Effects of unilateral pelvic ganglionectomy on urinary bladder function in the male rat

Micturition interval and micturition volume were measured in water loaded male rats before and up to 6 weeks after unilateral pelvic ganglionectomy. There was no effect on micturition interval until 7 days after the ganglionectomy. Micturition interval then remained increased. Maximal micturition volume was higher than in the control group from 4 to 14 days after surgery. Cystometrograms were recorded 12 days or 6 weeks after surgery. At 12 days the micturition pressure was lower in the unilaterally ganglionectomized than in the controls. After 6 weeks there was no significant difference in micturition pressure. A reduction of micturition pressure by about 50% was observed after i.v. injection of atropine, but no residual urine developed. Electron microscope investigation showed a considerable decrease in number of nerve terminals on the ganglionectomized side 3 days after surgery. Most of them were devoid of synaptic vesicles. On the contralateral side the majority of nerve terminals appeared normal, but many had a decreased number of vesicles. After 14 days the number of terminals was still lower than normal on the ganglionectomized side. They generally contained only a small number of vesicles. Also, on the contralateral side some nerve endings with the reduced complement of vesicles were found. We suggest that the effects of unilateral ganglionectomy on micturition volume and interval can be explained by a decreased sensory input from the bladder and that the effect on micturition pressure is due to a transient decrease in number and function of motor nerve terminals in the detrusor muscle.