Ureteral function is modulated by a local XXXX -angiotensin system.

@entity1 @entity1707 @entity2178 @entity9886 @entity916
PURPOSE: Although many aspects of ureteral physiology are well characterized, the exact mechanism of ureteral smooth muscle modulation has not been fully established. In other smooth muscle contractility is modulated by @entity2178 ( @entity2178 ). We determined the presence of a local ureteral @entity916 -angiotensin system and characterized the functional role of @entity2178 in ureteral smooth muscle. MATERIALS AND METHODS: Reverse transcriptase-polymerase chain reaction was performed to determine the expression of @entity2178 , @entity916 , angiotensin-converting enzyme and angiotensin receptor subtype 1 mRNA. The presence of @entity2178 in ureteral tissue was determined by immunohistochemistry. @entity1 and @entity1707 ureteral smooth muscle strips were suspended in tissue baths to determine the effect of the @entity2178 receptor antagonist @entity9886 on the frequency and amplitude of spontaneous ureteral contractions. Electrical field stimulation was performed before and after exposure to @entity9886 . RESULTS: @entity2178 , @entity916 , angiotensin-converting enzyme and angiotensin receptor subtype 1 mRNA expression was detected in @entity1 ureter. Immunoreactivity for @entity2178 was demonstrated in smooth muscle bundles and blood vessels of the ureter. @entity9886 decreased the amplitude and frequency of spontaneous ureteral contractions as well as the contractile response to electrical field stimulation in a dose dependent manner. CONCLUSIONS: Gene expression of @entity2178 precursors and receptor, and localization of @entity2178 in the ureter suggest the presence of a local @entity916 -angiotensin system in the ureter. The effect of @entity2178 receptor antagonist on contractile responses suggests that @entity2178 modulates ureteral smooth muscle contractile function. Therefore, a local @entity916 -angiotensin system may have an important role in ureteral function under physiological and pathological conditions.
