大鼠内侧内嗅皮层浅层主要神经元的特性
发布时间：2018-11-23 09:54
【摘要】：记忆可分为海马依赖性和海马非依赖性记忆，海马环路在海马依赖性记忆中发挥着重要作用[1]，作为海马结构的输入与输出中继站的内嗅皮层在海马与大脑新皮质之间起着信息的双向传递作用。锥体神经元和星型神经元是内侧内嗅皮层浅层中是主要的投射神经元。大脑皮层(包括嗅周皮质，联合皮质以及海马旁回皮质)的信息主要传入EC的浅层神经元，然后通过它们将这些高度处理的感觉信息传递至海马结构记忆环路。目前，许多的实验证明EC不仅在新皮质-海马对话中起重要作用，而且还主动参与了记忆的巩固和提取。所以，在了解MEC浅层主要神经元基本形态基础后，进而研究其基本电生理指标将可以帮助我们科学区分内嗅皮层浅层的两类神经元和了解MEC区在人脑的学习记忆过程中所担任的角色，进而为下步研究麻醉药物在MEC区的作用靶点提供实验依据。 在本次研究中，我们主要采用高尔基嗜银染色和体外脑片膜片钳技术相结合的方法来研究内侧内嗅皮层浅层锥体神经元和星型神经元的形态学特征和基本电生理特性：首先通过借助红外干涉相差(IR-DIC)显微镜的帮助，我们初步观察内侧内嗅皮层浅层锥体神经元和星形神经元的形态特征；并在此基础上，我们使用高尔基嗜银染色技术手段对内嗅皮层中细胞构筑和纤维联系进行了研究；在此基础上我们可以通过形态来对细胞进行分类，并通过离体脑片膜片钳技术，来研究各类细胞在不同的刺激条件下的电生理反应，依此得出各自的基本电生理特性，最后通过比较分析找出各自的差异所在。 通过实验我们了解到：MEC区浅层锥体细胞和星型细胞无论在形态学，还是基本电生理均存在较大差异。星型细胞呈方枕状，，其胞体发出多个主树突；而锥体神经元主要呈三角型，其胞体只有一个主树突和几个次要基树突穿出，而且细胞体积明显较星型神经元小；进一步离体脑片膜片钳实验，我们发现：两类神经元静息膜电位相近，但相比于星型神经元，锥体神经元具有更高的细胞兴奋性，即在相同的刺激电流下，锥体神经元更易发放。文献指出这种细胞兴奋性的差异源于两类神经元胞体高电压阈值激活的钙离子通道密度差异所致，这也就解释了为什么部分癫痫病人癫痫持续发作后EC区锥体神经元会发生选择性死亡；在注入-160pA的超极化电流观察HCN通道激活所产生电位“Sag”和“Ih”电流的实验过程中，我们发现在星型细胞上所记录的电信号明显大于锥体细胞，结合实验记录模式和生物电信号在胞膜传递的衰减因素，我们初步考虑这种差异源自于HCN通道分布差异：在星型细胞中HCN主要集中于胞体，而对于锥体神经元而言，则位于树突的远端。
[Abstract]:Memory can be divided into hippocampal dependent and hippocampal independent memory. The hippocampal loop plays an important role in hippocampal dependent memory [1]. The entorhinal cortex, which acts as an input and output relay for the hippocampal formation, plays a two-way role in the transmission of information between the hippocampus and the neocortex of the brain. Pyramidal neurons and star neurons are the main projective neurons in the superficial layer of the medial olfactory cortex. The information of cerebral cortex (including periolfactory cortex, associative cortex and para-hippocampal cortex) is mainly transmitted to the superficial neurons of EC, and then these highly processed sensory information are transmitted to the hippocampal structure memory loop. At present, many experiments have proved that EC not only plays an important role in neocortex-hippocampal dialogue, but also actively participates in the consolidation and extraction of memory. So, after understanding the basic morphological basis of the main neurons in the shallow layer of MEC, The study of its basic electrophysiological parameters will help us scientifically distinguish between two types of neurons in the superficial layer of the olfactory cortex and understand the role of the MEC region in the learning and memory process of the human brain. It provides the experimental basis for the next step to study the action targets of narcotic drugs in MEC region. In this study, We studied the morphological and basic electrophysiological characteristics of the superficial pyramidal neurons and star neurons in the medial olfactory cortex by using Golgi silver staining and patch clamp technique in vitro. Firstly, we studied the morphological and electrophysiological characteristics of the superficial pyramidal neurons and star neurons in the medial olfactory cortex. With the help of infrared interference phase contrast (IR-DIC) microscope, The morphological characteristics of superficial pyramidal neurons and star neurons in the medial olfactory cortex were preliminarily observed. On this basis, we used Golgi silver staining technique to study cell architecture and fiber connections in the endolfactory cortex. On this basis, we can classify the cells by morphology, and study the electrophysiological responses of all kinds of cells under different stimulation conditions by using in vitro patch clamp technology, so as to obtain their basic electrophysiological characteristics. Finally, through comparative analysis to find out their differences. We know that there are great differences in morphology and basic electrophysiology between superficial pyramidal cells and star cells in MEC region. The star cells were square occipital-shaped, and the pyramidal neurons were mainly triangular in shape, with only one main dendrite and several secondary basal dendrites perforated, and the cell volume was obviously smaller than that of the star-shaped neurons. Further in vitro patch clamp experiments, we found that the resting membrane potentials of the two types of neurons are similar, but the pyramidal neurons have higher cell excitability than star neurons, that is, under the same stimulation current, Pyramidal neurons are easier to release. It is suggested that the difference in excitability of these two types of neurons is due to the difference in the density of calcium channels activated by high voltage threshold in the cell body of two kinds of neurons. This may explain the selective death of EC pyramidal neurons in some epileptic patients after a sustained seizure. In the experiment of observing the "Sag" and "Ih" currents generated by the activation of HCN channels, we found that the electrical signals recorded on star cells were significantly larger than those in pyramidal cells. Considering the attenuation factors of experimental recording mode and bioelectrical signal transmission in the cell membrane, we preliminarily consider that this difference originates from the difference in the distribution of HCN channels: in star cells, HCN is mainly concentrated in the cell body, but for pyramidal neurons, Is located at the distal end of the dendrite.
