Hirohisa Tamagawa

• Gifu University

The Goldman Hodgkin and Katz equation (GHK) is regarded as a cornerstone in the field of biology. The GHK equation expands upon Bernstein's hypothesis. Bernstein had originally employed the Nernst equation to validate his theory. Consequently, the GHK equation is also logically derived from the Nernst equation. Contemporary understanding in chemist...

Julius Bernstein developed a membrane theory based on potassium diffusion and the Nernst equation, which is considered fundamental in electrochemistry. This foundational equation has been adapted for applications in biophysics and biology through the widely recognized Goldman Hodgkin Katz equation. The Nernst equation is one of the most frequently...

A well-known soft actuator, called ionic polymer–metal composite (IPMC), is a type of electroactive polymer (EAP) that operates in bending mode. Despite its ability to exhibit large bending, its bending controllability is often poor. Therefore, identifying the key factor that allows IPMC to bend without losing its large bending capability is a natu...

Julius Bernstein developed a membrane theory based on potassium diffusion and the Nernst equation, which is considered fundamental in electrochemistry. This foundational equation has been adapted for applications in biophysics and biology through the widely recognized Goldman Hodgkin Katz equation. The Nernst equation is one of the most frequently...

Thermogenesis, electro-chemical physiology (ECP), and electro-mechanical activities (EMAs) are fundamental facets of cellular functioning that are associated with powering, coherence, homeostasis, sensing, and response to stimuli. The classical Hodgkin–Huxley–Katz purview of ECP is derived from Nernst-based foundations for dilute solutions, whereas...

Bioenergetics is the study of how life-activities are powered within the cell. This also deals with the interactive exchange of matter/radiation between cellular components and their environment, and the accompanying changes thereof. The acclaimed bioenergetics paradigm has relied on “electron transport chains” and selective/stoichiometric electrog...

The generation and maintenance of membrane potential is considered a fundamental element of the cellular machinery. They are based on elements of physics and chemistry. Mathematics is used to validate the equations and evaluate the results. However, this computation process can lead to a misunderstanding of the phenomena involved or to the masking...

Membrane potential generation and maintenance are fundamental parts of membrane theory. However, since its inception, theories and assumptions have remained simple, whereas the amount of knowledge available has only grown. Unfortunately, this simplification and reductionism lead to its loss of validity on both microscopic and macroscopic scales. Th...

Bioenergetics is the study of how life-activities are powered within the cell. This also deals with the interactive exchange of matter/radiation between cellular components and their environment, and the accompanying changes thereof. The acclaimed bioenergetics paradigm has relied on ‘electron transport chains’ and selective/stoichiometric electrog...

It is common to say that the origin of the membrane potential is attributed to transmembrane ion transport, but it is theoretically possible to explain its generation by the mechanism of ion adsorption. It has been previously suggested that the ion adsorption mechanism even leads to potential formulae identical to the famous Nernst equation or the...

Bacterial flagellar system (BFS) was the primary example of a purported ‘rotary-motor’ functionality in a natural assembly. This mandates the translation of a circular motion of components inside into a linear displacement of the cell body outside, which is supposedly orchestrated with the following features of the BFS: (i) A chemical/electrical di...

Membrane theory makes it possible to compute the membrane potential of living cells accurately. The principle is that the plasma membrane is selectively permeable to ions and that its permeability to mobile ions determines the characteristics of the membrane potential. However, an artificial experimental cell system with an impermeable membrane can...

The redox metabolic paradigm of murburn concept advocates that diffusible reactive species (DRS, particularly oxygen-centric radicals) are mainstays of physiology, and not mere pathological manifestations. The murburn purview of cellular function also integrates the essential principles of bioenergetics, thermogenesis, homeostasis, electrophysiolog...

Bacterial flagellar system (BFS) was the first perceived example of a ‘natural rotary-motor” functionality, mandating the translation of a circular motion of components inside into a linear displacement of the cell body outside. This outcome is supposedly orchestrated with the following features of the BFS: (i) A chemical/electrical differential ge...

New techniques and elucidations in structural biology have enabled greater insights into the functioning of proteins. Since its discovery in 1957 by Jens Skou, the membrane protein of Na,K-ATPase (NKA, also known as sodium-potassium pump) has been a focus of intense study, owing to its centrality in neuro-cardio-musculo electrophysiology. Herein, w...

The occurrence of potential spikes in a cell is a sign of life, and it is called action potential. There is a common notion that neuron signal conduction is the conduction of action potential. Hence, action potential is a typical and essential life activity. However, such potential spikes occur even in simple nonliving systems. According to the exp...

