A mechanism of retrograde ejaculation after bilateral hypogastric nerve transections in the dog.

To pursue the mechanism of retrograde ejaculation after bilateral hypogastric nerve transections, the disability of the lumbosacral sympathetic trunk and the spermatic nerve to compensate bladder neck closure was investigated while both act as compensatory pathways for seminal emission. Five mongrel dogs were used for each experiment. By manual penis-stimulation, all dogs showed only retrograde ejaculation one month and six months after transection of bilateral hypogastric nerves. Bladder neck closure did not occur by electrical stimulation of either the lumbosacral sympathetic trunk or the spermatic nerve before and one month after transection of bilateral hypogastric nerves in all dogs examined and persistent relaxation of bladder neck was observed one and six months after transection of bilateral hypogastric nerves. The present results and our previous data indicate that retrograde ejaculation after bilateral hypogastric nerve transections is attributable to the absence of effective compensatory sympathetic pathways for bladder neck closure under the recovery of seminal emission by compensatory pathways.