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Nerve impulse transmission occurs based on three successive electrochemical processes: at rest, the concentration gradient of ions across the axon membrane produces the resting potential (−60 mV) called K+potential, leading to polarization; nerve impulse produces the action potential called Na+potential (+30 mV), causing depolarization (i.e., on excitation, there is a swing from a K+ potential of −60 mV to an Na+ potential of +30 mV) and the electrical current produced due to the action potential propagates forward; lastly, the resting potential is recovered by repolarization via an Na+ pump mechanism. The selectivity of Na+ and K+ ion channels has been rationalized in terms of their dehydration energies and size-matching factors. Synaptic transmission carrying the signal from one neuron to another neuron is mediated by the neurotransmitter through a chemical mechanism. Many drugs are known to affect the nervous system by interfering with the synaptic transmission mechanism. In this study, the biochemistry behind cocaine addiction and Parkinson's disease has been discussed. [ABSTRACT FROM AUTHOR]

Recently, in a paper entitled "Protonic conductor: Better understanding [sic] neural resting and action potential," Lee applied his Transmembrane Electrostatically-Localized Protons (TELP) hypothesis to neuronal signaling. He stated that Hodgkin's cable theory "could not fully explain the different conductive patterns in unmyelinated and myelinated nerves," whereas his TELP hypothesis "enables much better understanding of neural resting/action potential and [the biological significance of] axon myelination. . ." However, Lee's TELP hypothesis predicts that under resting conditions, the neuron "accumulat[es] excess negative charge (anions) inside," whereas resting chloride gradients actually feature excess Cl- outside of the cell. Experiments on the neuron have shown that raising external [Kþ] and decreasing external [Cl-] cause membrane potential depolarization, which is predicted by the Goldman equation, but opposite to TELP hypothesis predictions. Finally, based on his TELP hypothesis, Lee predicted that the main purpose of myelin is to insulate the axonal plasma membrane specifically against proton permeability. However, he cited literature showing that myelin contains proteins that may "serve as a proton conductor with the localized protons." Thus, we show here that Lee's TELP hypothesis is highly problematic, and does NOT offer a "better understanding" of neuronal transmembrane potentials. [ABSTRACT FROM AUTHOR]

The resting potential is the potential difference that exists between the inner and outer sides of the cell membrane when the cell is not stimulated. The resting membrane potential is a key regulator of phenomena such as cell proliferation, morphogenesis, migration and differentiation. In this paper, we proposed a model of electrified cell clusters that considers the resting potential of cell clusters in the resting state. By measuring the potential difference between the inner and outer sides of biological tissues, it is verified that the cell cluster has a negative potential difference when taking the outer potential as the reference. In the absence of external conductors, the tissue is electrically neutral; while in the presence of external conductors, the positive net charges escape freely under repulsive forces and the biological tissues form a negative electrical equilibrium system. The model proposed in this study explored the potential situation above the cellular level in the resting state, providing a new perspective for the research on resting potential.

The osmotic activity produced by internal, non‐permeable, anionic nucleic acids and metabolites causes a persistent and life‐threatening cell swelling, or cellular edema, produced by the Gibbs‐Donnan effect. This evolutionary‐critical osmotic challenge must have been resolved by LUCA or its ancestors, but we lack a cell‐physiology look into the biophysical constraints to the solutions. Like mycoplasma, early cells conceivably preserved their volume with Cl−, Na+, and K+‐channels, Na+/H+‐exchangers, and a light‐dependent bacteriorhodopsin‐like H+‐pump. Here, I simulated protocells having these ionic‐permeabilities and inhabiting an oceanic pond before the Great‐Oxygenation‐Event. Protocells showed better volume control and stable resting potentials at lower external pH and higher temperatures, favoring a certain type of extremophile life. Prevention of Na+‐influx at night, with low bacteriorhodopsin activity, required deep shutdown of highly voltage‐sensitive Na+‐channels and extremely selective K+‐channels, two conserved features essential for modern neuronal encoding. The Gibbs‐Donnan effect universality implies that extraterrestrial cells, if they exist, may reveal similar volume‐controlling mechanisms. [ABSTRACT FROM AUTHOR]

The transport processes of substances in various plant tissues are extremely diverse. However, models aimed at elucidating the mechanisms of such processes are almost absent in the literature. A unified view of all these transport processes is necessary, considering the laws of statistical physics and thermodynamics. A model of active ion transport was constructed based on the laws of statistical physics. Using this model, we traced the entire pathway of substances and energy in a plant. The pathway included aspects of the production of energy in the process of photosynthesis, consumption of energy to obtain nutrients from the soil, transport of such substances to the main organelles of all types of plant cells, the rise of water with dissolved substances along the trunk to the leaves, and the evaporation of water, accompanied by a change in the percentage of isotopes caused by different rates of evaporation. Models of ion transport in the chloroplasts and mitochondria of plant cells have been constructed. A generalized model comprising plant cells and their vacuoles was analyzed. A model of the transport of substances in the roots of plants was also developed. Based on this model, the problem of transport of substances in tall trees has been considered. The calculated concentrations of ions in the vacuoles of cells and resting potentials agreed well with the experimental data. [ABSTRACT FROM AUTHOR]

Morphogenesis results when cells cooperate to construct a specific anatomical structure. The behavior of such cell swarms exhibits not only robustness but also plasticity with respect to what specific anatomies will be built. Important aspects of evolutionary biology, regenerative medicine, and cancer are impacted by the algorithms by which instructive information guides invariant or stochastic outcomes of such collective activity. Planarian flatworms are an important model system in this field, as flatworms reliably regenerate a primary body axis after diverse kinds of injury. Importantly, the number of heads to which they regenerate is not determined genetically: lines of worms can be produced, which, with no further manipulation, regenerate as two-headed (2H) worms, or as "Cryptic" worms. When cut into pieces, Cryptic worms produce one-headed (1H) and 2H regenerates stochastically. Neural and bioelectric mechanisms have been proposed to explain aspects of the regenerative dataset. However, these models have not been unified and do not explain all of the Cryptic worm data. In this study, we propose a model in which two separate systems (a bioelectric circuit and a neural polarity mechanism) compete to determine the anatomical structure of a regenerate. We show how our model accounts for existing data and provides a consistent synthesis of mechanisms that explain both the robustness of planarian regeneration and its remarkable re-writability toward novel stable and stochastic anatomical states., (Copyright 2022, Mary Ann Liebert, Inc., publishers.)