Physiological requirements for action potential conduction, sensory awareness, and motor control

2021 ◽  
pp. 235-239
Author(s):  
Staffan Johansson
Keyword(s):  
Nervous System ◽  
Signal Transmission ◽  
Neuronal Cell ◽  
Memory Storage ◽  
Ion Concentration ◽  
Concentration Gradients ◽  
Nervous Impulse ◽  
Impulse Generation ◽  
Nervous System Function ◽  
Energy Dependent

Nervous system function depends on electrical and chemical signals. The nervous impulse is a fluctuation in voltage across the neuronal cell membrane, generated by ion currents through ion-selective, voltage-sensitive membrane channels. Neuronal information is encoded in the temporal pattern of such impulses propagated along the nerve fibres at speeds that may reach about 100 m/s in fibres electrically isolated by myelin. Signal transmission to other cells via synaptic contacts occurs mainly via chemical transmitters that control membrane ion channels and give rise to electrical responses in receiving cells, with plasticity in the process making the system capable of learning and memory storage. Since impulse generation as well as synaptic transmission depends on ion flux across the membrane, energy-dependent ion pumps are critical for maintaining the ion concentration gradients necessary for the nervous signals. As a consequence, the nervous system consumes a lot of energy and is sensitive to any lack of energy.

scholarly journals Drosophila ßHeavy-Spectrin is required in polarized ensheathing glia that form a diffusion-barrier around the neuropil

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nicole Pogodalla ◽  
Holger Kranenburg ◽  
Simone Rey ◽  
Silke Rodrigues ◽  
Albert Cardona ◽  
...  
Keyword(s):  
Nervous System ◽  
Plasma Membrane ◽  
Diffusion Barrier ◽  
Neuronal Cell ◽  
Apical Plasma Membrane ◽  
Neuronal Cell Bodies ◽  
The Central Nervous System ◽  
Basolateral Plasma Membrane ◽  
Nervous System Function ◽  
Spectrin Cytoskeleton

AbstractIn the central nervous system (CNS), functional tasks are often allocated to distinct compartments. This is also evident in the Drosophila CNS where synapses and dendrites are clustered in distinct neuropil regions. The neuropil is separated from neuronal cell bodies by ensheathing glia, which as we show using dye injection experiments, contribute to the formation of an internal diffusion barrier. We find that ensheathing glia are polarized with a basolateral plasma membrane rich in phosphatidylinositol-(3,4,5)-triphosphate (PIP3) and the Na+/K+-ATPase Nervana2 (Nrv2) that abuts an extracellular matrix formed at neuropil-cortex interface. The apical plasma membrane is facing the neuropil and is rich in phosphatidylinositol-(4,5)-bisphosphate (PIP2) that is supported by a sub-membranous ßHeavy-Spectrin cytoskeleton. ßHeavy-spectrin mutant larvae affect ensheathing glial cell polarity with delocalized PIP2 and Nrv2 and exhibit an abnormal locomotion which is similarly shown by ensheathing glia ablated larvae. Thus, polarized glia compartmentalizes the brain and is essential for proper nervous system function.

scholarly journals Neuronal cell models and methods simulating nervous system function to screen for neurotoxic compounds

2015 ◽  
Vol 49 ◽  
pp. 125
Author(s):  
Julia Sisnaiske ◽  
Denise Schäfer ◽  
Vanessa Hausherr ◽  
Marcel Leist ◽  
Tzutzuy Ramirez-Hernandez ◽  
...  
Keyword(s):  
Nervous System ◽  
Neuronal Cell ◽  
System Function ◽  
Cell Models ◽  
Nervous System Function

Overlapping and diverse distribution of Na–K ATPase isozymes in neurons and glia

1992 ◽  
Vol 70 (S1) ◽  
pp. S255-S259 ◽  
Author(s):  
Kathleen J. Sweadner
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Large Fraction ◽  
Ion Concentration ◽  
Concentration Gradients ◽  
Genes Encoding ◽  
A Cell ◽  
The Central Nervous System ◽  
The Brain

The Na–K ATPase is the plasma membrane enzyme that catalyzes the active uptake of K+ and extrusion of Na+, thereby establishing ion concentration gradients between the inside and outside of the cell. It consumes a large fraction of the energy used in the brain. The enzyme is present in both neurons and glia. Studies of ion flux and of the properties of membrane-associated ATPase activity have suggested that there is more than one functional type of Na–K ATPase in the central nervous system. Molecular cloning has demonstrated that there are three different genes encoding catalytic (α) subunits and at least two genes encoding glycoprotein (β) subunits; all are expressed in the brain. This brief review summarizes the current understanding of Na–K ATPase isozyme distribution and properties. Both neurons and glia can express different isoforms in a cell-specific manner.Key words: Na–K ATPase, monoclonal antibody, immunofluorescence, central nervous system, retina, in situ hybridization.

