Transduction mechanism in olfactory sensory neurons

描述(申请人提供)：这项提案的长期目标是定量了解嗅觉感觉神经元(OSNs)的转导机制。目前，关于转导过程中的每一步，几乎没有任何生物物理信息。这些信息对于真正了解这一过程并最终了解其疾病状态至关重要，过去20年来我们对视网膜光转导的知识进步充分证明了这一点。具体目标是： 1)研究气味物质与受体蛋白之间的相互作用，以及在没有气味物质的情况下，气味物质受体是否具有结构性活性。 2)了解宏观嗅觉反应背后的单一事件的性质，并观察OSN对单一气味分子的反应是否确实可检测到。我们还将剖析环核苷酸门控电流和钙激活CI电流对么正反应的贡献。 3)量化嗅觉传导过程的钙依赖性适应，以及 4)研究嗅觉过程的钙非依赖性适应，以及GRK3、RGS2和光导蛋白在嗅觉反应终止中的可能作用。 实验方法包括用吸管记录青蛙和小鼠的单个OSN。基因工程小鼠品系也将被使用。

DESCRIPTION (provided by applicant): The long-term objective of this proposal is to understand quantitatively the transduction mechanism in olfactory sensory neurons (OSNs). At present, there is hardly any biophysical information about each step in the transduction process. This information is crucial for truly understanding the process and ultimately its disease states, as amply exemplified in the advancements in our knowledge about retinal phototransduction in the past two decades. The specific aims are: 1) To examine the interaction between the odorant and the receptor protein, and to find out whether odorant receptors have any constitutive activity in the absence of odorants. 2) To understand the nature of the unitary event underlying the macroscopic olfactory response, and to see whether the response of an OSN to a single odorant molecule is indeed detectable. We shall also dissect the contributions of the cyclic nucleotide-gated current and the Ca-activated CI current to the unitary response. 3) To quantify Ca-dependent adaptation of the olfactory transduction process, and 4) To study Ca-independent adaptation of the process, and the possible roles of GRK3, RGS2 and phosducin in the termination of the olfactory response. The experimental approach involves recording from single OSNs from frog and mouse with a suction pipette. Genetically engineered mouse lines will also be used.