A study on electrophysiological properties of neurons in mouse cochlear nucleus and on TRPM2 cation channel in these neurons

Neurons in the cochlear nucleus have distinct anatomical and biophysical specializations and extract various aspects of auditory information which are transmitted to unitin the higher auditory centres. In the present study it was aimed to determine active and passive membrane properties of bushy and stellate neurons inthe ventral cochlear nucleus and to characterize electrophysiological of TRPM2 cation channel in these neurons. TRPM2, melastatin family of transient receptor potential is a non-selective Ca+2-permeable cation channel and is known to be activated by oxidative stress product.Active and passive membrane properties of stellate neurons, fired regular and sustained trains of action potentials in response to depolarizing current. Membrane potential, input resistance, time constant and capacitance membrane were found -64,5 ± 3,37 mV, 231± 116 M?, 6,17 ± 4,1 ms and 0,27 ± 0,14 µF/cm2 respectively.Active and passive membrane properties of bushy neurons, responded with a single action potential at the onset of depolarizing. Membrane potential, input resistance, and capacitance membrane time constant were found -63,6 ± 5,54 mV, 308 ± 185 M?, 4,6 ± 3,3 ms and 0,17 ± 0,05 µF/cm2 respectively.Application of TRPM2 cation channel agonist hydrogen peroxide resulted in hyperpolarization of membrane potential by 14 ± 20,6 mV and 21 ± 6,35 in stellate and bushy neurons respectively.Application of TRPM2 cation channel antagonist catalase cause the stellate and bushy neurons to depolarize by 9 ± 3,4 mV and 4 ± 1,14 mV respectively.In conclusion, the passive and active membrane properties of stellate and bushy neurons of cochlear nucleus were demonstrated in the study. However with the given agonist and antagonist TRPM2 ion channel of these neurons could not be characterized.