PKA inhibitor KT5720 but not PKG inhibitor KT5823 reverses cGMP-induced inhibition of platelet aggregation. Platelets were preincubated with DMSO (as a control), PKA inhibitor KT5720 (5 μM), or PKG inhibitors KT5823 (5 μM) (A-C,E) or Rp-Br-PET-cGMPS (0.2 mM) (D) for 5 minutes and then incubated with 1 mM 8-bromo-cGMP (A), 3 mM 8-bromo-cGMP (B), 0.1 mM 8-pCPT-cGMP (C-D), or 100 μM NO donor glyco-SNAP 1 (E) for additional 10 minutes. Ristocetin (1.25 mg/mL) (A) or α-thrombin (0.05 U/mL)(B-E) was then added to induce platelet aggregation. Presented in the figure are the representative results of at least 3 experiments.