Fig. 2. The baseline control (x) diameters (μm), and diameters after the 30-min test infusion (•) of nitroprusside (n = 8) or nitroglycerin (n = 8). Diameters are shown for (  A ) the feed and (  B ) branch arterioles at the first, third, and last branch points, as shown in  figure 1 . *Differs from control.