Optimal conditions for the long-term modulation of the micturition reflex by intravesical electrical stimulation:: an experimental study in the rat

Objective To determine whether induced bladder contractions influence the modulation by intravesical electrical stimulation (IVES) of the micturition reflex in anaesthetized rats, and to identify the optimal IVES frequency and duration, Materials and methods Seventy-six adult female rats, anaesthetized by cc-chloralose, were divided into four groups to study the effect of: (i) IVES in combination with bladder contractions; (ii) bladder contractions alone; (iii) IVES frequency; and (iv) IVES duration, IVES was administered using a catheter electrode in the bladder. The effect of various IVES procedures was evaluated by determining the micturition threshold volume obtained from repeated cystometries before and after stimulation. Results Administering IVES with standard parameters induced a significant decrease in the micturition threshold volume for about an hour. There was no difference in outcome between IVES with the bladder filled and contracting during the stimulation or empty and not contracting. Imposed bladder contractions per se had no effect on the micturition threshold volume. IVES at low frequencies (less than or equal to 20Hz) had a better modulatory effect than higher frequencies and the optimum duration of IVES was 5 min. Conclusions Evoked bladder contractions did not improve the IVES-induced modulation of the micturition reflex. These findings might help to improve the clinical application of the IVES procedure.