International Urogynecology Journal

, Volume 23, Issue 11, pp 1631–1636 | Cite as

Paraurethral striated muscular structures and pelvic floor muscles contribute to resting urethral closure pressure in rats

  • Hung-Yen Chin
  • Kuan-Cheng Lin
  • Chin-Jung Wang
  • Chi-Hsin Chiang
  • Hann-Chorng KuoEmail author
Original Article


Introduction and hypothesis

We investigated physiological functions of the extraordinary muscular structure in the paraurethral area with pelvic floor muscle and the impact of these muscular structures on the resting maximal urethral closure pressure (MUCP) in rats.


Sixteen female Wister rats were divided into four groups: Groups I and II rats received 5 and 2.5 IU botulinum toxin A (BoNT-A), respectively, injected into the bilateral paraurethral striated muscles. Group III rats received 2.5 IU BoNT-A injected into the bilateral pelvic floor muscles, and group IV rats received 2.5 IU BoNT-A injected into the unilateral pelvic floor muscles. Measurements of MUCP were made at different time points after BoNT-A injection.


All groups showed a rapid reduction in average MUCP by 70–80 % after BoNT-A injection, regardless of injection site or side.


Paraurethral striated muscular structures and the pelvic floor muscles possess the function of maintaining resting MUCP in rats.


Botulinum toxin Maximal urethral closure pressure Pelvic floor Striated muscle Urethra Urethral rhabdosphincter Urethral sphincter 



This study was supported by the Medical Research Project (CMRPG 290231) in Chang Gung Memorial Hospital at Keelung and its laboratory animal center. This animal study was granted approval by the Institutional Animal Care and Use Committee (IACUC) at Chang Gung Memorial Hospital. The authors thank Ms. Yang, Hsiu Ping for her contribution working in the laboratory.

Conflicts of interest



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Copyright information

© The International Urogynecological Association 2012

Authors and Affiliations

  • Hung-Yen Chin
    • 1
  • Kuan-Cheng Lin
    • 2
  • Chin-Jung Wang
    • 3
  • Chi-Hsin Chiang
    • 4
  • Hann-Chorng Kuo
    • 5
    Email author
  1. 1.Department of Obstetrics & GynecologyTaipei Country Hospital, Chang Gung Memorial Hospital at Keelung and Chang Gung University College of MedicineTaipeiRepublic of China
  2. 2.Department of Management Information SystemsNational Chung Hsing UniversityTaichungRepublic of China
  3. 3.Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital at LinkouChang Gung University College of MedicineTaoyuanRepublic of China
  4. 4.Department of Obstetrics and GynecologyChang Gung Memorial Hospital at KeelungKeelungRepublic of China
  5. 5.Department of UrologyBuddhist Tzu Chi General Hospital and Tzu Chi UniversityHualienRepublic of China

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