岛叶皮质GABAB受体在匹罗卡品致痫大鼠再认记忆损害中的作用及机制研究

In healthy individuals, the insular cortex has been implicated in a myriad of physiologic functions. Recently, the insular cortex has been specially highlighted in human imaging literature and outcomes from brain surgery findings that have demonstrated its importance in several complex cognitive functions like emotion, perceptual functions, sensory-motor integration and body awareness. Emerging evidence suggests that atypical engagement of specific subdivisions of the insular cortex within the salience network is a feature of many neuropsychiatric disorders..Temporal lobe epilepsy is the most prevalent form of complex partial seizures with temporal lobe origin of electrical abnormality. Studies have shown that recurrent seizures affect all aspects of cognitive functioning, including memory, language, praxis, executive functions, and social judgment, among several others. However, little is known about anatomical and physiological features of the insular lobe in models of temporal lobe epilepsy. .Sustained inhibitory signaling in the brain is mediated by GABABRs. GABABRs are thought to play an important role in regulating physiological and pathological brain network activities, changes in the efficacy of GABABRs are critical for the control of neuronal activity and cognitive performance. However, the functions of these receptors in insular cortex remain unexplored. .Our previous research has shown that the recognition memory was impaired after kindling induced by electrical stimulation in the insular cortex of rats. Intra-peritoneal injection of GABABR agonists baclofen resulted in the impairment of the performance of rats in the Morris water maze tests. Conversely, GABABR antagonists improve cognitive performance epilepsy rats..This project study was designed to investigate the role and mechanisms of GABABRs of insular cortex on recognition memory formation in lithium-pilocarpine-induced status epilepticus (SE) in rats. Rats were implanted bilaterally with guide cannulae aimed either at the anterior insular cortex, hippocampus, or perirhinal cortex. Protein synthesis blocker anisomycin, GABABR agonist (baclofen), antagonist (CGP35348), and GABAB1R siRNA was bilaterally microinfused into the insular, hippocampus, or perirhinal cortices, different behavioral tasks were performed using the step through test, morris water maze, novel object recognition test, 3-chambered social test and/or the IntelliCage for rats. The expression of Arc, CREB, p-CREB and its upstream regulating factors PKA, CaMKⅡ, ERK, downstream target genes BDNF in the insular cortex, will be analyzed using Immunohistochemistry, Protein blots, RT-PCR, and In situ hybridization. .This study would open a new horizon in cortical research involving cognitive functions like recognition memory consolidation and retrieval, creating exciting avenues in translational models for the treatment of epilepsy.

岛叶是突显网络的关键节点，与认知密切相关，其在再认记忆中的作用渐受关注。颞叶癫痫常伴记忆障碍，岛叶在其中的作用及机制尚不清。前期研究显示，GABABR与记忆巩固及颞叶癫痫密切相关。据此提出，岛叶是再认记忆形成的核心区域，岛叶GABABR参与颞叶癫痫记忆障碍发生。我们拟岛叶内蛋白合成封闭剂、GABABR干扰剂、siRNA灌注，行为学实验测试大鼠空间记忆、新事物再认、社会适应等能力，探讨岛叶及GABABR在再认记忆中作用；分子生物学技术检测岛叶GABABR活性对即早基因Arc，转录因子CREB、pCREB及其上游调控因子、下游靶基因的影响，免疫共沉淀检测GABABR与pCREB的相互作用，明确GABABR对岛叶突触可塑性、转录活性的影响及激活途径；观察匹罗卡品颞叶癫痫大鼠再认记忆损害情况，研究岛叶在其中所起作用及机制。本项目有助于进一步认识岛叶功能、再认记忆形成机制，并为癫痫治疗提供新视角。

岛叶位于脑核心区，功能神秘复杂，近年研究显示岛叶在信息整合过程中起到核心作用。再认记忆被认为是信息整合的基础，涉及众多脑区，与众多神经、精神类疾病的发生存在密切关系，本项目围绕岛叶GABAB神经元及受体，探讨岛叶在认知功能中的作用及机制。.项目采用药物微灌注，分别于岛叶、海马等结构灌注蛋白合成封闭剂，GABABR激动、拮抗剂及siRNA，避暗试验、新物体识别、全自动大（小）鼠行为学检测系统等测试空间记忆、新事物识别、社会适应等能力，探讨岛叶及GABABR与再认记忆的关系；荧光免疫、原位杂交、PCR等检测岛叶GABABR活性水平对Arc、CREB、BDNF等的影响，明确GABABR对岛叶皮质突触可塑性、转录活性的影响及激活途径；建立药物点燃癫痫模型，探讨颞叶癫痫再认记忆损害特征，岛叶及GABABR在其中所起作用。研究证实：岛叶电点燃影响大鼠再认记忆；岛叶GABABR与神经元活性及再认记忆密切相关；岛叶GABABR通过调控BDNF和ARC/Arg3.1影响颞叶癫痫大鼠的再认记忆。.研究过程中，课题组发现，记忆再巩固与岛叶密切相关，很好地支持了岛叶再认记忆功能，研究证实：提取后激活岛叶无颗粒皮质GABABR可消除吗啡奖赏记忆，岛叶无颗粒皮质 GABABR在药物线索记忆再巩固中具有重要作用；岛叶GABA能神经元激活可通过破坏吗啡奖赏记忆再巩固来消除已建立的CPP，从而达到预防复吸的效果，Arc和Erg-1是其潜在的分子学机制。.项目已发表论文9篇，其中SCI收录8篇。已培养博士3名，硕士2名。继续以岛叶与记忆功能为主题，获2020年度国家自然科学基金项目1项（慢性电刺激吗啡成瘾大鼠前岛叶对成瘾行为的影响及机制研究，82060261）。同时课题组积极开展岛叶病变临床研究，相关成果获宁夏科技进步二等奖1项（岛叶癫痫发生机制及临床诊治研究）。圆满完成项目既定目标。