Visceromotor responses (VMR) from urinary bladder distension (UBD).

(A) Schematic of UBD setup. Compressed air is delivered into bladder via urethral catheter. During distensions, electrodes in abdominal muscle record EMG. Temperature is maintained throughout the procedure using a battery operated heating pad and overhead lamp. (B) Example EMG traces during UBD. As pressure increases, electrical output from abdominal muscles increases congruently. (C) Example VMR from one complete set of distensions. During each set, the bladder is distended three times at each pressure. VMRs are normalized with 20 s pre-distension interval then averaged for each pressure.