Regulation of Olfactory Signal Transduction

描述(申请人提供)：嗅觉传导是嗅觉感觉神经元(OSN)将气味信息转化为神经元电信号的过程。在过去的25年里，广泛的研究导致了脊椎动物OSNs的核心转导通路的阐明。然而，调节转导以允许适当的敏感性和反应动力学的过程还没有被很好地理解。钙是一种关键的嗅觉转导调节因子。在气味反应过程中，钙通过嗅觉环核苷酸门控(CNG)通道进入感觉纤毛，放大OSN去极化，也对几种嗅觉转导成分进行负性调节。这种负面调节支配着OSN的适应--这一现象表现为持续或重复刺激时敏感度降低。在这项建议中，我们建议利用我们培育的多个转基因小鼠品系：1)研究OSN适应中多种钙依赖反馈机制的整合(目标1)；以及2)研究在终止和适应中起作用的负调控机制在将OSN敏感性设置为静止状态(目标2)中的作用。电生理分析，在水平上 将在携带钙依赖反馈机制双重或三倍突变的小鼠(目标1)以及缺乏钙依赖反馈机制和缺乏有效钙排出的小鼠(目标2)上进行完整嗅觉上皮和分离的单细胞水平的研究。这项提议的长期目标是阐明嗅觉的分子机制。这项拟议的研究将通过调节敏感度和反应动力学，更好地理解OSN如何编码气味刺激的强度和时间特征。从拟议的研究中获得的知识将加深我们对正常嗅觉功能和嗅觉功能障碍的理解。

DESCRIPTION (provided by applicant): Olfactory transduction is the process by which olfactory sensory neurons (OSNs) transform odor information into neuronal electrical signals. Over the past two and a half decades, extensive investigations have led to the elucidation of a core transduction pathway in vertebrate OSNs. However, the processes that regulate transduction to allow for proper sensitivity and response kinetics are not well understood. Calcium is a key olfactory transduction regulator. Calcium enters the sensory cilium through the olfactory cyclic nucleotide-gated (CNG) channel during the odor response, amplifies OSN depolarization, and also negatively regulating several olfactory transduction components. This negative regulation governs OSN adaptation--a phenomenon manifested as reduced sensitivity upon sustained or repeated stimulation. In this proposal, we propose to take advantage of multiple genetically modified mouse strains that we generated to: 1) investigate the integration of multiple Ca2+-dependent feedback mechanisms in OSN adaptation (Aim 1); and 2) investigate the role of negative regulatory mechanisms, which function in termination and adaptation, in setting OSN sensitivity at rest (Aim 2). Electrophysiological analysis, at the level of intact olfactory epithelium and the isolated single cell level, will be conducted on mice carrying double or triple mutations for calcium-dependent feedback mechanisms (Aim 1) as well as on mice that lack a calcium-dependent feedback mechanism and also lack efficient calcium extrusion (Aim 2). The long-term goal of this proposal is to elucidate the molecular mechanisms underlying olfaction. The proposed investigation will lead to a better understanding of how OSNs encode the intensity and temporal features of odor stimulations by regulating sensitivity and response kinetics. The knowledge gained from the proposed research will enhance our understanding of normal olfactory function and olfactory dysfunctions.