Effects of different inhibitors and endothelium removal on the H2O2-induced responses.

Effects of various treatments on the diameter of isolated, cannulated, pressurized (80 mmHg) arterioles of the rat. The tissue sources of the arteriolar beds are indicated (coronary arterioles or skeletal muscle arterioles). Diameters are shown as means±S.E.M. in absolute values (µm). The number of experiments performed is also indicated. Arteriolar diameters are shown at the beginning of the experiments (initial diameter) and after treatment with 100 µM (maximum constrictor dose in the control) or 10 mM (maximum dilator dose in the control) H2O2. The effects of preincubations with the inhibitors (diameter after the inhibitor) and the maximum diameter of the vessels (passive diameter) are also shown. Significant effects of the treatments on the arteriolar diameters are indicated by asterisks (paired t-test relative to the initial diameter).