抄録
Most terrestrial vertebrates have at least two segregated chemosensory neurons in the nasal cavity: the olfactory receptor neurons (ORNs) and vomeronasal neurons (VNs). Recent studies have revealed that the receptive spectrum of molecular structure appears to be partially overlapping between ORNs and VNs. For example, MHC class I peptides which function directly as chemosignals, have been shown to activate both ORNs and VNs, in contrast to the widely held view that ORNs are stimulated by volatile chemosignals only. These observations give rise to a possibility that there may be volatile odorants which are detected by VNs to cause biological responses such as changes in hart rate and body temperature. As an initial step to explore the additional role of the vomeronasal system on animal behavior, we examined the sensitivity of the rat VNs to chemicals considered not to be related to pheromones by using Ca2+-imaging approach. In the present study, we observed that (±)-propane-1,2-diol (propireneglycol), a common organic solvent, elicited Ca2+ responses in a dose-dependent manner. We found detection thresholds for this compound at concentrations near or below 1 μM. These results reveal a sensitivity of the rat VNs for this chemical, which seems comparable to that of ORNs, supporting the idea mentioned above that some non-pheromonal volatile odorants may affect animals behavior via the vomeronsal system in rodent. [J Physiol Sci. 2008;58 Suppl:S166]
