Temperature dependence of the effects of tertiary amines on osmotic hemolysis

The effects of four tertiary amines (procaine, lidocaine, tetracaine and dibucaine) on the osmotic fragility and the rate of hemolysis of human erythrocytes were investigated in the range between 22-42 degrees C. The temperature dependence of the relative hemolysis indicates the existence of certain critical points in the antihemolytic effect of these substances. The relative rate of hemolysis, which is well known to be a parameter accounting for the fluidity of erythrocyte membrane, decreases with increasing drug concentration, indicating a decrease in membrane fluidity. The amount of drugs actually bound to the erythrocytes increases linearly with the external concentration, as shown by UV-absorption.