Effects Of Visual Experience On Homeostasis Plasticity Of Pyramidal Neurons Synaptic In Ⅱ/Ⅲ Layer Of V1B Area Of Primary Visual Cortex In Mice

ObjectiveTo explore the effects of different visual experiences on the synaptic homeostasis plasticity and the content of AMPA receptor GluR1 subunits of Ⅱ/Ⅲ pyramidal cells in V1B area of primary visual cortex in mice,and further explore the neuroelectrophysiological mechanism and therapeutic opportunity of binocular deprivation amblyopia.MethodElectrophysiological experiment: 10-day-old(P10)healthy C57BL/6J mice were randomly divided into 4 groups:(1)normal control group(NR)P10,P17,P21,P28,P35,P49,a total of 6 stages,10 mice in each stage;(2)binocular deprivation group(BD)Corresponding to NR;(3)during the critical period,binocular deprivation mice were transformed into right eye deprivation group(BD+MD P28),10 mice;And normal mice right eye was deprived group(MD P28),10 mice,distinguish between left and right;(4)Binocular deprivation mice were removed deprivation group(BD+L P49)at the end of critical period,10 mice.Patch clamp technique was used to record the changes of AMPA receptor-mediated mEPSC amplitude,frequency,decay time and 10-90% rise time of Ⅱ/Ⅲ pyramidal cells in V1B region of each group.Protein immunoblotting test: 10-day-old(P10)healthy C57BL/6J mice were selected and divided into 4 groups:(1)normal control(NR)group P10,P17,P21,P28,P35,P49,a total of 6 stages,5 mice in each stage;(2)binocular deprivation group(BD)P10,P17,P21,P28,P35,P49,a total of 6 stages,5 mice in each stage;(3)during the critical period,the binocular deprivation mice were transferred to the right eye deprivation group(BD+MD P28),5 mice,distinguish between left and right;(4)Binocular deprivation mice were removed deprivation group(BD+L P49)at the end of critical period,5 mice.The expression of AMPA receptor GluR1 subunit in neurons of Ⅱ/Ⅲ layer in V1B region of each group was detected by western blot.ResultsEelectrophysiological experiments:(1)During the development of normal control mice,the mEPSC amplitude of layer Ⅱ/Ⅲ pyramidal cells in V1B region gradually decreased,and the mEPSC amplitude of binocular deprivation mice tended to be stable,there was a significant difference between the two groups at the beginning of P28;The mEPSC frequency of normal control mice increased with development,and the mEPSC frequency of binocular deprivation mice was stable.(2)Before,during and after the critical period,the cumulative amplitude curve of the synapses of pyramidal neurons in layer Ⅱ/Ⅲ of the primary visual cortex of binocular deprivation mice shifted significantly to the right,The changes are all scaled according to y=ax+b.(3)Binocular deprivation mice and normal control mice were deprived of the right eye for one week at the critical stage.For the deprived side,the changes of mEPSC amplitudes were scaled according to y=ax+b and y=ax,respectively.(4)In the whole process of the experiment,the mEPSC kinetics of each group of experimental mice remained basically unchanged.Protein immunoblotting test:(1)The expression of AMPA receptor GluR1 subunit in Ⅱ/Ⅲ layer of V1B region remained constant during the development of normal control mice.(2)GluR1 expression in binocular deprivation mice decreased during the development.(3)Monocular deprivation of mice with abnormal visual experience,the GluR1 content in the dedeprivation side was significantly higher than that in the dedeprivation side.(4)After opening the eyelids of binocular deprivation mice after the critical period,the expression of GluR1 did not increase.ConclusionBefore,during and after the critical period,the cumulative amplitude curves of pyramidal cells in layer Ⅱ/Ⅲ of V1B area of the primary visual cortex of binocular deprived mice all moved to the right compared with the normal curve,and were multiplied and scaled according to y=ax+b or y=ax.Diffuse light stimulation from binocular deprivation may be sufficient to mature the kinetics associated with mEPSC.The AMPA receptor subunit GluR1 is involved in the process of synaptic plasticity,but it is not positively correlated with the homeostasis changes of the synapses at layer Ⅱ/Ⅲ of zone V1B in binocular mice.