scholarly journals Glial Cells Promote Myelin Formation and Elimination

2021 ◽  
Vol 9 ◽  
Author(s):  
Alexandria N. Hughes
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Glial Cells ◽  
Cell Types ◽  
Brain Functions ◽  
Myelin Sheaths ◽  
Local Signaling ◽  
The Brain ◽  
Vertebrate Central Nervous System

Building a functional nervous system requires the coordinated actions of many glial cells. In the vertebrate central nervous system (CNS), oligodendrocytes myelinate neuronal axons to increase conduction velocity and provide trophic support. Myelination can be modified by local signaling at the axon-myelin interface, potentially adapting sheaths to support the metabolic needs and physiology of individual neurons. However, neurons and oligodendrocytes are not wholly responsible for crafting the myelination patterns seen in vivo. Other cell types of the CNS, including microglia and astrocytes, modify myelination. In this review, I cover the contributions of non-neuronal, non-oligodendroglial cells to the formation, maintenance, and pruning of myelin sheaths. I address ways that these cell types interact with the oligodendrocyte lineage throughout development to modify myelination. Additionally, I discuss mechanisms by which these cells may indirectly tune myelination by regulating neuronal activity. Understanding how glial-glial interactions regulate myelination is essential for understanding how the brain functions as a whole and for developing strategies to repair myelin in disease.

scholarly journals Insights Into Central Nervous System Glial Cell Formation and Function From Zebrafish

2021 ◽  
Vol 9 ◽  
Author(s):  
Sarah A. Neely ◽  
David A. Lyons
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Glial Cell ◽  
Glial Cells ◽  
Large Body ◽  
Cell Types ◽  
Cell Interactions ◽  
Glial Cell Interactions ◽  
And Function

The term glia describes a heterogenous collection of distinct cell types that make up a large proportion of our nervous system. Although once considered the glue of the nervous system, the study of glial cells has evolved significantly in recent years, with a large body of literature now highlighting their complex and diverse roles in development and throughout life. This progress is due, in part, to advances in animal models in which the molecular and cellular mechanisms of glial cell development and function as well as neuron-glial cell interactions can be directly studied in vivo in real time, in intact neural circuits. In this review we highlight the instrumental role that zebrafish have played as a vertebrate model system for the study of glial cells, and discuss how the experimental advantages of the zebrafish lend themselves to investigate glial cell interactions and diversity. We focus in particular on recent studies that have provided insight into the formation and function of the major glial cell types in the central nervous system in zebrafish.

scholarly journals Mitochondrial Calcium Uptake Capacity Modulates Neocortical Excitability

2013 ◽  
Vol 33 (7) ◽  
pp. 1115-1126 ◽  
Author(s):  
Basavaraju G Sanganahalli ◽  
Peter Herman ◽  
Fahmeed Hyder ◽  
Sridhar S Kannurpatti
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cell Types ◽  
Dependent Manner ◽  
Evoked Responses ◽  
Blood Oxygen Level ◽  
Calcium Uniporter ◽  
Sensory Evoked

Local calcium (Ca2 +) changes regulate central nervous system metabolism and communication integrated by subcellular processes including mitochondrial Ca2 + uptake. Mitochondria take up Ca2 + through the calcium uniporter (mCU) aided by cytoplasmic microdomains of high Ca2 +. Known only in vitro, the in vivo impact of mCU activity may reveal Ca2 + -mediated roles of mitochondria in brain signaling and metabolism. From in vitro studies of mitochondrial Ca2 + sequestration and cycling in various cell types of the central nervous system, we evaluated ranges of spontaneous and activity-induced Ca2 + distributions in multiple subcellular compartments in vivo. We hypothesized that inhibiting (or enhancing) mCU activity would attenuate (or augment) cortical neuronal activity as well as activity-induced hemodynamic responses in an overall cytoplasmic and mitochondrial Ca2 + -dependent manner. Spontaneous and sensory-evoked cortical activities were measured by extracellular electrophysiology complemented with dynamic mapping of blood oxygen level dependence and cerebral blood flow. Calcium uniporter activity was inhibited and enhanced pharmacologically, and its impact on the multimodal measures were analyzed in an integrated manner. Ru360, an mCU inhibitor, reduced all stimulus-evoked responses, whereas Kaempferol, an mCU enhancer, augmented all evoked responses. Collectively, the results confirm aforementioned hypotheses and support the Ca2 + uptake-mediated integrative role of in vivo mitochondria on neocortical activity.

