Synaptic mechanisms underlying the rapid antidepressant actions of scopolamine

东莨菪碱快速抗抑郁作用的突触机制

• 批准号: 8810419
• 负责人: RONALD S. DUMAN
• 金额: $ 48万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-25 至 2019-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8810419
• 关键词: AMPA Receptors; Address; Affect; Anhedonia; Antidepressive Agents; Behavioral; Biochemical; Brain-Derived Neurotrophic Factor; Calcium Channel; Cells; Chronic; Chronic stress; Clinical Research; Complex; Data; Depressed mood; Development; Disease; Disinhibition; Dose; Economic Burden; Glutamates; Infusion procedures; Interneurons; Major Depressive Disorder; Maps; Medial; Mental Depression; Microdialysis; Modeling; Molecular; Mus; Muscarinic Acetylcholine Receptor; Muscarinics; Mutant Strains Mice; Neurons; Pathway interactions; Patients; Pharmaceutical Preparations; Population; Prefrontal Cortex; Protein Biosynthesis; Receptor Activation; Resistance; Rodent; Rodent Model; Role; Scopolamine; Signal Pathway; Signal Transduction; Sirolimus; Stress; Synapses; Testing; Therapeutic; Time; Vertebral column; Viral Vector; base; calmodulin-dependent protein kinase II; density; extracellular; gamma-Aminobutyric Acid; hippocampal pyramidal neuron; inhibitor/antagonist; interdisciplinary approach; mTOR protein; monoamine; multidisciplinary; mutant; neutralizing antibody; novel; optogenetics; postsynaptic; promoter; public health relevance; receptor; response; reuptake; small hairpin RNA; synaptogenesis; transmission process

DESCRIPTION (provided by applicant): Major depressive disorder (MDD) is one of the most prevalent and debilitating illnesses world wide, affecting ~17 percent of the population and causing enormous personal and economic burden. The impact of MDD is underscored by the limitations of currently available medications, including low response rates, treatment resistance, and therapeutic time-lag (weeks to months). These data highlight a major unmet need for more efficacious and faster-acting antidepressants. Recent studies demonstrate that a single low dose of scopolamine, a muscarinic receptor antagonist, produces rapid and long-lasting antidepressant actions in treatment resistant patients. This rapid action, by a mechanism completely different from typical monoamine reuptake inhibitors, represents one of the most significant findings in the field of depression over the past 60 years. The mechanisms underlying the rapid antidepressant actions of scopolamine have not been identified, and the current application addresses this issue. Preliminary studies have found that scopolamine rapidly stimulates the mammalian target of rapamycin complex 1 (mTORC1), a pathway involved in synaptic protein synthesis, rapidly increases spine number and function of PFC neurons, and produces rapid antidepressant behavioral responses in rodent models. Moreover, the actions of scopolamine are blocked by rapamycin, demonstrating a requirement for mTORC1. Based on these findings, we hypothesize that the rapid antidepressant actions of scopolamine result from stimulation of mTORC1 and increased synaptic connectivity in PFC that occur via a burst of glutamate and release of brain derived neurotrophic factor (BDNF). This application describes an integrated multidisciplinary approach, including molecular, biochemical, electrophysiological, morphological, optogenetic, and behavioral studies to test this hypothesis. Aim 1 will characterize the time course and regional localization of scopolamine-stimulation of mTORC1, spine density, and behavioral responses, and confirm the requirement for mTORC1 and BDNF using a combination of pharmacological, viral vector, and mutant mouse approaches. The hypothesis that scopolamine can rapidly reverse the synaptic and behavioral deficits caused by chronic stress will also be tested. Aim 2 will determine the role of glutamate-AMPA receptor transmission, which has been implicated in activity-dependent stimulation of BDNF-mTORC1 signaling and synapse formation, using microdialysis and selective inhibitors. Microinfusions and optogenetic approaches will be used to test the role of glutamate transmission in subregions of PFC and to identify target circuits that underlie rapid antidepressant responses. Aim 3 will test if the glutamate burst occurs via muscarinic-1 (M1) receptors located on GABA interneurons, resulting in disinhibition of glutamate transmission, using cell specific virally expressed floxed shRNA, M1 deletion mutants, and cell specific Cre mice. Characterization of the signaling pathways for scopolamine will identify fundamental mechanisms for rapid acting antidepressants and novel targets for safer, rapid-acting agents.

描述（由申请人提供）：重度抑郁症 (MDD) 是全世界最普遍、最使人衰弱的疾病之一，影响约 17% 的人口，并造成巨大的个人和经济负担。目前可用药物的局限性凸显了 MDD 的影响，包括低反应率、治疗抵抗和治疗时间滞后（数周至数月）。这些数据凸显了对更有效、更快速起效的抗抑郁药的主要未满足需求。最近的研究表明，单次低剂量的东莨菪碱（一种毒蕈碱受体拮抗剂）可以对治疗耐药的患者产生快速且持久的抗抑郁作用。这种快速作用的机制与典型的单胺再摄取抑制剂完全不同，是过去 60 年来抑郁症领域最重要的发现之一。东莨菪碱快速抗抑郁作用的机制尚未确定，当前的申请解决了这个问题。初步研究发现，东莨菪碱快速刺激哺乳动物雷帕霉素复合物1（mTORC1）靶点（参与突触蛋白合成的通路），快速增加PFC神经元的棘数量和功能，并在啮齿动物模型中产生快速的抗抑郁行为反应。此外，东莨菪碱的作用被雷帕霉素阻断，表明需要 mTORC1。基于这些发现，我们推测东莨菪碱的快速抗抑郁作用是由于刺激 mTORC1 以及通过谷氨酸爆发和脑源性神经营养因子 (BDNF) 释放而增加的 PFC 突触连接所致。该应用描述了一种综合的多学科方法，包括分子、生物化学、电生理学、形态学、光遗传学和行为研究来检验这一假设。目标 1 将描述东莨菪碱刺激 mTORC1 的时间过程和区域定位、脊柱密度和行为反应，并结合药理学、病毒载体和突变小鼠方法确认对 mTORC1 和 BDNF 的需求。东莨菪碱可以迅速逆转慢性压力引起的突触和行为缺陷的假设也将得到检验。目标 2 将使用微透析和选择性抑制剂确定谷氨酸-AMPA 受体传递的作用，谷氨酸-AMPA 受体传递与 BDNF-mTORC1 信号传导和突触形成的活性依赖性刺激有关。微输注和光遗传学方法将用于测试 PFC 亚区域中谷氨酸传输的作用，并确定快速抗抑郁反应的靶标回路。目标 3 将使用细胞特异性病毒表达 floxed shRNA、M1 缺失突变体和细胞特异性 Cre 小鼠，测试谷氨酸爆发是否通过位于 GABA 中间神经元上的毒蕈碱-1 (M1) 受体发生，从而导致谷氨酸传输去抑制。东莨菪碱信号通路的表征将确定快速起效抗抑郁药的基本机制以及更安全、快速起效药物的新靶点。