Quantitative analysis of activation and inactivation of asymmetry currents in biological membranes, based on a conformational transition model.

A basic voltage-dependent conformational transition mechanism is proposed. It comprises one relatively fast conversion between two individual states which are comparatively slowly coupled with a third state. Having introduced voltage as an additional parameter of state, standard methods of thermodynamics and rate theory are employed to describe the equilibrium and kinetic behavior of the system. In particular, a quantitative discussion is given regarding the asymmetrical displacement currents generated by switching on and off a voltage pulse. Effects of temperature, pulse duration, and application of a conditioning prepulse are examined. The results provide a comprehensive basis for a quantitative analysis of pertinent experimental work. The so far presented measuring data can indeed by very well described along these lines.