 14000, Caen, France
| | - Quentin Gerard
- UNICAEN, INSERM UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), GIP Cyceron, Institute Blood and Brain @ Caen-Normandie (BB@C), Normandie University, 14000, Caen, France
| | - Gaëlle Letort
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Philippe Mailly
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | | | - Antoinette Gelot
- Service d'anatomie et cytologie pathologie, Assistance Publique-Hôpitaux de Paris, Hôpital Armand Trousseau, Paris, France
| | - Mathilde Lefebvre
- Service de foetopathologie, Centre hospitalier régional d'Orleans, Orléans, France
| | | | - Karine Dias
- GenomiqueENS, Institut de Biologie de L'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, 75005, Paris, France
| | - Laurent Jourdren
- GenomiqueENS, Institut de Biologie de L'ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL, 75005, Paris, France
| | - Laetitia Federici
- Optimisation Thérapeutique en Neuropsychopharmacologie, INSERM, Université de Paris, Paris, France
| | - Sylvain Auvity
- Optimisation Thérapeutique en Neuropsychopharmacologie, INSERM, Université de Paris, Paris, France
- Service Pharmacie, Assistance Publique-Hôpitaux de Paris, Hôpital Universitaire-Necker-Enfants Malades, Paris, France
| | - Salvatore Cisternino
- Optimisation Thérapeutique en Neuropsychopharmacologie, INSERM, Université de Paris, Paris, France
- Service Pharmacie, Assistance Publique-Hôpitaux de Paris, Hôpital Universitaire-Necker-Enfants Malades, Paris, France
| | - Denis Vivien
- UNICAEN, INSERM UMR-S U1237, Physiopathology and Imaging of Neurological Disorders (PhIND), GIP Cyceron, Institute Blood and Brain @ Caen-Normandie (BB@C), Normandie University, 14000, Caen, France
- Department of Clinical Research, Caen-Normandie University Hospital, CHU, Avenue de la côte de Nacre, Caen, France
| | - Martine Cohen-Salmon
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France.
| | - Anne-Cécile Boulay
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
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3
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Szczygielski J, Kopańska M, Wysocka A, Oertel J. Cerebral Microcirculation, Perivascular Unit, and Glymphatic System: Role of Aquaporin-4 as the Gatekeeper for Water Homeostasis. Front Neurol 2021; 12:767470. [PMID: 34966347 PMCID: PMC8710539 DOI: 10.3389/fneur.2021.767470] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/12/2021] [Indexed: 12/13/2022] Open
Abstract
In the past, water homeostasis of the brain was understood as a certain quantitative equilibrium of water content between intravascular, interstitial, and intracellular spaces governed mostly by hydrostatic effects i.e., strictly by physical laws. The recent achievements in molecular bioscience have led to substantial changes in this regard. Some new concepts elaborate the idea that all compartments involved in cerebral fluid homeostasis create a functional continuum with an active and precise regulation of fluid exchange between them rather than only serving as separate fluid receptacles with mere passive diffusion mechanisms, based on hydrostatic pressure. According to these concepts, aquaporin-4 (AQP4) plays the central role in cerebral fluid homeostasis, acting as a water channel protein. The AQP4 not only enables water permeability through the blood-brain barrier but also regulates water exchange between perivascular spaces and the rest of the glymphatic system, described as pan-cerebral fluid pathway interlacing macroscopic cerebrospinal fluid (CSF) spaces with the interstitial fluid of brain tissue. With regards to this, AQP4 makes water shift strongly dependent on active processes including changes in cerebral microcirculation and autoregulation of brain vessels capacity. In this paper, the role of the AQP4 as the gatekeeper, regulating the water exchange between intracellular space, glymphatic system (including the so-called neurovascular units), and intravascular compartment is reviewed. In addition, the new concepts of brain edema as a misbalance in water homeostasis are critically appraised based on the newly described role of AQP4 for fluid permeation. Finally, the relevance of these hypotheses for clinical conditions (including brain trauma and stroke) and for both new and old therapy concepts are analyzed.
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Affiliation(s)
- Jacek Szczygielski
- Department of Neurosurgery, Institute of Medical Sciences, University of Rzeszów, Rzeszów, Poland.,Department of Neurosurgery, Faculty of Medicine and Saarland University Medical Center, Saarland University, Homburg, Germany
| | - Marta Kopańska
- Department of Pathophysiology, Institute of Medical Sciences, University of Rzeszów, Rzeszów, Poland
| | - Anna Wysocka
- Chair of Internal Medicine and Department of Internal Medicine in Nursing, Faculty of Health Sciences, Medical University of Lublin, Lublin, Poland
| | - Joachim Oertel
- Department of Neurosurgery, Faculty of Medicine and Saarland University Medical Center, Saarland University, Homburg, Germany
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4
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Roy RK, Althammer F, Seymour AJ, Du W, Biancardi VC, Hamm JP, Filosa JA, Brown CH, Stern JE. Inverse neurovascular coupling contributes to positive feedback excitation of vasopressin neurons during a systemic homeostatic challenge. Cell Rep 2021; 37:109925. [PMID: 34731601 PMCID: PMC9488983 DOI: 10.1016/j.celrep.2021.109925] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 08/09/2021] [Accepted: 10/12/2021] [Indexed: 01/03/2023] Open
Abstract
Neurovascular coupling (NVC), the process that links neuronal activity to cerebral blood flow changes, has been mainly studied in superficial brain areas, namely the neocortex. Whether the conventional, rapid, and spatially restricted NVC response can be generalized to deeper and functionally diverse brain regions remains unknown. Implementing an approach for in vivo two-photon imaging from the ventral surface of the brain, we show that a systemic homeostatic challenge, acute salt loading, progressively increases hypothalamic vasopressin (VP) neuronal firing and evokes a vasoconstriction that reduces local blood flow. Vasoconstrictions are blocked by topical application of a VP receptor antagonist or tetrodotoxin, supporting mediation by activity-dependent, dendritically released VP. Salt-induced inverse NVC results in a local hypoxic microenvironment, which evokes positive feedback excitation of VP neurons. Our results reveal a physiological mechanism by which inverse NVC responses regulate systemic homeostasis, further supporting the notion of brain heterogeneity in NVC responses.
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Affiliation(s)
- Ranjan K Roy
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA
| | | | | | - Wenting Du
- Department of Physiology, Augusta University, Augusta, GA, USA
| | - Vinicia C Biancardi
- Department of Anatomy, Physiology and Pharmacology, Auburn University, Auburn, AL, USA
| | - Jordan P Hamm
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA
| | | | - Colin H Brown
- Department of Physiology, University of Otago, Dunedin, New Zealand
| | - Javier E Stern
- Neuroscience Institute, Georgia State University, Atlanta, GA, USA.
