Action potentials of single frog nerve fibers were recorded with the air-gap method in "low Ca" (0.26 mM) and "high Ca" (4.2 mM) solutions and compared to spikes in normal Ringer's (1.05 mM Ca). On increasing (Ca)o the action potentials became shorter, the "knee" during the falling phase as well as the threshold for abolition moved to internal potentials more positive, and the spike recovery during the relative refractory period was faster. Outward current pulses applied during an action potential affected its configuration more in low Ca than in high Ca. The onset of the delayed rectification (in the absence of Na) was found faster in high Ga. After-potentials during anelectrotonus declined more rapidly in high Ca than in low Ca. The results are compared primarily with the voltage-clamp analysis of Ca effects on squid axons and satisfactory qualitative agreement is reached.
Article| September 01 1964
Some Effects of Calcium Ions on the Action Potential of Single Nodes of Ranvier
From the Department of Physiology, The Saar University, Homburg-Saar, Germany, and the Department of Physiology, Duke University Medical Center, Durham, North Carolina.
Dr. Ulbricht's present address is the Department of Physiology, The Saar University, Homburg-Saar, Germany
Received: January 02 1964
Online Issn: 1540-7748
Print Issn: 0022-1295
Copyright © 1965 by The Rockefeller Institute Press
- Views Icon Views
- Share Icon Share
- Search Site
Werner Ulbricht; Some Effects of Calcium Ions on the Action Potential of Single Nodes of Ranvier . J Gen Physiol 1 September 1964; 48 (1): 113–127. doi: https://doi.org/10.1085/jgp.48.1.113
Download citation file: