Non-olfactory chemoreceptors of the nose: recent advances in understanding the vomeronasal and trigeminal systems

Abstract

Recent experimental data on the influence of non-olfactory nasal chemoreception in physiology, sensation and behavior suggest the following, (i) The vomeronasal system may be a detector for pre-programmed chemical signals, especially for pheromones that trigger hormonal and behavioral responses. As animals gain experience with particular chemical signals, however, they may learn to use other cues, detected via the main olfactory system, and become less reliant on vomeronasal sensory input, (ii) The trigeminal chemosensory system responds to irritating chemical vapors in the nose, possibly via capsaicin-sensitive ‘pain’ fibers. The system also responds to non-irritating concentrations of some chemicals and, at all concentrations, may influence olfactory sensation by increasing total sensation but decreasing apparent odor intensity.