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5
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Contribution of animal models toward understanding resting state functional connectivity. Neuroimage 2021; 245:118630. [PMID: 34644593 DOI: 10.1016/j.neuroimage.2021.118630] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 08/06/2021] [Accepted: 09/29/2021] [Indexed: 12/27/2022] Open
Abstract
Functional connectivity, which reflects the spatial and temporal organization of intrinsic activity throughout the brain, is one of the most studied measures in human neuroimaging research. The noninvasive acquisition of resting state functional magnetic resonance imaging (rs-fMRI) allows the characterization of features designated as functional networks, functional connectivity gradients, and time-varying activity patterns that provide insight into the intrinsic functional organization of the brain and potential alterations related to brain dysfunction. Functional connectivity, hence, captures dimensions of the brain's activity that have enormous potential for both clinical and preclinical research. However, the mechanisms underlying functional connectivity have yet to be fully characterized, hindering interpretation of rs-fMRI studies. As in other branches of neuroscience, the identification of the neurophysiological processes that contribute to functional connectivity largely depends on research conducted on laboratory animals, which provide a platform where specific, multi-dimensional investigations that involve invasive measurements can be carried out. These highly controlled experiments facilitate the interpretation of the temporal correlations observed across the brain. Indeed, information obtained from animal experimentation to date is the basis for our current understanding of the underlying basis for functional brain connectivity. This review presents a compendium of some of the most critical advances in the field based on the efforts made by the animal neuroimaging community.
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6
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Kourosh-Arami M, Hosseini N, Mohsenzadegan M, Komaki A, Joghataei MT. Neurophysiologic implications of neuronal nitric oxide synthase. Rev Neurosci 2021; 31:617-636. [PMID: 32739909 DOI: 10.1515/revneuro-2019-0111] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/21/2020] [Indexed: 12/12/2022]
Abstract
The molecular and chemical properties of neuronal nitric oxide synthase (nNOS) have made it a key mediator in many physiological functions and signaling transduction. The NOS monomer is inactive, but the dimer form is active. There are three forms of NOS, which are neuronal (nNOS), inducible (iNOS), and endothelial (eNOS) nitric oxide synthase. nNOS regulates nitric oxide (NO) synthesis which is the mechanism used mostly by neurons to produce NO. nNOS expression and activation is regulated by some important signaling proteins, such as cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB), calmodulin (CaM), heat shock protein 90 (HSP90)/HSP70. nNOS-derived NO has been implicated in modulating many physiological functions, such as synaptic plasticity, learning, memory, neurogenesis, etc. In this review, we have summarized recent studies that have characterized structural features, subcellular localization, and factors that regulate nNOS function. Finally, we have discussed the role of nNOS in the developing brain under a wide range of physiological conditions, especially long-term potentiation and depression.
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Affiliation(s)
- Masoumeh Kourosh-Arami
- Department of Neuroscience, School of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Islamic Republic of Iran
| | - Nasrin Hosseini
- Neuroscience Research Center, Iran University of Medical Sciences, Tehran, Islamic Republic of Iran
| | - Monireh Mohsenzadegan
- Department of Laboratory Sciences, Allied Medical College, Iran University of Medical Sciences, Tehran, Islamic Republic of Iran
| | - Alireza Komaki
- Department of Physiology, Medical College, Hamedan University of Medical Sciences, Hamedan, Islamic Republic of Iran
| | - Mohammad Taghi Joghataei
- Department of Neuroscience, School of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Islamic Republic of Iran
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7
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Lorenzi T, Sagrati A, Montanari E, Senzacqua M, Morroni M, Fabri M. Hypoxia-induced expression of neuronal nitric oxide synthase in astrocytes of human corpus callosum. Brain Struct Funct 2021; 226:1353-1361. [PMID: 33709161 DOI: 10.1007/s00429-021-02244-5] [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: 08/06/2020] [Accepted: 02/22/2021] [Indexed: 10/22/2022]
Abstract
Nitric oxide (NO) is a gaseous neurotransmitter largely diffused in the brain; among other functions, it regulates the cerebral blood flow in response to hypoxia. NO can be synthetized by three different isoforms of the enzyme NO synthase: neuronal (nNOS), typical of neurons, endothelial and inducible. The aim of this study was to assess nNOS expression in human corpus callosum (CC) astrocytes, and its relationship with the hypoxia duration. Autoptic samples of CC from adult human subjects have been processed with immunohistochemistry and immunofluorescence using antibodies anti-nNOS and anti-glial fibrillary acidic protein (GFAP), the astrocyte marker. Results demonstrated for the first time the presence of nNOS-immunopositive astrocytes in the human CC. In particular, nNOS-positive astrocytes were absent in subjects deceased after a short hypoxia; their number and labeling intensity, however, increased with hypoxia prolongation. Neuronal NOS immunopositivity of CC astrocytes seems thus related to the hypoxia duration and the consequent brain damage.
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Affiliation(s)
- Teresa Lorenzi
- Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, School of Medicine, Università Politecnica delle Marche, Via Tronto 10/A, 60126, Ancona, Italy
| | - Andrea Sagrati
- Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, School of Medicine, Università Politecnica delle Marche, Via Tronto 10/A, 60126, Ancona, Italy
| | - Eva Montanari
- Department of Biomedical Sciences and Public Health, Section of Legal Medicine, Università Politecnica delle Marche, Via Tronto 10/A, 60126, Ancona, Italy
| | - Martina Senzacqua
- Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, School of Medicine, Università Politecnica delle Marche, Via Tronto 10/A, 60126, Ancona, Italy
| | - Manrico Morroni
- Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, School of Medicine, Università Politecnica delle Marche, Via Tronto 10/A, 60126, Ancona, Italy.,Electron Microscopy Unit, United Hospitals, Via Conca 71, 60020, Ancona, Italy
| | - Mara Fabri
- Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, School of Medicine, Università Politecnica delle Marche, Via Tronto 10/A, 60126, Ancona, Italy.
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8
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Beyeler A, Ju A, Chagraoui A, Cuvelle L, Teixeira M, Di Giovanni G, De Deurwaerdère P. Multiple facets of serotonergic modulation. PROGRESS IN BRAIN RESEARCH 2021; 261:3-39. [PMID: 33785133 DOI: 10.1016/bs.pbr.2021.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The serotonergic system of the central nervous system (CNS) has been implicated in a broad range of physiological functions and behaviors, such as cognition, mood, social interaction, sexual behavior, feeding behavior, sleep-wake cycle and thermoregulation. Serotonin (5-hydroxytryptamine, 5-HT) establishes a plethora of interactions with neurochemical systems in the CNS via its numerous 5-HT receptors and autoreceptors. The facets of this control are multiple if we consider the molecular actors playing a role in the autoregulation of 5-HT neuron activity including the 5-HT1A, 5-HT1B, 5-HT1D, 5-HT2B, 5-HT7 receptors as well as the serotonin transporter. Moreover, extrinsic loops involving other neurotransmitters giving the other 5-HT receptors the possibility to impact 5-HT neuron activity. Grasping the complexity of these interactions is essential for the development of a variety of therapeutic strategies for cognitive defects and mood disorders. Presently we can illustrate the plurality of the mechanisms and only conceive that these 5-HT controls are likely not uniform in terms of regional and neuronal distribution. Our understanding of the specific expression patterns of these receptors on specific circuits and neuronal populations are progressing and will expand our comprehension of the function and interaction of these receptors with other chemical systems. Thus, the development of new approaches profiling the expression of 5-HT receptors and autoreceptors should reveal additional facets of the 5-HT controls of neurochemical systems in the CNS.
