scholarly journals Magnesium Ions Depolarize the Neuronal Membrane via Quantum Tunneling through the Closed Channels

2020 ◽  
Vol 2 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Abdallah Barjas Qaswal
Keyword(s):  
Membrane Potential ◽  
Quantum Tunneling ◽  
Magnesium Concentration ◽  
Resting Membrane Potential ◽  
Neuronal Membrane ◽  
Magnesium Ions ◽  
Quantum Conductance ◽  
Depolarization Effect ◽  
Bipolar Patients ◽  
Quantum Mechanical Approach

Magnesium ions have many cellular actions including the suppression of the excitability of neurons; however, the depolarization effect of magnesium ions seems to be contradictory. Thus several hypotheses have aimed to explain this effect. In this study, a quantum mechanical approach is used to explain the depolarization action of magnesium. The model of quantum tunneling of magnesium ions through the closed sodium voltage-gated channels was adopted to calculate the quantum conductance of magnesium ions, and a modified version of Goldman–Hodgkin–Katz equation was used to determine whether this quantum conductance was significant in affecting the resting membrane potential of neurons. Accordingly, it was found that extracellular magnesium ions can exhibit a depolarization effect on membrane potential, and the degree of this depolarization depends on the tunneling probability, the channels’ selectivity to magnesium ions, the channels’ density in the neuronal membrane, and the extracellular magnesium concentration. In addition, extracellular magnesium ions achieve a quantum conductance much higher than intracellular ones because they have a higher kinetic energy. This study aims to identify the mechanism of the depolarization action of magnesium because this may help in offering better therapeutic solutions for fetal neuroprotection and in stabilizing the mood of bipolar patients.

The Neuron at Rest

2017 ◽  
Author(s):  
Peggy Mason
Keyword(s):  
Membrane Potential ◽  
Ion Channels ◽  
Ionic Species ◽  
Membrane Resistance ◽  
Chloride Ions ◽  
Resting Membrane Potential ◽  
Neuronal Membrane ◽  
Nernst Potential ◽  
State Potential ◽  
Pass Through

Neuronal membrane potential depends on the distribution of ions across the plasma membrane and the permeability of the membrane to those ions afforded by transmembrane proteins. Ions cannot pass through a lipid bilayer but enter or exit neurons through ion channels. When activated by voltage or a ligand, ion channels open to form a pore through which selective ions can pass. The ion channels that support a resting membrane potential are critical to setting a cell’s excitability. From the distribution of an ionic species, the Nernst potential can be used to predict the steady-state potential for that one ion. Neurons are permeable to potassium, sodium, and chloride ions at rest. The Goldman-Hodgkin-Katz equation takes into consideration the influence of multiple ionic species and can be used to predict neuronal membrane potential. Finally, how synaptic inputs affect neurons through synaptic currents and changes in membrane resistance is described.

scholarly journals Mathematical Modeling of Ion Quantum Tunneling Reveals Novel Properties of Voltage-Gated Channels and Quantum Aspects of Their Pathophysiology in Excitability-Related Disorders

2021 ◽  
Vol 28 (1) ◽  
pp. 116-154
Author(s):  
Abdallah Barjas Qaswal ◽  
Omar Ababneh ◽  
Lubna Khreesha ◽  
Abdallah Al-Ani ◽  
Ahmad Suleihat ◽  
...  
Keyword(s):  
Quantum Mechanics ◽  
Membrane Potential ◽  
Quantum Tunneling ◽  
Experimental Studies ◽  
Classical Mechanics ◽  
Membrane Conductance ◽  
Resting Membrane Potential ◽  
Voltage Gated ◽  
Voltage Gated Channels ◽  
Quantum Aspects

Voltage-gated channels are crucial in action potential initiation and propagation and there are many diseases and disorders related to them. Additionally, the classical mechanics are the main mechanics used to describe the function of the voltage-gated channels and their related abnormalities. However, the quantum mechanics should be considered to unravel new aspects in the voltage-gated channels and resolve the problems and challenges that classical mechanics cannot solve. In the present study, the aim is to mathematically show that quantum mechanics can exhibit a powerful tendency to unveil novel electrical features in voltage-gated channels and be used as a promising tool to solve the problems and challenges in the pathophysiology of excitability-related diseases. The model of quantum tunneling of ions through the intracellular hydrophobic gate is used to evaluate the influence of membrane potential and gating free energy on the tunneling probability, single channel conductance, and quantum membrane conductance. This evaluation is mainly based on graphing the mathematical relationships between these variables. The obtained mathematical graphs showed that ions can achieve significant quantum membrane conductance, which can affect the resting membrane potential and the excitability of cells. In the present work, quantum mechanics reveals original electrical properties associated with voltage-gated channels and introduces new insights and implications into the pathophysiology of excitability- related disorders. In addition, the present work sets a mathematical and theoretical framework that can be utilized to conduct experimental studies in order to explore the quantum aspects of voltage-gated channels and the quantum bioelectrical property of biological membranes.

