Innervation of the chinchilla testis, epididymis, and vas deferens

The study was performed on six male chinchillas. The animals were anaesthetised with ether and the anaesthesia was deepened with nembuthal injected intraperitoneally. The chinchillas were then transcardially perfused with 0.4 L of 4% buffered paraformaldehyde, and testes, epididymides, and vasa deferentia were collected. The tunica albuginea from one testis from each chinchilla was stained as whole-mount preparation. The tissues were cut into 12 μm-thick cryostat sections, and processed for double-immunofluorescence method. In all organs studied, the most abundant nerve fibres were dopamine β hydroxylase positive (DβH⁺). Some of them contained neuropeptide Y (NPY). Sporadically NPY-positive-only nerve fibres were found. Single DβH⁺ nerve terminals contained also galanine. Small numbers of the nerve fibres supplying studied organs were stained for substance P (SP) and calitonin gene related peptide (CGRP). Almost all SP⁺ fibres were also CGRP⁺, whereas single CGRP⁺ nerves were SPimmunonegative. Some nerve terminals were immunoreactive to vesicular acetylcholine transporter and vasoactive intestinal peptide. The organs studied were innervated unevenly. The highest density of the nerves was found in the areas of the tunica albuginea adjacent to the mesorchial border of the testis and their number gradually decreased towards the free border of the gonad. None of the vascular tissue of the testicular parenchyma was free of the nerve fibres, except sporadically encountered DβH⁺ nerves which supply seminiferous tubules. Within the head of the epididymis a moderate number of nerve terminals were found, but in the body and tail of the organ the number of nerves gradually increased. The vas deferens was supplied with very numerous nerve fibres. There were no differences in the density of the innervation between the funicular and abdominal part of the vas deferens.