Study of the effect of external urethral sphincter contraction on the mechanical activity of the ureterovesical junction and urinary bladder: recognition of the sphinctero-ureterovesical reflex.
OBJECTIVE
To study the effect of external urethral sphincter (EUS) contraction on the urinary bladder and ureterovesical junction (UVJ).


METHODS
The study was comprised of 9 healthy volunteers (7 men, 2 women; mean age 40.8 +/- 6.6 years). A manometric catheter was introduced into each of the two UVJs and urinary bladder. The EUS was made to contract by voluntary squeezing and by electromyographic stimulation with a needle electrode inserted into the sphincter. The response of the bladder and the UVJs to EUS contraction was determined before and after anesthetization of the EUS, bladder, and the two UVJs, each at a different time.


RESULTS
On voluntary squeezing or electromyographic needle stimulation of the EUS, the pressure in both the UVJs and the urinary bladder showed a significant drop (P < 0.05 in both instances). There was no pressure response in the UVJs or in the urinary bladder 10 minutes after separate anesthetization of either the EUS or the UVJs and the bladder; however, 2 hours later, the pressure response was similar to that before anesthesia (P > 0.05).


CONCLUSIONS
Bladder and UVJ relaxation on EUS contraction postulate a reflex relationship that was reproducible and absent on anesthetization of either of the suggested two arms of the reflex: the EUS on one end and the bladder and UVJs on the other end. We call this reflex the "sphinctero-ureterovesical reflex." Further studies are needed to evaluate the possible role of this reflex in the micturition mechanism and disorders.
Shafik
A
A
Department of Surgery and Experimental Research, Faculty of Medicine, Cairo University, Egypt.
D000328:Adult; D000772:Anesthesia, Local; D004576:Electromyography / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008365:Manometry / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D008875:Middle Aged; D009119:Muscle Contraction; D009130:Muscle, Smooth / Q000502:physiology*; D012016:Reference Values; D012018:Reflex; D014513:Ureter / Q000502:physiology*; D014521:Urethra / Q000502:physiology*; D001743:Urinary Bladder / Q000502:physiology*; D014554:Urination; D014563:Urodynamics