Effect of periurethral denervation on function of the female urethra.
OBJECTIVE
The purpose of this study was to determine the effect of periurethral denervation on contractile function of the female rat urethra.


METHODS
Periurethral nerve transection or sham operation was performed in 16 young female rats. After 2 weeks, contractile function of the external urethra sphincter (EUS) and longitudinal smooth muscle was determined. Inhibitors of nitric oxide (NO) signaling were used to evaluate the role of nitric oxide in nerve-mediated relaxation. Statistical comparisons were conducted by Student t test.


RESULTS
Periurethral nerve transection resulted in gross evidence of urinary retention and bladder distention. In normal and sham-operated rats, nerve-mediated relaxation of urethral smooth muscle was inhibited by L-nitroarginine and oxadiazolo quinoxalin-1-one (ODQ), and this relaxation response was impaired significantly after periurethral nerve injury. Relaxation responses to the NO donor sodium nitroprusside remained intact. Contractile function of the EUS was not altered by periurethral nerve injury.


CONCLUSIONS
Neurons surrounding the urethra contain NO and innervate smooth muscle of the inner urethra. Periurethral denervation results in impaired urethral smooth muscle relaxation with no appreciable effect on contractility of the external striated sphincter.
Wai
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Division of Urogynecology and Reconstructive Pelvic Surgery, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, G6.220, Dallas, TX 75390-9032, USA. clifford.wai@utsouthwestern.edu
Liehr
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Tibbals
H F
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Sager
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M
Schaffer
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JI
Word
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RA
D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D009119:Muscle Contraction; D009121:Muscle Denervation / Q000009:adverse effects*; D009126:Muscle Relaxation; D009130:Muscle, Smooth / Q000502:physiology; D009482:Neurophysiology; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D014521:Urethra / Q000294:innervation* / Q000601:surgery*; D014549:Urinary Incontinence / Q000209:etiology* / Q000503:physiopathology