ABSTRACT
The role of cyclic guanosine monophosphate (cGMP) versus cyclic adenosine monophosphate (cAMP) mediated mechanism in modulating platelet adhesion was investigated in balloon catheter injured rat carotid arteries. Vascular injury with balloon angioplasty significantly increased the adherence of platelets to the injured carotid arteries. Intravenous infusion of zaprinast (1 mg/kg/min), a cGMP phosphodiesterase inhibitor, or sodium nitroprusside (8 micrograms/kg/min), a stimulator of soluble guanylate cyclase, significantly attenuated the adherence of platelets to the injured carotid arteries. In comparison, infusion of milrinone, a cAMP phosphodiesterase inhibitor, or 8-bromo-cAMP failed to affect the platelet deposition in the injured carotid arteries. Nifedipine or aspirin also failed to attenuate the adherence of platelets to the injured carotid arteries. In conclusion, agents known to elevate intracellular platelet cGMP but not cAMP appear to afford the most effective protection in vivo against the adhesion of platelets to the vessel wall without intact endothelium.
