Imaging Dynamics in Anxiogenic Serotonin Circuitry

项目摘要 血清素长期以来被认为是情绪和行为的重要调节剂，但它的投射- 具体的动力学知之甚少。虽然5-羟色胺在抗焦虑方面已经得到了很好的研究，但 某些5-羟色胺的投射会增加压力行为。特别是， 已经证明，终纹的前背床核的中缝背核是致焦虑的。尽管 针对5-羟色胺几十年来，缺乏对5-羟色胺功能和释放动力学的共识。 药理学方法、微透析和化学遗传学操作已经产生了关键的见解， 没有一个能提供5-羟色胺释放的毫秒级分辨率以及特定反应和行为的相关性 直到最近Tian实验室正在开发两种血清素特异性生物传感器（sLight和 iSeroSnFR），为血清素研究的新可能性打开了大门。我将这些传感器与 光学测量焦虑性5-羟色胺回路中行为驱动的5-羟色胺释放的光纤光度法 具有很高的时间和空间分辨率。 在这个建议中概述的一系列实验是重要的，因为它们将： 展示了5-羟色胺传感器在解剖焦虑回路中的体内效用，为最终用户提供了重要的 快速技术实施的协议和指南;目标2）绘制血清素释放的动态图， 焦虑电路的压力行为，并发现如何在这个电路的活动是在焦虑的动物的影响， 并确定急性与慢性SSRI给药对焦虑性5-羟色胺的机制影响 目的3）确定青春期睾酮对焦虑性神经元成熟的发育影响， 5-羟色胺活性和SSRI功效。

PROJECT SUMMARY Serotonin has been long been recognized as an important modulator of mood and behavior, yet it projection- specific dynamics are little understood. While serotonin has been well studied in anxiolytic contexts, activity of certain serotonin projections works to increase stress behaviors. In particular, serotonergic projections from dorsal raphe to the anterodorsal bed nucleus of the stria terminalis have been shown to be anxiogenic. Despite decades of targeting serotonin, a consensus on serotonin function and release dynamic is lacking. Pharmacological approaches, microdialysis, and chemogenetic manipulations have produced key insights, but none provide millisecond resolution for serotonin release and correlates of specific reactions and behaviors until recently. The Tian lab is in the final stages of developing two serotonin specific biosensors (sLight and iSeroSnFR) that open the door for new possibilities in serotonin research. I will these sensors combined with fiber-photometry to optically measure behaviorally driven serotonin release in an anxiogenic serotonin circuit with high temporal and spatial resolution. The series of experiments outlined in this proposal are significant because they will: Aim 1) rigorously demonstrate the in vivo utility of serotonin sensors in dissecting anxiety circuit, providing end users important protocols and guidelines for fast technological implementation; Aim2) map dynamics of serotonin release in anxiogenic circuits to stress behavior, and discover how activity in this circuit is impacted in anxious animals and determine the mechanistic impacts of acute vs. chronic SSRI administration on anxiogenic serotonin signaling; Aim 3) determine the developmental effects of pubertal testosterone on the maturation of anxiogenic serotonin activity and SSRI efficacy.