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Affiliation(s)
- Anna Beyeler
- Neurocentre Magendie, INSERM 1215, Université de Bordeaux, Bordeaux, France.
| | - Anes Ju
- Neurocentre Magendie, INSERM 1215, Université de Bordeaux, Bordeaux, France
| | - Abdeslam Chagraoui
- Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Institute for Research and Innovation in Biomedicine of Normandy (IRIB), Normandie University, UNIROUEN, INSERM U1239, Rouen, France; Department of Medical Biochemistry, Rouen University Hospital, Rouen, France
| | - Lise Cuvelle
- Centre National de La Recherche Scientifique, Institut des Neurosciences Intégratives et Cognitives d'Aquitaine, UMR 5287, Bordeaux, France
| | - Maxime Teixeira
- Centre National de La Recherche Scientifique, Institut des Neurosciences Intégratives et Cognitives d'Aquitaine, UMR 5287, Bordeaux, France
| | - Giuseppe Di Giovanni
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Neuroscience Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom.
| | - Philippe De Deurwaerdère
- Centre National de La Recherche Scientifique, Institut des Neurosciences Intégratives et Cognitives d'Aquitaine, UMR 5287, Bordeaux, France
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9
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Howarth C, Mishra A, Hall CN. More than just summed neuronal activity: how multiple cell types shape the BOLD response. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190630. [PMID: 33190598 PMCID: PMC7116385 DOI: 10.1098/rstb.2019.0630] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2020] [Indexed: 12/11/2022] Open
Abstract
Functional neuroimaging techniques are widely applied to investigations of human cognition and disease. The most commonly used among these is blood oxygen level-dependent (BOLD) functional magnetic resonance imaging. The BOLD signal occurs because neural activity induces an increase in local blood supply to support the increased metabolism that occurs during activity. This supply usually outmatches demand, resulting in an increase in oxygenated blood in an active brain region, and a corresponding decrease in deoxygenated blood, which generates the BOLD signal. Hence, the BOLD response is shaped by an integration of local oxygen use, through metabolism, and supply, in the blood. To understand what information is carried in BOLD signals, we must understand how several cell types in the brain-local excitatory neurons, inhibitory neurons, astrocytes and vascular cells (pericytes, vascular smooth muscle and endothelial cells), and their modulation by ascending projection neurons-contribute to both metabolism and haemodynamic changes. Here, we review the contributions of each cell type to the regulation of cerebral blood flow and metabolism, and discuss situations where a simplified interpretation of the BOLD response as reporting local excitatory activity may misrepresent important biological phenomena, for example with regards to arousal states, ageing and neurological disease. This article is part of the theme issue 'Key relationships between non-invasive functional neuroimaging and the underlying neuronal activity'.
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Affiliation(s)
- Clare Howarth
- Department of Psychology, University of Sheffield, Sheffield S1 2LT, UK
| | - Anusha Mishra
- Department of Neurology, Jungers Center for Neurosciences Research, and Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR 97239, USA
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10
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Haselden WD, Kedarasetti RT, Drew PJ. Spatial and temporal patterns of nitric oxide diffusion and degradation drive emergent cerebrovascular dynamics. PLoS Comput Biol 2020; 16:e1008069. [PMID: 32716940 PMCID: PMC7410342 DOI: 10.1371/journal.pcbi.1008069] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 08/06/2020] [Accepted: 06/17/2020] [Indexed: 02/07/2023] Open
Abstract
Nitric oxide (NO) is a gaseous signaling molecule that plays an important role in neurovascular coupling. NO produced by neurons diffuses into the smooth muscle surrounding cerebral arterioles, driving vasodilation. However, the rate of NO degradation in hemoglobin is orders of magnitude higher than in brain tissue, though how this might impact NO signaling dynamics is not completely understood. We used simulations to investigate how the spatial and temporal patterns of NO generation and degradation impacted dilation of a penetrating arteriole in cortex. We found that the spatial location of NO production and the size of the vessel both played an important role in determining its responsiveness to NO. The much higher rate of NO degradation and scavenging of NO in the blood relative to the tissue drove emergent vascular dynamics. Large vasodilation events could be followed by post-stimulus constrictions driven by the increased degradation of NO by the blood, and vasomotion-like 0.1-0.3 Hz oscillations could also be generated. We found that these dynamics could be enhanced by elevation of free hemoglobin in the plasma, which occurs in diseases such as malaria and sickle cell anemia, or following blood transfusions. Finally, we show that changes in blood flow during hypoxia or hyperoxia could be explained by altered NO degradation in the parenchyma. Our simulations suggest that many common vascular dynamics may be emergent phenomena generated by NO degradation by the blood or parenchyma.
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Affiliation(s)
- William Davis Haselden
- Neuroscience Graduate Program, MD/PhD Medical Scientist Training Program, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Ravi Teja Kedarasetti
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Patrick J. Drew
- Neuroscience Graduate Program, MD/PhD Medical Scientist Training Program, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Departments of Biomedical Engineering and Neurosurgery, Pennsylvania State University, University Park, Pennsylvania, United States of America
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11
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Krawchuk MB, Ruff CF, Yang X, Ross SE, Vazquez AL. Optogenetic assessment of VIP, PV, SOM and NOS inhibitory neuron activity and cerebral blood flow regulation in mouse somato-sensory cortex. J Cereb Blood Flow Metab 2020; 40:1427-1440. [PMID: 31418628 PMCID: PMC7307010 DOI: 10.1177/0271678x19870105] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 07/24/2019] [Accepted: 07/25/2019] [Indexed: 12/31/2022]
Abstract
The impact of different neuronal populations on local cerebral blood flow (CBF) regulation is not well known and insight into these relationships could enhance the interpretation of brain function and dysfunction from brain imaging data. We investigated the role of sub-types of inhibitory neuron activity on the regulation of CBF using optogenetics, laser Doppler flowmetry and different transgenic mouse models (parvalbumin (PV), vasoactive intestinal peptide (VIP), somatostatin (SOM) and nitric oxide synthase (NOS)). Whisker stimulation was used to verify that typical CBF responses were obtained in all mice. Photo-stimulation of SOM-cre and NOS-cre mice produced significant increases in CBF that were similar to whisker responses. In NOS-cre mice, CBF responses scaled with the photo-stimulus pulse duration and frequency. In SOM-cre mice, CBF increases were followed by decreases. In VIP-cre mice, photo-stimulation did not consistently produce significant changes in CBF, while slower increases in CBF that peaked 14-18 s after stimulation onset were observed in PV-cre mice. Control experiments performed in non-expressing regions showed no changes in CBF. These findings suggest that dysfunction in NOS or SOM neurons can have a significant impact on vascular responses that are detected by brain imaging methods like functional magnetic resonance imaging (fMRI).
