Increased resistance to membrane deformation of shape-transformed human red blood cells.

The study of shape-transformed human erythrocytes is of hematological interest since several clinical conditions are associated with erythrocyte shape changes. Using the micropipette technique, we examined the rheological behaviors of echinocytes induced by sodium salicylate or ATP depletion and of stomatocytes induced by chlorpromazine. Both the discocyte-echinocyte and discocyte-stomatocyte transformations resulted in an increased resistance to extension. Sodium salicylate-treated erythrocytes could be returned to normal morphology and normal membrane rheology by addition of chlorpromazine. We conclude that these morphological changes are associated with detrimental effects on the intrinsic membrane deformability of the human erythrocyte.