Influence of Cytochalasin B on the Shape Change Induced in Platelets by Cold

The present investigation has employed transmission and scanning electron microscopy to examine the influence of cytochalasin B (CB) on the shape change and pseudopod formation that develop when discoid blood platelets are exposed to low temperature. CB in two concentrations protected platelets from the physical alterations induced by cold. The greater of the two amounts of drug was more effective, suggesting a dose dependence. Microtubules were absent from untreated control platelets chilled for brief periods of time but remained in approximately 20% of CB-treated cells exposed to low temperature for an hour. The findings support the concept that CB preserves discoid shape by stabilizing structural elements of the cytoskeletal support system in blood platelets.