Effect of tetracaine chlorhydrate on the mechanical properties of the erythrocyte membrane

Pharmacologically active agents that locate in the cell membrane are useful tools to investigate the interactions taking place between its molecular c omponents. In the present work, the effect of tetracaine chlorhydrate (Tc) on the membrane mechanical properties of intact and desialated erythrocytes was studied. Our results evince the complex interaction between the drug a nd the membrane structures. The effect of Tc on erythrocyte shape suggests that this drug locates in the inner hemilayer of the lipid bilayer. Since T c also modifies osmotic fragility and mechanical properties ascribed to the cytoskeleton, it can be inferred that the lipid bilayer has an effect on t he theology of the membrane, in a direct or indirect way, in this case thro ugh the close interaction with the structural proteins. Moreover, our resul ts support the hypothesis of a second localization of the drug in the membr ane, i.e., as monovalent cations intercalated among the glycocalix sialic e ndings, where it generates an effect superimposed on that produced from its typical site in the lipid bilayer. (C) 2001 Academic Press.