Odor induced cAMP production in Drosophila melanogaster olfactory sensory neurons

Abstract

Insect odorant receptors are seven transmembrane domain proteins that form cation channels, whose functional properties such as the receptor sensitivity are subject of regulation by intracellular signaling cascades. Here we used the cAMP fluorescent indicator Epac1-camps to investigate the presence of an odor-induced cAMP production in olfactory sensory neurons (OSNs) of Drosophila melanogaster. We show that stimulation of the receptor complex with an odor mixture or with the synthetic agonist VUAA1 induces a cAMP response. Moreover, we show that while the intracellular Ca2+ concentration influences the cAMP production, an OSN-specific receptor OrX is necessary to elicit cAMP responses in Ca2+-free conditions. These results provide direct evidence of a relationship between odorant receptor stimulation and cAMP production in olfactory sensory neurons in the fly antenna and show that this method can be used to further investigate the role that this second messenger plays in insect olfaction.