正常及慢性脑低灌注大鼠海马神经网络在体电生理特性及药物干预作用研究

发布时间：2018-03-21 16:28

本文选题：长时程增强　切入点：双脉冲易化　出处：《华中科技大学》2014年博士论文　论文类型：学位论文

【摘要】：第一部分：海马-皮层神经网络的电生理特性在大鼠学习记忆过程中的作用目的：分析海马-皮层神经网络的电生理特性,探讨其在学习记忆过程中的作用。方法：采用在体电生理技术同时记录双侧海马CA1区和顶叶联合皮层区突触传递,观察Schaffer侧枝-CA1通路(SC)、Schaffer侧枝/联合纤维通路(SAC)和Schaffer侧枝/联合纤维-皮层通路(SACC)的电生理特性的差异与联系。结果：(1)SAC和SACC通路的突触传递依赖于海马联合纤维[背侧和腹侧海马联合纤维,内侧隔核(MS)和海马CA3联合纤维]；(2) SACC通路的神经传导速度可能比SAC通路快；(3)与SAC和SACC通路相比,SC通路的I/O曲线向左移；(4)这三种通路都可以诱导稳定的LTP,但SAC和SACC通路LTP比SC通路LTP更强；(5)与SAC和SACC通路相比,SC通路的双脉冲易化较弱；(6)切断脑肼胝体和联合纤维,大鼠空间学习记忆能力受损,探索新事物能力减弱,同时自发活动也减弱。结论：海马联合纤维在大脑两半球之间的信息传递中起重要作用,SC、SAC和SACC三种通路相互联系并共同参与学习记忆的形成和巩固。第二部分：α2肾上腺素受体激动剂clonidine对在体大鼠海马Schaffer侧枝-CA1区突触LTP诱导的影响及机制研究目的：观察α2肾上腺素受体对在体海马Schaffer侧枝-CA1区突触的影响,并探讨其机制。方法：本研究应用在体电生理技术探究α2肾上腺素受体激动齐clonidine对在体海马Schaffer侧枝-CA1区LTP和PPF的影响。结果：Clonidine (0.05mg/kg,0.1mg/kg, ip)可剂量依赖性的抑制突触传递,同时可显著降低麻醉大鼠的心率和血压。Clonidine (1.25μg/kg,2.5μg/kg, icv, HFS前10min给药)亦可剂量依赖性的抑制突触传递,但对心率和血压无显著影响。但是,在HFS后20min给予clonidine对LTP无显著影响。Clonidine (2.5pg/kg)对LTP的抑制作用可被yohimbine (18μg/kg, icv)和ZD7288(5μg/kg, icv)拮抗。此外,clonidine对LTP的抑制作用伴随着PPF的显著增加。结论：Clonidine可以显著抑制海马CA1区LTP的诱导,可能与突触前膜α2受体的激活及其对HCN通道功能的调控有关。第三部分：GABAB受体激动剂baclofen对大鼠慢性低灌注脑缺血诱导的认知损伤的神经保护作用及机制研究目的：本实验旨在通过观察HCN通道和GABAB受体在病理情况下的变化,探讨GABAB受体激动所介导的神经保护作用及慢性低灌性脑缺血大鼠海马CA1区的GABAB受体与HCN通道之间的相互调控。方法：采用双侧颈总动脉永久性结扎(2VO)建立大鼠慢性低灌注脑缺血模型；应用水迷宫和新事物认知实验评价其认知功能的变化；采用免疫荧光技术观察神经元丢失情况；高尔基染色测定海马树突棘数目的变化；Western blot检测GABAB1, GABAB2受体,HCN1,HCN2通道以及PKA, p-PKA, TRIP8b(1a-4), TRIP8b(1b-2), AAK1, p-AP2等蛋白表达变化。结果：2VO模型组大鼠空间学习记忆能力受损,对新旧事物的辨别能力降低；海马CA1区神经元的数量及树突棘的数目显著减少；海马CA1区GABAB1,GABAB2受体以及HCN1通道的膜表达降低,而HCN2的膜表达增加。GABAB受体激动剂baclofen可以显著改善学习记忆损伤,减轻海马CA1区神经元损伤。在低灌性脑缺血情况下,baclofen也可能通过间接激活PKA而抑制GABAB1,GABAB2受体膜表达下调。此外,baclofen可以恢复海马CA1区HCN1和HCN2膜表达的平衡,其可能机制为：(1)增加TRIP8b(1a-4)和TRIP8b(1b-2)的表达；(2)通过AAK1和P-AP2μ2调控TRIP8b(1a-4)和TRIP8b(lb-2)的功能。结论：GABAB受体的激活可重新平衡HCN1和HCN2的膜表达,进而改善慢性低灌性脑缺血引起的认知功能的损伤。
[Abstract]:Part 1: the role of electrophysiological characteristics of the hippocampus cortical neural network in the learning and memory process of rats
Objective: to analyze the electrophysiological characteristics of hippocampal - cortical neural network, and explore its role in the process of learning and memory. Methods by using in vivo electrophysiological techniques while recording synaptic bilateral hippocampal CA1 and parietal cortex joint transmission, observe the Schaffer -CA1 pathway (SC), collateral Schaffer collateral / combined fiber pathway (SAC) and Schaffer collateral / combined fiber (SACC) and cortical pathway differences of electrophysiological characteristics. Results: (1) SAC and SACC of synaptic transmission in hippocampus depends on the dorsal hippocampus and ventral joint combined with fiber fiber, the medial septum (MS) and hippocampus CA3 joint (2) nerve fiber]; the conduction velocity of the SACC pathway may be faster than the SAC pathway; (3) compared with the SAC and SACC pathway, SC pathway I/O curve to the left shift; (4) the three pathway can induce stable LTP, but the SAC and SACC pathway LTP than SC pathway LTP stronger; (5) and SAC and SACC pathway Ratio of double pulse SC pathway to weak; (6) to cut off the brain corpus callosum and combined with fiber, the ability of spatial learning and memory impairment, to explore new things and the ability to weaken, spontaneous activity is reduced. Conclusion: the hippocampus between the two cerebral hemispheres combined with fiber information transmission plays an important role, SC, SAC SACC and three pathways connect with each other and jointly participate in the formation of learning and memory and consolidation.
