title: Interaction between cAMP and intracellular Ca(2+)-signaling pathways during odor-perception and adaptation in Drosophila.
abstract: Binding of an odorant to olfactory receptors triggers cascades of second messenger systems in olfactory receptor neurons (ORNs). Biochemical studies indicate that the transduction mechanism at ORNs is mediated by cyclic adenosine monophosphate (cAMP) and/or inositol,1,4,5-triphosphate (InsP3)-signaling pathways in an odorant-dependent manner. However, the interaction between these two second messenger systems during olfactory perception or adaptation processes is much less understood. Here, we used interfering-RNAi to disrupt the level of cAMP alone or in combination with the InsP3-signaling pathway cellular targets, InsP3 receptor (InsP3R) or ryanodine receptor (RyR) in ORNs, and quantify at ORN axon terminals in the antennal lobe, the odor-induced Ca(2+)-response. In-vivo functional bioluminescence Ca(2+)-imaging indicates that a single 5s application of an odor increased Ca(2+)-transients at ORN axon terminals. However, compared to wild-type controls, the magnitude and duration of ORN Ca(2+)-response was significantly diminished in cAMP-defective flies. In a behavioral assay, perception of odorants was defective in flies with a disrupted cAMP level suggesting that the ability of flies to correctly detect an odor depends on cAMP. Simultaneous disruption of cAMP level and InsP3R or RyR further diminished the magnitude and duration of ORN response to odorants and affected the flies' ability to detect an odor. In conclusion, this study provides functional evidence that cAMP and InsP3-signaling pathways act in synergy to mediate odor processing within the ORN axon terminals, which is encoded in the magnitude and duration of ORN response.
authors.affiliation: Institut des Neurosciences Paris-Saclay (Neuro-PSI), Team: Imagerie Cérébrale Fonctionnelle et Comportement, UMR-9197, CNRS/Université Paris Sud, 1, Avenue de la Terrasse, Bat. 32/33, 91198 Gif-sur-Yvette Cedex, France. Electronic address: Meena-Sriti.Murmu@versailles.inra.fr.
authors.forename: Meena Sriti
authors.initials: MS
authors.lastname: Murmu
authors.affiliation: Institut des Neurosciences Paris-Saclay (Neuro-PSI), Team: Imagerie Cérébrale Fonctionnelle et Comportement, UMR-9197, CNRS/Université Paris Sud, 1, Avenue de la Terrasse, Bat. 32/33, 91198 Gif-sur-Yvette Cedex, France. Electronic address: jean-rene.martin@inaf.cnrs-gif.fr.
authors.forename: Jean-René
authors.initials: JR
authors.lastname: Martin
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001522:Behavior, Animal; D020013:Calcium Signaling; D000242:Cyclic AMP / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000502:physiology*; D055785:Gene Knockdown Techniques; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism; D042541:Intracellular Space / Q000378:metabolism*; D016014:Linear Models; D008954:Models, Biological; D009474:Neurons / Q000502:physiology; D009812:Odorants; D055696:Olfactory Perception; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D018035:Receptors, Odorant / Q000378:metabolism; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism; D012903:Smell / Q000502:physiology
chemical_list: D053496:Inositol 1,4,5-Trisphosphate Receptors; D018035:Receptors, Odorant; D019837:Ryanodine Receptor Calcium Release Channel; D000242:Cyclic AMP; D010727:Phosphoric Diester Hydrolases
keywords: InsP(3) receptor; Odor adaptation; Olfactory perception; Ryanodine receptor; Second messengers; cAMP