Mechanisms Underlying TAAR1-induced Wakefulness and REM Sleep Suppression

项目摘要 痕量胺相关受体1（TAAR 1）是一种G蛋白偶联受体，参与调节 多巴胺能、多巴胺能和多巴胺能活性。TAAR 1激动剂具有抗焦虑、抗抑郁和抗抑郁作用。 在啮齿动物和非人灵长类动物中具有抗精神病样特性; TAAR 1激动剂正在进行临床试验， 精神分裂症和帕金森氏症精神病。我们之前已经证明TAAR 1激动剂是唤醒的- 在小鼠、大鼠和最近的非人类灵长类动物中促进，其特征在于睡眠/觉醒表型， Taar 1敲除（KO）和过表达（OE）小鼠，并评估了TAAR 1激动剂对 在野生型（WT）、KO和OE小鼠中的睡眠/觉醒。我们还发现两种不同的TAAR 1激动剂抑制了 在发作性睡病小鼠模型中，REM睡眠和减少的cataerosis，正是在一个研究中所期望的特性。 嗜睡症治疗。在确立了TAAR 1激动剂作为发作性睡病的潜在新型治疗方法后，我们 现在将研究潜在的体内神经生物学。在Taar 1-LacZ小鼠中，我们将确定TAAR 1 在单胺能、谷氨酸能或其他细胞类型中表达，并使用RNAscope技术 测定WT和KO小鼠和大鼠中内源性Taar 1 mRNA的表达。由于TAAR 1阴性 调节多巴胺能（DA）神经元的活动在体外，我们将测试的假设，TAAR 1部分激动 通过调节多巴胺唤醒系统来促进清醒。为了解决这个问题，我们将评估 用体内Ca ~（2+）测定DAT-ires-Cre小鼠腹侧被盖区和中缝背核的神经元活动 显微内窥镜检查，并确定是否与DA D1和D2受体拮抗剂预处理减弱 TAAR 1介导的唤醒促进。由于TAAR能神经元是唤醒活跃的和REM不活跃的， 在体外负调节TAAR能神经元的活动，我们还将测试TAAR 1部分 激动作用通过调节肾上腺素能唤醒系统促进觉醒。我们将决定 TAAR 1部分激动剂通过体内Ca ~（2+）显微内窥镜调节DRN β-肾上腺素能神经元的活性 在Fev-Cre小鼠中，并评估阻断肾上腺素能信号传导是否减弱促醒作用 TAAR 1部分激动剂。我们已经发现TAAR 1缺失提高了高频伽马EEG活动， 表明TAAR 1调节皮质功能。为了确定TAAR 1介导的 γ活性在物种间是保守的，并且是TAAR 1特有的，我们将研究基础睡眠/觉醒 在Taar 1 KO和OE大鼠以及Taar 2 -9 KO小鼠中进行生理学和定量EEG分析。在一起， 这些目标将开始建立TAAR 1疗效的神经回路和机制 激动剂

PROJECT SUMMARY Trace amine-associated receptor 1 (TAAR1) is a G protein-coupled receptor involved in the regulation of dopaminergic, serotonergic and glutamatergic activity. TAAR1 agonists have anxiolytic, antidepressant-, and antipsychotic-like properties in both rodent and non-human primates; TAAR1 agonists are in clinical trials for schizophrenia and Parkinson’s disease psychosis. We have previously shown that TAAR1 agonists are wake- promoting in mice, rats and, most recently, non-human primates, characterized the sleep/wake phenotype of Taar1 knockout (KO) and overexpressing (OE) mice, and evaluated the effects of TAAR1 agonists on sleep/wake in wildtype (WT), KO and OE mice. We also showed that two different TAAR1 agonists suppressed REM sleep and reduced cataplexy in mouse models of narcolepsy, precisely the properties desirable in a narcolepsy therapeutic. Having established TAAR1 agonists as potential novel treatments for narcolepsy, we will now investigate the underlying in vivo neurobiology. In Taar1-LacZ mice, we will determine whether TAAR1 is expressed in monoaminergic, glutamatergic or other cell types and use the RNAscope technology to determine endogenous Taar1 mRNA expression in WT and KO mice and rats. Since TAAR1 negatively regulates dopaminergic (DA) neuronal activity in vitro, we will test the hypothesis that TAAR1 partial agonism promotes wakefulness by modulating DA arousal systems. To address this hypothesis, we will assess neuronal activity in the ventral tegmental area and dorsal raphe nuclei of DAT-ires-Cre mice using in vivo Ca2+ microendoscopy, and determine whether pretreatment with DA D1- and D2-receptor antagonists attenuates TAAR1-mediated wake-promotion. Since serotonergic neurons are wake-active and REM-inactive and TAAR1 negatively regulates serotonergic neuronal activity in vitro, we will also test the hypothesis that TAAR1 partial agonism promotes wakefulness by modulating serotonergic arousal systems. We will determine whether TAAR1 partial agonists modulate the activity of DRN serotonergic neurons using in vivo Ca2+ microendoscopy in Fev-Cre mice and assess whether blockade of serotonergic signaling attenuates the wake-promoting effects of TAAR1 partial agonists. We have found that TAAR1 deletion elevates high-frequency gamma EEG activity, suggesting that TAAR1 modulates cortical function. To determine whether TAAR1-mediated elevation of gamma activity is conserved across species and specific to TAAR1, we will investigate basal sleep/wake physiology and conduct quantitative EEG analyses in Taar1 KO and OE rats and Taar2-9 KO mice. Together, these Aims will begin to establish the neural circuitry and mechanisms that underlie the efficacy of TAAR1 agonists.