Role of L-Type Calcium Channels in Hippocampal Neuronal Network Activity

描述（由申请人提供）：自闭症谱系障碍（ASD）是一种普遍但知之甚少的神经系统疾病。Timothy综合征是一种与ASD高度相关的疾病，最近已被证明在L型Ca 2+通道内的单核苷酸取代中具有单基因起源。这种突变导致通道开放，这种效应可以通过L型Ca 2+通道激动剂BayK 8644来模拟。通过这种方式，我们可以在动物模型中重现TS，以产生可能推广到其他ASD的发现。这种动物模型允许TS从分子机制到海马电路的详细调查。该提案的目标是表征BayK 8644对海马体中从突触到回路的多个水平的生理过程的影响，并为单个分子故障如何影响神经回路的功能导致疾病表型提供路线图。具体目的1 -检验BayK 8644导致突触后神经元激活增强的假设。 兴奋性突触传递过程中Ca ~（2+）激活的K ~+电导。我们已经证明BayK 8644对大鼠海马急性切片中的兴奋性突触传递具有抑制作用。我们提出了一系列的实验来表征这种惊人的效果背后的细胞生理学。二.具体目标2 -开发一种用于研究海马切片制备中的行为相关网络动力学的系统。我们已经开发了一种新的系统，使用多单元四极管记录研究模式分离在急性海马切片。使用这种良好控制的切片准备，我们建议探测模式完成和模式分离之间的网络过渡点。三.具体目的3 -检验BayK 8644通过扰乱回路中兴奋性和抑制性影响的平衡来干扰海马回路动力学的假设。通过应用BayK 8644在一系列的实验类似于目标2中所描述的，我们建议测试如何在自闭症谱系障碍的急性模型的行为相关的电路动态的影响。我们将联合收割机结合细胞内和四极记录，以便将亚细胞与这种疾病模型的宏观效应联系起来。公共卫生相关性：自闭症谱系障碍是一种常见的严重衰弱的心理障碍。虽然最近的证据暗示了这种疾病的遗传基础，但我们对如何将基因功能与[最终]治疗联系起来知之甚少。我们在这里提出了一系列的实验，以更深入地了解自闭症谱系障碍的一个模型如何在多个层面上发挥作用，从基因到分子再到神经回路，因为它们在大脑中发挥作用。

DESCRIPTION (provided by applicant): Autism spectrum disorder (ASD) is a pervasive but poorly understood neurological disorder. Timothy Syndrome, a disorder with a highly significant link to ASD, has recently been shown to have a monogenetic origin in a single nucleotide substitution within the L-type Ca2+ channel. This mutation prolongs channel opening, an effect that can be mimicked pharmacologically by the L-type Ca2+ channel agonist BayK 8644. In this way we can recapitulate TS in an animal model to generate findings that can potentially generalize to other ASDs. This animal model allows for a detailed investigation of TS from molecular mechanisms to hippocampal circuitry. The goal of this proposal is to characterize the effects of BayK 8644 on physiological processes in the hippocampus at multiple levels from synapses to circuits and to provide a roadmap for how a single molecular malfunction can affect the functioning of a neural circuit leading to a disease phenotype.l. Specific Aim 1 - To test the hypothesis that BayK 8644 leads to enhanced activation of a postsynaptic Ca2+-activated K+ conductances during excitatory synaptic transmission. We have demonstrated that BayK 8644 has a dampening effect on excitatory synaptic transmission in acute slices of rat hippocampus. We propose a series of experiments to characterize the cellular physiology underlying this surprising effect. II. Specific Aim 2 - To develop a system for studying behaviorally relevant network dynamics in a hippocampal slice preparation. We have developed a novel system using multi-unit tetrode recordings to study pattern separation in an acute hippocampal slice. Using this well-controlled slice preparation, we propose to probe the network transition point between pattern completion and pattern separation. III. Specific Aim 3 - To test the hypothesis that BayK 8644 interferes with hippocampal circuit dynamics by upsetting the balance of excitatory and inhibitory influences in the circuit. By applying BayK 8644 during a series of experiments similar to those described in Aim 2, we propose to test how the behaviorally relevant circuit dynamics are affected in an acute model of autism spectrum disorder. We will combine intracellular and tetrode recordings in order to connect the subcellular to the macroscopic effects of this disease model. PUBLIC HEALTH RELEVANCE: Autism spectrum disorder is a common and profoundly debilitating psychological disorder. While recent evidence has implied a genetic basis for this disease, we know very little about how to connect genes to function to [eventually] treatment. We propose here a series of experiments to develop a deeper understanding of how one model of autism spectrum disorder might function at multiple levels from genes to molecules to neural circuits as they function in the brain.