Fig. 7.
NDHP does not induce tolerance in mesenteric arteries. Panels A and C show concentration-response curves for GTN and NDHP (10–12–10−3 mol/L), respectively, in endothelium-denuded superior mesenteric arteries from rats. GTN induced a concentration-dependent vasorelaxation in arterial rings (A). When the ring vessels were pre-treated for 30 min in GTN (100 µM), the potency (pD2) and maximum relaxation effects (Emax) were significantly reduced (B). Conversely, NDHP pretreatment induced no significant changes either pD2 or Emax (D) suggesting that in opposition to GTN, NDHP is not subjected to development of tolerance in mesenteric arteries. N = 6–7 per group. N.S. = non-significant. Data are shown as mean ± S.E.M.