Figure 2.

Tetanus toxin light chain does not affect secretion from permeabilized human platelets. SLO-permeablized human platelets and secretion assays were performed as described. Aliquots of permeabilized human platelets (50 μl; 5 × 10⁸/ml) were incubated with increasing concentrations of tetanus toxin light chain. Platelet secretion was stimulated with 10 μM CaCl₂. Release of [³H]5-HT from dense core granules (■), of PF4 from alpha granules (□), and of β-hexosaminidase from lysosomes (▩) was measured and percent secretion was calculated. Data points represent the average of triplicate measurements and the SD is indicated (A). A separate set of samples was probed by Western blotting for VAMP-3 (B).