Protonic conductor: better understanding neural resting and action potential

2020 ◽  
Vol 124 (4) ◽  
pp. 1029-1044
Author(s):  
James Weifu Lee
Keyword(s):  
Action Potential ◽  
Time Domain ◽  
Biological Significance ◽  
Mirror Image ◽  
Potential Equation ◽  
Potential Spike ◽  
Neuron Electrophysiology ◽  
Localized Protons ◽  
Potential Signal ◽  
Nonlinear Curve

The newly formulated action potential equation provides biophysical insights for neuron electrophysiology, which may represent a complementary development to the classic Goldman–Hodgkin–Katz equation. The nonlinear curve of the localized protons/cations charge density in the real-time domain of an action potential spike appears as an inverse mirror image to the action potential. The biological significance of axon myelination is now elucidated as to provide protonic insulation and prevent any ions from interfering with action potential signal.

Effects of sodium on beta-cell electrical activity

1982 ◽  
Vol 242 (5) ◽  
pp. C296-C303 ◽  
Author(s):  
B. Ribalet ◽  
P. M. Beigelman
Keyword(s):  
Membrane Potential ◽  
Action Potential ◽  
Beta Cell ◽  
Pancreatic Beta Cell ◽  
Input Resistance ◽  
Resting Membrane Potential ◽  
Two Phase ◽  
Sodium Permeability ◽  
Potential Spike ◽  
Presence And Absence

The present studies, designed to evaluate the contribution of Na+ to the mouse pancreatic beta-cell membrane potential, were performed utilizing intracellular microelectrodes. Complete removal of external sodium, in the presence of glucose, did not significantly affect spike peak potential. However, it caused a negative shift of the resting membrane potential, both in the presence and absence of glucose. After this initial hyperpolarization, the membrane gradually depolarized, the rate of depolarization being slower in the absence of glucose. This two-phase hyperpolarization-depolarization pattern remained when ouabain was added, both in the presence and absence of glucose. An increase of input resistance was associated with the slow depolarization. During this depolarization the maximum rate of rise (dV/dtmax) of the action potential (“spike”) decreased. There was no direct relationship between dV/dtmax and [Na]0. Readdition of low [Na]0 (14 mM) to a glucose medium reactivated the postburst hyperpolarization (PBH), even in the presence of ouabain. These observations indicate that there is a significant resting sodium permeability (PNa). However, the action potential (spike) is not generated by activation of a voltage-dependent (gated) sodium channel. The membrane depolarization after Na+ removal reflects concomitant inhibition of the Na+-K+ pump and decrease of potassium permeability (PK). The blockage of PBH in the absence of Na+ is not related to the inhibition of an oscillatory Na+-K+ pump but to the inactivation of a PK. Aside from its effect on the Na+-K+ pump, ouabain may stimulate PNa.

scholarly journals The Mechanical Basis of Memory - the MeshCODE Theory

2020 ◽  
Author(s):  
Benjamin T. Goult
Keyword(s):  
Action Potential ◽  
Synaptic Transmission ◽  
Data Storage ◽  
Spike Trains ◽  
Binary Format ◽  
Potential Spike ◽  
Mechanical Basis ◽  
The Mind ◽  
And Storage ◽  
The Brain

The MeshCODE framework outlined here represents a unifying theory of data storage in animals, providing read/write storage of both dynamic and persistent information in a binary format. Mechanosensitive proteins, that contain force-dependent switches, can store information persistently which can be written/updated using small changes in mechanical force. These mechanosensitive proteins, such as talin, scaffold each and every synapse creating a meshwork of switches that forms a code, a MeshCODE. Synaptic transmission and action potential spike trains would operate the cytoskeletal machinery to write and update the synaptic MeshCODEs, propagating this coding throughout the brain and to the entire organism. Based on established biophysical principles, a mechanical basis for memory provides a physical location for data storage in the brain. Furthermore, the conversion and storage of sensory and temporal inputs into a binary format identifies an addressable read/write memory system supporting the view of the mind as an organic supercomputer.

scholarly journals Simulating Notch-Dome Morphology of Action Potential of Ventricular Cell: How the Speeds of Positive and Negative Feedbacks on Transmembrane Voltage Can Influence the Health of a Cell?

