The DREAM method of odorant receptor deorphanisation (von der Weid et al., 2015) allowed for the identification of potentially all the receptors that respond to a specific molecule. In this work, I present findings in two categories. We identified and refined the experimental conditions that affected DREAM and then used this method to identify the olfactory signature of complex and natural odors. The mechanism that mediates odorant-induced mRNA downregulation is still unknown, yet we present evidence suggesting that it is mediated by cAMP via the olfactory transduction cascade. Our results suggest that the odorant-induced mRNA downregulation is a large-scale downregulation effect that affects a majority of transcripts in the activated sensory neurons. Finally, using DREAM we identified the olfactory signatures of cheese and of the individual odorant that make up the smell of cheese.