Brainstem and spinal cord expression of novel and existing neuronal connexins determined using transgenic reporter mice.

大脑包含数以百万计的神经细胞(神经元)，通常被组织成离散的集合来执行特定的功能。这些神经元与选定的伙伴进行交流，从而使这些功能成为可能。直到最近，人们认为脑细胞相互交流的唯一方式是通过化学突触，即一个神经元中的电脉冲释放一种化学物质，该化学物质在一个小空间内扩散，在另一个神经元中建立电信号。然而，最近出现的情况是，神经元可以通过允许两个细胞直接耦合/缝隙连接的通道进行通信。这些缝隙连接允许电信号和其他一些细胞代谢物直接在细胞之间传递。这种直接连接允许细胞之间快速传递信息，并允许一组神经元在其电活动中变得同步。这种同步性现在被视为决定许多大脑功能的重要因素。缝隙连接由不同的蛋白质组成，其中一些是被称为连接蛋白的家族。连接蛋白有很多种，但目前已知只有两种连接蛋白存在于大脑内的神经元中，即Cx36和Cx45。然而，它们在脑干和脊髓中的分布尚不清楚，神经系统中直接影响呼吸、血压、心率、痛觉和运动等的区域。此外，我们的初步数据显示，在这些区域的许多神经元中存在一种新的连接蛋白Cx30.2。因此，我们建议研究这些连接蛋白在脑干和脊髓中的分布。不幸的是，两种确定连接蛋白分布的传统方法已被证明是不可靠的，有许多错误的答案。因此，我们的研究将基于一种新的、经过验证的方法，即对小鼠进行基因改造，使其在细胞内产生一个标记，使每个个体产生连接蛋白。通过一个简单的反应，我们可以在组织切片中看到制造连接蛋白的细胞。由于脑干和脊髓包含具有不同功能的神经元，我们将使用其他解剖学和生理学方法找出哪些细胞类型表达特定的连接蛋白。我们还将用不同类型的标记物杂交小鼠，看看一个细胞是否可以产生不止一种连接蛋白。这一点很重要，因为单个细胞中不同连接蛋白的存在可能会影响特定缝隙连接的工作方式。因此，这些研究将提供有关神经元连接蛋白的分布、细胞类型和共定位的新数据。由于我们的初步研究表明，在以前未知的表达缝隙连接的神经元组中存在连接蛋白，因此全面的分析可能会为未来的研究揭示新的群体。识别这些具有同步活动能力的神经元组，将为理解这些大脑区域的功能提供新的领域。

The brain contains millions of nerve cells (neurones), generally organised into discrete collections to perform specific functions. These neurones communicate with selected partners to make such functions possible. Until recently the only way that brain cells were thought to communicate with one another was through chemical synapses where an electrical impulse in one neurone releases a chemical which diffuses across a small space to set up an electrical signal in another neurone. However, it has recently emerged that neurones can communicate by channels which allow two cells to be directly coupled / gap junctions. These gap junctions allow the passage of electrical signals and some other cellular metabolites directly between the cells. This direct connection permits fast transfer of information between the cells and allows groups of neurones to become synchronised in their electrical activity. Such synchrony is now seen as important for determining many brain functions. The gap junctions are made up of different proteins, some of which are a family called connexins. There are many connexins, but only two of these have been known to be present in neurones within the brain, Cx36 and Cx45. However, their distribution is not known in the brainstem and spinal cord, areas of the nervous system directly affecting breathing, blood pressure, heart rate, pain sensation and movement etc. In addition, our preliminary data shows that a new connexin, Cx30.2, is present in many neurones in these regions. We therefore propose to investigate the distribution of these connexins in the brainstem and spinal cord. Unfortunately, two conventional approaches to determining connexin distribution have proven unreliable, with many false answers. We will therefore base our studies on a new, validated approach where mice have been genetically altered to produce a marker within the cells that make each individual connexin. By a simple reaction we can see in tissue sections the cells where the connexins are made. Since the brainstem and spinal cord contain neurones with different functions we will work out which cell types express the particular connexins using additional anatomical and physiological methods. We will also cross breed mice with different types of markers to see if one cell can produce more than one connexin. This is important as the presence of different connexins in a single cell may influence how the particular gap junction works. These studies will therefore provide new data about the distribution, cell types and co-localisation of the neuronal connexins. Since our preliminary studies have suggested the presence of connexins in neuronal groups not previously known to express gap junctions, full analysis is likely to reveal novel populations for future studies. The identification of such neuronal groups with the capabilities of synchronising their activity will provide new areas of understanding of how these brain regions function.