Concurrent effects of microsieve aspiration and the ionophore A23187 on the morphologic characteristics of the surface of normal erythrocytes.

Previous studies using the calcium ionophore A23187 have shown that pathologic changes in erythrocyte shape and deformability can be induced by modest increases in intracellular calcium with the concomitant depletion of cellular adenosine triphosphate. Efforts to modify the cellular response to such ionophore-induced calcium loading by means of environmental and chemical manipulation of the erythrocyte membrane have suggested that the state of the membrane prior to calcium uptake influences the response of the cell. The present investigation used the microsieve aspiration technic to induce membrane tension mechanically prior to calcium loading with A23187, and thereby to evaluate the response of the membrane to another form of stress. Erthrocytes subjected to conditions of membrane tension in the microsieve were found to resist completely the A23187-calcium-induced conversion to echinocytes or spheroechinocytes. These results support the hypothesis that the state of the membrane before calcium loading has a marked influence on the response of the cell. This may be related to the mechanism underlying the development of irreversibly sickled cells in patients with sickle cell anemia.