Effect of vesical contraction on the non-sphincteric part of the urethra: recognition of vesicourethral inhibitory reflex.
OBJECTIVE
The effect of vesical contraction on the non-sphincteric part of the urethra has been scarcely addressed in the literature. In this study, the hypothesis that detrusor contraction effects dilatation of the non-sphincteric part of the urethra was investigated.


METHODS
Non-sphincteric urethral pressure response to vesical balloon distension with normal saline in increments of 50 mL was recorded in 21 healthy volunteers (mean age 40.7 +/- 10.3 years, 13 men) before and after individual anesthetization of the urethra and urinary bladder. Vesical distension was effected by a 10F balloon-ended catheter introduced into bladder per urethram. Urethral and vesical pressures were measured by means of a two-channel microtip catheter.


RESULTS
Small-volume vesical distension effected no significant urethral or vesical pressure changes while distension with 350 and 400 mL of saline produced vesical pressure elevation (P < 0.01) and urethral pressure decrease (P < 0.01). Vesical distension after individual vesical and urethral anesthetization effected no change in the urethral pressure. These results were reproducible.


CONCLUSIONS
Dilatation of the non-sphincteric part of the urethra upon vesical contraction is suggested to be mediated through a 'vesicourethral inhibitory reflex' and to facilitate passage of urine through the urethra. The reflex may prove to be of diagnostic significance in micturition disorders.
Shafik
Ahmed
A
Department of Surgery, Faculty of Medicine, Cairo University, Cairo, Egypt. shafik@ahmed-shafik.org
Shafik
Ali A
AA
El-Sibai
Olfat
O
Ahmed
Ismail
I
D000328:Adult; D000779:Anesthetics, Local / Q000494:pharmacology; D002404:Catheterization; D005260:Female; D005782:Gels; D006801:Humans; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D008365:Manometry; D009119:Muscle Contraction / Q000502:physiology*; D012018:Reflex / Q000502:physiology*; D014521:Urethra / Q000187:drug effects / Q000294:innervation / Q000502:physiology*; D001743:Urinary Bladder / Q000187:drug effects / Q000294:innervation / Q000502:physiology*; D014563:Urodynamics / Q000502:physiology
D000779:Anesthetics, Local; D005782:Gels; D008012:Lidocaine