Vasoreactivity in an adult rat model of marginal copper deficiency

Short-term severe copper deficiency has been shown to significantly reduce acetylcholine (Ach)-induced vascular smooth muscle relaxation. The current study was designed to examine the long-term relationship of marginal dietary Cu to vasoreactivity. Male adult rats were fed a purified diet with adequate (6.0 μg) or marginal (3.0 or 1.5 μg) Cu/g diet for 6 months. Luminal diameter changes were measured in isolated resistance arterioles. Liver and kidney Cu concentrations were used as indices of Cu status. The results showed a significant decrease in kidney Cu in the 1.5-μg group compared with the adequate controls but no effect on liver Cu. There was a significant correlation between dilation to 10−6 mol/L Ach and kidney Cu but no relationship between Cu status and 10−5 mol/L norepinephrine-induced constriction or flow-induced dilation. There was also no dietary effect on baseline vessel tone or dilator capacity. The data are the first to establish a linear relationship between Ach-induced vasodilation and systemic Cu status in a mature long-term model of marginal Cu deficiency.