scholarly journals Drosophila beta-Heavy-Spectrin is required in polarized ensheathing glia that form a diffusion-barrier around the neuropil

2021 ◽  
Author(s):  
Nicole Pogodalla ◽  
Holger Kranenburg ◽  
Simone Rey ◽  
Silke Rodrigues ◽  
Albert Cardona ◽  
...  
Keyword(s):  
Nervous System ◽  
Plasma Membrane ◽  
Diffusion Barrier ◽  
Neuronal Cell ◽  
Apical Plasma Membrane ◽  
Neuronal Cell Bodies ◽  
Insect Cns ◽  
The Central Nervous System ◽  
Nervous System Function ◽  
Spectrin Cytoskeleton

In the central nervous system (CNS), functional tasks are often allocated to distinct compartments. This is also evident in the insect CNS where synapses and dendrites are clustered in distinct neuropil regions. The neuropil is separated from neuronal cell bodies by ensheathing glia, which as we show using dye injection experiments forms an internal diffusion barrier. We find that ensheathing glial cells are polarized with a basolateral plasma membrane rich in phosphatidylinositol-(3,4,5)-triphosphate (PIP3) and the Na+/K+-ATPase Nervana2 (Nrv2) that abuts an extracellular matrix formed at neuropil-cortex interface. The apical plasma membrane is facing the neuropil and is rich in phosphatidylinositol-(4,5)-bisphosphate (PIP2) that is supported by a sub-membranous beta-Heavy-Spectrin cytoskeleton. beta-Heavy-spectrin mutant larvae affect ensheathing glial cell polarity with delocalized PIP2 and Nrv2 and exhibit an abnormal locomotion which is similarly shown by ensheathing glia ablated larvae. Thus, polarized glia compartmentalizes the brain and is essential for proper nervous system function.

The Red Neuronal Pigment in the Nervous System of the Mussel, Mytilus Edulis: Localization and Its Effect on Lateral Ciliary Activity with Spectral and Analytical Changes

1981 ◽  
Vol 39 ◽  
pp. 494-495
Author(s):  
Anthony A. Paparo ◽  
Judith A. Murphy
Keyword(s):  
Nervous System ◽  
Mytilus Edulis ◽  
Neuronal Cell ◽  
Ciliary Activity ◽  
Neuronal Cell Bodies ◽  
The Central Nervous System ◽  
Intracellular Organelles ◽  
The Common ◽  
The Individual ◽  
Cryostat Sections

The purpose of this study was to localize the red neuronal pigment in Mytilus edulis and examine its role in the control of lateral ciliary activity in the gill. The visceral ganglia (Vg) in the central nervous system show an over al red pigmentation. Most red pigments examined in squash preps and cryostat sec tions were localized in the neuronal cell bodies and proximal axon regions. Unstained cryostat sections showed highly localized patches of this pigment scattered throughout the cells in the form of dense granular masses about 5-7 um in diameter, with the individual granules ranging from 0.6-1.3 um in diame ter. Tissue stained with Gomori's method for Fe showed bright blue granular masses of about the same size and structure as previously seen in unstained cryostat sections.Thick section microanalysis (Fig.l) confirmed both the localization and presence of Fe in the nerve cell. These nerve cells of the Vg share with other pigmented photosensitive cells the common cytostructural feature of localization of absorbing molecules in intracellular organelles where they are tightly ordered in fine substructures.

Glial Cells in the Auditory Brainstem

2018 ◽  
pp. 680-706
Author(s):  
Giedre Milinkeviciute ◽  
Karina S. Cramer
Keyword(s):  
Nervous System ◽  
Glial Cells ◽  
Sound Localization ◽  
Auditory Brainstem ◽  
Synaptic Function ◽  
System Function ◽  
Auditory Neurons ◽  
System P ◽  
The Central Nervous System ◽  
Nervous System Function

The auditory brainstem carries out sound localization functions that require an extraordinary degree of precision. While many of the specializations needed for these functions reside in auditory neurons, additional adaptations are made possible by the functions of glial cells. Astrocytes, once thought to have mainly a supporting role in nervous system function, are now known to participate in synaptic function. In the auditory brainstem, they contribute to development of specialized synapses and to mature synaptic function. Oligodendrocytes play critical roles in regulating timing in sound localization circuitry. Microglia enter the central nervous system early in development, and also have important functions in the auditory system’s response to injury. This chapter highlights the unique functions of these non-neuronal cells in the auditory system.

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