Effect of deficiency of SLP-76 on granule release.

Granule release in SLP-76^+/− (A) or SLP-76^−/− (B) platelets was monitored by flow cytometric measurement of surface expression of P-selectin in unstimulated platelets (dotted line) or after stimulation with 0.5 U/mL thrombin (solid line) or 250 ng/mL convulxin (dashed line). (C) The percentage of platelets staining positively for P-selectin, defined as region M1 as shown in panels A and B, was determined for SLP-76^+/−(open bars; n = 7) or SLP-76^−/− (filled bars; n = 7) platelets that were either left unstimulated (control) or stimulated with thrombin (0.5 U/mL), convulxin (250 ng/mL), or ionomycin (3 μM). *P < .05 versus control; †P < .05 versus SLP-76^+/− platelets.