Simulation on the Physical Process of Neural Electromagnetic Signal Generation Based on a Simple but Functional Bionic Na+ Channel

Abstract The physical processes occurring at open Na+ channels in neural fibers are essential for understanding the nature of neural signals and the mechanism by which the signals are generated and transmitted along nerves. However, there is less generally accepted description of these physical processes. We studied changes in the transmembrane ionic flux and the resulting two types of electromagnetic signals by simulating the Na+ transport across a bionic nanochannel model simplified from voltage-gated Na+ channels. Results show that the Na+ flux can reach a steady state in approximately 10 ns owing to the dynamic equilibrium of Na+ ions concentration difference between the both sides of membrane. After characterizing the spectrum and transmission of these two electromagnetic signals, the low-frequency transmembrane electric field is regarded as the physical quantity transmitting in waveguide-like lipid dielectric layer and triggering the neighboring voltage-gated channels. Factors influencing the Na+ flux transport are also studied. The impact of the Na+ concentration gradient is found higher than that of the initial transmembrane potential on the Na+ transport rate, and introducing the surface-negative charge in the upper third channel could increase the transmembrane Na+ current. This work can be further studied by improving the simulation model; however, the current work helps to better understand the electrical functions of voltage-gated ion channels in neural systems.

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Roles of Microglial Ion Channel in Neurodegenerative Diseases

Journal of Clinical Medicine ◽

10.3390/jcm10061239 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1239

Author(s):

Alexandru Cojocaru ◽

Emilia Burada ◽

Adrian-Tudor Bălșeanu ◽

Alexandru-Florian Deftu ◽

Bogdan Cătălin ◽

...

Keyword(s):

Ion Channels ◽

Neurodegenerative Diseases ◽

Excitable Cells ◽

Proton Channels ◽

Voltage Gated ◽

Cellular Processes ◽

Pathological Conditions ◽

The Common ◽

Transient Receptor ◽

The Impact

As the average age and life expectancy increases, the incidence of both acute and chronic central nervous system (CNS) pathologies will increase. Understanding mechanisms underlying neuroinflammation as the common feature of any neurodegenerative pathology, we can exploit the pharmacology of cell specific ion channels to improve the outcome of many CNS diseases. As the main cellular player of neuroinflammation, microglia play a central role in this process. Although microglia are considered non-excitable cells, they express a variety of ion channels under both physiological and pathological conditions that seem to be involved in a plethora of cellular processes. Here, we discuss the impact of modulating microglia voltage-gated, potential transient receptor, chloride and proton channels on microglial proliferation, migration, and phagocytosis in neurodegenerative diseases.

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Gravitational and Electromagnetic Perturbations of a Charged Black Hole in a General Gauge Condition

Particles ◽

10.3390/particles4020012 ◽

2021 ◽

Vol 4 (2) ◽

pp. 106-128

Author(s):

Claudia Moreno ◽

Juan Carlos Degollado ◽

Darío Núñez ◽

Carlos Rodríguez-Leal

Keyword(s):

Black Hole ◽

Scalar Function ◽

Gauge Condition ◽

Fluid Distribution ◽

Electromagnetic Signal ◽

Charged Fluid ◽

Coupled Equations ◽

Electromagnetic Signals ◽

Limiting Case ◽

Weyl Scalar

We derive a set of coupled equations for the gravitational and electromagnetic perturbation in the Reissner–Nordström geometry using the Newman–Penrose formalism. We show that the information of the physical gravitational signal is contained in the Weyl scalar function Ψ4, as is well known, but for the electromagnetic signal, the information is encoded in the function χ, which relates the perturbations of the radiative Maxwell scalars φ2 and the Weyl scalar Ψ3. In deriving the perturbation equations, we do not impose any gauge condition and as a limiting case, our analysis contains previously obtained results, for instance, those from Chandrashekhar’s book. In our analysis, we also include the sources for the perturbations and focus on a dust-like charged fluid distribution falling radially into the black hole. Finally, by writing the functions on the basis of spin-weighted spherical harmonics and the Reissner–Nordström spacetime in Kerr–Schild type coordinates, a hyperbolic system of coupled partial differential equations is presented and numerically solved. In this way, we completely solve a system that generates a gravitational signal as well as an electromagnetic/gravitational one, which sets the basis to find correlations between them and thus facilitates gravitational wave detection via electromagnetic signals.

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Statistical Approach to Incorporating Experimental Variability into a Mathematical Model of the Voltage-Gated Na+ Channel and Human Atrial Action Potential

Cells ◽

10.3390/cells10061516 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1516

Author(s):

Daniel Gratz ◽

Alexander J Winkle ◽

Seth H Weinberg ◽

Thomas J Hund

Keyword(s):

Action Potential ◽

Mathematical Models ◽

Cardiac Myocyte ◽

Population Level ◽

Na Channel ◽

Model Parameters ◽

Healthy Population ◽

Experimental Measurements ◽

Voltage Gated ◽

Experimental Variability

The voltage-gated Na+ channel Nav1.5 is critical for normal cardiac myocyte excitability. Mathematical models have been widely used to study Nav1.5 function and link to a range of cardiac arrhythmias. There is growing appreciation for the importance of incorporating physiological heterogeneity observed even in a healthy population into mathematical models of the cardiac action potential. Here, we apply methods from Bayesian statistics to capture the variability in experimental measurements on human atrial Nav1.5 across experimental protocols and labs. This variability was used to define a physiological distribution for model parameters in a novel model formulation of Nav1.5, which was then incorporated into an existing human atrial action potential model. Model validation was performed by comparing the simulated distribution of action potential upstroke velocity measurements to experimental measurements from several different sources. Going forward, we hope to apply this approach to other major atrial ion channels to create a comprehensive model of the human atrial AP. We anticipate that such a model will be useful for understanding excitability at the population level, including variable drug response and penetrance of variants linked to inherited cardiac arrhythmia syndromes.

