基于成串刺激计算立即释放囊泡池(RRP)大小的改进方法  

An Improved Method to Calculate RRP Size Based on Train Stimulation

作　　者：朱颖 孙坚原[1,3] ZHU Ying;SUN Jian-Yuan(Institute of Biophysics,Chinese Academy of Sciences,Beijing 100101,China;University of Chinese Academy of Sciences,Beijing 100049,China;Shenzhen Institutes of Advanced Technology,Chinese Academy of Sciences,Shenzhen 518055,China)

机构地区：[1]中国科学院生物物理研究所,北京100101 [2]中国科学院大学,北京100049 [3]中国科学院深圳先进技术研究院,深圳518055

出　　处：《生物化学与生物物理进展》2021年第7期846-854,共9页Progress In Biochemistry and Biophysics

基　　金：国家自然科学基金(31871033)资助项目。

摘　　要：突触囊泡的立即释放囊泡池(RRP)概念已被广泛用于突触传递的分析.基于这些囊泡池中囊泡性质是均匀的假设,通过外推成串刺激累积诱发的突触后兴奋性电流,已经开发了几种确定RRP大小的方法.然而,使用不同刺激频率确定这些成串刺激得到的RRP大小结果不同.这种频率依赖性显示了这些估算方法的不完备性,与RRP的定义相矛盾.因此,我们提出了基于成串刺激计算RRP大小的改进算法.假设RRP的填充率正比于RRP释放的部分,并且矫正RRP的未使用部分,给出RRP释放过程的完整数学描述,得到具体的解析结果.与已知的两种常用方法做比较,该方法很好地描述了RRP的释放和填充过程,得到了比较良好的RRP大小和囊泡释放概率大小的评估.该方法不受刺激频率的条件限制,可以很好地适用于不能给予高频刺激的细胞.Readily releasable pool(RRP) of synaptic vesicles as the concept that defines the capacity of vesicle availability has been widely used in the study of synaptic transmission. Several approaches have been developed to determine the size of RRP by extrapolating the cumulative EPSCs corresponding to a train stimulation based on the assumption that the properties of vesicle in this pool are homogeneous. However, the estimated RRP sizes by these approaches often vary with different stimulation frequencies. The frequency dependence displays the incompletion of estimation and contradictory to the definition of RRP. Here, we proposed an improved approach to estimate RRP size. Given the replenishment rate proportional to the released part of RRP and corrected the unreleased part of RRP, we obtained a complete mathematical description of the RRP release process and derived the analytic solution. Compared with the two commonly used methods, it has been found that this scheme well describes the dynamic process of RRP, and obtains a relatively good evaluation of RRP size and release probability. This approach is not limited by the stimulation frequency and can be well applied to the cells that cannot be stimulated by high frequency.

关 键 词：RRP calyx of Held突触 STP 突触囊泡循环 

分 类 号：Q6[生物学—生物物理学] R338[医药卫生—人体生理学]