6533b838fe1ef96bd12a385a

RESEARCH PRODUCT

Postnatal odorant exposure induces peripheral olfactory plasticity

subject

description

Olfactory sensory neurons (OSNs) form an interface between the environment and the brain, converting chemical information (odorants) into electrical signals and sending these signals to the brain. Little is known about the consequences of long term odorant exposure on OSNs. Our goal is to understand the anatomical, molecular and physiological effects of odorant exposure at the cellular level and more precisely in the context of an early postnatal olfactory exposure. We focus our work on specific populations of OSNs expressing particular ORs using gene-targeted mice. MOR23-GFP mice were exposed daily to Lyral and anatomical, molecular and physiological properties of these neurons were analyzed. The density of MOR23 neurons decreased after odorant exposure while the level of mRNA for the receptor remained stable at the entire mucosa level. To investigate molecular changes within individual OSNs, mRNA levels for olfactory signaling pathway components were quantitatively analyzed using qPCR on GFP-containing neurons (7 per mouse). The levels of mRNAs for CNGA2, PDE1C and MOR23 olfactory receptor were higher in exposed OSNs compared to control. Using patch-clamp recordings on the dendritic knobs of MOR23 neurons in an intact preparation we observed that exposed OSNs displayed a lower detection threshold compared to control OSNs while the dynamic range of the dose-response was broader. Responses of exposed neurons were also faster and shorter than the responses of control neurons. Postnatal odorant exposure induces molecular and physiological plasticity in individual MOR23 neurons. Taken together, our data suggest that the olfactory epithelium presents deep anatomical, molecular and functional changes when chronically exposed to odorant molecules in early stage of life. Acknowledgements: Funding was provided by CNRS (ATIP grant), by Conseil Régional de Bourgogne (FABER and PARI grants), and by Université de Bourgogne (BQR program).