Pharmacology and Regulation of Nicotinic Receptor Subtypes

描述（由申请方提供）：我们的目的是评估哺乳动物中枢神经系统（CNS）中不同异聚体神经元烟碱胆碱能受体（nAChR）亚型的药理学和调节。这些受体广泛分布于中枢神经系统中，在中枢神经系统中它们调节重要神经元通路中几种神经递质的释放。因此，它们影响了广泛的功能，并且它们显然与尼古丁成瘾有关。此外，这些受体被认为在广泛的其他CNS疾病中起重要作用，包括帕金森病、阿尔茨海默病、图雷特综合征和神经性疼痛。尼古丁受体对自主神经系统的正常功能也至关重要，因此它们几乎影响身体中的所有器官系统。这些受体是由代表2类1和2的11个亚基组装的五聚体结构。受体的亚基组成定义了它的亚型，并决定了它的药理学和生物物理学性质，这些性质在特定亚型之间有细微的变化，或不那么细微。两种nAChR亚型似乎形成了CNS和自主神经系统中发现的其他几种异聚体受体的主要模板。基于1422亚型的受体在CNS的大部分区域中占主导地位;而1324亚型提供了主要的自主神经节模板。本研究的具体目的是：1）定量研究142215亚型在脑区的分布，并确定15亚基对尼古丁调节这些受体的影响; 2）研究含16亚基的nAChRs的亚基组成、药理学和调节作用;和3）使用一种强有力的新方法，表达由融合成单一确定受体的所有五个亚基组成的多联体受体，以确定已知亚基组成、化学计量，和亚单位的顺序。本提案中描述的研究将有助于更好地了解这些不同受体亚型之间药理学和调节的重要差异，并帮助我们了解尼古丁如何调节CNS nAChR。尼古丁是一种滥用药物，通过与大脑中称为烟碱乙酰胆碱受体的神经元细胞表面蛋白结合而起作用。除了参与药物滥用之外，这些受体被认为在广泛的其他神经系统疾病中起重要作用，包括帕金森病、阿尔茨海默病、图雷特综合征和神经性疼痛。这些烟碱乙酰胆碱受体通常参与通过神经递质乙酰胆碱在大脑中从神经元到神经元的信息传递。当这些受体与乙酰胆碱或尼古丁结合时，会打开细胞膜上的通道，允许钠、钾和钙等离子通过，从而引起细胞活性的显著变化。这些受体是由五种不同的蛋白质组成的复合物，称为亚基，它们通过相互吸引而聚集在一起，形成功能性受体。有两类受体亚基蛋白，称为1和2。这些类别中的每一个都有几个不同的亚基蛋白（例如12至16和22至24），当两个拷贝的特定1蛋白与三个拷贝的特定2蛋白结合形成所谓的异聚体烟碱受体时，可以产生功能性受体。因为有几个不同的1和2亚基，可能的组合数量很大。我们和其他人已经开发出方法来确定哪些亚基实际上与其他亚基组装在一起，形成不同大脑区域的功能受体。根据形成受体的亚基，药理学和生物物理学性质是不同的。本提案的目的1和2是针对更完整地了解哪些类型的亚基相互组装形成烟碱受体。由于含有多于一种类型的1和/或多于一种类型的2亚基的最复杂的受体的性质是未知的，在本提案的目的3中，我们开发了一种方法，利用该方法我们可以产生已知亚基组成和顺序的受体，然后研究它们的功能和药理学性质。本提案中描述的研究将有助于更好地了解这些不同受体亚型之间药理学、生理学和调节的重要差异，并帮助我们了解尼古丁如何调节其在中枢神经系统中的受体。

DESCRIPTION (provided by applicant): Our objectives are to assess the pharmacology and regulation of the diverse heteromeric neuronal nicotinic cholinergic receptor (nAChR) subtypes in the mammalian central nervous system (CNS). These receptors are widely distributed in the CNS, where they modulate release of several neurotransmitters in important neuronal pathways. Thus, they influence a wide range of functions, and they have been clearly implicated in nicotine addiction. In addition, these receptors are thought to play an important role in a wide range of other CNS disorders including Parkinson's disease, Alzheimer's disease, Tourette's syndrome and neuropathic pain. Nicotinic receptors are also crucial for normal functioning of the autonomic nervous system, and thus they influence virtually all organ systems in the body. These receptors are pentameric structures assembled from 11 subunits representing 2 classes, 1 and 2. The subunit composition of a receptor defines its subtype and determines its pharmacological and biophysical properties, which vary subtly, or not so subtly, among the particular subtypes. Two nAChR subtypes seem to form the main templates for several other heteromeric receptors found in the CNS and autonomic nervous systems. Receptors based on the 1422 subtype predominate in most areas of the CNS; whereas, the 1324 subtype provides the main template autonomic ganglia. The specific aims of the studies described in this proposal are: 1) To quantify the 142215 subtype in brain areas and determine the influence of the 15 subunit on the regulation of these receptors by nicotine; 2) To study the subunit composition, pharmacology and regulation of nAChRs containing 16 subunits; and 3) To use a powerful new method, expression of concatameric receptors consisting of all five subunits fused into a single defined receptor, to determine the properties of mixed heteromeric nAChRs of known subunit composition, stoichiometry, and subunit order. The studies described in this proposal will lead to a better understanding of important differences in the pharmacology and regulation among these different receptor subtypes and help us to understand how nicotine regulates CNS nAChRs. Nicotine is a drug of abuse that acts by binding to neuronal cell-surface proteins in the brain called nicotinic acetylcholine receptors. In addition to being involved in drug abuse, these receptors are thought to play an important role in a wide range of other disorders of the nervous system including Parkinson's disease, Alzheimer's disease, Tourette's syndrome and neuropathic pain. These nicotinic acetylcholine receptors normally are involved in transmitting information in the brain from neuron to neuron via the neurotransmitter acetylcholine. These receptors, when bound to acetylcholine or nicotine, open a channel in the membrane of the cell and allow ions such as sodium, potassium, and calcium to pass, and by so doing cause marked changes in the activity of the cells. These receptors are complexes of five separate proteins, called subunits, which come together by mutual attraction to form the functional receptor. There are two categories of receptor subunit proteins, called 1 and 2. Each of these categories has several distinct subunit proteins (e.g. 12 through 16 and 22 through 24) and a functional receptor can be generated when two copies of a specific 1 protein associates with three copies of a specific 2 protein to form what is known as a heteromeric nicotinic receptor. Because there are several different 1 and 2 subunits, the number of possible combinations is large. We, and others, have developed methods to determine which subunits actually assemble with which other subunits to form functional receptors in various brain regions. Depending on which subunits form the receptor, the pharmacological and biophysical properties are different. Aims 1 and 2 of this proposal are directed at a more complete understanding of which types of subunits assemble with each other to form nicotinic receptors. Because the properties of the most complex receptors containing more than one type of 1 and/or more than one type of 2 subunit are unknown, in Aim 3 of this proposal we have developed a method with which we can generate receptors of known subunit composition and order and then study their functional and pharmacological properties. The studies described in this proposal will lead to a better understanding of important differences in the pharmacology, physiology, and regulation among these different receptor subtypes and help us to understand how nicotine regulates its receptors in the central nervous system.