Cell proliferation in the repairing adult insect central nervous system: incorporation of the thymidine analogue 5-bromo-2-deoxyuridine in vivo

1990 ◽  
Vol 95 (4) ◽  
pp. 599-604
Author(s):  
P.J. Smith ◽  
E.A. Howes ◽  
J.E. Treherne
Keyword(s):  
Central Nervous System ◽  
Cell Proliferation ◽  
Nervous System ◽  
Blood Brain Barrier ◽  
Glial Cells ◽  
Past Research ◽  
Thymidine Analogue ◽  
Adult Insect ◽  
Insect Central Nervous System

Uptake of the thymidine analogue 5-bromo-2-deoxyuridine into non-neuronal cells of the insect central nervous system has been examined following a controlled lesioning of the glial elements. The pattern of BUdR labelling along the penultimate abdominal connective was examined over a period of 17 days. Cell proliferation occurred in and immediately around the site of damage in both perineurial and subperineurial glial cells but at different times post-lesion for the two regions. Proliferation in the perineurial zone was maximal at 6–8 days post-lesion but continued for at least 17 days. Subperineurial proliferation was less dramatic and peaked between days 8–11 post-lesion. In both areas division appears to be confined to the reactive glial cells. These results are discussed in the context of past research on this system, particularly with regard to the restoration of the blood-brain barrier.

scholarly journals Role of Adiponectin in Central Nervous System Disorders

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Jenna Bloemer ◽  
Priyanka D. Pinky ◽  
Manoj Govindarajulu ◽  
Hao Hong ◽  
Robert Judd ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Energy Homeostasis ◽  
Peripheral Circulation ◽  
Hippocampal Neurogenesis ◽  
Cns Disorders ◽  
Brain Functions ◽  
Glucose And Lipid Metabolism ◽  
Antidepressant Effects ◽  
The Brain

Adiponectin, the most abundant plasma adipokine, plays an important role in the regulation of glucose and lipid metabolism. Adiponectin also possesses insulin-sensitizing, anti-inflammatory, angiogenic, and vasodilatory properties which may influence central nervous system (CNS) disorders. Although initially not thought to cross the blood-brain barrier, adiponectin enters the brain through peripheral circulation. In the brain, adiponectin signaling through its receptors, AdipoR1 and AdipoR2, directly influences important brain functions such as energy homeostasis, hippocampal neurogenesis, and synaptic plasticity. Overall, based on its central and peripheral actions, recent evidence indicates that adiponectin has neuroprotective, antiatherogenic, and antidepressant effects. However, these findings are not without controversy as human observational studies report differing correlations between plasma adiponectin levels and incidence of CNS disorders. Despite these controversies, adiponectin is gaining attention as a potential therapeutic target for diverse CNS disorders, such as stroke, Alzheimer’s disease, anxiety, and depression. Evidence regarding the emerging role for adiponectin in these disorders is discussed in the current review.

scholarly journals Cholesterol: Its Regulation and Role in Central Nervous System Disorders

Cholesterol ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-19 ◽  
Author(s):  
Matthias Orth ◽  
Stefano Bellosta
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Metabolic Pathways ◽  
Cholesterol Metabolism ◽  
Major Constituent ◽  
Normal Brain ◽  
Lipoprotein Receptors ◽  
Brain Cholesterol ◽  
Brain Functions ◽  
The Brain

