Skip to main content
ARS Home » Plains Area » Grand Forks, North Dakota » Grand Forks Human Nutrition Research Center » Healthy Body Weight Research » Research » Publications at this Location » Publication #160799
Title: VASOREACTIVITY IN AN ADULT RAT MODEL OF MARGINAL COPPER DEFICIENCY

Author
item FALCONE, JEFF - UNIV OF LOUISVILLE
item Saari, Jack
item KANG, Y - UNIV OF LOUISVILLE
item SCHUSCHKE, DALE - UNIV OF LOUISVILLE

Submitted to: Nutrition Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/5/2004
Publication Date: 2/1/2005
Citation: Falcone, J.C., Saari, J.T., Kang, Y.J., Schuschke, D.A. 2005. Vasoreactivity in an adult rat model of marginal copper deficiency. Nutrition Research. 25:;177-186.

Interpretive Summary: Changes in the diameter of blood vessels affect blood flow to the tissues they serve and also influence blood pressure. The ability of blood vessels to increase in diameter is impaired in dietary copper deficiency, which may reduce blood flow to tissues or cause high blood pressure. Previous studies have only observed this effect in severe dietary copper deficiency in young animals. The purpose of the present study was to examine dilation of blood vessels in adult rats fed copper at marginal versus adequate levels. We found that dilation of blood vessels of adult rats fed test diets for six months did not vary when comparisons between diets were made or when dilation was compared at different levels of liver copper. However, when dilation was compared at varying levels of kidney copper, an apparently more sensitive indicator of copper status, dilation to a particular dilator, acetylcholine, was found to vary significantly with copper status. This confirms that dilation of blood vessels is impaired in adult animals fed marginal levels of copper, as it is in young animals fed severely-deficient amounts of copper, but that a more sensitive indicator of copper status, e.g., kidney copper, must be used to make comparisons in adult animals. These findings are important because they indicate that dietary conditions likely to be met by humans, i.e., marginal as opposed to severe copper deficiency, have the potential to affect an important aspect of cardiovascular function.

Technical Abstract: Short-term 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 copper to vasoreactivity. Male adult rats were fed a purified basal diet supplemented with adequate (6.0), or marginal (3.0 or 1.5 µg Cu/g) diet for 6 mos. Luminal diameter changes were measured in isolated resistance arterioles from the cremaster muscle. Liver and kidney Cu concentrations were used as indices of copper status. The results showed a significant decrease in kidney Cu in the 1.5 µg group compared to the adequate controls but no effect on liver Cu. There was a significant correlation between dilation to 10**-6 M Ach and kidney Cu but no relationship between Cu status and 10**-5 M 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 copper status in a mature long-term model of marginal copper deficiency. The results may have important implications for blood pressure regulation during extended suboptimal copper intake.