Region-specific differences in aortic mRNA abundance of AT1a and AT1b receptors.

<p>mRNA abundance of (<b>A</b>) AT1a receptors (N = 4) and (<b>B</b>) AT1b receptors (N = 4) in aortic regions of C57BL6/J mice. * denotes P<0.05 in supra-renal versus ascending and descending aortic regions (one way ANOVA with Holm-Sidak post hoc test). # denotes P<0.001 in the infra-renal region versus all the other aortic regions (one way ANOVA with Holm-Sidak post hoc test).</p

AT1b receptor deficiency had no effect on AngII-induced aortic arch and descending aortic dilation.

<p>Intimal area of (<b>A</b>) aortic arch region and (<b>B</b>) descending thoracic aorta was measured using an en face method (N = 16: AT1b receptor +/+, and N = 10: AT1b receptor −/− mice). Inverted triangles represent values from individual mice, circles represent means, and error bars are SEM.</p

AngII-induced regional contractions were markedly reduced by AT1b receptor deficiency.

<p>Regional contractility of aortic rings harvested from the infra-renal aorta of (<b>A</b>) C57BL/6, (B) AT1a receptor −/−, or (C) AT1b receptor −/− mice. Aortic rings were contracted during 5-minute incubation with potassium chloride (KCl; 80 mM), 5-hydroxytryptamine (5-HT; 1 µM), or Ang II (1 µM). Contractions are represented as percent of the maximal contraction achieved during incubation with KCl (80 mM). Red arrows indicate the return to normal Krebs–Henseleit solution.</p

AT1b receptor deficiency had no effect on AngII-induced abdominal aortic dilation in vivo.

<p>(<b>A</b>) Maximal luminal diameters of suprarenal aortas were measured in vivo by ultrasonography at baseline (Day 0) and on Day 28 during AngII infusion (N = 16: AT1b receptor +/+, and N = 10: AT1b receptor −/− mice). * denotes P<0.001 saline versus AngII within AT1b genotypes (two way repeated measures ANOVA). (<b>B</b>) Maximum width of supra-renal aortas was measured ex vivo (N = 16: AT1b receptor +/+, and N = 10: AT1b receptor −/− mice). Inverted triangles represent individual mice, circles represent means and error bars are SEM. (<b>C</b>) Examples of ultrasound images (Day 0 and Day 28) and ex vivo pictures (after termination) of suprarenal aortas, which represent aortic diameters nearest the mean of each group.</p

Characterization of AT1b receptor +/+ and −/− mice infused with AngII.

<p>Body weight, plasma cholesterol and renin concentrations were measured after termination. SBP was measured during the last week of the study. Values are represented as mean ± SEM. There were no significant differences between the two AT1b receptor genotypes.</p