Abstract
The detection of chemicals in the external environment -so called, chemosensation- is essential for the survival in many organisms. Odorants (volatile odorous chemicals) and pheromones (species and gender-specific chemicals) are two major olfactory cues by which information about food and suitable mating partners is transmitted. I herein describe how odorant or pheromone signal is detected and transduced via olfactory sensory systems in vertebrate and invertebrate. I will first present our data demonstrating molecular mechanisms underlying odorant and pheromone detection in the insect olfactory system. It turns out that there is a unique and previously-unappreciated receptor signal transduction mechanism, which appears to be the basis for the remarkable sensitivity and selectivity in insect chemosensation. Unlike insect, social and reproductive behaviors in mammals are modulated by not only volatile pheromones but also non-volatile cues that are likely detected by the vomeronasal organ located at the base of the nasal septum. We identified a male-specific peptide that was encoded by a gene from a previously-unrecognized large family in mice. This peptide, named ESP1, is secreted from male mice and transferred to the female vomeronasal organ wherein it elicits an electrical response. I will summarize current knowledge on structure and function of the ESP family and also describe most recent data on ESP1 receptor and its neural signaling pathway in the vomeronasal system. Supported in part by PROBRAIN, JSPS, and MEXT. [J Physiol Sci. 2007;57 Suppl:S39]
