Abstract
Patch pipettes were used to record the current arising from small populations of Na channels in voltage-clamped cut-open squid [Loligo pealei and L. opalescens] axons. The current fluctuations associated with the time-variant Na conductance were analyzed with nonstationary statistical techniques in order to obtain an estimate for the conductance of a single Na channel. The results presented support the notion that the open Na channel in the squid axon has only one value of conductance, 3.5 pS.