#P049 Glial cells, which are supporting cells of the nervous system, are now clearly involved in nervous communications.These cells modulate odorant detection as soon as the peripheral level in the olfactory mucosa, acting on olfactory sensitive neurons. These neuronsare surrounded by glial like cells called sustentacular cells. These cells maintain both the structural and ionic integrity of the olfactory epithelium and are electrically coupled through GAP junctions. Our study focused on endothelin known to activate glial cells and to uncoupled GAP junctions in the central nervous system. Using patch clamp, we first demonstrate that endothelin also uncoupled sustentacular cells in vitro. We then confirmed in vivo by calcium imaging that endothelin limits electrical signal propagation in intact olfactory epithelial preparation, similarly as the known GAP junction uncoupling carbenoxone. Such modulation could affect olfactory response kinetics as we observed that both endothelin and carbenoxone treatments increase EOG (Electro-OlfactoGramme) signal repolarization. Our results are thus consistent with an implication of glial cell like modulation of nervous information at the peripheral level of the nervous system.