PERIPHERAL MECHANISMS OF OLFACTORY RECEPTION

嗅觉神经元的刺激激活是由可逆的 树突状细胞中气味物质与受体蛋白的相互作用 睫状膜 刺激物与受体结合， 膜去极化，动作电位产生， 突触传递 然而，分子事件的顺序 受体激活和膜去极化之间的联系 不完全特征化。 最近的生物化学和 几种脊椎动物的电生理学证据 表明G蛋白连接的第二信使系统可能是 参与嗅觉刺激反应耦合。 的主要目标 建议的研究是确定刺激调节第二 信使的嗅觉系统的渠道鲶鱼和 确定第二信使在离子事件中的作用 潜在的膜去极化。 生物化学， 神经生理学和生物物理学方法将用于 描述分子和细胞机制， 刺激-受体相互作用和随后的离子事件。 生物化学实验将被用来确定关系 第二信使代谢和受体特异性之间的联系， 占用率 G蛋白在介导第二信使中的作用 代谢将在分离的纤毛中进行生物化学研究， 建立G蛋白效应器。 这些实验结合起来 通过对重组的神经元进行电生理和生物物理学研究， 膜和解离的受体细胞，将用于确定 第二信使和G蛋白在离子调节中的作用 通道和细胞内离子浓度。 的应用 将这些技术应用于模型系统，其中刺激受体 互动是很好的特点，将提供一个全面的， 分子和细胞事件的综合描述 潜在的嗅觉信号转导。

Stimulus activation of olfactory neurons is initiated by reversible interactions of odorants with receptor proteins in the dendritic ciliary membrane. Stimulus binding to receptor subsequently leads to membrane depolarization, action potential generation, and synaptic transmission. However, the sequence of molecular events between receptor activation and membrane depolarization remains incompletely characterized. Recent bio-chemical and electrophysiological evidence in several vertebrate species has indicated that G-protein-linked second messenger systems may be involved in olfactory stimulus response coupling. The major goal of the proposed research is to identify stimulus regulated second messengers in the olfactory system of the channel catfish and to determine the role of second messengers in the ionic events underlying membrane depolarization. Biochemical, neurophysiological, and biophysical methods will be used to characterize the molecular and cellular mechanisms that link stimulus-receptor interaction and subsequent ionic events. Biochemical experiments will be used to determine the relationships between second messenger metabolism and receptor specificity and occupancy. The role of G-proteins in mediating second messenger metabolism will be studied biochemically in isolated cilia using established G-protein effectors. These experiments, in combination with electrophysiological and biophysical studies in reconstituted membranes and dissociated receptor cells, will be used to determine the roles of second messengers and G-protein in regulation of ion channels and intracellular ion concentrations. Application of these techniques to a model system in which stimulus receptor interaction is well characterized, will provide a comprehensive and integrated description of the molecular and cellular events underlying olfactory signal transduction.