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Affiliation(s)
- Michael B Krawchuk
- Department of Neuroscience, University of
Pittsburgh, Pittsburgh, PA, USA
| | - Catherine F Ruff
- Department of Neurobiology, University of
Pittsburgh, Pittsburgh, PA, USA
| | - Xiaoling Yang
- Department of Radiology, University of
Pittsburgh, Pittsburgh, PA, USA
| | - Sarah E Ross
- Department of Neurobiology, University of
Pittsburgh, Pittsburgh, PA, USA
| | - Alberto L Vazquez
- Department of Radiology, University of
Pittsburgh, Pittsburgh, PA, USA
- Department of Bioengineering University of
Pittsburgh, Pittsburgh, PA, USA
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12
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Vazquez AL, Fukuda M, Kim SG. Inhibitory Neuron Activity Contributions to Hemodynamic Responses and Metabolic Load Examined Using an Inhibitory Optogenetic Mouse Model. Cereb Cortex 2019; 28:4105-4119. [PMID: 30215693 PMCID: PMC6188559 DOI: 10.1093/cercor/bhy225] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 08/18/2018] [Indexed: 12/19/2022] Open
Abstract
Hemodynamic signals are routinely used to noninvasively assess brain function in humans and animals. This work examined the contribution of inhibitory neuron activity on hemodynamic responses captured by changes in blood flow, volume and oxygenation in the cortex of lightly anesthetized mice. Because cortical activity is not commonly initiated by inhibitory neurons, experiments were conducted to examine the neuronal activity properties elicited by photo-stimulation. We observed comparable increases in neuronal activity evoked by forelimb and photo-stimulation; however, significantly larger increases in blood flow and volume were produced by photo-stimulation of inhibitory neurons compared with forelimb stimulation. Following blockade of glutamate and GABA-A receptors to reduce postsynaptic activity contributions, neuronal activity was reliably modulated and hemodynamic changes persisted, though slightly reduced. More importantly, photo-stimulation-evoked changes in blood flow and volume were suppressed by 75–80% with the administration of a nitric oxide synthase inhibitor, suggesting that inhibitory neurons regulate blood flow mostly via nitric oxide. Lastly, forelimb and photo-stimulation of excitatory neurons produced local decreases in blood oxygenation, while large increases were generated by photo-stimulation of inhibitory neurons. Estimates of oxygen metabolism suggest that inhibitory neuron activity has a small impact on tissue metabolic load, indicating a mismatch between the metabolic demand and blood flow regulation properties of inhibitory and excitatory neurons.
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Affiliation(s)
- Alberto L Vazquez
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mitsuhiro Fukuda
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Seong-Gi Kim
- Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Korea.,Center for Neuroscience Imaging Research, Institute for Basic Science, Sungkyunkwan University, Suwon, Korea
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13
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Farahani RM, Rezaei-Lotfi S, Simonian M, Xaymardan M, Hunter N. Neural microvascular pericytes contribute to human adult neurogenesis. J Comp Neurol 2018; 527:780-796. [PMID: 30471080 DOI: 10.1002/cne.24565] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 10/06/2018] [Accepted: 10/17/2018] [Indexed: 12/17/2022]
Abstract
Consistent adult neurogenic activity in humans is observed in specific niches within the central nervous system. However, the notion of an adult neurogenic niche is challenged by accumulating evidence for ectopic neurogenic activity in other cerebral locations. Herein we interface precision of ultrastructural resolution and anatomical simplicity of accessible human dental pulp neurogenic zone to address this conflict. We disclose a basal level of adult neurogenic activity characterized by glial invasion of terminal microvasculature followed by release of individual platelet-derived growth factor receptor-β mural pericytes and subsequent reprogramming into NeuN+ local interneurons. Concomitant angiogenesis, a signature of adult neurogenic niches, accelerates the rate of neurogenesis by amplifying release and proliferation of the mural pericyte population by ≈10-fold. Subsequent in vitro and in vivo experiments confirmed gliogenic and neurogenic capacities of human neural pericytes. Findings foreshadow the bimodal nature of the glio-vascular assembly where pericytes, under instruction from glial cells, can stabilize the quiescent microvasculature or enrich local neuronal microcircuits upon differentiation.
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Affiliation(s)
- Ramin M Farahani
- Institute of Dental Research, Westmead Institute for Medical Research and Westmead Centre for Oral Health, Westmead, New South Wales, Australia.,Department of Life Sciences, Faculty of Medicine and Health Sciences, University of Sydney, Camperdown, New South Wales, Australia
| | - Saba Rezaei-Lotfi
- Department of Life Sciences, Faculty of Medicine and Health Sciences, University of Sydney, Camperdown, New South Wales, Australia
| | - Mary Simonian
- Institute of Dental Research, Westmead Institute for Medical Research and Westmead Centre for Oral Health, Westmead, New South Wales, Australia
| | - Munira Xaymardan
- Institute of Dental Research, Westmead Institute for Medical Research and Westmead Centre for Oral Health, Westmead, New South Wales, Australia.,Department of Life Sciences, Faculty of Medicine and Health Sciences, University of Sydney, Camperdown, New South Wales, Australia
| | - Neil Hunter
- Institute of Dental Research, Westmead Institute for Medical Research and Westmead Centre for Oral Health, Westmead, New South Wales, Australia.,Department of Life Sciences, Faculty of Medicine and Health Sciences, University of Sydney, Camperdown, New South Wales, Australia
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14
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Pathology of nNOS-Expressing GABAergic Neurons in Mouse Model of Alzheimer's Disease. Neuroscience 2018; 384:41-53. [PMID: 29782905 DOI: 10.1016/j.neuroscience.2018.05.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 05/04/2018] [Accepted: 05/10/2018] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia that is often accompanied by mood and emotional disturbances and seizures. There is growing body of evidence that neurons expressing γ-aminobutyric acid (GABA) play an important role in regulation of cognition, mood, and emotion as well as seizure susceptibility, but participation of GABAergic neuronal pathology in Alzheimer's disease (AD) is not understood well at present. Here, we report that transgenic mice expressing human amyloid precursor protein Swedish-Dutch-Iowa mutant (APPSweDI) exhibit early loss of neurons expressing GAD67, a GABA-synthesizing enzyme, in advance of the loss of pyramidal neurons in hippocampal CA1 region. The loss of GAD67+ neurons in APPSweDI mice accompanied with decreased spatial cognition as well as increased anxiety-like behaviors and kainic acid-induced seizure susceptibility at early phase. In the hippocampal CA1 region, GAD67+ neurons expressed high basal levels of neuronal nitric oxide synthase (nNOS) and nitrosative stress (nitrotyrosine). Similarly, GAD67+ neurons in primary cortical and hippocampal neuron cultures also expressed high basal levels of nNOS and degenerated in response to lower Aβ concentrations due to their high basal levels of nitrosative stress. Given the role of GABAergic neurons in cognitive and neuropsychiatric functions, this study reports the role of nNOS-mediated nitrosative stress in dysfunction of GABAergic neurons and its potential participation in early development of cognitive and neuropsychiatric symptoms in AD.
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15
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The role of perivascular innervation and neurally mediated vasoreactivity in the pathophysiology of Alzheimer's disease. Clin Sci (Lond) 2017; 131:1207-1214. [DOI: 10.1042/cs20160769] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/22/2017] [Accepted: 02/24/2017] [Indexed: 11/17/2022]
Abstract
Neuronal death is a hallmark of Alzheimer's disease (AD) and considerable work has been done to understand how the loss of interconnectivity between neurons contributes to the associated dementia. Often overlooked however, is how the loss of neuronal innervation of blood vessels, termed perivascular innervation, may also contribute to the pathogenesis of AD. There is now considerable evidence supporting a crucial role for the neurovascular unit (NVU) in mediating the clearance of the β-amyloid (Aβ) peptide, one of the main pathological constituents of AD, from the brain. Moreover, efficient removal appears to be dependent on the communication of cells within the NVU to maintain adequate vascular tone and pulsatility. This review summarizes the composition of the NVU, including the sources of perivascular innervation and how the NVU mediates Aβ clearance from the brain. It also explores evidence supporting the hypothesis that loss of neurally mediated vasoreactivity contributes to Aβ pathology in the AD brain.
