Affiliations: Center for Applied Microcirculatory Research, University of Louisville School of Medicine, Louisville, KY 40292, USA | Food Science and Human Nutrition Department, University of Florida, Gainesville, FL 32611, USA | USDA**, ARS, Grand Forks Human Nutrition Research Center, Grand Forks, ND 58202, USA | Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, KY 40292, USA
Note: [] Correspondence to: Dale A. Schuschke, PhD, Center for Applied Microcirculatory Research, Health Sciences Center A1111, University of Louisville, Louisville, KY 40292, USA. Tel.: +1 502 852 7553; Fax: +1 502 852 7215; E‐mail: DASCHU01 @gwise.LOUISVILLE.EDU.
Abstract: Dietary copper deficiency has been shown to significantly reduce acetylcholine (Ach)‐induced vascular smooth muscle relaxation. The current study was designed to examine the relative relationship between dietary copper and the vasodilator response to Ach in the microcirculation of the rat. Male weanling rats were fed a purified basal diet supplemented with 6.0, 3.0, 1.5 or 0.0 \mug Cu/g diet for 4 weeks to provide an adequate, two marginal, and deficient intakes of dietary copper. Arteriole dilation in response to increasing concentrations of acetylcholine (10^{-7} to 10^{-4} M) was measured in the in vivo cremaster muscle microcirculation for each dietary group. Liver copper and both aortic and erythrocyte Cu,Zn‐SOD activity were used as indices of systemic copper status. Dilation to the increasing concentrations of Ach was only different in the 0 \mug Cu supplemented group compared to the copper‐adequate control values. However, the combined results showed an exponential increase in 10^{-5} M Ach‐induced vasodilation as liver copper concentration increases from 0 \mug Cu/g dry wt. This relationship suggests that dilation is attenuated at liver Cu concentrations below 5 \mug/g dry wt. The results indicate that Ach‐induced vasodilation is copper‐dependent but that the pathway is not very sensitive to short‐term marginal restriction of copper intake.
Keywords: Acetylcholine, copper, microcirculation, super oxide dismutase, vasodilation
Journal: Biofactors, vol. 10, no. 4, pp. 321-327, 1999
