FIG. 4.

Effect of pre-infusion of vasodilators on hemoglobin-induced vasoconstriction. (A) Experimental timeline. Rats were stabilized for 30 min after surgery, and blood gases were drawn as indicated (BG1 and BG2). After determining a baseline (BL), vasodilators were infused, followed by infusion of purified human hemoglobin (8.1 mM) until an end concentration of 175 mg/kg was reached. MAP at T=15, 30, and 45 min after hemoglobin infusion is displayed. (B) Effect of pre-infusion with Ringer's (n=6) (–), SNP (0.4 μg/kg/min, n=7) (–), or sildenafil (10 μg/kg/min, n=8) (–) and bolus administration of BAY 41-8543 (10 μg/kg, n=8) (–) and BAY 60-2770 (1 μg/kg, n=9) (–) on basal MAP and peak MAP after infusion of hemoglobin. *Significantly different (p<0.05) from Ringer's by two-way ANOVA with Bonferroni correction. (C) Area under the curve (AUC) values from the graphs in Fig. A expressed as percentage from Ringer's values. *Significantly different (p<0.001) from Ringer's by one-way ANOVA with Bonferroni correction. SNP, sodium nitroprusside. To see this illustration in color, the reader is referred to the web version of this article at www.liebertpub.com/ars