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16
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Uhlirova H, Kılıç K, Tian P, Thunemann M, Desjardins M, Saisan PA, Sakadžić S, Ness TV, Mateo C, Cheng Q, Weldy KL, Razoux F, Vandenberghe M, Cremonesi JA, Ferri CG, Nizar K, Sridhar VB, Steed TC, Abashin M, Fainman Y, Masliah E, Djurovic S, Andreassen OA, Silva GA, Boas DA, Kleinfeld D, Buxton RB, Einevoll GT, Dale AM, Devor A. Cell type specificity of neurovascular coupling in cerebral cortex. eLife 2016; 5. [PMID: 27244241 PMCID: PMC4933561 DOI: 10.7554/elife.14315] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Accepted: 05/30/2016] [Indexed: 12/16/2022] Open
Abstract
Identification of the cellular players and molecular messengers that communicate neuronal activity to the vasculature driving cerebral hemodynamics is important for (1) the basic understanding of cerebrovascular regulation and (2) interpretation of functional Magnetic Resonance Imaging (fMRI) signals. Using a combination of optogenetic stimulation and 2-photon imaging in mice, we demonstrate that selective activation of cortical excitation and inhibition elicits distinct vascular responses and identify the vasoconstrictive mechanism as Neuropeptide Y (NPY) acting on Y1 receptors. The latter implies that task-related negative Blood Oxygenation Level Dependent (BOLD) fMRI signals in the cerebral cortex under normal physiological conditions may be mainly driven by the NPY-positive inhibitory neurons. Further, the NPY-Y1 pathway may offer a potential therapeutic target in cerebrovascular disease.
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Affiliation(s)
- Hana Uhlirova
- Department of Radiology, University of California, San Diego, La Jolla, United States
| | - Kıvılcım Kılıç
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Peifang Tian
- Department of Neurosciences, University of California, San Diego, La Jolla, United States.,Department of Physics, John Carroll University, University Heights, United States
| | - Martin Thunemann
- Department of Radiology, University of California, San Diego, La Jolla, United States
| | - Michèle Desjardins
- Department of Radiology, University of California, San Diego, La Jolla, United States
| | - Payam A Saisan
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Sava Sakadžić
- Martinos Center for Biomedical Imaging, Harvard Medical School, Charlestown, United States
| | - Torbjørn V Ness
- Department of Mathematical Sciences and Technology, Norwegian University of Life Sciences, Ås, Norway
| | - Celine Mateo
- Department of Physics, University of California, San Diego, La Jolla, United States
| | - Qun Cheng
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Kimberly L Weldy
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Florence Razoux
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Matthieu Vandenberghe
- Department of Radiology, University of California, San Diego, La Jolla, United States.,NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, University of Oslo, Oslo, Norway
| | - Jonathan A Cremonesi
- Biology Undergraduate Program, University of California, San Diego, La Jolla, United States
| | - Christopher Gl Ferri
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Krystal Nizar
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, United States
| | - Vishnu B Sridhar
- Department of Bioengineering, University of California, San Diego, La Jolla, United States
| | - Tyler C Steed
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, United States
| | - Maxim Abashin
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, United States
| | - Yeshaiahu Fainman
- Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, United States
| | - Eliezer Masliah
- Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Srdjan Djurovic
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway.,NORMENT, KG Jebsen Centre for Psychosis Research, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Ole A Andreassen
- NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, University of Oslo, Oslo, Norway
| | - Gabriel A Silva
- Department of Bioengineering, University of California, San Diego, La Jolla, United States.,Department of Ophthalmology, University of California, San Diego, La Jolla, United States
| | - David A Boas
- Martinos Center for Biomedical Imaging, Harvard Medical School, Charlestown, United States
| | - David Kleinfeld
- Department of Physics, University of California, San Diego, La Jolla, United States.,Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, United States.,Section of Neurobiology, University of California, San Diego, La Jolla, United States
| | - Richard B Buxton
- Department of Radiology, University of California, San Diego, La Jolla, United States
| | - Gaute T Einevoll
- Department of Mathematical Sciences and Technology, Norwegian University of Life Sciences, Ås, Norway.,Department of Physics, University of Oslo, Oslo, Norway
| | - Anders M Dale
- Department of Radiology, University of California, San Diego, La Jolla, United States.,Department of Neurosciences, University of California, San Diego, La Jolla, United States
| | - Anna Devor
- Department of Radiology, University of California, San Diego, La Jolla, United States.,Department of Neurosciences, University of California, San Diego, La Jolla, United States.,Martinos Center for Biomedical Imaging, Harvard Medical School, Charlestown, United States
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17
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NPY+-, but not PV+- GABAergic neurons mediated long-range inhibition from infra- to prelimbic cortex. Transl Psychiatry 2016; 6:e736. [PMID: 26882036 PMCID: PMC4872436 DOI: 10.1038/tp.2016.7] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 12/22/2015] [Accepted: 01/14/2016] [Indexed: 01/10/2023] Open
Abstract
Anxiety disorders are thought to reflect deficits in the regulation of fear memories. While the amygdala has long been considered a site of storage of fear memories, newer findings suggest that the prefrontal cortex (PFC) is essential in the regulation of amygdala-dependent memories and fear expression. Here, activation of the prelimbic cortex (PrL) enhances the expression of fear, while an elevated activity in the infralimbic cortex (IL) enhances fear extinction. Despite the presence of these facts, we still know very little about the synaptic interconnectivity within the PFC. The aim of the present study was to investigate the inhibitory circuits between prelimbic and IL using morphological and electrophysiological methods. Our immunohistochemical analysis revealed that the distribution of PV(+)- and NPY(+)-GABAergic neurons was strikingly different within the PFC. In addition, we provided the first experimental evidence that the pyramidal neurons in the PrL received a direct inhibitory input mediated by bipolar NPY(+)-GABAergic projection neurons in the IL. Deletion of the anxiety-related neuroligin 2 gene caused a decrease of this direct synaptic inhibition that originated from the IL. Thus, our data suggested that activation of the IL might not only directly activate the corresponding downstream anxiolytic pathway, but also suppress the PrL-related anxiogenic pathway and thus could differentially bias the regulation of fear expression and extinction.
