Effects of external currents on duration and amplitude of normal and prolonged action potentials from single nodes of Ranvier.

Duration and amplitude of normal and prolonged action potentials from single nodes of Ranvier vary as functions of potential changes induced by currents from an external source. The quantitative relations between externally applied potential and the resulting potential generated within the system are analyzed in order to obtain information about the kinetics of the electromotance,-potential,-and chemical changes taking place during excitation. The following preliminary conclusions are drawn: A depolarizing and a repolarizing process (positive and negative electromotance) increase and decrease with the potential. For a sudden potential displacement the negative electromotance reaches its new value at a faster rate than the positive electromotance. Since the individual values of the two electromotances depend on the potential and since they both generate a potential which is proportional to the difference of their absolute values, the values of either electromotance are determined by this difference as well as by any externally induced potential change.