Effects of periurethral neuromuscular electrical stimulation on the voiding frequency in rats.
OBJECTIVE
This study aims to test the hypothesis that a urethra-to-bladder inhibitory pathway exists through which periurethral neuromuscular electrical stimulation (NMES) inhibits overactive bladder contractions in rats.


METHODS
Bladder overactivity was induced in 22 female Sprague Dawley rats by injection of ketamine/xylazine/acepromizine (K/X/A). A bipolar electrode was placed surgically in the periurethral region to deliver NMES. Intravesical pressure, bladder inter-contraction interval (ICI) and voided volume (VV) were monitored while the bladder was continuously infused with saline.


RESULTS
K/X/A induced more frequent bladder contractions (ICI = 48.6 +/- 20.1 s, before cutting the pubo-symphasis) compared to a 10-min ICI induced by urethane. NMES significantly increased ICI (63.1 +/- 31.3 s before vs. 97.2 +/- 42.9 s after NMES, p < 0.001) and VV (0.063 = 0.041 ml before vs. 0.088 = 0.044 ml after NMES, p < 0.02).


CONCLUSIONS
Injection of K/X/A may potentially be used as a model of bladder overactivity. NMES inhibits bladder contractions in rats with bladder overactivity, which supports the existence of a urethra-to-bladder inhibitory pathway.
Zhang
Yingchun
Y
Department of Urologic Surgery, University of Minnesota, 748 Mayo Memorial Building, 420 Delaware Street S.E, Minneapolis, MN 55455, USA. zhang320@umn.edu
Bicek
Andrew D
AD
Wang
Guangjian
G
Timm
Gerald W
GW
D000818:Animals; D004599:Electric Stimulation Therapy; D005260:Female; D009130:Muscle, Smooth / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014521:Urethra / Q000294:innervation / Q000502:physiology; D053201:Urinary Bladder, Overactive / Q000628:therapy*; D014554:Urination