Role of Rhythmic Oscillations in Neuronal Plasticity

节律振荡在神经元可塑性中的作用

• 批准号: 7137858
• 负责人: Alexei Morozov
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF MENTAL HEALTH
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7137858
• 关键词: acetylcholine; behavioral /social science research tag; brain electrical activity; emotions; gene expression; genetic promoter element; genetically modified animals; laboratory mouse; learning; memory; neural plasticity; neurogenetics; neurons; neuropsychology; tetanus toxin; tetracyclines

Among these groups, cholinergic neurons are considered the key modulators of the oscillatory activities. In the past, the functional role of cholinergic neurons has been studied by the elimination of these neurons with immunotoxins, however this irreversible elimination of neurons brings about irreversible changes compromising interpretation of behavioral experiments. To directly test the role of oscillations in learning, memory and mood, we will reversibly inactivate cholinergic neurons in the mouse brain using regulated expression of the light chain of tetanus toxin. This toxin does not kill neurons, but prevent secretion of neurotransmitter by cleaving synaptobrevin, which is required for the docking of synaptic vesicles. Once the expression of the toxin is turned off, neurons should recover their functions. We will test the role of rhythmic oscillations at different stages of memory formation, consolidation and retrieval taking advantage of the reversibility of the system. In vivo recording and analysis of neuronal activity will be performed by Dr. Buzsaki at Rutgers University. We have completed the design of the scheme for reversible genetic inactivation of cholinergic neurons. The scheme includes generation of 2 lines of genetically modified mice. The first line will express tetracycline transactivator in the cholinergic neurons. It will be produced by targeting cholinergic locus with the construct harboring a gene for tetracycline transactivator. The second line will carry modified inactive tetanus toxin, which could only be activated only in the brain following a withdrawal of doxycycline from mouse diet. During the past fiscal year, we have completed a generation of mice with the tetracyclin transactivator gene expressed from the cholinergic locus promoter. Specifically, as the last step, we have successfully excised a selectable marker used during targeting of the locus. We were continuing work on making a targeting construct containing the tetanus toxin gene.

其中，胆碱能神经元被认为是振荡活动的关键调节器。在过去，胆碱能神经元的功能作用已经通过用免疫毒素消除这些神经元来研究，然而，这种不可逆的神经元消除带来了不可逆的变化，损害了行为实验的解释。为了直接测试振荡在学习、记忆和情绪中的作用，我们将使用破伤风毒素轻链的调节表达可逆地抑制小鼠脑中的胆碱能神经元。这种毒素不杀死神经元，但通过裂解突触泡蛋白来阻止神经递质的分泌，这是突触囊泡对接所必需的。一旦毒素的表达被关闭，神经元应该恢复它们的功能。我们将利用系统的可逆性来测试节律振荡在记忆形成、巩固和提取的不同阶段的作用。神经元活动的体内记录和分析将由罗格斯大学的Buzsaki博士进行。 我们已经完成了胆碱能神经元可逆性基因失活方案的设计。该方案包括产生2系遗传修饰小鼠。第一条线将在胆碱能神经元中表达四环素反式激活因子。它将通过用含有四环素反式激活因子基因的构建体靶向胆碱能位点来产生。第二条线将携带经过修饰的无活性破伤风毒素，该毒素仅在小鼠饮食中停用强力霉素后才能在大脑中被激活。 在过去的财政年度，我们已经完成了一代小鼠的四环素反式激活基因表达的胆碱能基因座启动子。具体地，作为最后一步，我们已经成功地切除了在靶向基因座期间使用的选择性标记。我们继续研究制造含有破伤风毒素基因的靶向结构。