scholarly journals Proton Quantum Tunneling: Influence and Relevance to Acidosis-Induced Cardiac Arrhythmias/Cardiac Arrest

2021 ◽  
Vol 28 (3) ◽  
pp. 400-441
Author(s):  
Omar Ababneh ◽  
Abdallah Barjas Qaswal ◽  
Ahmad Alelaumi ◽  
Lubna Khreesha ◽  
Mujahed Almomani ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Membrane Potential ◽  
Sodium Channels ◽  
Cardiac Arrhythmias ◽  
Quantum Tunneling ◽  
Membrane Depolarization ◽  
Cardiac Cells ◽  
Quantum Model ◽  
Quantum Conductance ◽  
Voltage Gated Sodium Channels

Acidosis and its associated pathologies predispose patients to develop cardiac arrhythmias and even cardiac arrest. These arrhythmias are assumed to be the result of membrane depolarization, however, the exact mechanism of depolarization during acidosis is not well defined. In our study, the model of quantum tunneling of protons is used to explain the membrane depolarization that occurs during acidosis. It is found that protons can tunnel through closed activation and inactivation gates of voltage-gated sodium channels Nav1.5 that are present in the membrane of cardiac cells. The quantum tunneling of protons results in quantum conductance, which is evaluated to assess its effect on membrane potential. The quantum conductance of extracellular protons is higher than that of intracellular protons. This predicts an inward quantum current of protons through the closed sodium channels. Additionally, the values of quantum conductance are influential and can depolarize the membrane potential according to the quantum version of the GHK equation. The quantum mechanism of depolarization is distinct from other mechanisms because the quantum model suggests that protons can directly depolarize the membrane potential, and not only through indirect effects as proposed by other mechanisms in the literature. Understanding the pathophysiology of arrhythmias mediated by depolarization during acidosis is crucial to treat and control them and to improve the overall clinical outcomes of patients.

scholarly journals Quantum Tunneling of Ions through the Closed Voltage-Gated Channels of the Biological Membrane: A Mathematical Model and Implications

2019 ◽  
Vol 1 (2) ◽  
pp. 219-225 ◽  
Author(s):  
Abdallah Barjas Qaswal
Keyword(s):  
Mathematical Model ◽  
Quantum Tunneling ◽  
Essential Role ◽  
Biological Membrane ◽  
Resting Membrane Potential ◽  
Quantum Mechanical ◽  
Voltage Gated ◽  
Mechanical Approach ◽  
Voltage Gated Channels ◽  
Quantum Mechanical Approach

Voltage-gated channels play an essential role in action potential propagation when their closed gates open, but their role when they are closed needs to be investigated. So, in this study, a quantum mechanical approach using the idea of quantum tunneling was used to calculate the conductance of closed channels for different ions. It was found that the conductance due to quantum tunneling of ions through the closed channels does not affect the resting membrane potential. However, under different circumstances, including change in the mass or the charge of the ion and the residues of the hydrophobic gate, the model of quantum tunneling would be useful to understand and explain several actions, processes, and phenomena in the biological systems.

Measurement of spontaneous neuronal membrane activity by time lapse confocal microscopy

1995 ◽  
Vol 53 ◽  
pp. 972-973
Author(s):  
R H. Selinfreund ◽  
A. H. Cornell-Bell
Keyword(s):  
Membrane Potential ◽  
Confocal Microscopy ◽  
Patch Clamp ◽  
Electrical Activity ◽  
Time Lapse ◽  
Neuronal Firing ◽  
Neuronal Membrane ◽  
Pituitary Cells ◽  
Patch Clamp Recording ◽  
Spontaneous Electrical Activity

Cellular electrophysiological properties are normally monitored by standard patch clamp techniques . The combination of membrane potential dyes with time-lapse laser confocal microscopy provides a more direct, least destructive rapid method for monitoring changes in neuronal electrical activity. Using membrane potential dyes we found that spontaneous action potential firing can be detected using time-lapse confocal microscopy. Initially, patch clamp recording techniques were used to verify spontaneous electrical activity in GH4\C1 pituitary cells. It was found that serum depleted cells had reduced spontaneous electrical activity. Brief exposure to the serum derived growth factor, IGF-1, reconstituted electrical activity. We have examined the possibility of developing a rapid fluorescent assay to measure neuronal activity using membrane potential dyes. This neuronal regeneration assay has been adapted to run on a confocal microscope. Quantitative fluorescence is then used to measure a compounds ability to regenerate neuronal firing.The membrane potential dye di-8-ANEPPS was selected for these experiments. Di-8- ANEPPS is internalized slowly, has a high signal to noise ratio (40:1), has a linear fluorescent response to change in voltage.

