Figure 4. Comparison of effects of carbon monoxide-induced relaxation of endothelium denuded rat aortic rings contracted with 10^-8M and 2 x 10^-8M norepinephrine in the presence of halothane with rings contracted with the same concentrations of norepinephrine in the absence of halothane. (A) Rings contracted with 10^-8M norepinephrine. (B) Rings contracted with 2 x 10^-8M norepinephrine. Values are means +/-SEM. *Significant difference from preanesthetic treatment. P < 0.05, and n = 5 - 8.