Experimental evidence consistent with aggregation kinetics in the sodium current of Myxicola giant axons

Aggregation kinetics, in contrast to the Hodgkin-Huxley equations, predict that if an axon is subjected to a brief perturbing depolarization of large amplitude, the resulting perturbed current will cross over the response to a conventional maintained depolarization, and then remain smaller for the remainder of the depolarizing step. This has been experimentally tested using voltage-clamped Myxicola giant axons, compensated for series resistance and bathed in 10% Na+ sea water to minimize possible artifacts. Under such conditions perturbed and unperturbed currents are observed to cross over in a manner qualitatively consistent with the behavior predicted by an aggregation model. We suggest, therefore, that the aggregation concept may warrant further experimental and theoretical investigation.