Properties of sarcolemmal delayed rectification in glycerol-treated fibers of frog sartorius muscle.

Total current-voltage relations were analyzed on nine glycerol-treated surface fibers of frog sartorius muscles in tetrodotoxin-containing isotonic normal Ringer solution. The results indicate that delayed rectification occurs in the sarcolemma on large depolarization and that delayed rectification is only partially inactivated during 1 sec of depolarization and not converted into anomalous rectification. The time to peak, the time course of inactivation and the potassium activation potential determined in glycerol-treated fibers were comparable to those analyzed previously in intact fibers. The value of the conductance increase during delayed rectification in glycerol-treated fibers appeared to be smaller than that in intact fibers.