Resistivity of axoplasm: II. Internal resistivity of giant axons of squid and myxicola

Abstract

The specific resistivity of the axoplasm of giant axons of squid and Myxicola was measured utilizing a single metal microelectrode subjected to alternating current in a circuit in which the voltage output varies with the conducfivity of the thin layer of fluid at the exposed electrode tip. The average specific resistivity of stellar axons of Loligo pealei was 31 Ωcm (1.55 times seawater [× SW]) while for Loligo opalescens it was 32 Ωcm (1.30 × SW). Smaller giant axons had a higher average resistivity. Myxicola giant axons had a resistivity of 68 Ωcm (2.7 × SW) in normal seawater, and 53 Ωcm (2.1 × SW) in a hypertonic high-Mg++ seawater. The temperature dependence of squid axon resistivity does not differ from that of an equally conductive dilution of seawater. © 1975, Rockefeller University Press., All rights reserved.