THE SENSITIVITY OF FROG MUSCLE TO POTASSIUM AND ACETYLCHOLINE

I. EFFECT OF CURARE AND PHYSOSTIGMINE ON THIOCYANATE: POTASSIUM Sensitization

¹ Cardiovascukir Department, Medical Research Institute, Michael Reese Hospital, Chicago, Illinois

1. The properties of sodium thiocyanate as a sensitizer for the potassium ion are demonstrated by means of the frog rectus preparation. These include the effect of thiocyanate on the intensity, rapidity and reversibility of the action of potassium.

2. Curare slightly lessens the sensitivity of the preparation to potassium, but it does not quantitatively affect the process of sensitization to potassium produced by thiocyanate. Acetylcholine plays no significant part in the mechanism of the increased response to thiocyanate: potassium. The action of thiocyanate is therefore specific.

3. Thiocyanate increases somewhat the acetylcholine sensitivity of the preparation. This effect is not quantitatively affected by physostigmine.

4. The increased acetylcholine sensitivity appears to be due to the action of thiocyanate on a "potassium component" of the effect of acetylcholine.