Gene Expression and Drug Targets in the Rostromedial Tegmentum

描述（由申请人提供）：2009年，我们和其他人最近发现了一个以前被忽视的大脑区域，即前额内侧被盖核（RMTg）。这些神经元通过对多巴胺神经元的密集投射，以及来自外侧缰核、延伸杏仁核和其他涉及情感和动机的区域的主要输入，在厌恶学习、行为和成瘾中发挥关键作用。RMTg神经元对许多（尽管不是全部）与恐惧、焦虑、疼痛和药物戒断相关的厌恶行为至关重要。尽管最近关于RMTg的解剖、生理和行为特征的知识迅速增长，但这些神经元的遗传特性几乎完全未知。目前还不知道它们含有什么神经递质（除了GABA），也不知道它们是否表现出受体、摄取转运体或其他药物靶点，这些靶点可以选择性地控制它们的燃烧速率。此外，RMTg区域在尼氏染色上缺乏清晰的边界，如果没有神经示踪剂或即时早期基因诱导，则无法可视化，这些方法通常与其他实验范式不兼容。因此，该区域的基础科学和临床研究的进一步进展需要开发分子工具和药物靶点来选择性地识别和操纵这些神经元。为了满足这些需求，我们建议首先使用荧光激活细胞分选（FACS）从周围结构中分离这些神经元，然后使用全基因组表达阵列分析，最后使用原位杂交来确认候选基因的表达模式，从而检测RMTg基因的表达。我们希望这些结果能够填补我们对这一新兴大脑结构知识的主要空白，同时也为临床前和临床应用提供新的工具。

DESCRIPTION (provided by applicant): In 2009, we and others recently identified a previously overlooked brain region, the rostromedial tegmental nucleus (RMTg). These neurons play key roles in aversive learning, behavior, and addiction, via their dense projections to dopamine neurons, and major inputs from the lateral habenula, extended amygdala, and other regions implicated in affect and motivation. RMTg neurons are critically required for many (though not all) aversive behaviors related to fear, anxiety, pain, and drug withdrawal. Despite the rapid recent growth of knowledge regarding RMTg anatomic, physiological, and behavioral characteristics, the genetic properties of these neurons are almost entirely unknown. It is unknown what neurotransmitters (besides GABA) they contain, nor whether they exhibit receptors, uptake transporters, or other drug targets that could selectively manipulate their firin rates. Furthermore, the RMTg region lacks sharp boundaries on Nissl stains, and cannot be visualized without neural tracers or immediate early gene induction, methods often incompatible with other experimental paradigms. Hence, further progress in basic science and clinical studies of this region requires development of molecular tools and drug targets that selectively identify and manipulate these neurons. To meet these needs, we propose to examine RMTg gene expression by first using fluorescence activated cell sorting (FACS) to isolate these neurons from surrounding structures, followed by analysis on whole-genome expression arrays, and concluding with in situ hybridization to confirm expression patterns of candidate genes. We expect the results to fill in major gaps in our knowledge of this emerging brain structure, while also producing new tools for preclinical and clinical use.