Contractile properties of the denervated external anal sphincter.
OBJECTIVE
The purpose of this study was to evaluate the effect of denervation on contractile properties of the external anal sphincter (EAS) of the female rat.


METHODS
Sham operation, pudendal nerve transection, pelvic neurectomy, or combined pudendal nerve transection/pelvic neurectomy was performed in young female rats. Contractile function of the EAS was determined after 2 weeks.


RESULTS
Maximal force-generating capacity of the EAS was not impaired by bilateral pudendal denervation or pelvic neurectomy. Twitch tension, however, was decreased, and fatigability increased after pelvic neurectomy. Combined bilateral pudendal nerve-transection plus pelvic neurectomy resulted in compromised force-generating capacity, decreased twitch tension, and increased fatigability of the anal sphincter.


CONCLUSIONS
Subtle changes in EAS function are detectable after pelvic neurectomy, but not pudendal denervation. In contrast, combination pudendal and pelvic neurectomy resulted in severe compromise of EAS function. These data suggest that EAS function is relatively preserved unless injury occurs to > 1 source of innervation.
Wai
Clifford Y
CY
Division of Female Pelvic Medicine and Reconstructive Surgery, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
Word
R Ann
RA
D001003:Anal Canal / Q000294:innervation / Q000502:physiology*; D000818:Animals; D005260:Female; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000502:physiology*; D009121:Muscle Denervation; D051381:Rats; D017207:Rats, Sprague-Dawley