Repeat periods of electrical stimulation prolong the modulation of the micturition reflex in the rat

AimsMethodsThe aim of this study was to determine if the duration of the micturition reflex modulation could be prolonged by repeated periods of afferent stimulation in the decorticated rat. Eighteen female Sprague-Dawley rats were used for the study, 10 for intravesical electrical stimulation (IVES), and 8 for Ano-genital pudendal afferents stimulation. Repeated constant flow cystometries were performed with body-warm saline (0.06-0.1mL/min) at about 10min interval. The selected afferents were stimulated continuously for 5min at maximal intensity. The same stimulation was repeated six times with a pause of 5min between the stimulations. The mean threshold volume of cystometries performed during one hour before and each hour after the stimulation were compared. ResultsConclusionsAfter six periods of IVES, the micturition threshold volume decreased to its lowest value (62% of control) during the first hour and remained at 80% 4h later (n=10, P<0.01). Ano-genital afferent stimulation produced a corresponding increase in the micturition threshold volume. The long-lasting poststimulation effect was again observed for more than 5h. During the first hour the mean threshold volume increased to 211% of controls and it remained at about this level for the entire observation period (n=8, P<0.01). Repeated short periods of stimulation prolonged the modulatory effect well beyond the stimulation period. The findings provide experimental evidence supporting the clinical application of IVES and ano-genital stimulation for treatment of neurogenic urinary bladder dysfunction.