Murine and rat cavernosal responses to endothelin-1 and urotensin-II Vasoactive Peptide Symposium

• Published in: Journal of the American Society of Hypertension Vol. 2; no. 6; pp. 439 - 447
• Main Authors: Carneiro, Fernando S., MSc, Carneiro, Zidonia N, Giachini, Fernanda R.C., MSc, Lima, Victor V., BSc, Nogueira, Edson F., MD, Rainey, William E., PhD, Tostes, Rita C., PhD, Webb, R. Clinton, PhD
• Format: Journal Article
• Language: English
• Published: United States 01.11.2008
• Subjects: Cardiovascular; DOCA-salt hypertension; ET A receptor; erectile dysfunction; corpus cavernosum
• DOI: 10.1016/j.jash.2008.07.001
• ISSN: 1933-1711; 1878-7436

Abstract Endothelin-1 (ET-1) and urotensin-II (U-II) are the most potent constrictors of human vessels. Although the cavernosal tissue is highly responsive to ET-1, no information exists on the effects of U-II on cavernosal function. The aim of this study was to characterize ET-1 and U-II responses in corpora cavernosa from rats and mice. Male Wistar rats and C57/BL6 mice were used at 13 weeks. Cumulative concentration-response curves to ET-1, U-II, and IRL-1620, an ETB agonist, were performed. ET-1 increased force generation in cavernosal strips from mice and rats, but no response to U-II was observed in the presence or absence of Nω -nitro-L-arginine methyl ester (L-NAME), or in strips prestimulated with 20 mM KCl. IRL-1620 did not induce cavernosal contraction even in presence of L-NAME, but induced a cavernosal relaxation that was greater in rats than mice. No relaxation responses to U-II were observed in cavernosal strips precontracted with phenylephrine. mRNA expression of ET-1, ETA , ETB , and U-II receptors, but not U-II was observed in cavernosal strips. ET-1, via ETA receptors activation, causes contractile responses in cavernosal strips from rats and mice, whereas ETB receptor activation produces relaxation. Although the cavernosal tissue expresses U-II receptors, U-II does not induce contractile responses in corpora cavernosa from mice or rats.