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18
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Scharbarg E, Daenens M, Lemaître F, Geoffroy H, Guille-Collignon M, Gallopin T, Rancillac A. Astrocyte-derived adenosine is central to the hypnogenic effect of glucose. Sci Rep 2016; 6:19107. [PMID: 26755200 PMCID: PMC4709579 DOI: 10.1038/srep19107] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 12/02/2015] [Indexed: 12/11/2022] Open
Abstract
Sleep has been hypothesised to maintain a close relationship with metabolism. Here we focus on the brain structure that triggers slow-wave sleep, the ventrolateral preoptic nucleus (VLPO), to explore the cellular and molecular signalling pathways recruited by an increase in glucose concentration. We used infrared videomicroscopy on ex vivo brain slices to establish that glucose induces vasodilations specifically in the VLPO via the astrocytic release of adenosine. Real-time detection by in situ purine biosensors further revealed that the adenosine level doubles in response to glucose, and triples during the wakefulness period. Finally, patch-clamp recordings uncovered the depolarizing effect of adenosine and its A2A receptor agonist, CGS-21680, on sleep-promoting VLPO neurons. Altogether, our results provide new insights into the metabolically driven release of adenosine. We hypothesise that adenosine adjusts the local energy supply to local neuronal activity in response to glucose. This pathway could contribute to sleep-wake transition and sleep intensity.
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Affiliation(s)
- Emeric Scharbarg
- Brain Plasticity Unit, ESPCI-ParisTech, PSL Research University, Paris, F-75005, France
- CNRS, UMR 8249, Paris, F-75005, France
| | - Marion Daenens
- Brain Plasticity Unit, ESPCI-ParisTech, PSL Research University, Paris, F-75005, France
- CNRS, UMR 8249, Paris, F-75005, France
| | - Frédéric Lemaître
- Ecole Normale Supérieure-PSL Research University, Département de Chimie, Sorbonne Universités - UPMC Univ Paris 06, Paris, F-75005, France
- CNRS, UMR 8640 Pasteur, Paris, F-75005, France
| | - Hélène Geoffroy
- Brain Plasticity Unit, ESPCI-ParisTech, PSL Research University, Paris, F-75005, France
- CNRS, UMR 8249, Paris, F-75005, France
| | - Manon Guille-Collignon
- Ecole Normale Supérieure-PSL Research University, Département de Chimie, Sorbonne Universités - UPMC Univ Paris 06, Paris, F-75005, France
- CNRS, UMR 8640 Pasteur, Paris, F-75005, France
| | - Thierry Gallopin
- Brain Plasticity Unit, ESPCI-ParisTech, PSL Research University, Paris, F-75005, France
- CNRS, UMR 8249, Paris, F-75005, France
| | - Armelle Rancillac
- Brain Plasticity Unit, ESPCI-ParisTech, PSL Research University, Paris, F-75005, France
- CNRS, UMR 8249, Paris, F-75005, France
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19
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Hartmann DA, Underly RG, Watson AN, Shih AY. A murine toolbox for imaging the neurovascular unit. Microcirculation 2015; 22:168-82. [PMID: 25352367 DOI: 10.1111/micc.12176] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Accepted: 10/22/2014] [Indexed: 12/13/2022]
Abstract
The neurovascular unit (NVU) coordinates many essential functions in the brain including blood flow control, nutrient delivery, and maintenance of BBB integrity. These functions are the result of a cellular and molecular interplay that we are just beginning to understand. Cells of the NVU can now be investigated in the intact brain through the combined use of high-resolution in vivo imaging and non-invasive molecular tools to observe and manipulate cell function. Mouse lines that target transgene expression to cells of the NVU will be of great value in future work. However, a detailed evaluation of target cell specificity and expression pattern within the brain is required for many existing lines. The purpose of this review was to catalog mouse lines available to cerebrovascular biologists and to discuss their utility and limitations in future imaging studies.
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Affiliation(s)
- David A Hartmann
- Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina, USA
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20
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Saillet S, Quilichini PP, Ghestem A, Giusiano B, Ivanov AI, Hitziger S, Vanzetta I, Bernard C, Bénar CG. Interneurons contribute to the hemodynamic/metabolic response to epileptiform discharges. J Neurophysiol 2015; 115:1157-69. [PMID: 26745250 DOI: 10.1152/jn.00994.2014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 12/21/2015] [Indexed: 01/28/2023] Open
Abstract
Interpretation of hemodynamic responses in epilepsy is hampered by an incomplete understanding of the underlying neurovascular coupling, especially the contributions of excitation and inhibition. We made simultaneous multimodal recordings of local field potentials (LFPs), firing of individual neurons, blood flow, and oxygen level in the somatosensory cortex of anesthetized rats. Epileptiform discharges induced by bicuculline injections were used to trigger large local events. LFP and blood flow were robustly coupled, as were LFP and tissue oxygen. In a parametric linear model, LFP and the baseline activities of cerebral blood flow and tissue partial oxygen tension contributed significantly to blood flow and oxygen responses. In an analysis of recordings from 402 neurons, blood flow/tissue oxygen correlated with the discharge of putative interneurons but not of principal cells. Our results show that interneuron activity is important in the vascular and metabolic responses during epileptiform discharges.
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Affiliation(s)
- Sandrine Saillet
- INSERM, UMR 1106, Marseille, France; Aix-Marseille Université, Institut de Neurosciences des Systèmes, Marseille, France
| | - Pascale P Quilichini
- INSERM, UMR 1106, Marseille, France; Aix-Marseille Université, Institut de Neurosciences des Systèmes, Marseille, France
| | - Antoine Ghestem
- INSERM, UMR 1106, Marseille, France; Aix-Marseille Université, Institut de Neurosciences des Systèmes, Marseille, France
| | - Bernard Giusiano
- INSERM, UMR 1106, Marseille, France; Aix-Marseille Université, Institut de Neurosciences des Systèmes, Marseille, France; APHM, Timone Hospital, Division of Public Health, Marseille, France
| | - Anton I Ivanov
- INSERM, UMR 1106, Marseille, France; Aix-Marseille Université, Institut de Neurosciences des Systèmes, Marseille, France
| | | | - Ivo Vanzetta
- Aix-Marseille Université, CNRS, INT UMR 7289, Marseille, France
| | - Christophe Bernard
- INSERM, UMR 1106, Marseille, France; Aix-Marseille Université, Institut de Neurosciences des Systèmes, Marseille, France
| | - Christian-G Bénar
- INSERM, UMR 1106, Marseille, France; Aix-Marseille Université, Institut de Neurosciences des Systèmes, Marseille, France;
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21
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Optogenetic stimulation of GABA neurons can decrease local neuronal activity while increasing cortical blood flow. J Cereb Blood Flow Metab 2015; 35:1579-86. [PMID: 26082013 PMCID: PMC4640302 DOI: 10.1038/jcbfm.2015.140] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 05/04/2015] [Accepted: 05/20/2015] [Indexed: 12/27/2022]
Abstract
We investigated the link between direct activation of inhibitory neurons, local neuronal activity, and hemodynamics. Direct optogenetic cortical stimulation in the sensorimotor cortex of transgenic mice expressing Channelrhodopsin-2 in GABAergic neurons (VGAT-ChR2) greatly attenuated spontaneous cortical spikes, but was sufficient to increase blood flow as measured with laser speckle contrast imaging. To determine whether the observed optogenetically evoked gamma aminobutyric acid (GABA)-neuron hemodynamic responses were dependent on ionotropic glutamatergic or GABAergic synaptic mechanisms, we paired optogenetic stimulation with application of antagonists to the cortex. Incubation of glutamatergic antagonists directly on the cortex (NBQX and MK-801) blocked cortical sensory evoked responses (as measured with electroencephalography and intrinsic optical signal imaging), but did not significantly attenuate optogenetically evoked hemodynamic responses. Significant light-evoked hemodynamic responses were still present after the addition of picrotoxin (GABA-A receptor antagonist) in the presence of the glutamatergic synaptic blockade. This activation of cortical inhibitory interneurons can mediate large changes in blood flow in a manner that is by and large not dependent on ionotropic glutamatergic or GABAergic synaptic transmission. This supports the hypothesis that activation of inhibitory neurons can increase local cerebral blood flow in a manner that is not entirely dependent on levels of net ongoing neuronal activity.