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
S. H. Sabzpoushan ◽  
A. Ghajarjazy
Keyword(s):  
Action Potential ◽  
Heart Function ◽  
Variable Model ◽  
Ventricular Cell ◽  
Therapy Strategy ◽  
Ventricular Cells ◽  
Potential Spike ◽  
Biological Tool ◽  
Negative Feedbacks ◽  
The Impact

Ventricular action potential is well-known because of its plateau phase with a spike-notch-dome morphology. As such, the morphology of action potential is necessary for ensuring a correct heart functioning. Any distraction from normal notch-dome morphology may trigger a circus movement reentry in the form of lethal ventricular fibrillation. When the epicardial action potential dome propagates from a site where it is maintained to regions where it has been lost, it gives rise to the proposed mechanism for the Brugada syndrome. Despite the impact of notch-dome dynamics on the heart function, no independent and explicit research has been performed on the simulation of notch-dome dynamics and morphology. In this paper, using a novel mathematical approach, a three-state variable model is proposed; we show that our proposed model not only can simulate morphology of action potential of ventricular cells but also can propose a biological reasonable tool for controlling of the morphology of action potential spike-notch-dome. We show that the processes of activation and inactivation of ionic gating variables (as positive or negative feedbacks on the voltage of cell membrane) and the ratio of their speeds (time constants) can be treated as a reasonable biological tool for simulating ventricular cell notch-dome. This finding may led to a new insight to the quantification of the health of a ventricular cell and may also propose a new drug therapy strategy for cardiac diseases.

scholarly journals Structural coloured feathers of mallards act by simple multilayer photonics

2017 ◽  
Vol 14 (133) ◽  
pp. 20170407 ◽  
Author(s):  
Doekele G. Stavenga ◽  
Casper J. van der Kooi ◽  
Bodo D. Wilts
Keyword(s):  
Refractive Index ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Spectral Properties ◽  
Three Dimensional ◽  
Biological Significance ◽  
Reflectance Spectra ◽  
Male And Female ◽  
Spatial Parameters ◽  
Difference Time

The blue colours of the speculum of the mallard ( Anas platyrhynchos ), both male and female, and the green head feathers of the male arise from light interacting with stacks of melanosomes residing in the feather barbules. Here, we show that the iridescent colours can be quantitatively explained with an optical multilayer model by using a position-dependent effective refractive index, which results from the varying ratio of melanin and keratin. Reflectance spectra obtained by multilayer modelling and three-dimensional finite-difference time-domain calculations were virtually identical. The spectral properties of the barbules' photonic structures are sensitive to variations in the multilayer period and the cortex thickness, but they are surprisingly robust to variations in the spatial parameters of the barbules' melanosome stacks. The blue and green reflectance spectra of the structural-coloured feathers correspond with the sensitivity spectra of the short- and middle-wavelength-sensitive photoreceptors, indicating their biological significance for intraspecific signalling.

scholarly journals Induced capacitance in the squid giant axon. Lipophilic ion displacement currents.

1983 ◽  
Vol 82 (3) ◽  
pp. 331-346 ◽  
Author(s):  
J M Fernández ◽  
R E Taylor ◽  
F Bezanilla
Keyword(s):  
Action Potential ◽  
Frequency Domain ◽  
Time Domain ◽  
Numerical Solutions ◽  
Ionic Current ◽  
Induced Polarization ◽  
Resting Potential ◽  
Axonal Membrane ◽  
Cable Properties ◽  
The Time Domain

Voltage-clamped squid giant axons, perfused internally and externally with solutions containing 10(-5) M dipicrylamine (DpA-), show very large polarization currents (greater than or equal to 1 mA/cm2) in response to voltage steps. The induced polarization currents are shown in the frequency domain as a very large voltage-and frequency-dependent capacitance that can be fit by single Debye-type relaxations. In the time domain, the decay phase of the induced currents can be fit by single exponentials. The induced polarization currents can also be observed in the presence of large sodium and potassium currents. The presence of the DpA- molecules does not affect the resting potential of the axons, but the action potentials appear graded, with a much-reduced rate of rise. The data in the time domain as well as the frequency domain can be explained by a single-barrier model where the DpA- molecules translocate for an equivalent fraction of the electric field of 0.63, and the forward and backward rate constants are equal at -15 mV. When the induced polarization currents described here are added to the total ionic current expression given by Hodgkin and Huxley (1952), numerical solutions of the membrane action potential reproduce qualitatively our experimental data. Numerical solutions of the propagated action potential predict that large changes in the speed of conduction are possible when polarization currents are induced in the axonal membrane. We speculate that either naturally occurring substances or drugs could alter the cable properties of cells in a similar manner.

