Propranolol-induced structural changes in human erythrocyte ghost membranes. A spin label study.

The effect of propranolol on the structure of human erythrocyte membranes was studied using a spin labeling technique. Changes in electron spin resonance spectra of spin labeled membrane proteins were detected at concentration of the drug corresponding to its antihemolytic effect on intact erythrocytes. The character of spectral changes suggests that propranolol-induced alterations in organization of membrane proteins are connected mainly with perturbation of protein sites located on membrane surface. Propranolol also produces a decrease in order parameter of membrane lipids. The disordering effect is, however, small and detectable only at relatively high concentrations of the drug.