Representative synchrotron radiation angiogram of the coronary vasculature in control and diabetic rats showing segmental constrictions. Baseline lactate infusion (A &B), ACh infusion (C &D; 3.0 μg/kg/min), following administration of L-NAME (10 mg/kg iv. bolus) and meclofenamate ( combined, E &F; 2 mg/kg iv. bolus) and subsequent combined + fasudil treatment (G &H; 10 mg/kg iv). A &B, Baseline response to lactate infusion. C &D, Control and diabetic, large vessels maintained vessel ID greater than baseline (black asterisks). E, Control, vessel ID maintained. F, Diabetic segmental vasoconstriction (white arrow). G, Control, vessel ID maintained. H, Vasodilation of medium and small arteries (black arrows) and recruitment of newly visualised small arteries and arterioles relative to baseline (arrowheads). ‘w’ is a 50 μm tungsten wire for vessel ID determination.