Comparative study of lectin reactivity in the vomeronasal organ of human and nonhuman primates.
The main and accessory olfactory systems of certain mammals (e.g., rodents, ungulates, and carnivores) have been investigated using lectin histochemistry to probe for sugar residues that may reflect physiological aspects of signal transduction or development. Morphologically, the vomeronasal organs (VNOs) of strepsirrhine primates (lemurs and lorises) are typical of functional VNOs in other mammals, whereas in humans and chimpanzees the VNOs appear vestigial. However, the human VNO is considered functional by some authors. To elucidate the cellular nature of the VNO in human and chimpanzees, a panel of six lectins (Con-A, ECL, PNA, RCA, s-WGA, and UEA-1) was applied to the VNO in eight species of primates, including humans and chimpanzees. The results indicated that there were few, if any, lectin-reactive cells in the human or chimpanzee VNO that resembled those seen in the vomeronasal neuroepithelium in other primates. The overall pattern of lectin reactivity in the human and chimpanzee VNO is unlike that seen in mammals with chemosensory VNOs, suggesting that the VNO of these hominoids does not function similarly to that of other primates.