Rehabilitation of Atrophied Muscle in the Rheumatoid Arthritic Hand: A Comparison of Two Methods of Electrical Stimulation

1989 ◽  
Vol 14 (3) ◽  
pp. 294-297
Author(s):  
J. A. OLDHAM ◽  
J. K. STANLEY
Keyword(s):  
Electrical Stimulation ◽  
Action Potential ◽  
Spike Train ◽  
Motor Unit ◽  
Discharge Pattern ◽  
Motor Unit Action Potential ◽  
Rheumatoid Arthritic ◽  
Potential Spike ◽  
Motor Unit Action ◽  
Unit Action

This study compares the effectiveness of two therapeutic electrotherapies which result in plastic adaptation in the atrophied muscle of rheumatoid arthritic hands. The natural discharge pattern of a fatigue-resistant motor unit (eutrophic electrotherapy) was more effective than a uniform 10 Hz electrotherapy. It was concluded that uniform 10 Hz electrotherapy ignored the information carried in the motor unit action potential spike train, which was the signal inducing rapid and behaviourally effective plastic adaptation.

Relationships between Clinical Scales on Severity of Symptoms and Electrodiagnostic Measures on Abnormality of Nerve Conduction in Carpal Tunnel Syndrome

1998 ◽  
Vol 42 (12) ◽  
pp. 841-845 ◽  
Author(s):  
Heecheon You
Keyword(s):  
Carpal Tunnel Syndrome ◽  
Action Potential ◽  
Carpal Tunnel ◽  
Nerve Conduction ◽  
Biological Significance ◽  
Sensory Nerve ◽  
Nerve Fibers ◽  
Peak Amplitude ◽  
Clinical Scales ◽  
Tunnel Syndrome

This study examined the severity of carpal tunnel syndrome symptoms in relation to nerve conduction measures of the median nerve. The symptom scales include (1) numbness, (2) tingling, (3) nocturnal symptoms, (4) pain, (5) weakness, and (6) clumsiness; the nerve conduction measures are (1) peak amplitude and (2) peak latency of the sensory action potential, (3) conduction velocity of the sensory nerve fibers, (4) peak amplitude and (5) onset latency of the motor action potential. The symptom severity and nerve conduction impairment were evaluated for 34 affected hands of 24 patients (6 males and 18 females) by using a questionnaire developed by Levine et al. and an electromyographic instrument, respectively. Significant relationships identified among the clinical scales resulted in a dichotomous symptom classification scheme with a criterion of the relatedness to nerve damage: primary and secondary symptoms. Correlation analysis on the symptom and electrodiagnostic measures showed both the severity scales for the primary and all the symptoms had higher correlations with the extent of the nerve injury than that for the secondary symptoms. These results demonstrated a biological significance of the clinical scales, which can be used in evaluating the outcome of treatments and developing a model for exposure-severity relationship.

scholarly journals Effects of Ethanol and Temperature on a Crab Motor Axon Action Potential: A Possible Mechanism for Peripheral Spike Generation

1983 ◽  
Vol 103 (1) ◽  
pp. 289-301 ◽  
Author(s):  
PHILIP J. STEPHENS ◽  
PAUL A. FRASCELLA ◽  
NORMAN MINDREBO
Keyword(s):  
Action Potential ◽  
Refractory Period ◽  
Action Potentials ◽  
Time Course ◽  
Membrane Resistance ◽  
Temperature Threshold ◽  
Spike Generation ◽  
Axon Membrane ◽  
Potential Spike ◽  
Low Threshold

1. In autotomized walking limbs of Pachygrapsus crassipes, microelectrode recordings of evoked action potentials were made in the meropodite from the E2 excitor axon to the bender muscle. 2. The action potential spike was followed by a depolarizing after-potential. Increases in temperature resulted in a decline in the amplitude and time course of the spike, and an increase in the amplitude of the after-potential. Low levels of ethanol or increased levels of calcium increased the size of the after-potential and decreased the temperature threshold for peripheral spike generation. 3. At high temperatures a single orthodromic E2 axon spike provoked the generation of additional impulses at the periphery, with an inter-spike interval of 2–3.5 ms. 4. The after-potential lasted longer than the refractory period following the spike. The axon membrane, therefore, was depolarized after the refractory period and this resulted in a period of low threshold for spike generation. Increases in temperature shortened the refractory period. 5. We suggest that additional spikes are generated at the periphery where the E2 axon diameter is decreased. The increased membrane resistance at these sites increases the size of the depolarizing after-potential. Therefore, if the depolarization following the refractory period is at or above threshold for firing, additional action potentials will be generated at the periphery.

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