Evidence for the innervation of sperm storage tubules in the oviduct of the turkey (Meleagris gallopavo).

The presence of neural tissue and smooth muscle elements in the vicinity of the oviductal sperm storage tubules at the uterovaginal junction was assessed by several modes of light microscopy. Isolated neurones and small ganglia were identified in the uterovaginal junction of the turkey oviduct. The nerve cell bodies were observed in the tunica mucosa by bright field microscopy. Immunoreactivity against neurofilament antibody and recombinant fragment C of the tetanus toxin reacted with nerve fibres and the nuclei of neurones. Fluorescence microscopy and confocal laser scanning microscopy revealed that nerve fibres continued from the base of the tunica mucosa into the plicae. Axons appeared to terminate on, or run immediately adjacent to, individual sperm storage tubules. Neither phalloidin reacting with F-actin nor the monoclonal antibody against alpha-smooth muscle actin detected smooth muscle fibres in the tissue encapsulating individual sperm storage tubules. In contrast, F-actin was strongly localized in the apical region of the epithelial cells of the sperm storage tubule and in smooth muscle elements in the tunica mucosa and tunica muscularis. These observations present the first evidence for the innervation of the sperm storage tubules. It is suggested that a previously unrecognized neural factor may function in oviductal sperm storage in, and release of spermatozoa from, the sperm storage tubules of hens.