The Journal of General Physiology, Vol 64, 473-493,
Copyright © 1974 by The Rockefeller University Press
Effect on Membrane Potential and Electrical Activity of Adding Sodium to Sodium-Depleted Cardiac Purkinje Fibers
Jay R. Wiggins 1 and
Paul F. Cranefield 1
1 From The Rockefeller University, New York 10021
Canine cardiac Purkinje fibers exposed to Na-free solutions containing 128 mM TEA and 16 mM Ca show resting potentials in the range -50 to -90 mV; if the concentration of Na in the perfusate is raised from 0 to 4 to 24 mM, hyperpolarization follows. If the initial resting potential is low, the hyperpolarization tends to be greater; the average increase in the presence of 8 mM Na is 14 mV. Such hyperpolarization is not induced by adding Na to K-free solutions, is not seen in cooled fibers, or in fibers exposed to 10-3 M ouabain, nor is it induced by adding Li and thus may result from electrogenic sodium extrusion. Fibers exposed to Na-free solutions are often spontaneously active; if they are quiescent they often show repetitive activity during depolarizing pulses. Such spontaneous or repetitive activity is suppressed by the addition of Na. This suppression may or may not be related to the hyperpolarization.
Submitted on March 21, 1974
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
