6533b7d7fe1ef96bd1268161

RESEARCH PRODUCT

Perception des molécules chimiosensorielles en mélange : impact du métabolisme périphérique

subject

description

The chemosensory system is highly sensitive and discriminant. To ensure these properties, rapid and effective mechanisms are necessary to eliminate chemosensory molecules reaching the perception interface. The xenobiotic metabolizing enzymes (XMEs) present in the peri-receptor space may participate to the clearance of molecules thus limiting chemosensory receptors saturation and promoting the termination of the signal. In our PhD thesis, the involvement of these enzymes in the detection of stimuli in mixture was assessed in two animal models allowing to test complementary aspects. In Drosophila melanogaster, a sensory exposure to caffeine causes a reversible alteration of the taste perception. Functional analysis (behavioral and electrophysiological) of the perception of caffeine and sugar, after exposure, demonstrates a minima a peripheral alteration of sugar perception. Exposure modulates the expression of some cytochromes P450 (CYPs). One of these CYP, cyp14d4, is notably involved in the peripheral detection of caffeine. In the newborn rabbit the mammary pheromone (MP) is metabolized by glutathione transferases (GSTs) present in the olfactory epithelium. In vitro and ex vivo metabolic analyzes demonstrate that an odorant molecule metabolized by the same GSTs, in mixture with the MP, inhibits its metabolism by competition increasing its availability to the olfactory receptors. A synergistic response to MP, mixed with the odorant competitor, is observed by electrophysiological analysis. The behavioral study reveals that the degree of MP perception is increased in presence of the competitor.