Figure 5

Vascular reactivity across TAA, TDA and AIA aortic segments. (A) Contraction was assessed via concentration–response stimulation with phenylephrine (a₁-adrenoceptor). Significant (p < 0.05) regional differences were present. (B) L-NAME was added to PE to evaluate the effect of (basal) NO on PE contraction. (C) AIA had significantly lower NO compared to TAA (p < 0.01) and TDA (p < 0.05). (D, E) EC-dependent relaxation was assessed via a concentration–response curve for ACh and ATP. AIA showed markedly smaller (ACh) or even absent (ATP) relaxations. (F) Endothelium-independent vasorelaxation studied by a concentration–response stimulation with DEANO, revealed no regional differences. Statistical analyses: One-way ANOVA with Sidak post hoc test for multiple comparisons (B, C). Two-way ANOVA, repeated measures with Sidak post-hoc test for multiple comparisons (A, D–F). *p < 0.05; **p < 0.01; ****p < 0.0001. n = 6 per group. TAA Thoracic ascending aorta, TDA Thoracic descending aorta, AIA Abdominal infrarenal aorta, PE phenylephrine, ACh acetylcholine, L-NAME L-NG-Nitro arginine methyl ester, NO nitric oxide, ATP Adenosine-5′-triphosphate, DEANO 2-(N,N-diethylamino)-diazenolate-2-oxide sodium salt hydrate.