RESUMO
The internal conductivity of Aplysia neuron somata was measured by passing constant current pulses across a calibrated four-electrode array. The intracellular medium is less than one-tenth as conductive as seawater. The low conductivity probably results from structured cell water since ions are present in quantity and do not appear to be bound.
Assuntos
Condutividade Elétrica , Neurônios/fisiologia , Potenciais de Ação , Animais , Métodos , Microeletrodos , MoluscosRESUMO
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 conductivity of the thin layer of fluid at the exposed electrode tip. The average specific resistivity of stellar axons of Loligo pealei was 31 omegacm (1.55 times seawater [X SW]) while for Loligo opalescens it was 32 omegacm (1.30 X SW). Smaller giant axons had a higher average resistivity. Myxicola giant axons had a resistivity of 68 omegacm (2.7 X SW) in normal seawater, and 53 omegacm (2.1 X 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.