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Dendritic Membrane Properties of Crayfish Nonspiking Interneurons

小龙虾非尖峰中间神经元的树突膜特性

基本信息

批准号：
03640592
负责人：
TAKAHATA Masakazu
金额：
$ 1.28万
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：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

Physiological properties of the dendritic membrane of LDS interneuron, an identified nonspiking interneuron in the terminal abdominal ganglion of the crayfish Procambarus clarkii Girard, have been studied using the single electrode voltage clamp (SEVC) technique. The site of electrode penetration into the dendrite was visualized under the dissecting microscope in situ during experiment by epiilluminating the Lucifer-filled cell and the microelectrode with blue light.The dendritic membrane showed outward rectification to intracellularly injected current both at the thick branch on the midline and at the peripheral branches. Accordingly, the membrane time constant was shorter during depolarization than during hyperpolarization. The time course of compound PSP evoked by direct stimulation of presynaptic sensory neurons became shorter as the cell was more depolarized from the resting potential and vice versa. In contrast to the rectifying membrane property which was observed at any site of … More dendrites, the input resistance and membrane time constant were dependent of electrode penetration sites. Thus, the input resistance was significantly lower at the thick bridge portion than at peripheral branches.A single intracellular microelectrode was placed at the bridge portion and the SEVC technique was applied to LDS dendrites. In response to hypepolarizing command voltage (10-50mV) applied to the cell held at the resting potential, a small inward leakage current was observed in proportion to the hyperpolarization. By contrast, the cell showed an additional outward current superimposed on the outward leakage current. The amount of additional current was dependent of the amount of depolarization. This current showed transient increase at the onset of depolarization and became steady in about 80-100msec. The finding that the steady outward current was reduced to 70-80% by perfusion of 10mM TEA indicates that it resembles the well known delayed rectifier K current. Characteristics of the transient early current are to be further studied. Less

采用单电极电压钳（SEVC）技术研究了克氏原螯虾（Procambarusclarkii吉拉德）终末腹神经节中一种非棘突型中间神经元LDS的树突状膜的生理特性。实验过程中，在原位解剖显微镜下用蓝光照射荧光素填充的细胞和微电极，观察电极穿透树突的部位，树突膜对细胞内注入电流在中线粗分支和外周分支均表现出外向整流。因此，去极化过程中的膜时间常数比超极化过程中的膜时间常数短。直接刺激突触前感觉神经元诱发的复合PSP的时程随着细胞离静息电位的去极化程度的增加而缩短，反之亦然。相反，整流膜的性质，这是观察到在任何网站的 ...更多信息树突，输入电阻和膜时间常数依赖于电极穿透位点。因此，在较厚的桥部分的输入电阻明显低于周围分支。在桥部分放置单个细胞内微电极，并将SEVC技术应用于LDS树突。响应于施加到保持在静息电位的细胞的超极化命令电压（10- 50 mV），观察到与超极化成比例的小的内向漏电流。相比之下，电池显示出叠加在外向漏电流上的额外外向电流。附加电流的量取决于去极化的量。该电流在去极化开始时呈短暂性增加，在80- 100毫秒内趋于稳定。用10 mM TEA灌流可使稳定外向电流降低70-80%，这一发现表明它类似于众所周知的延迟整流钾电流。瞬变早期电流的特性有待进一步研究。少