L-ARGININE INHIBITS NEOINTIMAL FORMATION FOLLOWING BALLOON INJURY

Nitric oxide (NO)-generating vasodilators inhibit the mitogenesis and proliferation of cultured vascular smooth muscle cells. We investigate d the role of NO in the vascular response to arterial injury by admini stering L-arginine (precursor of NO), D-arginine or N-nitro L-arginine methylester(NAME; an inhibitor of NO synthesis) to a rat model of bal loon catheter-induced left carotid artery injury. Two weeks after the balloon injury, animals that received both oral (1.25g/l water) and lo cal (10mg in gel) administration of L-arginine showed suppression of n eointimal proliferation with no change in systolic blood pressure. Med ial proliferation was potentiated in NAME-treated animals with a highe r blood pressure. Tissue cGMP content (representative of NO generation ) of the injured arteries was similar to that of normal arteries with intact endothelium. These findings suggest that a higher local concen tration of NO produced from L-arginine can inhibit the migration and p roliferation of smooth muscle cells in the injured vascular wall.