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22
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Helboe L, Egebjerg J, de Jong IEM. Distribution of serotonin receptor 5-HT6 mRNA in rat neuronal subpopulations: A double in situ hybridization study. Neuroscience 2015; 310:442-54. [PMID: 26424380 DOI: 10.1016/j.neuroscience.2015.09.064] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 09/22/2015] [Accepted: 09/23/2015] [Indexed: 12/01/2022]
Abstract
The 5-HT6 receptor (5-HT6R) is almost exclusively expressed in the brain and has emerged as a promising target for cognitive disorders, including Alzheimer's disease. In the present study, we have determined the cell types on which the 5-HT6R is expressed by colocalizing 5-HT6R mRNA with that of a range of neuronal and interneuronal markers in the rat brain. Here, we show that 5-HT6R mRNA was expressed at high levels in medium spiny neurons in caudate putamen and in nucleus accumbens, as well as in the olfactory tubercle. Striatal 5-HT6R mRNA was colocalized with both dopamine D1 and D2 receptor mRNA. 5-HT6R mRNA was moderately expressed in the hippocampus and throughout cortical regions in glutamatergic neurons coexpressing vGluT1. A subset of GAD67-positive GABAergic interneurons (approximately 15%) expressed 5-HT6R mRNA in the cortex and hippocampus, the majority of which belonged to the 5-HT3a receptor (5-HT3aR)-expressing subpopulation. In contrast, 5-HT6R mRNA was only expressed to a minor extent in the parvalbumin and somatostatin subpopulations. A subset of calbindin- and calretinin-positive GABAergic interneurons expressed 5-HT6R mRNA while only a very minor fraction of VIP or NPY interneurons in forebrain structures expressed 5-HT6R mRNA. Serotonergic, dopaminergic or cholinergic neurons did not express 5-HT6R mRNA. These data indicate that the 5-HT6R is located on GABAergic and glutamatergic principal neurons, and on a subset of interneurons mainly belonging to the 5-HT3aR subgroup suggesting that the 5-HT6R is positioned to regulate the balance between excitatory and inhibitory signaling in the brain. These data provide new insights into the mechanisms of 5-HT6R signaling.
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Affiliation(s)
- L Helboe
- Department of Neurodegeneration, H. Lundbeck A/S, Ottiliavej 9, DK-2500 Valby, Denmark.
| | - J Egebjerg
- Department of Neurodegeneration, H. Lundbeck A/S, Ottiliavej 9, DK-2500 Valby, Denmark.
| | - I E M de Jong
- Department of Neurodegeneration, H. Lundbeck A/S, Ottiliavej 9, DK-2500 Valby, Denmark.
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23
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Cauli B, Zhou X, Tricoire L, Toussay X, Staiger JF. Revisiting enigmatic cortical calretinin-expressing interneurons. Front Neuroanat 2014; 8:52. [PMID: 25009470 PMCID: PMC4067953 DOI: 10.3389/fnana.2014.00052] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/05/2014] [Indexed: 12/18/2022] Open
Abstract
Cortical calretinin (CR)-expressing interneurons represent a heterogeneous subpopulation of about 10-30% of GABAergic interneurons, which altogether total ca. 12-20% of all cortical neurons. In the rodent neocortex, CR cells display different somatodendritic morphologies ranging from bipolar to multipolar but the bipolar cells and their variations dominate. They are also diverse at the molecular level as they were shown to express numerous neuropeptides in different combinations including vasoactive intestinal polypeptide (VIP), cholecystokinin (CCK), neurokinin B (NKB) corticotrophin releasing factor (CRF), enkephalin (Enk) but also neuropeptide Y (NPY) and somatostatin (SOM) to a lesser extent. CR-expressing interneurons exhibit different firing behaviors such as adapting, bursting or irregular. They mainly originate from the caudal ganglionic eminence (CGE) but a subpopulation also derives from the dorsal part of the medial ganglionic eminence (MGE). Cortical GABAergic CR-expressing interneurons can be divided in two main populations: VIP-bipolar interneurons deriving from the CGE and SOM-Martinotti-like interneurons originating in the dorsal MGE. Although bipolar cells account for the majority of CR-expressing interneurons, the roles they play in cortical neuronal circuits and in the more general metabolic physiology of the brain remained elusive and enigmatic. The aim of this review is, firstly, to provide a comprehensive view of the morphological, molecular and electrophysiological features defining this cell type. We will, secondly, also summarize what is known about their place in the cortical circuit, their modulation by subcortical afferents and the functional roles they might play in neuronal processing and energy metabolism.
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Affiliation(s)
- Bruno Cauli
- Sorbonne Universités, UPMC University Paris 06, UM CR18, Neuroscience Paris Seine Paris, France ; Centre National de la Recherche Scientifique, UMR 8246, Neuroscience Paris Seine Paris, France ; Institut National de la Santé et de la Recherche Médicale, UMR-S 1130, Neuroscience Paris Seine Paris, France
| | - Xiaojuan Zhou
- Institute for Neuroanatomy, UMG, Georg-August-University Göttingen Göttingen, Germany
| | - Ludovic Tricoire
- Sorbonne Universités, UPMC University Paris 06, UM CR18, Neuroscience Paris Seine Paris, France ; Centre National de la Recherche Scientifique, UMR 8246, Neuroscience Paris Seine Paris, France ; Institut National de la Santé et de la Recherche Médicale, UMR-S 1130, Neuroscience Paris Seine Paris, France
| | - Xavier Toussay
- Sorbonne Universités, UPMC University Paris 06, UM CR18, Neuroscience Paris Seine Paris, France ; Centre National de la Recherche Scientifique, UMR 8246, Neuroscience Paris Seine Paris, France ; Institut National de la Santé et de la Recherche Médicale, UMR-S 1130, Neuroscience Paris Seine Paris, France
| | - Jochen F Staiger
- Institute for Neuroanatomy, UMG, Georg-August-University Göttingen Göttingen, Germany
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Abstract
The cerebrovascular regulation involves highly complex mechanisms to assure that the brain is perfused at all times. These mechanisms depend on all components of the neurovascular units: neurons, glia, and vascular cells. All these cell types can produce nitric oxide (NO), a powerful vasodilator through different NO synthases. Many studies underlined the key role of NO in the maintenance of resting cerebral blood flow (CBF) as well as in the mechanisms that control cerebrovascular tone: autoregulation and neurovascular coupling. However, although the role of NO in the control of CBF has been largely investigated, the complexity of the NO system and the lack of specific NO synthase inhibitors led to still unresolved questions such as the origin of NO and the pathways by which it controls the vascular tone. In this chapter, the role of NO in the regulation of CBF is critically reviewed and discussed in the context of the neurovascular unit and the general principles of cerebrovascular regulation.
