Erectile function in two-kidney, one-clip hypertensive rats is maintained by a potential increase in nitric oxide production.

Abstract

Introduction - Hypertension is closely associated with erectile dysfunction (ED) as it has been observed in many experimental models of hypertension. Additionally, epidemiological studies show that approximately a third of the hypertensive patients have ED. Aim—To test the hypothesis that the two-kidney one-clip (2K-1C) rat model of hypertension displays normal erectile function due to increased nitric oxide (NO) production in the penis. Methods—Ganglionic-induced increase in intracavernosal pressure (ICP)/mean arterial pressure (MAP) ratio was used as an index of erectile function in 2K-1C and in normotensive shamoperated (SHAM) anesthetized rats. Cavernosal strips from hypertensive and normotensive rats were used for isometric tension measurement. The contraction induced by alpha-adrenergic agonist phenylephrine, and the relaxation induced by the nitric oxide (NO) donor sodium nitroprusside (SNP) and by the Rho-kinase inhibitor Y-27632 were performed in the absence and in the presence of the nitric oxide synthase (NOS) inhibitor L-NNA. Results—Changes in ICP/MAP induced by ganglionic stimulation were not different between 2K-1C and SHAM rats. The contractile response induced by phenylephrine as well as the relaxation induced by SNP or the Y-27632 were similar in cavernosal strips from both groups. However, in the presence of L-NNA, the relaxation induced by Y-27632 was significantly impaired in 2K-1C compared to SHAM). Conclusions—These data suggest that hypertension and ED could be dissociated from high levels of blood pressure in some animal models of hypertension. Erectile function in 2K-1C hypertensive rats is maintained in spite of the increased Rho-kinase activity by increased NO signaling.