Effect of low chloride on relaxation in hamster diaphragm muscle

1986 ◽  
Vol 61 (1) ◽  
pp. 180-184 ◽  
Author(s):  
S. A. Esau ◽  
N. Sperelakis
Keyword(s):  
Membrane Potential ◽  
Muscle Fatigue ◽  
Time Constant ◽  
Diaphragm Muscle ◽  
Resting Membrane Potential ◽  
Krebs Solution ◽  
Sarcolemmal Membrane ◽  
Cl Conductance

With muscle fatigue the chloride (Cl-) conductance of the sarcolemmal membrane decreases. The role of lowered Cl- conductance in the prolongation of relaxation seen with fatigue was studied in isolated hamster diaphragm strips. The muscles were studied in either a Krebs solution or a low Cl- solution in which half of the NaCl was replaced by Na-gluconate. Short tetanic contractions were produced by a 160-ms train of 0.2-ms pulses at 60 Hz from which tension (T) and the time constant of relaxation were measured. Resting membrane potential (Em) was measured using KCl-filled microelectrodes with resistances of 15–20 M omega. Mild fatigue (20% fall in tension) was induced by 24–25 tetanic contractions at the rate of 2/s. There was no difference in Em or T in the two solutions, either initially or with fatigue. The time constant of relaxation was greater in low Cl- solution, both initially (22 +/- 3 vs. 18 +/- 5 ms, mean +/- SD, P less than 0.05) and with fatigue (51 +/- 18 vs. 26 +/- 7 ms, P less than 0.005). Lowering of sarcolemmal membrane Cl- conductance appears to play a role in the slowing of relaxation of hamster diaphragm muscle seen with fatigue.

Calcium channels and excitation–contraction coupling in cardiac cells. I. Two components of contraction in guinea-pig papillary muscle

1987 ◽  
Vol 65 (9) ◽  
pp. 1821-1831 ◽  
Author(s):  
E. Honoré ◽  
M. M. Adamantidis ◽  
B. A. Dupuis ◽  
C. E. Challice ◽  
P. Guilbault
Keyword(s):  
Membrane Potential ◽  
Guinea Pig ◽  
Papillary Muscle ◽  
Cardiac Cells ◽  
Resting Membrane Potential ◽  
Tonic Component ◽  
Contraction Coupling ◽  
Rich Solution ◽  
The Relationship ◽  
Guinea Pig Atria

Biphasic contractions have been obtained in guinea-pig papillary muscle by inducing partial depolarization in K+-rich solution (17 mM) containing 0.3 μM isoproterenol; whereas in guinea-pig atria, the same conditions led to monophasic contractions corresponding to the first component of contraction in papillary muscle. The relationships between the amplitude of the two components of the biphasic contraction and the resting membrane potential were sigmoidal curves. The first component of contraction was inactivated for membrane potentials less positive than those for the second component. In Na+-low solution (25 mM), biphasic contraction became monophasic subsequent to the loss of the second component, but tetraethylammonium unmasked the second component of contraction. The relationship between the amplitude of the first component of contraction and the logarithm of extracellular Ca2+ concentration was complex, whereas for the second component it was linear. When Ca2+ ions were replaced by Sr2+ ions, only the second component of contraction was observed. It is suggested that the first component of contraction may be triggered by a Ca2+ release from sarcoplasmic reticulum, induced by the fast inward Ca2+ current and (or) by the depolarization. The second component of contraction may be due to a direct activation of contractile proteins by Ca2+ entering the cell along with the slow inward Ca2+ current and diffusing through the sarcoplasm. These results do not exclude the existence of a third "tonic" component, which could possibly be mixed with the second component of contraction.

scholarly journals An intuitive approach to understanding the resting membrane potential

2016 ◽  
Vol 40 (4) ◽  
pp. 543-547 ◽  
Author(s):  
David Cardozo
Keyword(s):  
Membrane Potential ◽  
Resting Membrane Potential
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