The Electrophysiological Study Of Murine Spiral Ganglion Neurons And The Effect Of Cisplatin On Potassium Currents

Objective Spiral ganglion neuron is the primary neuron of auditory system,whose electrophysiological characteristics and mechanism of ototoxicity are important for clarifying the formation of audition and protecting auditory function. To investigate the basic electrophysiological features and effect of cisplatin on potassium current so as to find out the ionic base of ototoxicity of cisplatin, murine spiral ganglion neurons were dissociated and cultured without enzyme ,and ionic currents were recorded by patch clamp techniques of whole cell configure.Methods The cochlear of milk mouse within 5 days after birth was anatomized and dissociated to acquire tissue of spiral ganglion neurons,then primary culture was performed and NF-200 monoclonal antibody was applied to identified them with fluorescent microscope. Different ionic currents were recorded with patch clamp techniques of whole cell configure on the condition of different bath solutions, internal electrode solution, blockers and stimulus protocol. Different concentration solutions of cisplatin were addedto bath solution to study the effect of cisplatin on electrophysiological characteristics of potassium channels after potassium current was recorded.Results Ideal spiral ganglion neurons were acquired whose cell bodies were oval with bipolar or monopolar processes which initial section were narrow.The neurons were clearly showed with immunocytochemical method,which couldn't be confused with glial cells and fibroblasts,and which features could be identified .Inward iNaJh and outward Ik,Ia were recorded .Moreover,it was the first time that IA was recorded in our country.The electrophysiological properties of potassium channel current were influnced by different concentration solutions of cisplatin,which had concentration dependence.The changes of electrophysiological properties were showed by dynamics of activation and current amplitude.In our test,IC5O was 294 u M.Conclusion Ideal spiral ganglion neurons are acquired by culture without enzyme which shapes can be discerned easily and can be identified by immunocytochemical method.Various ionic currents are recorded which show spiral ganglion neurons have ionic channel base to complete formation,conduction and modulation of action potential.Cisplatin can change electrophysiological characteristics of potassium currents of spiral ganglion neurons which reveals ototoxicity of cisplatin has some ionic mechanism.