The second part: the effect and mechanism of alpha 2 adrenergic receptor agonist clonidine on the induction of synaptic LTP in the hippocampal Schaffer lateral branch -CA1 region of the rat
Objective: To observe the effects of alpha 2 adrenergic receptors to synapses in the hippocampal Schaffer region of the -CA1 branch, and to explore its mechanism. Methods: This study used in vivo electrophysiological techniques to explore effects of 2 alpha adrenergic receptor in hippocampus of Qi clonidine -CA1 LTP and PPF Schaffer collateral. Results: (0.05mg/kg, 0.1mg/kg, Clonidine IP) can inhibit dose dependent synaptic transmission at the same time, can significantly reduce the heart rate and blood pressure in.Clonidine anesthetized rats (1.25 g/kg, 2.5 g/kg, ICV, HFS before 10min administration) also dose dependent inhibitory synaptic transmission, but had no significant effect on heart rate and blood pressure. However, no significant clonidine effect of.Clonidine on LTP after HFS 20min (2.5pg/kg) inhibition of LTP by yohimbine (18 g/kg, ICV) and ZD7288 (5 g/kg ICV) antagonist. In addition, clonidine of LTP inhibited by accompanied by a significantly increased PPF. Conclusion: Clonidine can significantly inhibit the induction of LTP in the hippocampal CA1 region, which may be related to the activation of the alpha 2 receptor of the presynaptic membrane and the regulation of the function of the HCN channel.
The third part: the neuroprotective effect and mechanism of GABAB receptor agonist baclofen on cognitive impairment induced by chronic hypoplastic cerebral ischemia in rats
Objective: the purpose of this study is to observe the HCN channel and GABAB receptor in pathological conditions change, mutual control between GABAB receptor and HCN pathway to investigate the neuroprotective effect of GABAB receptor mediated and chronic hypoperfusion of cerebral ischemia in rat hippocampal CA1 area. Methods: double side carotid artery permanent ligation (2VO) to establish chronic hypoperfusion cerebral ischemia rat model; changes in the evaluation of cognitive function by water maze and new cognition experiment; loss of neurons were observed by immunofluorescence staining; Golgi determination of changes in the number of dendritic spines in the hippocampus; Western blot detection of GABAB1, GABAB2 receptor, HCN1, HCN2 channel, PKA, p-PKA TRIP8b, (1a-4), TRIP8b (1b-2), AAK1, expression of p-AP2 protein. Results: 2VO model rats, the ability of spatial learning and memory impairment, to identify new and old things can decrease hippocampal CA; The number of neurons in area 1 and the number of dendritic spines was significantly reduced; GABAB1 region CA1, GABAB2 receptor and HCN1 channel membrane expression decreased, while HCN2 increased expression of membrane agonist baclofen could significantly improve the learning and memory impairment of.GABAB receptor, reduce the damage of hippocampal CA1 neurons in cerebral ischemia. Low irrigation condition, baclofen may inhibit GABAB1 by indirect activation of PKA, GABAB2 receptor expression. In addition, the baclofen can be restored in CA1 area of hippocampus HCN1 and HCN2 membrane expression of the balance, the possible mechanism is: (1) TRIP8b (1a-4) and TRIP8b (1b-2) expression; (2) by AAK1 and P-AP2 2 TRIP8b (control 1a-4) and TRIP8b (LB-2) function. Conclusion: GABAB receptor activation can be re balanced HCN1 and HCN2 membrane expression, and improve the cognitive function of chronic hypoperfusion of cerebral ischemia induced injury.

【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：R965

【共引文献】