The role of spontaneous neurotransmission in synaptic plasticity and behavior

自发神经传递在突触可塑性和行为中的作用

• 批准号: 8765626
• 负责人: Devon C Crawford
• 金额: $ 5.42万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-12-01 至 2015-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8765626
• 关键词: Action Potentials; Acute; Adult; Alzheimer' s Disease; Animals; Antibodies; Antidepressive Agents; Area; Behavior; Behavior Therapy; Behavioral; Biochemistry; Biomedical Research; Calcium; Cell membrane; Chemosensitization; Depressed mood; Development; Dose; Electrophysiology (science); Epilepsy; Event; Frequencies; Functional disorder; Genetic; Glutamates; Goals; Green Fluorescent Proteins; Health; Hippocampus (Brain); Immunohistochemistry; In Vitro; Injection of therapeutic agent; Ketamine; Lead; Life; Link; Measures; Mediating; Mediator of activation protein; Membrane; Membrane Fusion; Mental Depression; Mental disorders; Methods; Microscopy; Molecular; Molecular Target; Mus; Nervous system structure; Neurons; Optics; Organelles; Pathway interactions; Pattern; Pharmaceutical Preparations; Physiological; Physiology; Play; Presynaptic Terminals; Process; Proteins; Recycling; Reporter; Resistance; Rodent; Role; SNAP receptor; Schizophrenia; Shapes; Signal Transduction; Slice; Synapses; Synaptic Cleft; Synaptic Transmission; Synaptic Vesicles; Synaptic plasticity; Tail; Techniques; Testing; Training; Translational Research; Vesicle; Virus; Work; career; cognitive change; enhanced green fluorescent protein; experience; hippocampal pyramidal neuron; in vivo; knock-down; nervous system disorder; neurotransmission; neurotransmitter release; patch clamp; postsynaptic; receptor; research study; response; skills; small hairpin RNA; synaptic function; synaptotagmin I; therapy development; transmission process; treatment-resistant depression; two-photon; vector control; vesicle-associated membrane protein

DESCRIPTION (provided by applicant): Neurotransmission requires the fusion of synaptic vesicles with the plasma membrane, which releases neurotransmitter into the synaptic cleft. Proteins called soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) mediate this fusion process by bringing the two membranes together and catalyzing fusion. Canonically, calcium entry during action potential stimulation of presynaptic terminals causes synchronous fusion of many synaptic vesicles arising from multiple synapses. In the absence of action potentials, however, some vesicles fuse spontaneously, releasing neurotransmitter in a sparse and temporally random pattern. It is unclear whether this spontaneous neurotransmission shapes neuronal function and alters synaptic plasticity and behavior, but prior work has implicated its inhibition in the fast-acting antidepressant effects of low-dose ketamine administration in treatment-resistant depression. Recently, two noncanonical vesicular SNAREs, vps10p tail interactor 1a (vti1a) and vesicle-associated membrane protein 7 (VAMP7/TI- VAMP), were identified as specific modulators of spontaneous neurotransmission. Reductions in these proteins in vitro reduce the frequency of spontaneous fusion events. The overall goal of the proposed project is to identify the roles spontaneous neurotransmission plays in vivo, especially in the fast-acting antidepressant response to ketamine. To achieve this goal, vti1a and VAMP7 will be knocked down in vivo via stereotaxic injection of virus encoding shRNA into the hippocampus, an area thought to be important for ketamine's effects. The first aim of the proposed project is to determine whether vti1a and VAMP7 knockdown alters spontaneous neurotransmission and synaptic plasticity by using a combination of electrophysiological and optical recording methods. The second aim of the proposed project is to determine whether knockdown of vti1a and VAMP7 modifies ketamine's ability to produce antidepressant responses. This will be tested by measuring behavior after ketamine treatment in mice that were previously injected with the virus knocking down vti1a and VAMP7. Together, these aims will determine whether a reduction in levels of vesicular SNAREs vti1a and VAMP7 alters synaptic function and in vivo behavior. Additionally, this project will clarify upstream mechanisms responsible for the fast-acting antidepressant effects of ketamine, potentially leading to identification of additional signaling cascades that can be modified to treat depression while avoiding the abuse potential inherent in ketamine administration. This proposed project also provides valuable training to the applicant in developing techniques and professional skills important for a career in biomedical research.

描述（由申请人提供）：神经传递需要突触囊泡与质膜融合，其将神经递质释放到突触间隙中。被称为可溶性N-乙基马来酰亚胺敏感因子附着蛋白受体（SNARE）的蛋白质通过将两种膜结合在一起并催化融合来介导这种融合过程。典型地，在突触前末梢的动作电位刺激期间钙进入引起由多个突触产生的许多突触囊泡的同步融合。然而，在没有动作电位的情况下，一些囊泡自发融合，以稀疏和时间随机的模式释放神经递质。目前还不清楚这种自发的神经传递是否会塑造神经元功能并改变突触的可塑性和行为，但先前的工作表明它抑制了快速起效的抗抑郁作用。 低剂量氯胺酮治疗难治性抑郁症最近，两个非经典的囊泡SNARE，vps 10 p尾相互作用因子1a（vti 1a）和囊泡相关膜蛋白7（VAMP 7/TI-VAMP）被鉴定为自发神经传递的特异性调节剂。这些蛋白质在体外的减少降低了自发融合事件的频率。该项目的总体目标是确定自发神经传递在体内发挥的作用，特别是在氯胺酮的速效抗抑郁反应中。为了实现这一目标，vti 1a和VAMP 7将通过立体定位注射编码shRNA的病毒到海马体中来体内敲低，海马体被认为是氯胺酮作用的重要区域。该项目的第一个目的是确定vti 1a和VAMP 7敲低是否会改变自发神经传递和突触可塑性，通过使用电生理和光学记录方法的组合。该项目的第二个目的是确定vti 1a和VAMP 7的敲低是否改变了氯胺酮产生抗抑郁反应的能力。这将通过测量氯胺酮治疗后小鼠的行为进行测试，这些小鼠先前注射了敲低vti 1a和VAMP 7的病毒。总之，这些目标将确定囊泡SNARE vti 1a和VAMP 7水平的降低是否会改变突触功能和体内行为。此外，该项目将阐明氯胺酮速效抗抑郁作用的上游机制，可能导致识别可以修改以治疗抑郁症的其他信号级联，同时避免氯胺酮给药中固有的滥用可能性。该项目还为申请人提供了宝贵的培训，以开发生物医学研究职业生涯中重要的技术和专业技能。