Effect of the anode and cathode of a direct current on the electrical activity of the isolated node of Ranvier in a medium with low sodium concentration and during the action of Novocain

Abstract

Experiments were performed on single nerve fibers ofRanatemporaria. The changes in the value and the form of action potential (AP) proved to be similar both in a low-sodium medium and in a Novocain solution. The action of a dc anode on the node of Ranvier in a low-sodium medium caused only an insignificant rise of the AP amplitude but restored the AP completely in a node treated with Novocain. The cathode placed on the node stressed the AP in both cases. The membrane depolarization critical level (CL) rose both in a low-sodium medium and in a Novocain solution. Direct current cathode raised CL to a still greater degree, whereas the anode, on the contrary, lowered it somewhat. However, complete CL restoration did not occur either in a low-sodium medium or in a Novocain solution. The possible mechanism of the changes occurring in the AP and CL amplitudes during dc polarization in a lowsodium medium and in a Novocain is discussed.