Percent changes in diameter of gracilis muscle arterioles in response to cumulative concentration of histamine (1 nmol/L–10 μmol/L, Panels A, C and E) and acetylcholine (ACh, 1 nmol/L–1 μmol/L, Panels B, D and F) in the presence of normal (5.5 mmol/L) or high glucose concentrations (30 mmol/L) and in the absence or in the presence of NO synthase inhibitor L-NAME (100 μM). Data are in means ± S.E.M, significant differences: * P≤0.05.