Taurine modulates calcium influx under normal and ototoxic conditions in isolated cochlear spiral ganglion neurons.

The effect of taurine on calcium homeostasis of isolated cochlear spiral ganglion neurons under normal and ototoxic conditions was investigated using fluo-3 calcium imaging. Sole application of taurine (15 mM) induced an increase in intracelluar Ca 2+ concentration ([Ca 2+ ] ι ), which was largely inhibited either by the application of an L-type calcium-channel blocker nifedipine or a calcium-free medium. Preincubation with 1 mM gentamicin induced an inhibition of the high K + -evoked elevation of [Ca 2+ ] ι . Short-term exposure to taurine prevented this inhibition. The results suggested that taurine at this concentration was able to increase [Ca 2+ ] ι mainly by calcium influx through L-type calcium channels in isolated spiral ganglion neurons and to antagonize gentamicin-induced inhibition of calcium elevation evoked by high K + by its calcium homeostatic effect.