P2X antagonists inhibit styryl dye entry into hair cells

摘要: The styryl pyridinium dyes, FM1-43 and AM1-43, are fluorescent molecules that can permeate the mechanotransduction channels of hair cells, sensory receptors inner ear. When these dyes applied to they enter cytoplasm rapidly, resulting in a readily detectable intracellular fluorescence is often used as molecular indication channel activity. However, such also ATP receptor, P2X(2). Therefore, we explored contribution P2X loading cells with AM1-43. chick ear was found express release ATP, similar mammals, allowing for endogenous stimulation receptors. involvement evaluated pharmacologically, by exposing epithelium 5 microM AM1-43 under different experimental conditions measuring after fixation tissue. Pre-exposure tissue mM EGTA 15 min, which should eliminate most gating "tip links" channels, deceased only 44%. In contrast, receptor antagonists (pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid [PPADS], suramin, 2',3'-O-(2,4,6-trinitrophenyl) [TNP-ATP], d-tubocurarine) had greater effects on dye loading. PPADS, TNP-ATP all decreased at least 69% when concentration 100 microM. difference between d-tubocurarine-treated control statistically insignificant d-tubocurarine blocks (200 microM). At P2X(2) (2 mM), 72%. From experiments, it appears through endogenously activated Thus, entry be considered using detect cell activity, especially absence explicit mechanical stereocilia.