Anode break excitation and Pflüger's law

¹ Department of Physiology, University of Florida College of Medicine, Gainesville, Florida

The relations between the nodes of stimulating current and excitation were studied on frog nerve with special emphasis on anode break excitation. The threshold for anode break excitation was several times greater than cathode make threshold. Following an exceedingly strong anodal pulse, there is a period of marked reduction in anode break threshold. The data indicate that anode break excitation in whole nerve results from node membrane breakdown, as concluded in a previous investigation on the single Ranvier node. The many confusing results often obtained in demonstrating Pflüger's law on whole nerve were found to be attributable to populations of nerve fibers in whole nerve and are readily explained by the results of single-fiber experiments.