There is a deep conviction that the generation of the action potentialis one of the most fundamental biological activities. According to themembrane theory, active ion transport and its flow variations across theplasma membrane are responsible for generating the action potential.However, in contrast to the living model, an in vitro model based on t...

The classical paradigm of visual physiology comprises of the following features: (i) rod/cone cells located at the rear end of the retina serve as the primary transducers of incoming photo‐information, (ii) cis–trans retinal (C20H28O) transformations on rhodopsin act as the transduction switch to generate a transmittable signal, (iii) signal amplif...

Although there is a common physiological notion that the origin of the membrane potential is attributed to transmembrane ion transport, it is theoretically possible to explain its generation by the mechanism of ion adsorption. It was previously suggested that the ion adsorption mechanism led even to the potential formulas which are even identical t...

The membrane potential or resting potential of the neuron has been the subject of many studies. Although this theory explains the generation and maintenance of the membrane potential by direct or even facilitated diffusion, there are too many contradictions to doubt that these forces are sufficient or even at work in a process whose initial conditi...

The generation and maintenance of membrane potential is a fundamental part of Membrane Pump Theory. One of the key points of this hypothesis is based on a natural or facilitated molecular diffusion through several types of ion channels and pumps like the Na/K ATPase. Following the principles of chemistry, electrostatics and geometry, it becomes cle...

Complex V or FoF1-ATPase is a multimeric protein found in bioenergetic membranes of cells and organelles like mitochondria/chloroplasts. The popular perception on Complex V deems it as a reversible molecular motor, working bi-directionally (breaking or making ATP) via a conformation-change based chemiosmotic rotary ATP synthesis (CRAS) mechanism, d...

Current physiology attributes the mechanism of membrane potential generation to transmembrane ion transport, but ion adsorption could just as well play this fundamental role. The evidence shows that the ion adsorption mechanism accurately reproduces the experimentally measured membrane potential. The Goldman-Hodgkin-Katz equation (GHK eq.) and the...

The classical paradigm of visual physiology comprises of the following features: (i) rod/cone cells located at the rear end of the retina serve as the primary transducers of incoming photo-information, (ii) cis-trans retinal (C20H28O) transformations on rhodopsin act as the transduction switch to generate a transmittable signal, (iii) signal amplif...

The generation and maintenance of membrane potential is a fundamental part of Membrane Pump Theory. One of the key points of this hypothesis is based on a natural or facilitated molecular diffusion through several types of ion channels and pumps like the Na/K ATPase. Chemistry, physics and especially electrochemistry, however, bring strong contradi...

Two mathematically distinct physiological concepts, the Goldman-Hodgkin-Katz eq. (GHK eq.) and the Hodgkin-Huxley model (HH model) were successfully associated with each other in a prior work. The previous work was performed on the following premises (i) The membrane potential is generated by ion adsorption, as opposed to the classical ion transpor...

Pursuits in modern cellular electrophysiology are fraught with disagreements at a fundamental level. While the membrane theory of homeostasis deems the cell membrane and proteins embedded therein as the chief players, the association‐induction (or sorption/bulk‐phase) hypothesis considers the aqueous phase of dissolved proteins (cytoplasm/protoplas...

Starting from the basic molecular structure and redox properties of its components, we build a macroscopic cellular electrophysiological model. We first present a murburn purview that could explain ion distribution in bulk-milieu/membrane-interface and support the origin of trans-membrane potential (TMP) in cells. In particular, the discussion focu...

First attempt to show the dynamics at the axon surface during action potential propagation. This view is very simplified as it ignores the movements of the cytoskeleton, but it does allow us to see the movements of water induced by the entry of positive ions. This entry attracts water molecules, which are polar, to the positive sources in a very tr...

An embryonic version of membrane theory can be date back to the Bernstein's work reported more than a hundred years ago. Such an originally old work has evolved conceptually and mathematically up until today, and it plays a central role in current membrane theory. Goldman-Hodgkin-Katz equation (GHK eq.) is one of the math-based monumental works, wh...

The most common and taught membrane theory assumes that the membrane behaves as a kind of electrical capacitance that is exposed to an electrical current generated by an ionic flow. If this statement is verifiable, it can be confirmed by the laws of physics, mathematics and in particular electricity. We will demonstrate that this hypothesis is not...

The cellular model we teach and have theorized assumes that the cell is the basic unit of multicellular living beings. This fundamental element has been the subject of many theories concerning its properties and the exchanges that exist with its environment. In this article, we demonstrate that certain functional aspects, in particular the electric...

