THE BEHAVIOR OF THE EMBRYONIC HEART IN SOLUTIONS OF OUABAIN

Abstract

The 48 hr. embryonic chick heart exposed to a 1:300,000 dilution of ouabain undergoes A-V block, ventricular stoppage and finally sino-atrial stoppage. The block is most constant as to time of appearance, with a mean of 4:01 minutes at 38 to 39[degree] C. Higher dilutions or lower temp. greatly delays these effects. These reactions are reversible since a quiescent heart can be revived by washing with Tyrode soln. The cause of block apparently lies primarily in depression of irritability.