Do olfactory receptors respond to explosives?

Olfactory receptors (ORs) comprise a large gene family (-1200 proteins encoded by OR genes) and thus are excellent candidates for the fabrication of sensitive biosensors for explosives and other chemicals of interest. Our research project aims to address these two fundamental questions: Which are the volatile components of landmines recognized specifically by animals? How do olfactory neurons located in their nasal cavity respond to the "perfume" of mines? As regards the first question, six different plastic components of six different kinds of landmines have been analyzed. To address the second question, the response of olfactory neurons to these volatile organic compounds present in the vapors of mines, as well as to TNT and RDX, has been studied both in the pig and in the rat. Studies on rat olfactory mucosa have been carried out with electro-olfactogram (EOG) and calcium imaging techniques, while changes in the cAMP levels following exposure to odorants and explosives were used as criterion to evaluate the interaction of TNT and RDX with olfactory receptors in a preparation of isolated pig olfactory cilia. Our studies demonstrate, for the first time, that mammalian olfactory receptors can be activated by explosives and chemical given off from explosive devices and represent a deeper understanding of the molecular mechanisms by which landmine volatiles interact with sensory olfactory neurons and their receptors, necessary for the preparation of a successful biosensor.