Effect of GIRK inhibitors on ADP-induced Akt phosphorylation. (A) Aspirin-treated, washed human platelets were stimulated with ADP in the presence or absence of reagents as indicated. Platelet lysates were then electrophoresed and probed with phospho-specific Ser473 anti-Akt antibodies as described in “Materials and methods.” (B) Densitometric analysis of the immunoblots from panel A was performed using the ImageGauge Program (Fujifilm Luminescent Image Analyzer). Lane numbers correspond to those in panel A. Data are representative of 3 independent experiments done using platelets from 3 donors, and error bars indicate SEM.