EFFECTS OF VARIOUS POTASSIUM SALTS AND PROTEASES UPON EXCITABILITY OF INTRACELLULARLY PERFUSED SQUID GIANT AXONS

Abstract

By the method of intracellular perfusion, the effects of various anions upon the resting and action potantials of the squid giant axon were studied. Among the anions examined, fluoride, aspartate, and glutamate ions were found to be most favorable for maintaining large action potentials. Anions could be arranged according to the magnitude of their intracellular effect in an order similar to the well-known lyotropic series. By using a mixture of NaF and KF in the perfusion fluid, a large overshoot of action potential was obtained with approximately equal Na-ion activities inside and outside the axon. Various endopeptidases, exopeptidases, and lipases were shown to destroy the axon membrane functionally. A close relationship between the protein layer of the membrane and electrical excitability is suggested.