title: Murine and rat cavernosal responses to endothelin-1 and urotensin-II Vasoactive Peptide Symposium.
abstract: BACKGROUND: Endothelin-1 (ET-1) and urotensin-II (U-II) are the most potent constrictors of human vessels. Although the cavernosal tissue is higly 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. METHODS AND RESULTS: 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 ET(B) 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 L-NAME, or in strips pre-stimulated with 20mM KCl. IRL-1620 did not induce cavernosal contraction even in presence of L-NAME, but induced a cavernosal relaxation which was greater in rats than mice. No relaxation responses to U-II were observed in cavernosal strips pre-contracted with phenylephrine. mRNA expression of ET-1, ET(A), ET(B) and U-II receptors, but not U-II was observed in cavernosal strips. CONCLUSION: ET-1, via ET(A) receptors activation, causes contractile responses in cavernosal strips from rats and mice whereas ET(B) 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.
authors.affiliation: Medical College of Georgia, Department of Physiology, Augusta, GA, USA.
authors.forename: Fernando S
authors.initials: FS
authors.lastname: Carneiro
authors.forename: Zidonia N
authors.initials: ZN
authors.lastname: Carneiro
authors.forename: Fernanda R C
authors.initials: FR
authors.lastname: Giachini
authors.forename: Victor V
authors.initials: VV
authors.lastname: Lima
authors.forename: Edson
authors.initials: E
authors.lastname: Nogueira
authors.forename: William E
authors.initials: WE
authors.lastname: Rainey
authors.forename: Rita C
authors.initials: RC
authors.lastname: Tostes
authors.forename: R Clinton
authors.initials: RC
authors.lastname: Webb