The Membrane Potential Has a Primary Key Equation.

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 Goldman-Hodgkin-Katz equation. Our further analysis, presented in this paper, indicates that the potential formula based on the ion adsorption mechanism leads to an equation that is a function of the surface charge density of the material and the surface potential of the material.

Questioning rotary functionality in the bacterial flagellar system and proposing a murburn model for motility.

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 differential generates proton motive force (, including a trans-membrane potential, TMP), which is electro-mechanically transduced by inward movement of protons via BFS. (ii) Membrane-bound proteins of BFS serve as stators and the slender filament acts as an external propeller, culminating into a hook-rod that pierces the membrane to connect to a 'broader assembly of deterministically movable rotor'.

Na,K-ATPase: A murzyme facilitating thermodynamic equilibriums at the membrane-interface.

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, electrophysiology, and coherence. In this context, any enzyme that generates/modulates/utilizes/sustains DRS functionality is called a murzyme.

The membrane potential arising from the adsorption of ions at the biological interface.

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 exhibit a nonzero membrane potential, and its characteristics are consistent with the prediction of the Goldman-Hodgkin-Katz eq.

Murburn model of vision: Precepts and proof of concept.

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 (C H O) transformations on rhodopsin act as the transduction switch to generate a transmittable signal, (iii) signal amplification occurs via GDP-GTP exchange at transducin, and (iv) the amplified signal is relayed (as an action potential) as a flux-based ripple of Na-K ions along the axons of neurons. Fundamental physical principles, chemical kinetics, and awareness of architecture of eye/retina prompt a questioning of these classical assumptions. In lieu, based on experimental and in silico findings, a simple space-time resolved murburn model for the physiology of phototransduction in the retina is presented wherein molecular oxygen plays key roles.

The physiological role of complex V in ATP synthesis: Murzyme functioning is viable whereas rotary conformation change model is untenable.

Complex V or FF-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, driven by proton-gradients or trans-membrane potential (TMP). In continuance of our pursuits against the CRAS model of cellular bioenergetics, herein we demonstrate the validity of the murburn model based in diffusible reactive (oxygen) species (DRS/DROS).

Analyses of HH and GHK equations with another perspective: Can ion adsorption also govern trans-membrane potential?

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.

Critical analysis of explanations for cellular homeostasis and electrophysiology from murburn perspective.

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/protoplasm) as the key determinant of cellular composition and ionic fluxes. In the first school of thought, trans-membrane potential (TMP) and selective ion pumps/channels are deemed as key operative principles.

The murburn precepts for cellular ionic homeostasis and electrophysiology.

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 focuses on how cells achieve disparity in the distribution of monovalent and divalent cations within (K  > Na  > Mg  > Ca ) and outside (Na  > K  > Ca  > Mg ).

The need for reconsideration of a mechanism of membrane potential generation using Ling's adsorption theory.

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.

What can S-shaped potential profiles tell us about the mechanism of membrane potential generation?

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 mechanism, both the membrane potential and the ISE potential exhibit quite similar characteristics. For instance, both become indifferent to the variation of the ion concentration in both the high and the low ion concentration environment.

GHK eq. and HH eq. for a real system is mathematically associable to each other but their physiological interpretation needs a reconsideration.

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.

Mathematical expression of membrane potential based on Ling's adsorption theory is approximately the same as the Goldman-Hodgkin-Katz equation.

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 potential virtually equivalent to the membrane potential is generated even across the impermeable membrane.

Another interpretation of the Goldman-Hodgkin-Katz equation based on Ling's adsorption theory.

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 the view of the long-dismissed adsorption theory of Ling.

Generation of membrane potential beyond the conceptual range of Donnan theory and Goldman-Hodgkin-Katz equation.

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 potential generation behaviors in conflict with those theories.

Ling's Adsorption Theory as a Mechanism of Membrane Potential Generation Observed in Both Living and Nonliving Systems.

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 potential including action potential-like potential was clearly observed.

Membrane potential generated by ion adsorption.

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: variation of membrane permeability to ion in accordance with ion species results in the variation of the membrane potential.

Experimental estimate of viscoelastic properties for ionic polymer-metal composites.

We propose an experimental method for estimating the general time-dependent elastic moduli of ionic polymer-metal composites (IPMCs). The materials exhibit fast and large bending motion even when a small voltage about 1 V is applied, and are expected to be used for polymer actuators. Experimental measurements for an IPMC beam of silver plated Nafion are given to demonstrate the usefulness of the proposed method.

Extension of Colacicco's experiment supporting the adsorption theory.

The pervasive concept of the cause of the potential occurring across a semipermeable membrane intervening between two ionic solutions is called the membrane theory; hence, this potential is called the membrane potential. Although almost nobody has doubted its validity, research results defying it have been continuously reported by a small number of researchers. They have claimed that the cause the potential lies in the adsorption of ions onto adsorption sites, which is the adsorption theory.

An interpretation of amphoteric gel hardness variation through potential and hardness measurement.

The hardness variation of amphoteric gel according to the surrounding solution conditions is quite unique. It hardens and softens reversibly regardless of its molecular network density. But this has been understood merely qualitatively.