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ISRN Urology
Volume 2012 (2012), Article ID 312487, 7 pages
http://dx.doi.org/10.5402/2012/312487
Research Article

The Inhibition of Ureteral Motility by Periureteral Adipose Tissue

Health Sciences Centre, UCD School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland

Received 29 November 2011; Accepted 21 December 2011

Academic Editors: T. G. Kwon, J. E. Reeder, and V. Serretta

Copyright © 2012 Lyndsey M. Killian and Stuart J. Bund. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Perivascular adipose tissue exerts an anticontractile influence on vascular smooth muscle. This study was conducted to determine whether periureteral adipose tissue (PUAT) could exert a similar influence upon ureteral smooth muscle. Acetylcholine-stimulated (10−7 M–10−4 M) contractile responses of ureteral segments obtained from male Wistar rats were recorded in the presence and absence of PUAT. Ureters with PUAT generated phasic contractile responses with significantly lower frequencies ( 𝑃 < 0 . 0 0 1 ) and magnitudes ( 𝑃 < 0 . 0 0 1 ) compared with ureters cleared of their periureteral adipose tissue. Removal of PUAT significantly increased the frequency ( 𝑃 < 0 . 0 1 ) and magnitude ( 𝑃 < 0 . 0 1 ) of the contractile responses. Bioassay experiments demonstrated that ureters with PUAT released a transferable factor that significantly reduced frequencies ( 𝑃 < 0 . 0 5 ), but not magnitudes, of the contractile responses of ureters cleared of PUAT. The nitric oxide synthase inhibitor L-NNA (10−4 M) did not significantly influence the anticontractile effect exerted by ureters with PUAT. This is the first study to demonstrate that ureteral motility is influenced by its surrounding adipose tissue. The PUAT has an anticontractile effect which is mediated by a transferable factor released from the PUAT. The identity of the factor is unknown but does not exert its effect through nitric oxide.