Stimulus-secretion-coupling in a central synapse measured by membrane capacitance and postsynaptic EPSCs in mouse brain slices
作者单位：Department of PhysiologyUniversity of TorontoTorontoCanada Institute of Molecule MedicinePeking University
会议名称：《中国神经科学学会第四次会员代表大会暨第七届全国学术会议》
会议日期：2007年
学科分类：0710[理学-生物学] 07[理学] 071006[理学-神经生物学]
基 金：supported by 973 program the National Nature Science Foundation of China
关 键 词：membrane capacitance brain slice action potential pattern
摘 要：正A fundamental question is whether AP encodes affect total neurotransmitter release in CNS *** a previous study,we showed that action potential（AP） encodes（time organization of APs） can modulate total presynaptic secretion in isolated adrenal chromaffin *** Calyx of Held is a large glutamatergic synapse in mammalian auditory brainstem and participates in sound *** secretion on its presynaptic terminal can be recorded by membrane capacitance（Cm） in mouse brainstem ***,we study modulation of evoked secretion by AP encodes in calyx synapses in mouse brain *** stimulus pattern is defined by a AP code function F（N,m,f,d） with N as number of total APs,m as number of AP bursts,f as AP frequency,and d as interval time between two AP *** results are:（1） F（100,m,100 Hz,0.2 s）-induced presynaptic capacitance was facilitated by 62%at m = 4 vs 1,termed mfacilitation;（2） The total postsynaptic EPSC-integration,which is proportional to total glutamate release,was facilitated by 33%;（3） The smaller m-facilitation measured by post synaptic EPSCs *** capacitance suggests,that the average quantal size of glutamate release from single synaptic vesicle is accompanied with the m-facilitation in the CNS synapses,implying that the facilitated release from recycled and late-released vesicles has lower glutamate concentration during a intensive synaptic *** conclude that synaptic transmission is modulated by AP encodes in mouse CNS.