Quinolinic Acid Effect On The Ca²⁺ Currents Of Nmda Receptor On The Spiral Ganglion Cells

Objection:To investigate the neurotoxicity and its mechanism of quinolinic acid (QA) to spiral ganglion cells(SGC) .the Role of quinolinic acid on secretory otitis media induced sensorineural hearing loss. Observe the protection of dextromethorphan hydrobromide DM on SGC.Methods: SGC which were cultured in vitro for 72 h were recorded in whole cell patch clamp technique and meanwhile take the notes that the effect of different concentrations of quinolinic acid. Also explored the dextromethorphan hydrobromide DM on QUIN-activated Ca²⁺ of NMDA receptors.Results: When SGC were exposed to different concentrations of 5ul quinolinic acid(150um/L,200um/L,250 um/L),NMDA-mediated ca2+ current average currents amplitude are different respectively (-0.41±1.1) nA(n=39) and(-0.62±1.3) nA(n=39)and(0.82±1.5)nA(n=39).DM can decreased quinolinic acid on Ca²⁺ currents amplitude of NMDA receptor.Conclusion:QA exssesive could injure SGC by activating Ca²⁺ curents of NMDA receptor on the cell membrane on the cell membrane. DM could reduce the neurotoxicity of QA.