Cholesterol is a major constituent of the human brain, and the brain is the most cholesterol-rich organ. Numerous lipoprotein receptors and apolipoproteins are expressed in the brain. Cholesterol is tightly regulated between the major brain cells and is essential for normal brain development. The metabolism of brain cholesterol differs markedly from that of other tissues. Brain cholesterol is primarily derived by de novo synthesis and the blood brain barrier prevents the uptake of lipoprotein cholesterol from the circulation. Defects in cholesterol metabolism lead to structural and functional central nervous system diseases such as Smith-Lemli-Opitz syndrome, Niemann-Pick type C disease, and Alzheimer’s disease. These diseases affect different metabolic pathways (cholesterol biosynthesis, lipid transport and lipoprotein assembly, apolipoproteins, lipoprotein receptors, and signaling molecules). We review the metabolic pathways of cholesterol in the CNS and its cell-specific and microdomain-specific interaction with other pathways such as the amyloid precursor protein and discuss potential treatment strategies as well as the effects of the widespread use of LDL cholesterol-lowering drugs on brain functions.

scholarly journals Glioendocrine System: Effects of Thyroid Hormones in Glia and their Functions in the Central Nervous System

2020 ◽  
Vol 3 (1) ◽  
pp. 1-11
Author(s):  
Mami Noda
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Cognitive Impairment ◽  
Thyroid Hormones ◽  
Glial Cells ◽  
Endocrine System ◽  
Cell Types ◽  
Development And Differentiation ◽  
The Central Nervous System ◽  
And Function

AbstractGlial cells play a significant role in the link between the endocrine and nervous systems. Among hormones, thyroid hormones (THs) are critical for the regulation of development and differentiation of neurons and glial cells, and hence for development and function of the central nervous system (CNS). THs are transported into the CNS, metabolized in astrocytes and affect various cell types in the CNS including astrocyte itself. Since 3,3’,5-triiodo-L-thyronine (T3) is apparently released from astrocytes in the CNS, it is a typical example of glia-endocrine system.The prevalence of thyroid disorders increases with age. Both hypothyroidism and hyperthyroidism are reported to increase the risk of cognitive impairment or Alzheimer’s disease (AD). Therefore, understanding the neuroglial effects of THs may help to solve the problem why hypothyroidism or hyperthyroidism may cause mental disorders or become a risk factor for cognitive impairment. In this review, THs are focused among wide variety of hormones related to brain function, and recent advancement in glioendocrine system is described.

scholarly journals Drug Penetration into the Central Nervous System: Pharmacokinetic Concepts and In Vitro Model Systems

Pharmaceutics ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1542
Author(s):  
Felix Neumaier ◽  
Boris D. Zlatopolskiy ◽  
Bernd Neumaier
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Model Systems ◽  
Pharmacokinetic Parameters ◽  
Special Focus ◽  
Drug Penetration ◽  
The Central Nervous System ◽  
The Brain

Delivery of most drugs into the central nervous system (CNS) is restricted by the blood–brain barrier (BBB), which remains a significant bottleneck for development of novel CNS-targeted therapeutics or molecular tracers for neuroimaging. Consistent failure to reliably predict drug efficiency based on single measures for the rate or extent of brain penetration has led to the emergence of a more holistic framework that integrates data from various in vivo, in situ and in vitro assays to obtain a comprehensive description of drug delivery to and distribution within the brain. Coupled with ongoing development of suitable in vitro BBB models, this integrated approach promises to reduce the incidence of costly late-stage failures in CNS drug development, and could help to overcome some of the technical, economic and ethical issues associated with in vivo studies in animal models. Here, we provide an overview of BBB structure and function in vivo, and a summary of the pharmacokinetic parameters that can be used to determine and predict the rate and extent of drug penetration into the brain. We also review different in vitro models with regard to their inherent shortcomings and potential usefulness for development of fast-acting drugs or neurotracers labeled with short-lived radionuclides. In this regard, a special focus has been set on those systems that are sufficiently well established to be used in laboratories without significant bioengineering expertise.

scholarly journals Brain Targeting of anti-HIV Nucleosides: in vitro and in vivo Evaluation of 6-chloro-2′,3′-dideoxypurine, a Lipophilic Prodrug of 2′,3′-dideoxyinosine