The characteristics of the experimentally measured trans-membrane potential (TMP) generated across an artificial membrane intervening two KCl solutions were found to be explicable using simple principles of electrochemistry, as given within the context of Association Induction Hypothesis (AIH). AIH suggests that the heterogeneous ion distribution w...

For more than 70 years, biologists and biophysicists have been trying to unravel the mystery surrounding the saltatory conduction of so-called myelinated neurons. This conduction is indeed very different and faster than for fibres “without” myelin. Many theories have been developed. Albert Einstein used the metaphor of the train to explain the theo...

Membrane theory attributes the mechanism of generation of membrane potential to transmembrane ion transport, and is typified by the Goldman-Hodgkin-Katz equation (GHK eq.). Despite broad acceptance of the GHK eq. in physiology, it seems unable to explain some characteristics of the membrane potential. The long-underrated Ling's adsorption theory (L...

Private copy of the draft concerning the article: The brilliant neuron.

Membrane theory attributes the generation mechanism of the membrane potential to transmembrane ion transport, while Cheng’s ISE (Ion selective electrode) mechanism attributes the ISE potential generation to ion adsorption on to the ISE surface. Although the membrane potential generation mechanism is different from the ISE potential generation mecha...

The oscillation of the plasma membrane causes a change in the membrane potential. The chaotic movements of the membrane lead to disturbances in the ion channel geometry. If the ion channel contains ions, the potential changes without any diffusion. https://youtu.be/t64uRPMveyc

It was with a certain delight that I read the "contradictory" answers from the English side regarding the article in Johnson and Winlow's "Mysteries of the action potential".

First attempt to show ionic dynamics at the level of an axon. Can do better.

Man has always been interested in animal electricity, which seems to be measured in every living cell. He has been fascinated by trying to elucidate the mechanisms by which this potential is created and maintained. Biology is the science that seeks to explain this mystery. Biology is based on basic sciences such as physics or chemistry. The latter,...

Despite the long and broad acceptance of the Goldman - Hodgkin - Katz equation (GHK eq.) and the Hodgkin - Huxley equation (HH eq.) as strong tools for the quantitative analysis of the membrane potential behavior, for a long time they have been utilized as separate concepts. That is the GHK eq. and the HH eq. have not been associated with each othe...

Pursuits in modern cellular physiology are fraught with disagreements on the chemico-physical logic of how a cell coordinates the core aspects of its life-sustaining activities. While the membrane theory of homeostasis deems the cell-membrane and the proteins embedded therein as the chief players, the association-induction (or sorption or bulk-phas...

Membrane theory attributes the cause of action potential generation to the ion transport across the plasma membrane. It even states that the action potential generation is a unique phenomenon in the living cell. There have been some reports that the action potential-like potential spike is induced even in the nonliving system. Ling’s adsorption the...

Conventional rigid actuators, such as DC servo motors, face challenges in utilizing them in artificial muscles and soft robotics. Dielectric elastomer actuators (DEAs) overcome all these limitations, as they exhibit complex and fast motions, quietness, lightness, and softness. Recently, there has been much focus on studies of the DEAs material’s no...

Man has always been interested in animal electricity, which seems to be measured in every living cell. He has been fascinated by trying to elucidate the mechanisms by which this potential is created and maintained. Biology is the science that seeks to explain this mystery. Biology is based on basic sciences such as physics or chemistry. The latter,...

For more than 70 years, biologists and biophysicists have been trying to unravel the mystery that exists regarding the saltatory conduction of so-called myelinated neurons. Albert Einstein used the train metaphor to explain the theory of relativity. It is possible to use a similar metaphor to better understand this transient functioning of the neur...

Number of noRs activated vs conduction velocity and AP duration. The numbers of nodes activated increases as the speed increases in myelinated neurons. This number depends also of AP duration.

Hodgkin and Huxley built their theoretical model of initiation and propagation of action potential on the work of their predecessors but also that of their contemporaries. Bernstein was the initiator of membrane theory but Hodgkin, Katz and especially Goldman sought to improve it. The integration of the constant electric field should have allowed a...

The action potential as recorded by Hodgkin and Huxley (in red), the conductances calculated in the HH model of sodium (in yellow) and potassium (in purple). The pale red area represents the area where the electric field changes direction. The reference voltage (0.00 V) is represented by a blue line.)

References

The Hodgkin-Huxley model [3] (HH) is based upon a bicompartmental system. The system has an external compartment (external milieu) and an internal (cell interior) separated by a membrane that acts as an insulator. It is said there is a tiny charge imbalance between the two sides of the membrane. This imbalance is at the origin of the membrane poten...

