Excitation of internally perfused squid giant axons in sodium-free media.

Abstract

Under intracellular perfusion with a dilute solution of RbF or CsF, squid giant axons were shown to maintain excitability in Na-free media containing polyatomic univalent cations. Nitrogenous cations known to substitute for Na-ion in frog nerve fibers were found to be favorable external cations for squid axons also. Some of the structural factors which may determine the "favorability" of various polyatomic univalent cations were studied by comparing the electrophysiological effects of a number of homologous series of compounds.