应激对大鼠海马突触可塑性和学习记忆的影响
文献类型：学位论文
| 作者 | 熊文勇 |
| 学位类别 | 博士 |
| 答辩日期 | 2004-06 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 徐林 |
| 关键词 | 应激 突触可塑性 长时程增强（LTP） 长时程抑制（LTD） Morris水迷宫 学习记忆 |
| 中文摘要 | 突触可塑性参与学习记忆，是学习记忆过程中必不可少的重要环节。应激能损伤或提高学习记忆、抑制长时程增强（Long一termPotentiation，LTP）、易化长时程抑制（Long一termdePressfon，LTD）。然而，应激经历依赖的长时程抑制（StressexperiencedePendentLTD，SLTD）在学习记忆中有什么意义还不清楚，这正是本文首先要探讨问题。其次，尽管我们在不同年龄时期的学习记忆能力不同，但是对所经历的重大应激事件仍然能产生牢固的记忆，这就有必要进一步通过阐明应激对突触可塑性的影响是否有年龄差异来解释SLTD的意义。再者，我们甚至不清楚为什么有的时候应激损伤学习记忆而有的时候又提高学习记忆。为了阐明这个问题，本文在最后一部分研究了哪些因素决定应激损伤还是提高学习记忆。为了探讨SLTD与学习记忆的关系，我们在第一部分实验中研究急性或亚急性的高台（ElevatedPlatform，EP）或足部电击（Footshock，Fs）对4周龄诚star大鼠海马CAI区LTD诱导的影响，以及这些应激条件对大鼠空间学习记忆的影响。结果显示：（l）急性EP易化LTD，亚急性EP不易化LTD；急性和亚急性FS都易化了LTD。（2）急性EP损伤空间记忆，亚急性EP对空间记忆没有影响；急性FS不影响空间记忆，亚急性FS却提高了空间记忆。这部分的实验结果表明：sLTD存在与否与应激对空间记忆的影响不是一一对应的关系，提示sLTD可能参与了应激记忆（对应激经历产生的记忆）。如果SLTD参与应激记忆，那么，研究应激对突触可塑性的影响是否有年龄依赖性将有助于解释不同年龄时期的学习记忆能力不同但是都能牢固记忆应激事件这一现象。为此，我们在第二部分实验中进一步研究EP对幼年、中年和老年动物（4，10和74周龄的Wistar大鼠）海马CAI区LTP／LTD诱导的影响。结果表明：（1）没有应激的情况下，LTP的大小随动物年龄的增加呈明显的倒U型关系，而低频刺激都不能诱导出LTD。（2）EP易化了这些年龄段大鼠的LTD，并完全阻断它们的LTP。值得注意的是，在三个年龄段大鼠中，EP易化的LTD大小一样。该部分实验结果提示：SLTD没有年龄依赖性，这与人和动物在不同年龄时期对所受到的重大应激事件都能产生牢固记忆这一现象相一致。所以，该部分结果进一步加强了第一部分结果的推测：SLTD参与应激记忆。应激有的时候提高动物的空间记忆能力，有的时候又损伤其空间记忆。为了阐明是什么因素决定应激损伤还是提高学习记忆，我们在第三部分实验中研究EP、FS和水迷宫游泳应激经历对六个年龄段动物（4，10，13，20，67，76周龄）在水迷宫任务中的影响。结果显示：（l）EP应激损伤无水迷宫游泳应激经历大鼠的空间记忆。（2）EP应激提高有游泳应激经历幼年大鼠的空间记忆；训练前外源性补充皮质酮或FS都抑制皮质酮或FS导致的空间记忆受损。（3）糖皮质激素受体的拮抗剂RU38486阻断上述的空间记忆成绩提高。所以，不同的应激经历和动物年龄两个因素共同决定了应激损伤还是提高学习记忆。 |
| 英文摘要 | Behavioral stress can either block or facilitate learning and memory, inhibited the induction of long-term potentiation (LTP) and facilitated long-term depression (LTD). However, the relevance of the stress experience dependent LTD (SLTD) to spatial learning and memory task was unknown; also, the effect of stress on age-related synaptic plasticity in vivo was primarily known; we even didn't know why stress either enhanced or impaired spatial memory under different conditions.In the first part, we investigated the effects of acute and sub-acute elevated platform (EP) and footshock (FS) stress on LTD induction in CA1 region of the hippocampus in anesthetized 4 weeks old Wistar rats and spatial memory in Morris water maze (a useful model of spatial learning and memory). The results showed that: (1) LTD was facilitated by acute but not sub-acute EP stress; but FS stress facilitated LTD induction both in acute and sub-acute treatment. (2) Acute EP stress impaired the spatial memory but the sub-acute EP stressed animals performed the spatial memory task as well as the controls; however, acute FS stress did not affect the spatial memory, and sub-acute FS even enhanced the spatial memory retrieval. Our findings exhibited that the effect of stress on spatial memory was disassociated with the effect of stress on LTD, but was associated with the stress experience and the stress types (EP or FS). Thus, SLTD may relate to certain stress memory. March 18~22, 2002 and dust storm process during April 13-17, 2002 that sand and dust emissions in modeling area in these two processes are weak in west area and strong in east area. On the west of 95°E, there are disperse dust emissions only around Taklimakan Desert and the vertical dust fluxes are not too large, so this region only is a weak dust source area during these two dusty weather processes, which are consist with concerned observational data. On the east of 100°E, dust emission areas in these two processes are very wide and their intensities are very high, which is consistent with the phenomenon reflected by observational data concerned; at the same time, prevailing wind in this region are west or westerly, leading that dusts suspended in air are easily transported eastwardly and arousing far and wide dusty weather, therefore, this region should be a main dust source area in these two processes. On the south of 40°N and between 90°E~100°E, sand and dust emissions are also always high and vertical dust fluxes even exceed lO^kgnfV1. However, the simulated results in these two processes are not consistent with observational results of visibility completely, so this region is likely to be a bogus dust source area, and the possible reasons lie in that the modeled friction velocities are on the high side and the surface data is not proper.(6), from the point of molded factors, during the intense dust storm process between March 18 and 22 of 2002, spatial variations and distributions of intensity of sand and dust emissions are mainly influenced by friction velocity. Surface relative humidity and threshold friction velocity are minor factors. While the dust storm process between April 13 and 17 of 2002 is companied with a precipitation process in north China, inducing large variations in temporal and spatial of surface relative humidity, and resulting in that both surface relative humidity and friction velocity are main factors influencing sand and dust emissions, and secondary factor is threshold friction velocity. In addition, from the point of comparison with observational data, modeling effect of intense dust storm is better than that of general dust storm. |
| 语种 | 中文 |
| 公开日期 | 2010-10-15 |
| 源URL | [http://159.226.149.42:8088/handle/152453/6189]  |
| 专题 | 昆明动物研究所_学习记忆的分子神经机制 |
| 推荐引用方式 GB/T 7714 | 熊文勇. 应激对大鼠海马突触可塑性和学习记忆的影响[D]. 北京. 中国科学院研究生院. 2004. |
入库方式： OAI收割
来源：昆明动物研究所
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