The membrane potential and the action potential (an active variation of the primer) are since a very long time subjects of theories and hypothesis. In the twentieth century, Bernstein and then Hodgkin, Huxley and Goldman were the leaders of novel theories. The papers were however very cautious in their findings and the descriptions of possible func...

Artistic view of the electric field inside a K ion channel

The “batteries” of the membrane Questioning the HH model with known physics and chemistry.

Mathematical proof the HH model is not valid.

Explaining why diffusion can't happen in the HH model.

Mathematical demonstration of the invalidity of the membrane capacitance and the Nernst equation

Creating a robust model in Sciences is a tough project. Many aspects must be considered, and tons of questions must be answered.

The theory of the Hodgkin–Huxley model explains there are multiple ionic fluxes between the two sides of the cell membrane. Ions are components of electrolytes and as such are diluted in a solvent; water. The HH model discard totally the possible participation of water in the elaboration of membrane potential or action potential.

Mathematical demonstration of the invalidity of the membrane capacitance and the Nernst equation

Crystalline structure of KCl.

Crystalline structure of KCl (detail)

Arstistic view of some KCl entering in a bottle Made with Blender 2.80

Conventional conductive materials face challenges when utilizing them for flexible and wearable electronics and soft robotics. Carbon nanotube/polydimethylsiloxane (CNT/PDMS) composites are a promising alternative to the conventional hard conductors because they are light and can realize large deformation. To date, well dispersion of CNTs into PDMS...

The exhibition of significantly large bending is a remarkable characteristic of an ionic polymer-metal composite (IPMC). However, its inability to generate a high enough force is a major problem in achieving a practical IPMC actuator. The simultaneous enhancement of bending and force generation is needed for broadening the potential of the IPMC act...

The Goldman–Hodgkin–Katz equation (GHK equation), one of the most successful achievements of membrane theory in electrophysiology, can precisely predict the membrane potential. Its conceptual foundation lies in the idea that the transmembrane ion transport across the plasma membrane is responsible for the membrane potential generation. However, the...

Conventional actuators such as geared servos suffer drawbacks in utilizing them in robots which work closely with humans. Dielectric elastomer actuators (DEAs) overcome these challenges since they can realize natural motion patterns which are inspired by those of human muscle. To date, fabrication of such bio-mimetic soft actuators is hindered by l...

According to standard membrane theory, the generation of membrane potential is attributed to transmembrane ion transport. However, there have been a number of reports of membrane behavior in conflict with the membrane theory of cellular potential. Putting aside the membrane theory, we scrutinized the generation mechanism of membrane potential from...

Donnan theory and Goldman-Hodgkin-Katz equation (GHK eq.) state that the nonzero membrane potential is generated by the asymmetric ion distribution between two solutions separated by a semipermeable membrane and/or by the continuous ion transport across the semipermeable membrane. However, there have been a number of reports of the membrane potenti...

Fabrication of a practical electroactive polymer-based actuator is one of significantly important topics in the material science field. It is expected that the electroactive polymer-based actuator motion is quite similar to the real muscle motion due to its innate softness. Therefore a number of scientists acknowledge that the electroactive polymer...

Despite the promising characteristics of Dielectric Elastomel Actuator (DEA) as a practical soft actuator, the need of high voltage for its operation prevents the successful fabrication of a practical DEA, that is, the high voltage generation takes a bulky and costly power supply. Induction of complex shape change motion of DEA such as oscillatory...

The potential between two electrolytic solutions separated by a membrane impermeable to ions was measured and the generation mechanism of potential measured was investigated. From the physiological point of view, a nonzero membrane potential or action potential cannot be observed across the impermeable membrane. However, a nonzero membrane potentia...

IPMC (Ionic Polymer Metal Composite) actuators have numerous promising applications in designing electroactive soft motion structures. It was reported that the bending behavior of Selemion CMV-based IPMC in response to the electrical stimulation was quite susceptible to the environmental absolute humidity, and the environmental absolute humidity in...

It has been widely acknowledged that the Goldman-Hodgkin-Katz (GHK) equation fully explains membrane potential behavior. The fundamental facet of the GHK equation lies in its consideration of permeability of membrane to ions, when the membrane serves as a separator for separating two electrolytic solutions. The GHK equation describes that: variatio...

Current view about cell is that the cell is a watery solution coated with semi-permeable membrane and there exists nonzero potential, so-called membrane potential, across the semi-permeable cell membrane. Goldman-Hodgkin-Katz equation and Donnan theory are the fundamental existing theories for explaining the cause of membrane potential generation....

