Mechanism of ATP release from cultured marginal cells of stria vascularis in neonatal rat / 中华耳鼻咽喉头颈外科杂志

ABSTRACT

<p><b>OBJECTIVE</b>To further confirm release of adenosine triphosphate (ATP) from cultured marginal cells in vitro of stria vascularis in neonatal rat, and to explore the mechanism of ATP release from marginal cells.</p><p><b>METHODS</b>Isolation and in vitro culture of marginal cells of neonatal rats' cochlea. ATP released by marginal cells in extracellular fluid were detected using bioluminescence assay when add regain separately as follow bafilomycin A(1), didecyl adipate (DDA), extracellular K(+), thapsigargin, extracellular Ca(2+), U73122, and aristolochic acid.</p><p><b>RESULTS</b>The concentrations of ATP in the extracellular fluid significantly and gradually decreased along with increasing concentrations of bafilomycin A(1). The concentrations of ATP in the extracellular fluid were in linear increased with DDA was added to marginal cell suspensions. ATP concentrations increased as the concentration of extracellular K(+) was increased, and reached the peak with a K(+) concentration of 9.15 mmol/L. At higher K(+) concentrations, ATP concentrations decreased. With the addition of increasing concentrations of thapsigargin to test marginal cells, ATP concentrations were significantly decreased. When extracellular Ca(2+) was completely chelated, marginal cells continued to release ATP. Moreover, as extracellular Ca(2+)increased, the release of ATP decreased. However, the amount of ATP releas remained to a baseline when extracellular concentration of Ca(2+) reached 1.25 mmol/L or above. When concentrations of U73122 remained within the range of 0.25 to 1.25 µmol/L, as U73122 increased, the release of ATP decreased. When concentrations of aristolochic acid ranging from 12.5 to 100.0 µmol/L were added to the marginal cells suspension, the release of ATP was significantly decreased. However, with concentrations of aristolochic acid less than 100.0 µmol/L, the release of ATP tended to be not significantly different from the amount of ATP released by control group.</p><p><b>CONCLUSIONS</b>ATP could be release from marginal cells cultured in vitro of vascular stria in neonatal rats. ATP release from marginal cells has relevant with calcium pump, K(+) channel state and signaling pathway related enzymes.</p>