Origin of neurons supplying the vas deferens of the rat.

Retrograde axonal tracing methods using Fluoro-Gold were used to examine the neuronal input to the vas deferens in the adult Wistar rat. The greatest number of labelled efferent neurons were found in the ipsilateral pelvic accessory ganglion (PAG) (68%) and the major pelvic ganglion (MPG) (15%). Fewer than 3% of labelled neurons were localized to the inferior mesenteric and sympathetic chain ganglia. Labelled neurons were also located in the ipsilateral L1, L2, and L6, S1 dorsal root ganglia (DRG), corresponding to afferents that travel in the hypogastric and pelvic nerves, respectively. Contributions from contralateral neurons in the PAG, MPG and L1 DRG were also documented. The role of afferents supplying the vas deferens is not known but they may relay nociceptive or mechanoreceptive input. Efferent input from peripheral ganglia probably contributes to contractility of the vas deferens based on previous investigations.