Vesiculation induced by hydrostatic pressure in human erythrocytes.

When human erythrocytes were subjected to hydrostatic pressure (1.1-2.0 kbar), it was found that membrane vesicles were released from the red cells above 1.4 kbar. As with hemolysis under high pressure, the amount of released vesicles was increased with increasing pressure but decreased by the cross-linking of membrane proteins with diamide. Vesicles obtained at 2.0 kbar were heterogeneous in size but similar to intact erythrocytes in phospholipid composition. Although it has been reported that spectrin-free vesicles are released by echinocytogenic agents, pressure-induced vesicles did contain considerable and similar amounts of spectrin irrespective of the difference in size. These results suggest that vesiculation by high pressure is associated with the disruption of the membrane skeleton, as previously seen in pressure-induced hemolysis [Yamaguchi et al. (1989) J. Biochem. 106, 1080-1085].