Mathematical Model of the Proton Balance in the Outer Mantle Epithelium of Anodonta cygnea L

• Published in: The Journal of membrane biology Vol. 223; no. 2; pp. 59 - 72
• Main Authors: Oliveira, P. F, Rebelo da Costa, A, Ferreira, H. G
• Format: Journal Article
• Language: English
• Published: New York New York : Springer-Verlag 01.05.2008; Springer-Verlag; Springer Nature B.V
• Subjects: 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid - pharmacology; 4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid - pharmacology; Acetates - pharmacology; Acetazolamide - pharmacology; Amiloride - pharmacology; Animals; Anodonta - physiology; Biochemistry; Biomedical and Life Sciences; Cellular biology; Chlorides - physiology; Computer Simulation; Epithelium - physiology; Human Physiology; Hydrogen-Ion Concentration; Indenes - pharmacology; Life Sciences; Macrolides - pharmacology; Mathematical models; Membrane Potentials - drug effects; Membrane Potentials - physiology; Metabolism; Models, Biological; Mollusks; Ouabain - pharmacology; Potassium - physiology; Proton Pumps - drug effects; Proton Pumps - physiology; Protons; Sodium - physiology; Short-circuit current; Berkeley Madonna; Voltage clamp; pH; Mantle; Bivalve; Freshwater; Proton transport
• ISSN: 0022-2631; 1432-1424
• DOI: 10.1007/s00232-008-9114-8

In the freshwater mollusc Anodonta cygnea and other unionids, the mantle plays an important role in the regulation of the movements of ions between the shell and the extrapaleal fluid. In this report, a mathematical model that attempts to describe the cell metabolic mechanisms underlying the operation of the outer mantle epithelium as a source of protons is presented. We encoded the information gathered by studying the epithelium in vitro, which includes the electrophysiology of the preparation, measurements of basic rates of transport of protons and base, the effect of metabolic and transport inhibitors on its electrical behavior and the dynamic measurements of pH i . The model was conceived so that the short-circuit current (Isc) and fluxes of Na⁺, K⁺ and Cl⁻; intracellular volume; electrical potential; and ionic concentrations can be computed as a function of time. Furthermore, the analytical descriptions of all ionic fluxes involved are such that the effect of transport inhibitors can be simulated. In all the simulations performed, it was possible to reproduce the experimental results obtained with specific inhibitors of transport systems on the Isc and on pH i . In some cases, it was necessary to make alterations to one or more parameters of the reference condition. For each simulation carried out, the analysis of the results was consistent. The model is an analytical tool that can be used to show the internal coherence of the qualitative model previously proposed and to plan further experiments.