Cellular and Molecular Physiology of Sympathetic Innervation of Vascular Smooth Muscle

我的NSERC研究项目的目标是了解血压和血液流经身体的控制。血管周围的交感神经引起血管平滑肌细胞收缩，使血管直径减小；如果这些神经过于活跃，就会导致高血压，而它们的活动不足则会导致昏厥。与大多数只释放一种神经递质（NT）的脑神经细胞不同，交感神经“共同释放”多种NT。在分子水平上对递质共释放的调控知之甚少。在接下来的五年里，我的NSERC研究将探索交感神经如何储存和释放多种nt的三个基本方面，以解决我们对交感神经调节血管直径的理解长期存在的空白。******去甲肾上腺素（NE）和ATP是释放到血管上的主要nt。交感神经是将NE和ATP储存在相同的可释放囊泡中还是在不同的囊泡中已经争论了30年。我们最近报道了令人信服的证据，表明NE和ATP储存在不同的囊泡中。在目标1中，我们将使用先进的（超分辨率）显微和分子方法来了解NT单独储存和共同释放的分子基础。这项工作将阐明这些神经如何对广泛的生理条件作出反应。******NT释放需要钙通过CaV2家族的电压门控钙通道进入神经末梢。这些通道的不同形式可以针对细胞和神经末梢的特定位置。了解哪些通道导致一种或多种NT的释放，将有助于我们理解一组神经如何在不同情况下释放不同的NT。在目标2中，我们将使用新的成像方法确定在不同的血管床和细胞培养模型中，哪些NTs通过三个通道（CaV2.1、CaV2.2和CaV2.3）释放。******线粒体是最著名的制造ATP的细胞器，但它们也调节局部钙信号。我们将研究这些线粒体功能如何影响交感神经中NE和ATP的释放。在目标3中，我们将测试线粒体在生理刺激频率上是否会影响NE或ATP的释放。这些研究将提高我们对线粒体丢失如何影响交感神经功能和平滑肌在老化血管中的调节的理解。******这个研究项目的新颖之处在于创造性地使用现代方法来解决关于NT共同发布的几十年的问题。我们的研究将丰富我们对血管神经控制的知识，并将立即用于其他研究NT共释放的研究，并有助于确定治疗高血压的治疗靶点。研究大脑和激素分泌的研究人员将受益于我们的基因编码报告器，显微镜学家将受益于我们创建的图像分析算法和软件

The goal of my NSERC research program is to understand control of blood pressure and blood flow through the body. Sympathetic nerves surrounding blood vessels cause contraction of vascular smooth muscle cells and reduce vessel diameter; if these nerves are over-active, they can cause high blood pressure, while their under-activity promotes fainting. In contrast to most brain nerve cells, which release one type of neurotransmitter (NT), sympathetic nerves “co-release” multiple NTs. Regulation of transmitter co-release is poorly understood at the molecular level. In the next five years, my NSERC research will explore three fundamental aspects of how sympathetic nerves store and release multiple NTs in order to address long-standing gaps in our understanding of sympathetic regulation of blood vessel diameter. ******Norepinephrine (NE) and ATP are the main NTs released onto blood vessels. Whether sympathetic nerves store NE and ATP in the same releasable vesicles or separate vesicles has been debated for 30 years. We recently reported compelling evidence that NE and ATP are stored in separate vesicles. In Objective 1, we will use advanced (super-resolution) microscopic and molecular methods to understand the molecular basis of separate NT storage and co-release. This work will clarify how these nerves respond to a wide range of physiological conditions.******NT release requires calcium to enter nerve terminals through voltage-gated calcium channels from the CaV2 family. Different forms of these channels can be targeted to specific locations in cells and nerve terminals. Knowing which channels cause the release of one or more types of NT will help us to understand how one set of nerves can release different NTs in different situations. In Objective 2, we will determine which NTs are released by three channels (CaV2.1, CaV2.2 and CaV2.3) in differential vascular beds and cell culture models using novel imaging methods.******Mitochondria are organelles best known for making ATP, but they also modulate localized calcium signals. We will study how these mitochondrial functions impact the release of NE and ATP from sympathetic nerves. In Objective 3, we will test if mitochondria differentially affect NE or ATP release, over physiological stimulation frequencies. These studies will improve our understanding of how the loss of mitochondria might affect sympathetic nerve function and smooth muscle regulation in aging blood vessels.******The novelty of this research program lies in creatively using modern methods to address decades-old questions about NT co-release. Our research will enrich our knowledge of neural control of blood vessels and will be of immediate use to others studying NT co-release and help identify therapeutic targets for the treatment of hypertension. Researchers studying the brain and hormone secretion will benefit from our genetically encoded reporters, and microscopists will benefit from the image analysis algorithms and software that we create.**