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Congenital Deletion of Nedd4-2 in Lung Epithelial Cells Causes Progressive Alveolitis and Pulmonary Fibrosis in Neonatal Mice

International Journal of Molecular Sciences ◽

10.3390/ijms22116146 ◽

2021 ◽

Vol 22 (11) ◽

pp. 6146

Author(s):

Dominik H. W. Leitz ◽

Julia Duerr ◽

Surafel Mulugeta ◽

Ayça Seyhan Agircan ◽

Stefan Zimmermann ◽

...

Keyword(s):

Epithelial Cells ◽

Pulmonary Fibrosis ◽

Growth Failure ◽

Lung Epithelial Cells ◽

Na Channel ◽

Preclinical Development ◽

Neonatal Mice ◽

Mucin Expression ◽

Lung Epithelial ◽

The Impact

Recent studies found that expression of Nedd4‑2 is reduced in lung tissue from patients with idiopathic pulmonary fibrosis (IPF) and that the conditional deletion of Nedd4‑2 in lung epithelial cells causes IPF-like disease in adult mice via multiple defects, including dysregulation of the epithelial Na+ channel (ENaC), TGFβ signaling and the biosynthesis of surfactant protein-C proprotein (proSP-C). However, knowledge of the impact of congenital deletion of Nedd4‑2 on the lung phenotype remains limited. In this study, we therefore determined the effects of congenital deletion of Nedd4‑2 in the lung epithelial cells of neonatal doxycycline-induced triple transgenic Nedd4‑2fl/fl/CCSP‑rtTA2S‑M2/LC1 mice, with a focus on clinical phenotype, survival, lung morphology, inflammation markers in BAL, mucin expression, ENaC function and proSP‑C trafficking. We found that the congenital deletion of Nedd4‑2 caused a rapidly progressive lung disease in neonatal mice that shares key features with interstitial lung diseases in children (chILD), including hypoxemia, growth failure, sterile pneumonitis, fibrotic lung remodeling and high mortality. The congenital deletion of Nedd4‑2 in lung epithelial cells caused increased expression of Muc5b and mucus plugging of distal airways, increased ENaC activity and proSP-C mistrafficking. This model of congenital deletion of Nedd4‑2 may support studies of the pathogenesis and preclinical development of therapies for chILD.

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Voltage-Gated Na+ Channel Isoforms and Their mRNA Expression Levels and Protein Abundance in Three Electric Organs and the Skeletal Muscle of the Electric Eel Electrophorus electricus

PLoS ONE ◽

10.1371/journal.pone.0167589 ◽

2016 ◽

Vol 11 (12) ◽

pp. e0167589 ◽

Cited By ~ 5

Author(s):

Biyun Ching ◽

Jia M. Woo ◽

Kum C. Hiong ◽

Mel V. Boo ◽

Wai P. Wong ◽

...

Keyword(s):

Skeletal Muscle ◽

Mrna Expression ◽

Na Channel ◽

Protein Abundance ◽

Expression Levels ◽

Voltage Gated ◽

Electrophorus Electricus ◽

Electric Organs ◽

Electric Eel ◽

Mrna Expression Levels

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Ocean resurge-induced impact melt dynamics on the peak-ring of the Chicxulub impact structure, Mexico

International Journal of Earth Sciences ◽

10.1007/s00531-021-02008-w ◽

2021 ◽

Author(s):

Felix M. Schulte ◽

◽

Axel Wittmann ◽

Stefan Jung ◽

Joanna V. Morgan ◽

...

Keyword(s):

Impact Structure ◽

Physical Processes ◽

Hydrothermal Conditions ◽

Chemical Examination ◽

Impact Melt ◽

Target Rock ◽

Single Process ◽

Chicxulub Impact ◽

The Impact

AbstractCore from Hole M0077 from IODP/ICDP Expedition 364 provides unprecedented evidence for the physical processes in effect during the interaction of impact melt with rock-debris-laden seawater, following a large meteorite impact into waters of the Yucatán shelf. Evidence for this interaction is based on petrographic, microstructural and chemical examination of the 46.37-m-thick impact melt rock sequence, which overlies shocked granitoid target rock of the peak ring of the Chicxulub impact structure. The melt rock sequence consists of two visually distinct phases, one is black and the other is green in colour. The black phase is aphanitic and trachyandesitic in composition and similar to melt rock from other sites within the impact structure. The green phase consists chiefly of clay minerals and sparitic calcite, which likely formed from a solidified water–rock debris mixture under hydrothermal conditions. We suggest that the layering and internal structure of the melt rock sequence resulted from a single process, i.e., violent contact of initially superheated silicate impact melt with the ocean resurge-induced water–rock mixture overriding the impact melt. Differences in density, temperature, viscosity, and velocity of this mixture and impact melt triggered Kelvin–Helmholtz and Rayleigh–Taylor instabilities at their phase boundary. As a consequence, shearing at the boundary perturbed and, thus, mingled both immiscible phases, and was accompanied by phreatomagmatic processes. These processes led to the brecciation at the top of the impact melt rock sequence. Quenching of this breccia by the seawater prevented reworking of the solidified breccia layers upon subsequent deposition of suevite. Solid-state deformation, notably in the uppermost brecciated impact melt rock layers, attests to long-term gravitational settling of the peak ring.

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