Effect of losartan and benazepril on mesenteric arteries in spontaneously hypertension rats

Abstract

The aim of this study is to investigate the effect of losartan, benazepril on vasomotion function of mesenteric arteries in spontaneously hypertensive rats. 16 wks male SHR were treated for 16 weeks with losartan (10 mg · kg−1 · d−1), benazepril (10 mg · kg−1 · d−1) and the combination of these two agents (10 mg · kg−1 · d−1 losartan, 10 mg · kg−1 · d−1 benazepril), respectively. Sex- and age-matched SHR and WKY served as controls. Vascular reactivity to vasoactive substances was studied with isolated rings of mesenteric arteries from rats. SHR was characterized by a decreased endothelium-dependent relaxation in response to ACh. Both concomitant and alone treatment of losartan, benazeptil increased the relaxation sensitivity to ACh. Effect of concomitant treatment on relaxation sensitivity to ACh was similar to that in losartan group, and was more significant than benazepril alone (pD2: SHR-L: 7.28 ± 0.26, SHR-BL: 7.48 ± 0.70 VS SHR-B: 6.32 ± 0.62 P < 0.05). ACh also caused remarked endothelium-dependent contraction in SHR mesenteric arteries compared with WKY, which was augmented by inhibitors of NO-syntheses L-NAME. At the present of L-NAME, ACh-induced endothelium-dependent contraction was similarly inhibited by the three therapies (Cmax: SHR-BL: 2.00 ± 0.49, SHR-B: 2.42 ± 1.64, SHR-L: 2.67 ± 1.94 VS SHR-C: 6.18 ± 1.12 P < 0.05). SNP-induced endothelium-independent relaxation was impaired, which was completely normalized by the treatment of either losartan, benazepril or their concomitant. These results indicate that the treatment of losartan and benazepril had effects on meliorated the endothelial dysfunction in mesenteric arteries rings from SHR. The effect of concomittant treatment is more effective or equivalent to the treatment of each alone.