1994 ◽  
Vol 5 (5) ◽  
pp. 304-311 ◽  
Author(s):  
K. J. Doshi ◽  
F. D. Boudinot ◽  
J. M. Gallo ◽  
R. F. Schinazi ◽  
C. K. Chu
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Oral Administration ◽  
Intravenous Administration ◽  
Brain Targeting ◽  
The Central Nervous System ◽  
Intravenous And Oral Administration ◽  
The Brain

Lipophilic 6-halo-2′,3′-dideoxypurine nucleosides may be useful prodrugs for the targeting of 2′,3′-dideoxyinosine (ddl) to the central nervous system. The purpose of this study was to evaluate the potential effectiveness of 6-chloro-2′,3′-dideoxypurine (6-CI-ddP) for the targeting of ddl to the brain. In vitro studies indicated that the adenosine deaminase-mediated biotransformation of 6-CI-ddP to ddl was more rapid in mouse brain homogenate than in mouse serum. The brain distribution of 6-CI-ddP and ddl was assessed in vivo in mice following intravenous and oral administration of the prodrug or parent drug. Brain concentrations of ddl were similar after intravenous administration of 6-CI-ddP or ddl. However, after oral administration of the 6-CI-ddP prodrug, significantly greater concentrations of ddl were seen in the brain compared to those found after oral administration of ddl. The brain:serum AUG ratio (expressed as a percentage) of ddl after intravenous administration of 50 mg kg−1 of the active nucleoside was 3%. Following oral administration of 250 mg kg−1 ddl, low concentrations of ddl were detected in the brain. Brain:serum AUC ratios following intravenous and oral administration of the prodrug 6-CI-ddP were 19–25%. Thus, brain:serum AUC ratios were 6- to 8-fold higher after prodrug administration than those obtained after administration of the parent nucleoside. Oral administration of 6-CI-ddP yielded concentrations of ddl in the brain similar to those obtained following intravenous administration. The results of this study provide further evidence that 6-CI-ddP may be a useful prodrug for delivering ddl to the central nervous system, particularly after oral administration.

New dimensions of connectomics and network plasticity in the central nervous system

2017 ◽  
Vol 28 (2) ◽  
pp. 113-132 ◽  
Author(s):  
Diego Guidolin ◽  
Manuela Marcoli ◽  
Guido Maura ◽  
Luigi F. Agnati
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Network Architecture ◽  
Cell Phenotype ◽  
Brain Functions ◽  
Brain Connectome ◽  
Communication Processes ◽  
Cell Components ◽  
The Central Nervous System ◽  
The Brain

AbstractCellular network architecture plays a crucial role as the structural substrate for the brain functions. Therefore, it represents the main rationale for the emerging field of connectomics, defined as the comprehensive study of all aspects of central nervous system connectivity. Accordingly, in the present paper the main emphasis will be on the communication processes in the brain, namely wiring transmission (WT), i.e. the mapping of the communication channels made by cell components such as axons and synapses, and volume transmission (VT), i.e. the chemical signal diffusion along the interstitial brain fluid pathways. Considering both processes can further expand the connectomics concept, since both WT-connectomics and VT-connectomics contribute to the structure of the brain connectome. A consensus exists that such a structure follows a hierarchical or nested architecture, and macro-, meso- and microscales have been defined. In this respect, however, several lines of evidence indicate that a nanoscale (nano-connectomics) should also be considered to capture direct protein-protein allosteric interactions such as those occurring, for example, in receptor-receptor interactions at the plasma membrane level. In addition, emerging evidence points to novel mechanisms likely playing a significant role in the modulation of intercellular connectivity, increasing the plasticity of the system and adding complexity to its structure. In particular, the roamer type of VT (i.e. the intercellular transfer of RNA, proteins and receptors by extracellular vesicles) will be discussed since it allowed us to introduce a new concept of ‘transient changes of cell phenotype’, that is the transient acquisition of new signal release capabilities and/or new recognition/decoding apparatuses.

Sign in / Sign up

Export Citation Format

Share Document