The Effect Of Sodium Salicylate On The I_KDR And I_k-tail Of Spiral Ganglion Neurons Of Neonatal Rats

Part 1 The effect of serum culture shortly and polylysine in patch clamp research on SGNsObjective To study the effective of serum culture shortly and polylysine in patch clamp research on SGNs.Methods The better activity of SGN with serum culture shortly and the promoting adherence of SGN with polylysine were observed.Results The SGN with serum culture for a short time can last for at least 5 hours, it is enough for us to do some kinds of tests on the SGN, however, the SGN without serum culture just last only half an hour. The SGN with polylysine in the culture dish can hold tightly when shaking the test table, but they mostly disperse when there is no polylysine. Conclusion The SGN with serum culture for a short time can last for a long time, and hold tightly with polylysine in the dish. Part 2 The effect of sodium salicylate on outward delayed rectifier potassium currents and tail currents in isolated SGNsObjective To investigate the effect of sodium salicylate on outward delayed rectifier potassium currents (IKDR currents) and tail currents in isolated spiral ganglion neurous, and then to analyze possible intracellular mechanism of this effects by using the patch-clamp technique.Method The IKDR and tail curents was recorded and measured before and after the application of 1mmol/L sodium salicylate in external solution by using the whole cell patch-clamp technique. As to observe the concentration effect on the currents of SGN, we change the concentration of extracellular sodium salicylate during test.Results Sodium salicylate could inhibit SGNs voltage-dependent polassium channels, also cause a rightward shift in the I-V curve. Moreover, the maxinal magnitude of IKDR currents were dicreased by 46.3±2% when giving the test pulse at 60mV. Sodium salicylate's inhibitation on IKDR has dose-dependence with sodium salicylate of concentration in extracellular fluid and the currents recoverd mostly after sodium salicylate being washed out. Sodium salicylate profoundly reduce the amplitude of tail currents, which can also accelerate the deactivation time course of potassium channels.Conclusion This research explained the otoxic mechanis of sodium salicylate through its action on keeping from spiral ganglion neuron's IKDR and tail currents from the eletrophysiological aspect and set a foundation for further research.