| The Hypoglossal Motoneuron is one of twelve pairs of cranial nerves that originate from the dorsal medulla oblongata nucleus and exit from the anterolateral sulcus of the medulla oblongata cone to control the movement of the lingual muscles.Damage of sublingual motor neurons can lead to lingual muscle paralysis,resulting in a series of diseases,such as tongue paralysis and inability to extend,causing serious harm to life and health.Therefore,it is very important to study the membrane properties of sublingual motor neurons,especially the regulation mechanism of neuron excitability,which is the basis for the treatment of lingual palsy from the mechanism.Studies have shown that cell membrane oscillations generated by synaptic transmission signals in the nervous system play an important role in regulating neuronal excitability,and injection of white noise current signals into hypoglossal motor neurons can artificially simulate highly similar cell membrane oscillations.It has a regulating effect on the excitability of neurons,especially on the input-output relationship of neurons,that is,the frequency-current(Frequency-Current: FI)relationship.However,the ion channel mechanism of this excitability regulation is still unclear.In view of this,based on this unsolved problem in physiological research,this paper studies the ionic mechanism of white noise on the regulation of sublingual motor neuron excitability through the technical means of mathematical modeling and simulation.Based on the electrophysiological parameters of hypoglossal motor neurons,this paper established a hypoglossal motor neuron model by using Cable theory,Compartment theory and Hodgkin-Huxley theory.The model contains six different types of voltage-gated ion channels,namely transient sodium(Na T),persistent sodium(Na P),delayed rectifier potassium(K(DR)),calcium-activated potassium(K(AHP)),L-type calcium ions(Ca L),and hyperactivated H-current(H-current)ion channels.The model can completely and consistently simulate the cell membrane parameters of hypoglossal motor neurons measured by physiological experiments under the condition of white noise signal input,including the voltage threshold,current threshold,and derecruitment current intensity of neurons.However,The simulation results of the F-I relationship show a large deviation.The simulation results of the FI relationship show a large deviation.To this end,this paper introduces an oscillation factor into the gating model of ion channels,which strengthens the oscillation effect of white noise signals on ion channels,and further improves the response intensity of neurons to membrane oscillation signals.The model simulation results show that the order of ion channels that can best simulate the slope change of the F-I relationship in hypoglossal motor neurons is: Na T > K(DR)> Na P >Ca L;the order of simulating the intercept change of the FI relationship is: Na T > K(DR)> Na P > Ca L.Therefore,this paper concludes that the modulation of hypoglossal motor neuron excitability by white noise(especially the modulation of the F-I relationship)is achieved through the synergistic regulation of ion channels Na T and K(DR)by oscillatory factors.In this paper,the cell membrane properties of hypoglossal motor neurons under white noise were studied by means of model simulation;According to the gating characteristics of ion channels,the membrane oscillation factor was introduced into the kinetic equation of ion channels,and the ion channel mechanism of the regulation of neuronal excitability by white noise was systematically explored;The synergistic regulation of the ion channels Na T and K(DR)is predicted to be the mechanism by which cell membrane oscillations can modulate the excitability of hypoglossal motor neurons.The research results of this paper provide ideas for the follow-up physiological experimental research,and have a certain reference effect on the treatment of paralysis of the tongue muscle in the sense of neurophysiological mechanism. |
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