Unresolved roles of platelet nitric oxide synthase

Endothelial-derived nitric oxide (NO) is a key regulator of platelet function, inhibiting both adhesion to the extracellular matrix and aggregation at sites of vascular injury. Platelets also have the capacity to synthesize and release bioactive NO, which is thought to make a significant contribution to the vascular pool of NO. The regulation of platelet NO production is poorly understood and studies examining the physiological role of platelet-derived NO have produced contradictory and controversial findings. In the present article, we discuss the current understanding of the biochemical and molecular regulation of platelet NO synthesis and outline the potential physiological and clinical significance of this molecule.