Fourteen vomeronasal organs (VNOs) of adult males one-humped camels (Camelus dromedarius) and Egyptian water buffaloes (Bubalus bubalis) (n=7/each) were examined immunohistochemically with neuronal markers; synaptophysin (SYP) and glial fibrillary acidic protein (GFAP) to clarify the distribution of the vomeronasal (VN) receptor cells and nerve fibers, in addition to elucidate the existence of non-neuronal elements via S-100 and endothelial nitric oxide synthase (eNOS). In both animals, the VNO was lined medially with VN sensory (olfactory) epithelium and non-sensory (respiratory) epithelium laterally. Immunohistochemically, both animals showed SYP immunolabeling only in the receptor cells of VN sensory epithelium while GFAP labeled the ensheathing cells of the nerve fibers of VNOs. Both S-100 and eNOS labeled non-neuronal elements of the VNO; the supporting cells of sensory epithelium and the VN glands. In view of these observations, we postulate that the VNOs of both animals contain various cells populations that express several neuronal and non-neuronal markers. As well as, SYP and GFAP are suggested as markers for receptor cells and ensheathing cells of nerves of the VNOs respectively. However, no clear differences can be detected in the expressions of neuronal and non-neuronal markers in VNOs of camel and buffalo since they are ruminant species.
KEY WORDS: Vomeronasal organ; Camel; Buffalo; Immunohistochemistry.