Electrically induced bending behavior of a highly dehydrated Selemion CMV-based IPMC was analyzed theoretically. The experimental observation suggested that even the highly dehydrated IPMC bending was under the influence of not only Faradaic current but also non-Faradaic current. Hence, it was essential to know the Faradaic and non-Faradaic current...

Electrically-induced bending of Selemion IPMC is caused by the charge induced into the IPMC. This induced charge quantity is susceptible to the absolute humidity of environment. There are two types of charges, the charge causing bending and the rest of charge that causes no bending. In the high humidity environments, where absolute humidity is abov...

This paper presents feedforward, feedback and two-degree-of-freedom control applied to an Ionic Polymer-Metal Composite (IPMC) actuator. It presents a high potential for development of miniature robots and biomedical devices and artificial muscles. We have reported in the last few years that dehydration treatment improves the electrical controllabi...

The design of a reversible bending actuator based on a SMA/SMP composite is presented. The SMA/SMP composite is made of SMA NiTi wires with a bent ‘U’-shape in the austenite phase embedded in an epoxy SMP matrix which has a memorized flat shape. The bending motion is caused by heating the composite above TAf to activate the NiTi recovery. Upon cool...

Unlike well-investigated polymer-based soft actuators such as gel, Ionic Polymer-Metal Composite, conducting polymer, a CFRP-based polymeric laminate possesses quite distinguished properties. It was previously reported that a CFRP-PVC laminate exhibited two-way deflection in accordance with environmental temperature, but it could not exhibit symmet...

Highly dehydrated gold foil-coated Selemion AMV exhibited large bending under electrical stimulation. It bore a relatively well-controllable bending characteristic by the control of electrical stimulation. Conventional ionic polymer–metal composite bending mechanisms could not explain its bending behavior. We speculated that Joule heat played a cen...

Unlike well-investigated polymer-based soft actuators such as gel, Ionic Polymer-Metal Composite, conducting polymer, a CFRP-based polymeric laminate possesses quite distinguished properties. It was previously reported that a CFRP-PVC laminate exhibited two-way deflection in accordance with environmental temperature, but it was asymmetric deflectio...

Electrical bending control of Nafion-based ionic polymer–metal composite (IPMC) is quite difficult. Unlike a conventional fully hydrated noble metal-coated Nafion type IPMC, however, highly dehydrated silver-coated Nafion type IPMC exhibited better electrical bending controllability. Embedding of the multi-walled carbon nanotube (MWCNT) into Nafion...

A simple synthesis method of porous acrylamide gel is proposed. Pore formation in gel body is dominated by the amount of polymerization initiator, accelerator and gelation temperature. We investigated the influence of these factors on the number and the size of pores. Gelation temperature control is the easiest and the most effective way to create...

Mathematical models predicting the behaviour of IMPCs (Ionic Polymer-Metal Composites ) were built and their validity was verified computationally as well as experimentally. A transfer function associating the applied input voltage with the IPMC tip displacement was derived based on results obtained by vibration analysis. Employing the derived tran...

This paper describes the position control of a dual-stage actuator with piezoelectric actuator using self-sensing actuation. The dual-stage servo system consists of a coarse actuator and a fine actuator. A DC servo motor is used as the coarse actuator, and a piezoelectric actuator provides fine control. The position control of the dual-stage actuat...

This paper presents methods of end point motion control of an Ionic Polymer-Metal Composite actuator. Feedforward control with the inverse system is used. Through frequency analysis of the IPMC, an inverse transfer function is formulated. Validity of the proposed control methods was verified with numerical simulations and experiments. The results s...

A thermo-responsive bimorph actuator consisting of all-polymeric components, primarily a polyvinylchloride (PVC) plate and a carbon fiber-reinforced plastic plate (CFRP), was fabricated. The strain change of the CFRP plate resulting from environmental temperature change was quite small, while that of the PVC plate was quite large. Such a large stra...

This research was has been conducted primarily to create a thermo-responsive two-way shape change polymer. Such a material could work as a thermo-responsive actuator, a thermo-responsive valve, a thermo-responsive switch in broad range of engineering field. Two-way shape change materials such as a shape memory alloy (SMA) and a piezoelectric are be...

Contrary to our intuition and strenuous efforts, the thermo-responsive two-way shape changeable polymer was successfully fabricated by an unexpectedly simple method. In fact, the structure of specimen was the laminate. It merely consisted of two pieces of polymer plates. Despite its simple structure, it deflected relatively largely in the heated st...

Electrospinning displays its high efficiency for fabricating a two-dimensional mat consisting of fine fibers. By the use of electrospinning, for example, a two-dimensional filter with superior functionality can be easily fabricated. However, individually fabricating fibers is a difficult task for the electrospinning technology, since electro-spun f...