权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Synaptic Integration in Crayfish Nonspiking Interneurons

小龙虾非尖峰中间神经元的突触整合

基本信息

批准号：
01540585
负责人：
TAKAHATA Masakazu
金额：
$ 1.22万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

项目摘要

Multicompartment models of crayfish nonspiking interneurons were developed in order to investigate how the synaptic input to interneurons could be converted into the synaptic output to motoneurons. Electrical properties of the interneuron dendrite were studied by intracellular current injection test with relation to the site of electrode penetration into the dendrite. A method for identifying the penetration site in situ has been established. The model was based on (1) morphological measurement of the cell which was filled with the fluorescent dye, Lucifer yellow and (2) the membrane resistivity obtained from the result of step current injection. The model was evaluated by comparing the experimental result of current injection test with the calculated one in the simulation of that test on the model. The fine dendritic branches missing in the constructed model due to imperfect staining of the cell was compensated by expanding the membrane area of the model until the optimal one was finally obtained.Simulation of synaptic activities on the interneuron model revealed that the synaptic potential in the interneuron was smoothed during the electrotonic spread over the dendrite more effectively than in the motoneurons. The result is consistent with the finding that the input resistance and the membrane time constant of nonspiking interneurons are significantly greater than those of motoneuron dendrites. It is concluded that the nonspiking interneurons function as an extended dendrites of motoneurons by gathering synaptic inputs from spatially wider range of presynaptic cells and processing them in such a way that the general excitability of motoneurons can be adjusted in a more delicate way through the continuous membrane potential change meicated by the interneuron.

为了研究对中间神经元的突触输入如何转化为对运动神经元的突触输出，建立了淡水螯虾非尖峰中间神经元的多隔室模型。通过细胞内电流注入实验研究了中间神经元树突的电特性与电极插入树突位置的关系。建立了一种原位识别侵彻位置的方法。该模型基于（1）填充有荧光染料荧光黄的细胞的形态测量和（2）从阶跃电流注入的结果获得的膜电阻率。通过比较电流注入试验的实验结果与模型模拟试验的计算结果，对模型进行了评价。由于不完全染色的细胞在所构建的模型中丢失的细树突分支通过扩大模型的膜面积来补偿，直到最终获得最优的一个。在中间神经元模型上的突触活动的模拟显示，在中间神经元的突触电位平滑过程中的电紧张性蔓延的树突比运动神经元更有效。这一结果与非尖峰中间神经元的输入阻力和膜时间常数显着大于运动神经元树突的结果一致。得出的结论是，非尖峰中间神经元通过从空间上更广泛的突触前细胞收集突触输入并以这样一种方式处理它们，从而可以通过连续的膜电位变化以更微妙的方式调节运动神经元的总体兴奋性，从而发挥运动神经元延伸树突的作用。由中间神经元引起的变化。