Neurotrophins and specific receptors in the oviduct tracts of Japanese quail (Coturnix coturnix japonica)

Neurotrophins (NGF, BDNF and NT-3) and their specific receptors (TrkA, TrkB and TrkC) were studied in the oviduct of egg laying quails. Neurotrophins (NTs) are mainly involved in the development and maintenance of neuronal populations in the central and peripheral nervous system, but also in reproductive system. In this survey, we first studied the morphological organization of the quail oviduct, distinguished in infundibulum, magnum, isthmus, uterus and vagina, and then we analyzed the expression and localization of NTs and Trks receptors in the whole tracts. By western blotting we detected that the investigated NTs and Trks receptors are expressed in all oviductal tracts. By immunohistochemistry we were able to define the distribution of NTs and Trks. Specifically, NGF, BDNF and NT3 were localized in lining and ductal epithelial cells, and NGF was also detected in secretory cells of tubular glands and in nervous fibers of vessel wall. TrkA and TrkB were present in the lining and ductal epithelium; TrkA and TrkC were present in nervous fibers of vessel wall in all oviductal tracts. Furthermore, we also observed NGF and BDNF co-localized with TrkA and TrkB in cells of the lining and ductal epithelium, suggesting an autocrine mechanism of action.