Long-term Nitric Oxide Synthase Inhibition and Distensibility of Carotid Artery in Intact Rats

The goal of the present study was to evaluate the effect of long-term nitric oxide synthase inhibition by N-nitro- L-arginine-methyl ester (L-NAME) on the morphology and viscoelastic properties of the carotid arteries in rats. Twelveweek- old Wistar-Kyoto rats were treated for 6 weeks with either the nitric oxide synthase inhibitor L-NAME (0.4 g/L in drinking water; L-NAME rats, n=13) or tap water (control rats, n=13). Age-matched spontaneously hypertensive rats (SHR, n=14) received tap water for the same period. The internal diameter of the common carotid artery was measured continuously with an echo-tracking device with the rats under anesthesia with halothane. Intra-arterial pressure was monitored on the contralateral side. L-NAME rats exhibited arterial pressures similar to those of SHR. The distensibility pressure-curve determined in L-NAME rats was a direct continuation of that obtained in control rats. In contrast the distensibility in SHR was increased (P