Pharmacology and Regulation of Nicotinic Receptor Subtypes

描述（由申请人提供）：我们的目标是评估哺乳动物中枢神经系统（CNS）中不同异质神经元尼古丁胆碱能受体（nAChR）亚型的药理学和调控。这些受体广泛分布于中枢神经系统，在中枢神经系统中，它们调节重要神经通路中几种神经递质的释放。因此，它们影响了广泛的功能，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中枢神经系统疾病中发挥重要作用，包括帕金森病、阿尔茨海默病、图雷特综合征和神经性疼痛。烟碱受体对自主神经系统的正常功能也是至关重要的，因此它们几乎影响身体的所有器官系统。这些受体是由11个亚基组成的五聚体结构，分别代表2类，1和2。受体的亚基组成决定了它的亚型，并决定了它的药理学和生物物理特性，这些特性在特定亚型之间变化微妙或不那么微妙。两种nAChR亚型似乎形成了在中枢神经系统和自主神经系统中发现的其他几种异质受体的主要模板。基于1422亚型的受体在中枢神经系统的大部分区域占主导地位；而1324亚型则提供了自主神经节的主要模板。本提案所述研究的具体目的是：1)量化脑区142215亚型，确定15亚基对尼古丁调节这些受体的影响；2)研究含有16个亚基的nAChRs的亚基组成、药理及调控；3)利用一种强大的新方法，表达由所有五个亚基组成的串联受体融合成一个单一的定义受体，以确定已知亚基组成，化学计量和亚基顺序的混合异质nachr的性质。本提案中描述的研究将使我们更好地了解这些不同受体亚型之间的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中枢神经系统nachr。尼古丁是一种滥用药物，通过与大脑中被称为尼古丁乙酰胆碱受体的神经元细胞表面蛋白质结合而起作用。除了参与药物滥用，这些受体被认为在广泛的其他神经系统疾病中发挥重要作用，包括帕金森病、阿尔茨海默病、妥瑞氏综合征和神经性疼痛。这些烟碱乙酰胆碱受体通常通过神经递质乙酰胆碱参与大脑神经元间的信息传递。当这些受体与乙酰胆碱或尼古丁结合时，就会在细胞膜上打开一条通道，允许钠、钾和钙等离子通过，从而引起细胞活性的显著变化。这些受体是五种不同蛋白质的复合物，称为亚基，它们通过相互吸引聚集在一起形成功能性受体。有两类受体亚基蛋白，分别称为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到16和22到24），当特定1蛋白的两个拷贝与特定2蛋白的三个拷贝结合形成所谓的异源性尼古丁受体时，可以产生一个功能性受体。因为有几个不同的1和2亚基，所以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合在一起，形成大脑不同区域的功能受体。受体的亚基不同，其药理和生物物理性质也不同。本提案的目的1和2是为了更全面地了解哪些类型的亚基相互组合形成尼古丁受体。由于最复杂的受体含有一种以上类型的1和/或一种以上类型的2亚基的性质是未知的，在本提案的Aim 3中，我们已经开发了一种方法，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使我们更好地了解这些不同受体亚型之间在药理学、生理学和调节方面的重要差异，并帮助我们了解尼古丁如何调节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.