Figure 4.

Aggregation and secretion of ATP is defective in endobrevin/VAMP-8^−/− platelets. Wild-type (WT, black traces) and VAMP-8 null (V8^−/−, gray traces) mouse platelets were prepared and after adding 0.7 mM CaCl₂, and aliquots (2.5 × 10⁸/ml) were stimulated with indicated concentrations of thrombin (A–F), collagen (G, H, J, and K) or A23187 (I and L). Platelet aggregation (A–C and G–I) and ATP release (D–F and J–L) were measured with constant stirring.