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. The previous work was performed on the following premises (i) The membrane potential is generated by ion adsorption, as opposed to the classical ion transport mechanisms, (ii) The living cell is a thermodynamically real system rather than an ideal system, and (iii) The conductance employed in the HH model is replaced by the ion activity coefficient, which is weighted with the role of conductance. Consequently, the GHK eq. was mathematically associated with the HH model through the intermediary of Boltzmann ion distribution and mass action law. To verify if our theoretical formularization could afford a physiologically, physically and chemically viable model, we performed computational analysis using the formulae (quantitative correlations between various variables) we derived in the previous work. The computational results obtained through associating the GHK eq. with the HH model validated our model and its predictions. This outcome suggests that the current prevailing physiological concepts could be expanded further, to incorporate the newly proposed mechanisms. That is, GHK eq. and HH model could be interpreted via another set of founding principles that incorporate the ubiquitous phenomena of ion-adsorption.

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. That is the GHK eq. and the HH eq. have not been associated with each other mathematically. In this paper, an attempt to associate these equations to each other mathematically was demonstrated and was successful by viewing the system in question as a thermodynamically real system rather than an ideal system. For achieving that, two fundamental physical chemistry concepts, the mass action law, and the Boltzmann distribution were employed. Hence, this paper's achievement is completely within the framework of common thermodynamics. Through this work, the origin of the membrane potential generation attributed to the ion adsorption-desorption process and governed by the mass action law and the Boltzmann distribution is expressed to be plausible, whereas the existing membrane potential generation mechanism states that membrane potential is generated by transmembrane ion transport. As at this moment, this work does not intend to deny the transmembrane ion transport as a membrane potential generation mechanism but urges the readers to reconsider its validity, since this work suggests that the ion adsorption-desorption mechanism is as plausible as the transmembrane ion transport mechanism as a cause of membrane potential generation.

Extracellular matrix and its role in conveying glial/neural interactions in health and disease.

We review the concepts and findings that may be related to the occurrence of non-linear glial/neural dynamics involving interactions between polyelectrolytes of the extracellular matrix and the basement membranes that cover the endfeet of glia at CNS interfaces. Distortions of perception and blocking of learning expressed in functional syndromes are interpreted as macroscopic electrochemical patterns that emerge in grey matter through glial/neural interactions.

The Plastic Glial-Synaptic Dynamics within the Neuropil: A Self-Organizing System Composed of Polyelectrolytes in Phase Transition.

Several explanations have been proposed to account for the mechanisms of neuroglial interactions involved in neural plasticity. We review experimental results addressing plastic nonlinear interactions between glial membranes and synaptic terminals. These results indicate the necessity of elaborating on a model based on the dynamics of hydroionic waves within the neuropil. These waves have been detected in a small scale experimental model of the central nervous system, the in vitro retina. We suggest that the brain, as the heart and kidney, is a system for which the state of water is functional. The use of nonlinear thermodynamics supports experiments at convenient biological spatiotemporal scales, while an understanding of the properties of ions and their interactions with water requires explanations based on quantum theories. In our approach, neural plasticity is seen as part of a larger process that encompasses higher brain functions; in this regard, hydroionic waves within the neuropil are considered to carry both physiological and cognitive functions.

Membrane-modifying properties of crotamine, a small peptide-toxin from Crotalus durissus terifficus venom.

BACKGROUND: Crotamine is a small, highly basic myotoxin from the venom of the South American rattlesnake Crotalus durissus terifficus. It is structurally well defined and exhibits some similarities with the ß-defensins of vertebrates. An amazing variety of functions and targets that range from analgesia and tumor-related activity to cell penetration have been associated with crotamine. Similar to defensins, it had been argued that crotamine has antimicrobial activity, and this supposition was recently proven.Moreover, it has been argued that the antimicrobial activity of crotamine is due to the membrane permeabilizing properties of the peptide. However, until now, the detailed mechanism of this postulated membrane permeabilization was still unclear. METHODS: In this paper, we used gradient SDS-gels, mass spectroscopy (MALDI-TOF), and monolayer and planar lipid bilayer experiments to investigate the membrane modifying properties of crotamine. RESULTS: We showed that crotamine itself forms stable monolayers because of its amphipathic structure, is easily incorporated into lipid monolayers and forms well-defined pores with low cationic selectivity in planar lipid bilayers; these properties might account for the antimicrobial activity of crotamine. The pores are probably oligomericaggregates of crotamine molecules, as suggested by the tendency of crotamine to form oligomers in aqueous solution and the fact that the structure of crotamine does not allow pore formation by monomers. CONCLUSIONS: The membrane modifying and antimicrobial properties of crotamine are probably due to homo oligomeric pore formation in membranes. GENERAL SIGNIFICANCE: The results should be highly interesting to researchers in the fields of biophysics, pharmacology,toxicology and antibiotics.

Development of one experimental module to study the modulation of the propagation velocity of chemical excitation waves in gel by weak external force (gravity).

Biological and chemical systems in which the pattern of flow of energy and matter imposes self-organization can be seen as examples of excitable media. One property of such media is the presence of excitation waves. The Belouzov-Zabotinsky(B-Z) reaction system and the retinal spreading depression wave are examples of experimental models of excitable media in which the influence of gravity can be studied. In this paper we describe one especial module constructed to test the influence of gravity in gels of the B-Z system. In the gel condition, convection effects are minimized. The results will be directly comparable to retinal experiments programmed by the same group and complete a series of investigations of systematic comparison of the modulation of chemical and biological excitation waves by weak external forces.