Neural circuit basis for neurovascular coupling

摘要 神经血管偶联(NVC)是神经活动和脑血流量之间的时间关系 (CBF)。这种神经诱发的血流动力学反应是局部脑血管内稳态和 在脑血管疾病中被破坏，如中风、脑淀粉样血管病、创伤性脑损伤、 以及阿尔茨海默氏症。表达神经元型一氧化氮合酶(Nos1)的神经元是理想的。 由于一氧化氮(NO)是一种非常有效的血管扩张剂，因此可能是NVC的调节对象。我们的团队已经 最近开发出一种Tacr1Creer等位基因，可以对这些神经元进行可视化和操作。我们 现在已经有了令人兴奋的初步数据，支持Tacr1神经元介导血管扩张的假设。这里, 我们建议通过一系列实验来测试这一想法，这些实验将：确定Tacr1与 神经元和血管；检查Tacr1神经元调节NVC的因果关系 底层电路。这些实验包括相关研究，将确定结构是否 Tacr1神经元的(位置)和功能(活动)使它们能够调节CBF。我们还将使用光生技术 方法和激光多普勒血流仪(LDF)记录清醒行为小鼠的脑血流，以测试Tacr1 神经元是血管扩张所必需的，也是充分的。最后，我们将使用光遗传的组合 手法、GCaMP6f-和2P-成像，以阐明NVC的潜在电路。总体而言，我们的建议 将解决与构成大胆行为的特定神经机制有关的严重知识空白 Signal，这是一种广泛使用但知之甚少的研究和临床工具。此外，这种对 NVC是我们理解常见脑血管疾病发病机制的基础 以脑血流为靶点的药物治疗研究进展。

Abstract Neurovascular coupling (NVC) is the temporal relationship between neural activity and cerebral blood flow (CBF). This neural-evoked hemodynamic response is fundamental to local cerebrovascular homeostasis and is disrupted in cerebrovascular diseases, such as stroke, cerebral amyloid angiopathy, traumatic brain injury, as well as Alzheimer's Disease. The neurons that express neuronal nitric oxide synthase (Nos1) are ideal candidates for the regulation of NVC since nitric oxide (NO) is a very potent vasodilator. Our group has recently developed a Tacr1CreER allele that enables the visualization and manipulation of these neurons. We now have exciting preliminary data supporting the hypothesis that Tacr1 neurons mediate vasodilation. Here, we propose to test this idea through a set of experiments that will: determine the relationship between Tacr1 neurons and blood vessels; examine causality in the regulation of NVC by Tacr1 neurons; and investigate the underlying circuitry. These experiments include correlative studies that will establish whether the structure (place) and function (activity) of Tacr1 neurons positions them to regulate CBF. We will also use optogenetic approaches and laser Doppler flowmetry (LDF) to record CBF in awake behaving mice to test whether Tacr1 neurons necessary and sufficient for vasodilation. Finally, we will use a combination of optogenetic manipulation, GCaMP6f-, and 2P-imaging to elucidate the underlying circuitry of NVC. Overall, our proposal will address a critical gap in knowledge with respect to the specific neural mechanisms that underlie the BOLD signal, which is a widely used, but poorly understood research and clinical tool. Moreover, this insight into NVC is fundamental to our understanding of the pathogenesis of common cerebrovascular diseases and the advancement of pharmacotherapeutics targeting cerebral perfusion.