Vomeronasal Epithelial Cells of Human Fetuses Contain Immunoreactivity for G Proteins, Goα and Giα2

Two G protein subfamilies, Go α and Gi α2 , were identified and localized immunohistochemically in the vomeronasal organ (VNO) of 5-month-old human fetuses. Immunoreactivity for Go α and Gi α2 was present in a subset of vomeronasal epithelial cells. Prominent immunoreactivity was observed in apical processes and their apical terminals facing onto the vomeronasal lumen. Nerve fibers associated with the VNO exhibited intense immunoreactivity for Go α and weak immunoreactivity for Gi α2 . Since Go α and Gi α2 are characteristically expressed and coupled with putative pheromone receptors in rodent vomeronasal receptor neurons, the present results suggest the possibility that vomeronasal epithelial cells containing Go α and Gi α2 in human fetuses are chemosensory neurons.