Balloon injury induces nitric oxide synthase activity in rat carotid arteries

Experiments were performed to investigate whether or not balloon injury induces nitric oxide (NO) synthase activity in the arterial wall removed. Contractions to phenylephrine were compared in left carotid arteries of the rat, previously injured by balloon catheterization and collected 24 h after the procedure, and in control right carotid arteries in which the endothelium was removed acutely. Phenylephrine evoked concentration-dependent contractions in balloon-injured and control carotid arteries without endothelium. However, in the balloon-injured carotid arteries, the concentration-contraction curves to phenylephrine were shifted significantly to the right compared to those observed in control carotid arteries without endothelium. In balloon-injured arteries, nitro-L-arginine restored full contractions, whereas superoxide dismutase potentiated the hyporesponsiveness to phenylephrine. The depressed contractions were associated with a concomitant increase in the basal level of guanosine-3',5'-cyclic monophosphate; this production was abolished by nitro-L-arginine. These observations indicate that in vivo endothelial injury of the rat carotid arteries induces the production of nitric oxide from L-arginine in the arterial wall.