The bioelectrical characteristics of a crab nerve fiber subjected to solutions containing the impermeant anions ferrocyanide, glutamate, or ethanolsulfate substituted for chloride include prolonged slow depolarizations that elicit prolonged trains of impulses sulperimposed on the plateau portion. Propionate and nitrate depress repetitive firing while thiocyancite has only a slighit effect. Nerves treated with ferrocyanide lose potassium and gain sodium, which fact may account for their depolarization. On the other hand, studies with interference microscopy reveal shift by ferrocyanide in the interference fringe pattern of the sheath material; this suggests a reorientation of fixed charges in the protein layers by direct action of the anion on these layers. This may also account for the electrical manifestations observed.
Action Potentials Animals