The aim in this study is to achieve by computer simulation the consolidation of known modes of actions of frog skin on Na ions into a carefully premediated multicompartment model system. Previous research has already shown that when well adjusted kinetic parameters are selected (some of which are experimentally established), the dynamics of the model is in good agreement with hitherto tested kinetic and thermodynamic data obtained on skin. The objective of the new research proposed in this grant application is to impose upon the model system: "edgedamage"; a process of volume regulation; variations in the (Na ion) at the dermal side of the skin which alters the thermodynamic efficiency of the Na ion pump; conditions which will lead to damped, sinusoidal flux changes. In these studies stress will also be laid on the disclosure of experimentally testable predictions derived from the model.