The innervation of the porcine testis was studied in 20 pigs, aged from 3 days to 2.5 years, and revealed remarkable changes in the period from birth to adulthood. Testes in piglets of 3 to 5 weeks have the most intense and most constant innervation, which reaches the gonad by three different routes: the funicular, caudal and mesorchial. Nerve fibers supply the vascular structures of the spermatic cord, the tunica albuginea, nearly all the septula testis and the mediastinum. Only exceptionally are axons in contact with Leydig cells. Nearly all the testicular nerves are positive for DBH and therefore represent postganglionic sympathetic axons. From their association with blood vessels it can be concluded that the majority of nerves are vasomotor in function. No cholinergic and myelinated fibers can be detected in the porcine testis. NPY-immunoreactive fibers are the dominating peptide-containing neuronal component. In the testes of 3- and 7-day-old piglets the degree of septal and mediastinal innervation is significantly smaller than in 3- to 5-week-old animals. In 7- to 10-week-old pigs, testicular innervation shows varying degrees of withdrawal, and the testes of adult boars are completely devoid of intrinsic nerves. Only the funicular nerves supplying the testicular artery and pampiniform plexus are preserved in the adult age group. So, the vasomotor control of intratunical, septal and mediastinal vessels and of the complete micro-circulation within the testicular parenchyma is effected without any direct nerve participation in the sexually mature boar.
Acetylcholinesterase Aging