The effects of some ions on the membrane potential of the giant axon of Myxicola

The effects of various ions on the resting membrane potential of the giant axons of Myxicola were determined. The mean resting potential in artificial sea water is 69 mv, inside negative. The membrane potential decreases with incresing external potassium concentrations, while changes in the sodium and chloride concentrations have little or no effect. For potassium concentrations greater than 50 mM/L the relation between membrane potential and concentration approximates that of a perfectly selective potassium electrode. The data for the whole range of concentrations examined can be well fitted by the equation:\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm E} = \frac{{{\rm RT}}}{{\rm F}}\,{\rm log}_{\rm e} \,\frac{{[{\rm K}^ +]_{\rm o}\, + 0.031\,[{\rm Na}^ +]_{\rm o}}}{{[{\rm K}^ +]_{\rm i}\, + \,0.031\,[{\rm Na}]_{\rm i}}} $$\end{document}It was pointed out that the Myxicola giant axons can be studied under space voltage clamp and can be made available in the laboratory for 12 months out of the year. Myxicola then should become a very useful preparation for the study of membrane phenomena.