The role of the vomeronasal organ (VNO) as the pheromone detection system in rats was first demonstrated by Johns, et al. These findings have been confirmed, and generalized to other mammals.
The human VNO was discovered by Ruysch in 1703. Since that time there have been many reports; some confirm Ruysch, while others state that in adult humans theVNO is nonexistent, vestigial or atrophic. It is only recently that several different research groups, using more extensive investigations, have established unequivocally that the VNO is present in all normal humans from neonates to adults. In addition. histochemical techniques using specific neuronal markers have demonstrated the presence of neuroepithelial cells in the human VN0. The bilateral location of the vomeronasal organ in the human nose (Figure 1) ensures access to substances present in inspired air.
The functional nature of the human VNO was described in 1991. Substances present in human skin were found to activate the human VNO in a species-specific and sexually dimorphic fashion. Thus our “sixth sense” is actually a real sensory system providing us with another window on the world.