Developing Tools towards Ion Homeostasis in Spatially Polarized Excitable Cells

Abstract

In 1800, Volta, inspired by the electric organs of a genus of electric fish, the Electrophorus, invented the first electric batteries, which were termed "artificial electric organs." Since then, the far-reaching implications of the fishes’ electrogenesis have come under greater attention and interest. In these fishes, the electric organ resembles a series of batteries. The electric organs are formed by electrocytes (the "batteries") with a distinct cytomorphology for discharging and charging. Although the arrangements of electrocytes in the electric organ are well-understood, the mechanisms involved in generating electric discharges within equivalent circuits remain unclear. In this thesis, the first element consists of adapting spatially defined models that we use to investigate the process of electrocyte charging and recharging under the added assumption of ion homeostasis, the process by which a cell restores its internal milieu. The study focuses on Eigenmannia and Electrophorus, two genera of electric fish. Eigenmannia's steady high-frequency dipole oscillator-like electric organ discharges enables electro-sensing and electro-communication, whilst Electrophorus's brief taser-like electric bursts serve as tetanizing predatory assaults. In addition, the second section of this study proposes a one-dimensional charge difference model that focuses on the modification of endogenous electric fields resulting from the uneven distribution of ions in a homeostatic apparatus.