【学位授予单位】：第三军医大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R614
本文编号：2351155
[Abstract]:Memory can be divided into hippocampal dependent and hippocampal independent memory. The hippocampal loop plays an important role in hippocampal dependent memory [1]. The entorhinal cortex, which acts as an input and output relay for the hippocampal formation, plays a two-way role in the transmission of information between the hippocampus and the neocortex of the brain. Pyramidal neurons and star neurons are the main projective neurons in the superficial layer of the medial olfactory cortex. The information of cerebral cortex (including periolfactory cortex, associative cortex and para-hippocampal cortex) is mainly transmitted to the superficial neurons of EC, and then these highly processed sensory information are transmitted to the hippocampal structure memory loop. At present, many experiments have proved that EC not only plays an important role in neocortex-hippocampal dialogue, but also actively participates in the consolidation and extraction of memory. So, after understanding the basic morphological basis of the main neurons in the shallow layer of MEC, The study of its basic electrophysiological parameters will help us scientifically distinguish between two types of neurons in the superficial layer of the olfactory cortex and understand the role of the MEC region in the learning and memory process of the human brain. It provides the experimental basis for the next step to study the action targets of narcotic drugs in MEC region. In this study, We studied the morphological and basic electrophysiological characteristics of the superficial pyramidal neurons and star neurons in the medial olfactory cortex by using Golgi silver staining and patch clamp technique in vitro. Firstly, we studied the morphological and electrophysiological characteristics of the superficial pyramidal neurons and star neurons in the medial olfactory cortex. With the help of infrared interference phase contrast (IR-DIC) microscope, The morphological characteristics of superficial pyramidal neurons and star neurons in the medial olfactory cortex were preliminarily observed. On this basis, we used Golgi silver staining technique to study cell architecture and fiber connections in the endolfactory cortex. On this basis, we can classify the cells by morphology, and study the electrophysiological responses of all kinds of cells under different stimulation conditions by using in vitro patch clamp technology, so as to obtain their basic electrophysiological characteristics. Finally, through comparative analysis to find out their differences. We know that there are great differences in morphology and basic electrophysiology between superficial pyramidal cells and star cells in MEC region. The star cells were square occipital-shaped, and the pyramidal neurons were mainly triangular in shape, with only one main dendrite and several secondary basal dendrites perforated, and the cell volume was obviously smaller than that of the star-shaped neurons. Further in vitro patch clamp experiments, we found that the resting membrane potentials of the two types of neurons are similar, but the pyramidal neurons have higher cell excitability than star neurons, that is, under the same stimulation current, Pyramidal neurons are easier to release. It is suggested that the difference in excitability of these two types of neurons is due to the difference in the density of calcium channels activated by high voltage threshold in the cell body of two kinds of neurons. This may explain the selective death of EC pyramidal neurons in some epileptic patients after a sustained seizure. In the experiment of observing the "Sag" and "Ih" currents generated by the activation of HCN channels, we found that the electrical signals recorded on star cells were significantly larger than those in pyramidal cells. Considering the attenuation factors of experimental recording mode and bioelectrical signal transmission in the cell membrane, we preliminarily consider that this difference originates from the difference in the distribution of HCN channels: in star cells, HCN is mainly concentrated in the cell body, but for pyramidal neurons, Is located at the distal end of the dendrite.
【学位授予单位】：第三军医大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：R614
【参考文献】
相关期刊论文 前1条
1 喻欣;郭莲军;殷光甫;宗贤刚;艾永循;;Effect of Non-specific HCN_1 Blocker CsCl on Spatial Learning and Memory in Mouse[J];华中科技大学学报(医学英德文版);2006年02期
本文编号：2351155
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