Dietary copper deficiency reduces the elevation of blood pressure caused by nitric oxide synthase inhibition in rats

Nitric oxide (NO)-mediated vasodilation is diminished in blood vessels of copper (Cu)-deficient rats. This study examined whether Cu deficiency affects blood pressure regulation via an effect on NO metabolism. Male, weanling rats were fed diets ranging from 0.4 to 7.2 mg Cu/kg diet for 5 weeks. Blood pressure was measured via arterial cannulation before and after intravenous injection of N-G-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg body weight), a NO synthase inhibitor. Plotting blood pressure against the liver Cu concentration (22-241 nmol/g) revealed that control mean arterial blood pressure (MAP; 104-152 mm Hg) was not correlated with the liver Cu concentration. However, both MAP after L-NAME treatment (MAP(1), 148-190 mm Hg) and the elevation of MAP caused by L-NAME (DeltaMAP; 8-68 mm Hg) were positively correlated with the liver Cu concentration (r = 0.52 for MAP(1), r = 0.42 for DeltaMAP; p < 0.05). This finding suggests that NO plays a significant role in maintaining basal blood pressure in Cu-adequate rats that is impaired by Cu deficiency. Copyright (C) 2002 S. Karger AG, Basel.