【作者】 刘晶；

【导师】 安利佳；

【作者基本信息】 大连理工大学 ， 生物化工， 2006， 博士

【摘要】 本研究我们旨在探讨(1)发育和衰老过程中Y迷宫空间分辨学习和突触素(synaptophysin，SYN)的变化及窖蛋白(caveolin-1)对突触素的调节机制；(2)梓醇对衰老过程中Y迷宫空间分辨学习、行为能力及突触前蛋白包括突触素和神经生长相关蛋白(growth-associated protein 43，GAP-43)的影响，并从相关信息传递途径探讨作用机制。(3)梓醇及学习记忆训练对发育过程中突触前蛋白(突触素和GAP-43)的作用及机理。 应用行为学实验(Y迷宫)评价1-，4-，22-24月龄三个年龄组SD雄性大鼠Y迷宫空间分辨学习，western blotting技术检测各组大鼠海马、大脑皮层、小脑皮层突触素及caveolin-1的蛋白表达水平，分析二者的相关性。研究发现无论在海马、大脑皮层还是小脑，caveolin-1蛋白都表现出年龄依赖性的变化特点，而突触素则表现出与之相似的表达方式，二者呈显著正相关。海马突触素表达与动物Y迷宫空间分辨学习能力，主要是记忆成绩正性相关。提示在生物体发育、成熟和衰老的各过程，学习记忆能力与突触可塑性密切相关；caveolin-1在突触可塑性的调节中发挥重要作用，这种作用贯穿动物一生。 对1月龄幼鼠研究显示梓醇能提高发育过程中海马GAP-43、突触素表达水平，从而提高神经可塑性，其作用途径可能是激活蛋白激酶C(protein kinase C，PKC)及作用于caveolin-1。而学习记忆训练主要提高发育中海马突触素、caveolin-1蛋白表达，并不影响GAP-43水平，提示在发育过程学习训练能通过作用于caveolin-1，上调海马突触素表达水平而提高突触可塑性。表明梓醇与学习记忆训练对发育过程中神经可塑性具有不同的作用，作用位点及途径各不相同。 Y迷宫评价梓醇对22-24月龄老年大鼠空间分辨学习能力的作用，用旷场实验检测梓醇对老年大鼠探究能力、自发活动等行为功能的影响，western blotting及免疫组织化学技术检测青年对照组、老年对照组、梓醇治疗老年组大鼠海马GAP-43、突触素的表达水平。梓醇应用(连续腹腔注射)10天后，老年大鼠在记忆获得、记忆再现测试中达标所需的训练次数均明显少于老年对照组，正确反应率则高于老年对照组，表明梓醇长期治疗对老年大鼠Y迷宫空间分辨学习记忆能力有促进效应。用药5天时梓醇仅仅提高了老年大鼠记忆再现测试中的正确反应率。结果提示梓醇改善衰老伴发的学习记忆障碍具有时间依赖性特点。梓醇还能引起老年大鼠行为变化，主要表现为提高活动能力评分，缩短中央格停留时间，提示梓醇能提高动物的自发活动、探究能力。研究结果证明更多还原

【Abstract】 In this study, we attempt to investigate: (1) the changes and adjusting machnism of synaptic plasticity and spatial learning ability during development. (2) the effect of catalpol on cognitive and behavioral defect and presynaptic proteins and a potential mechanism during aging. (3) the effect and mechanism of catapal and training on neuroplasticity during development.We investigate the changes in the protein amount of caveolin-1, and the correlation with synaptophysin levels in various brain regions (the hippocampus, cortex and cerebellum) obtained from different age rats (1-, 4-, 22-24month rats). In the hippocampus, a concomitant decrease in caveolin-1 and synaptophysin protein levels has been observed, while in the cortex caveolin-1 and synaptophysin increased in parallel in 22-24month old rats. And in the cerebellum, there is no obvious difference in caveolin-1 and synaptophysin levels among three groups. Hippocampal synaptophysin levels are related to cognitive ability. Our results suggest caveolin-1 may play an important role on the modulating synaptic plasticity throughout life and down-regulated caveolin-1 in the hippocampus may contribute to the decrease of synaptic plasticity in physiological aging process.Behavioral tests (Y-maze and open-field test) are used to estimate the the cognitive and behavioral ability of 3 groups SD male rats (1-, 4-, 22-24 moths). We have reported a time-dependent effect of catalpol in the spatial learning and memory on Y maze. The application of catalpol reduced both the number of errors in learning and memory retention after ten days treatment, thus prevented the impairment of spatial learning, and increased memory. However, 5 days treatment only had effect on spatial memory not on learning. These results demonstrate the ability of catalpol to reverse memory deficits and further confirmed the therapeutic potential of catalpol in the treatment of cognitive deficits in aging. The evaluation of the different behavioral measures obtained in the open-field test provides clear evidence that application of catalpol induce obviously behavioral alteration. Catalpol-treated animals have displayed high scores of locomotor. And shorten entering center time that reflects exploratory motivation. These novel finding represents direct demonstration of catalpol preventing behavioral deficits of aged rats.The hippocampal levels of GAP-43 and synaptophysin in 3 groups of 4 months (young group), 22-24 months (aged group) and catalpol-treated 22-24 months (catalpol-treated group) rats are evaluated by western blotting. Results clearly show a significant decrease in synaptophysin (46.6%) and GAP-43 (61.4%) levels in the aged group against the young animals and an increase (45.0% and 31.8% respectively) in the catalpol-treated aged rats in comparison with the untreated aged group. By immunohistochemistry, furthermore, we have found that catalpol selectively enhance synaptophysin-IR within the neurons in dentate gyrus layer, while it does not affect synaptophysin-IR in CA1 and CA3 subregions of the更多还原