bioRxiv preprint doi: https://doi.org/10.1101/2020.05.02.073635; this version posted May 4, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. A simple description of biological transmembrane potential from simple biophysical considerations and without equivalent circuits Marco Arieli Herrera-Valdez1; 1 Systems Physiology Laboratory, Department of Mathematics, Facultad de Ciencias, Universidad Nacional Autónoma de México, CDMX, México.
[email protected] Abstract Biological membranes mediate different physiological processes necessary for life, including but not limited to electrical signalling, volume regulation, and other different forms of communica- tion within and between cells. Ion movement is one of the physical processes underlying many of such processes. In turn, the difference between the electrical potentials around a biological membrane, called transmembrane potential, or membrane potential for short, is one of the key biophysical variables affecting ion movement. Most of the equations available to describe the change in membrane potential are based on analogies with resistive-capacitative electrical circuits. These equivalent circuit models were originally proposed in seminal studies dating back to 1872, and possibly earlier, and assume resistance and capacitance as measures of the permeable and the impermeable properties of the membrane, respectively. These models have been successful in shedding light on our understanding of electrical activity in cells, especially at times when the basic structure, biochemistry and biophysics of biological membrane systems were not well known.