Fig. 4.

NDHP-mediated vasorelaxation and the role of nitric oxide. Concentration-response curves were induced by cumulative addition of NDHP (10^–12–10⁻³ M) in PHE-precontracted (10 μM) superior mesenteric artery rings. Panel A shows NDHP inducing concentration-dependent vasorelaxation in both, intact and denuded-endothelium vessel segments (*p < 0.05 versus intact endothelium. Panel B shows the effect of NOS inhibition by L-NAME in intact-endothelium vessel segments (*p < 0.05 comparing to intact-endothelium control segments). Panel C shows the effect of NO scavenger PTIO alone or in combination with HDX in NDHP inducing vasorelaxation (*p < 0.05 for denuded-endothelium pretreated with PTIO + HDX versus denuded-endothelium control). Padel D shows the effect of sGC inhibitor ODQ in the vasorelaxation elicit NDHP (*p < 0.05 versus denuded-endothelium). Data are shown as mean ± SEM. n = 6–8 per group.