Endothelium-dependent vasodilation in isolated small mesenteric arterioles from rats fed either Chow, HSD, or HFD ( n = 6-8 per group). Vasodilatory responses to acetylcholine were measured in pre-constricted arteries (50% of resting inner diameter). There were no significant differences in pre-constricted diameters between, or within, groups (Table 2). Compared to Chow fed controls, arteries from HSD and HFD rats exhibited significantly attenuated vasodilation. Data are expressed as means ± SEM. *p ≤ 0.05 vs. Chow controls.