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25
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Dunn KM, Nelson MT. Neurovascular signaling in the brain and the pathological consequences of hypertension. Am J Physiol Heart Circ Physiol 2013; 306:H1-14. [PMID: 24163077 DOI: 10.1152/ajpheart.00364.2013] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The execution and maintenance of all brain functions are dependent on a continuous flow of blood to meet the metabolic needs of the tissue. To ensure the delivery of resources required for neural processing and the maintenance of neural homeostasis, the cerebral vasculature is elaborately and extensively regulated by signaling from neurons, glia, interneurons, and perivascular nerves. Hypertension is associated with impaired neurovascular regulation of the cerebral circulation and culminates in neurodegeneration and cognitive dysfunction. Here, we review the physiological processes of neurovascular signaling in the brain and discuss mechanisms of hypertensive neurovascular dysfunction.
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Affiliation(s)
- Kathryn M Dunn
- Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont; and
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Vitalis T, Ansorge MS, Dayer AG. Serotonin homeostasis and serotonin receptors as actors of cortical construction: special attention to the 5-HT3A and 5-HT6 receptor subtypes. Front Cell Neurosci 2013; 7:93. [PMID: 23801939 PMCID: PMC3686152 DOI: 10.3389/fncel.2013.00093] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 05/27/2013] [Indexed: 12/15/2022] Open
Abstract
Cortical circuits control higher-order cognitive processes and their function is highly dependent on their structure that emerges during development. The construction of cortical circuits involves the coordinated interplay between different types of cellular processes such as proliferation, migration, and differentiation of neural and glial cell subtypes. Among the multiple factors that regulate the assembly of cortical circuits, 5-HT is an important developmental signal that impacts on a broad diversity of cellular processes. 5-HT is detected at the onset of embryonic telencephalic formation and a variety of serotonergic receptors are dynamically expressed in the embryonic developing cortex in a region and cell-type specific manner. Among these receptors, the ionotropic 5-HT3A receptor and the metabotropic 5-HT6 receptor have recently been identified as novel serotonergic targets regulating different aspects of cortical construction including neuronal migration and dendritic differentiation. In this review, we focus on the developmental impact of serotonergic systems on the construction of cortical circuits and discuss their potential role in programming risk for human psychiatric disorders.
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Affiliation(s)
- Tania Vitalis
- Laboratoire de Neurobiologie, ESPCI ParisTech, Centre National de la Recherche Scientifique-UMR 7637 Paris, France
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27
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Battaglia D, Karagiannis A, Gallopin T, Gutch HW, Cauli B. Beyond the frontiers of neuronal types. Front Neural Circuits 2013; 7:13. [PMID: 23403725 PMCID: PMC3566547 DOI: 10.3389/fncir.2013.00013] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 01/21/2013] [Indexed: 11/13/2022] Open
Abstract
Cortical neurons and, particularly, inhibitory interneurons display a large diversity of morphological, synaptic, electrophysiological, and molecular properties, as well as diverse embryonic origins. Various authors have proposed alternative classification schemes that rely on the concomitant observation of several multimodal features. However, a broad variability is generally observed even among cells that are grouped into a same class. Furthermore, the attribution of specific neurons to a single defined class is often difficult, because individual properties vary in a highly graded fashion, suggestive of continua of features between types. Going beyond the description of representative traits of distinct classes, we focus here on the analysis of atypical cells. We introduce a novel paradigm for neuronal type classification, assuming explicitly the existence of a structured continuum of diversity. Our approach, grounded on the theory of fuzzy sets, identifies a small optimal number of model archetypes. At the same time, it quantifies the degree of similarity between these archetypes and each considered neuron. This allows highlighting archetypal cells, which bear a clear similarity to a single model archetype, and edge cells, which manifest a convergence of traits from multiple archetypes.
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Affiliation(s)
- Demian Battaglia
- Department of Nonlinear Dynamics, Max Planck Institute for Dynamics and Self-Organization (MPIDS) Göttingen, Germany ; Bernstein Center for Computational Neuroscience Göttingen, Germany
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28
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Tricoire L, Vitalis T. Neuronal nitric oxide synthase expressing neurons: a journey from birth to neuronal circuits. Front Neural Circuits 2012; 6:82. [PMID: 23227003 PMCID: PMC3514612 DOI: 10.3389/fncir.2012.00082] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 10/25/2012] [Indexed: 12/17/2022] Open
Abstract
Nitric oxide (NO) is an important signaling molecule crucial for many physiological processes such as synaptic plasticity, vasomotricity, and inflammation. Neuronal nitric oxide synthase (nNOS) is the enzyme responsible for the synthesis of NO by neurons. In the juvenile and mature hippocampus and neocortex nNOS is primarily expressed by subpopulations of GABAergic interneurons. Over the past two decades, many advances have been achieved in the characterization of neocortical and hippocampal nNOS expressing neurons. In this review, we summarize past and present studies that have characterized the electrophysiological, morphological, molecular, and synaptic properties of these neurons. We also discuss recent studies that have shed light on the developmental origins and specification of GABAergic neurons with specific attention to neocortical and hippocampal nNOS expressing GABAergic neurons. Finally, we summarize the roles of NO and nNOS-expressing inhibitory neurons.
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Affiliation(s)
- Ludovic Tricoire
- CNRS-UMR 7102, Laboratoire de Neurobiologie des Processus Adaptatifs, Université Pierre et Marie Curie Paris, France
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29
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Duchemin S, Boily M, Sadekova N, Girouard H. The complex contribution of NOS interneurons in the physiology of cerebrovascular regulation. Front Neural Circuits 2012; 6:51. [PMID: 22907993 PMCID: PMC3414732 DOI: 10.3389/fncir.2012.00051] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 07/19/2012] [Indexed: 12/23/2022] Open
Abstract
Following the discovery of the vasorelaxant properties of nitric oxide (NO) by Furchgott and Ignarro, the finding by Bredt and coll. of a constitutively expressed NO synthase in neurons (nNOS) led to the presumption that neuronal NO may control cerebrovascular functions. Consequently, numerous studies have sought to determine whether neuraly-derived NO is involved in the regulation of cerebral blood flow (CBF). Anatomically, axons, dendrites, or somata of NO neurons have been found to contact the basement membrane of blood vessels or perivascular astrocytes in all segments of the cortical microcirculation. Functionally, various experimental approaches support a role of neuronal NO in the maintenance of resting CBF as well as in the vascular response to neuronal activity. Since decades, it has been assumed that neuronal NO simply diffuses to the local blood vessels and produce vasodilation through a cGMP-PKG dependent mechanism. However, NO is not the sole mediator of vasodilation in the cerebral microcirculation and is known to interact with a myriad of signaling pathways also involved in vascular control. In addition, cerebrovascular regulation is the result of a complex orchestration between all components of the neurovascular unit (i.e., neuronal, glial, and vascular cells) also known to produce NO. In this review article, the role of NO interneuron in the regulation of cortical microcirculation will be discussed in the context of the neurovascular unit.
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Affiliation(s)
- Sonia Duchemin
- Department of Pharmacology, Université de Montréal Montreal, QC, Canada
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