Role of the pelvic nerve in the dynamics of micturition in the decerebrate dog as determined by suprapubic endoscopical and urodynamic evaluation.

The role of the pelvic nerves on the dynamics of micturition was evaluated in 13 decerebrate dogs, four male and nine female, by direct observation of bladder movement, by suprapubic cystoscopic observation of urethral behavior, and by pressure flow EMG studies. Experiments were performed before and after unilateral pelvic nerve transection. In control conditions and after unilateral pelvic nerve transection, the bladder neck was not tightly closed during the collecting phase, the membranous portion of the urethra opened and closed spasmodically during the emptying phase, and reflex micturition developed. Direct observation showed that after unilateral pelvic nerve transection, the ipsilateral bladder did not contract. A pressure flow EMG study showed that unilateral pelvic nerve transection produced a significant increase in threshold volume, threshold pressure, bladder compliance and residual volume, and a significant decrease in contraction pressure and flow rate. The present study shows that unilateral pelvic nerve transection has no demonstrable effect on urethral function, but has effects on bladder function during the collecting and emptying phases and that bladder innervation is unilateral in the dog.